Hypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto's disease (autoimmune thyroiditis) is the leading cause in non–iodine-deficient regions. Primary hypothyroidism occurs with thyroid gland disorders, while the central type arises from pituitary and hypothalamic conditions. Thyroid hormones are integral in metabolic processes and in the development of the brain and other organs. Congenital hypothyroidism can result in significant mental disability due to the loss of thyroid hormones. The features of acquired hypothyroidism also reflect the effects of slowed organ function, such as fatigue, bradycardia, cold intolerance, and exertional dyspnea. Diagnosis is by thyroid function testing. Elevated thyroid stimulating hormone and low free thyroxine (T4) levels are noted. Treatment is with synthetic T4.
HypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism is an endocrine disorder resulting from thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy hormone deficiency.
Epidemiology[1,2,9]
PrevalencePrevalenceThe total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time.Measures of Disease Frequency: 0.1%–2%
More common in women than in men: 5–8 times higher
Congenital hypothyroidismCongenital hypothyroidismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism:
Annual incidenceIncidenceThe number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time.Measures of Disease Frequency: 1 in 4000 births in the United States
High incidenceIncidenceThe number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time.Measures of Disease Frequency in Down syndromeDown syndromeDown syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems.Down syndrome (Trisomy 21) (trisomy 21Trisomy 21Down syndrome, or trisomy 21, is the most common chromosomal aberration and the most frequent genetic cause of developmental delay. Both boys and girls are affected and have characteristic craniofacial and musculoskeletal features, as well as multiple medical anomalies involving the cardiac, gastrointestinal, ocular, and auditory systems.Down syndrome (Trisomy 21))
Primary hypothyroidismPrimary HypothyroidismHypothyroidism (thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland involved):
Findings:
Low thyroxineThyroxineThe major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood.Thyroid Hormones/tetraiodothyronineTetraiodothyronineThe major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form triiodothyronine which exerts a broad spectrum of stimulatory effects on cell metabolism.Thyroid Hormones (T4)
Low triiodothyronineTriiodothyronineA T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5′ position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly t3.Thyroid Hormones (T3)
Cause: ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy disease → ↓ free T3/ free T4 from the thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland → compensatory ↑ thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy stimulating hormone (TSH) and thyrotropin-releasing hormoneThyrotropin-releasing hormoneA tripeptide that stimulates the release of thyrotropin and prolactin. It is synthesized by the neurons in the paraventricular nucleus of the hypothalamus. After being released into the pituitary portal circulation, TRH stimulates the release of TSH and PRL from the anterior pituitary gland.Hypothalamic and Pituitary Hormones (TRH)
Types:
Subclinical: elevated TSH, but normal FT3/FT4
Overt: elevated TSH, low FT4/low-normal FT3
Central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
Secondary (pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types involved): low TSH→ ↓ FT3/FT4 levels
Tertiary (hypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus involved): low TRH→ ↓ TSH → ↓ FT3/FT4
Etiology of congenital hypothyroidismCongenital hypothyroidismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism[1,8]
TSH receptorReceptorReceptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.Receptorsgene mutationGene MutationMyotonic Dystrophies
TSH signaling defect (in pseudohypoparathyroidismPseudohypoparathyroidismA hereditary syndrome clinically similar to hypoparathyroidism. It is characterized by hypocalcemia; hyperphosphatemia; and associated skeletal development impairment and caused by failure of response to parathyroid hormone rather than deficiencies. A severe form with resistance to multiple hormones is referred to as type 1a and is associated with maternal mutant allele of the alpha chain of stimulatory g protein.Hypocalcemia 1A)
Central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
Rare
Associated with congenital syndromes
Other rare causes (outside the hypothalamic–pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types–thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy axis):
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy hormone transport disorder: mutationMutationGenetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations in transporter geneGeneA category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Basic Terms of Genetics
Tissue resistanceResistancePhysiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.Ventilation: Mechanics of Breathing to thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy hormone
Transient hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
Temporary decline in thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy function for weeks to months, then recovery occurs in the natural course or with treatment up to a certain age
Causes:
IodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones deficiency
High-dose iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones exposure
Gland in situ: normal-sized gland in normal location with some degree of dyshormonogenesis
Maternal intake of antithyroid drugs (which cross the placentaPlacentaA highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones).Placenta, Umbilical Cord, and Amniotic Cavity)
Maternal autoimmune thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy disease (antibodiesAntibodiesImmunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.Immunoglobulins: Types and Functions cross the placentaPlacentaA highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones).Placenta, Umbilical Cord, and Amniotic Cavity)
Hepatic hemangiomas
Loss-of-function mutations
Etiology of acquired hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism[2,3]
Hashimoto’s thyroiditisThyroiditisThyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel’s thyroiditis). Thyroiditis: most common cause in the United States and in areas with adequate iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones intake
IodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones deficiency: most common cause worldwide
IodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones excess: inhibits hormone synthesisSynthesisPolymerase Chain Reaction (PCR), and iodideIodideInorganic binary compounds of iodine or the i- ion.Thyroid Hormones organification (Wolff–Chaikoff effectWolff–Chaikoff EffectHypothyroidism)
RadiationRadiationEmission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles).Osteosarcoma therapy
Radioiodine (I-131) treatment
Drugs:
Antithyroid drugs: propylthiouracilPropylthiouracilA thiourea antithyroid agent. Propylthiouracil inhibits the synthesis of thyroxine and inhibits the peripheral conversion of thyroxine to triiodothyronine. It is used in the treatment of hyperthyroidism.Antithyroid Drugs, methimazoleMethimazoleA thioureylene antithyroid agent that inhibits the formation of thyroid hormones by interfering with the incorporation of iodine into tyrosyl residues of thyroglobulin. This is done by interfering with the oxidation of iodide ion and iodotyrosyl groups through inhibition of the peroxidase enzyme.Antithyroid Drugs
LithiumLithiumAn element in the alkali metals family. It has the atomic symbol li, atomic number 3, and atomic weight [6. 938; 6. 997]. Salts of lithium are used in treating bipolar disorder.Ebstein’s Anomaly
AmiodaroneAmiodaroneAn antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting potassium channels and voltage-gated sodium channels. There is a resulting decrease in heart rate and in vascular resistance.Pulmonary Fibrosis (iodine-containing)
TyrosineTyrosineA non-essential amino acid. In animals it is synthesized from phenylalanine. It is also the precursor of epinephrine; thyroid hormones; and melanin.Synthesis of Nonessential Amino Acids kinase inhibitors such as sunitinib
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy infiltration:
Riedel’s thyroiditisThyroiditisThyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel’s thyroiditis). Thyroiditis
AmyloidosisAmyloidosisAmyloidosis is a disease caused by abnormal extracellular tissue deposition of fibrils composed of various misfolded low-molecular-weight protein subunits. These proteins are frequently byproducts of other pathological processes (e.g., multiple myeloma). Amyloidosis
HemochromatosisHemochromatosisA disorder of iron metabolism characterized by a triad of hemosiderosis; liver cirrhosis; and diabetes mellitus. It is caused by massive iron deposits in parenchymal cells that may develop after a prolonged increase of iron absorption.Hereditary Hemochromatosis
SarcoidosisSarcoidosisSarcoidosis is a multisystem inflammatory disease that causes noncaseating granulomas. The exact etiology is unknown. Sarcoidosis usually affects the lungs and thoracic lymph nodes, but it can also affect almost every system in the body, including the skin, heart, and eyes, most commonly. Sarcoidosis
SclerodermaSclerodermaScleroderma (systemic sclerosis) is an autoimmune condition characterized by diffuse collagen deposition and fibrosis. The clinical presentation varies from limited skin involvement to diffuse involvement of internal organs. Scleroderma
Postpartum thyroiditisPostpartum thyroiditisTransient autoimmune thyroiditis occurring in the postpartum period. It is characterized by the presence of high titers of autoantibodies against thyroid peroxidase and thyroglobulin. Clinical signs include the triphasic thyroid hormone pattern: beginning with thyrotoxicosis, followed with hypothyroidism, then return to euthyroid state by 1 year postpartum.Postpartum Complications
Environmental exposure: flame retardants
Central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
SecondaryhypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism (pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types disorders):
PituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types adenomas (most common cause of central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism)
Can interfere with TSH production by their massMassThree-dimensional lesion that occupies a space within the breastImaging of the Breast/compressionCompressionBlunt Chest Trauma effect on the TSH-producing cells and/or by interrupting the hypothalamic–pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types portal blood flowBlood flowBlood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute).Vascular Resistance, Flow, and Mean Arterial Pressure and blocking the TRH signal from the hypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus
PituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types adenomas can also interfere with TSH production if they hemorrhage or become infarcted.
MassMassThree-dimensional lesion that occupies a space within the breastImaging of the Breast lesions other than pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types adenoma: cystsCystsAny fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues.Fibrocystic Change, abscesses, meningiomas, dysgerminomas, metastatic tumors, craniopharyngiomas
Effects of surgery or radiationRadiationEmission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles).Osteosarcoma therapy for pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types adenomas or other masses
Infiltrative or inflammatory causes: tuberculosisTuberculosisTuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis complex bacteria. The bacteria usually attack the lungs but can also damage other parts of the body. Approximately 30% of people around the world are infected with this pathogen, with the majority harboring a latent infection. Tuberculosis spreads through the air when a person with active pulmonary infection coughs or sneezes. Tuberculosis, syphilisSyphilisSyphilis is a bacterial infection caused by the spirochete Treponema pallidum pallidum (T. p. pallidum), which is usually spread through sexual contact. Syphilis has 4 clinical stages: primary, secondary, latent, and tertiary. Syphilis, sarcoidosisSarcoidosisSarcoidosis is a multisystem inflammatory disease that causes noncaseating granulomas. The exact etiology is unknown. Sarcoidosis usually affects the lungs and thoracic lymph nodes, but it can also affect almost every system in the body, including the skin, heart, and eyes, most commonly. Sarcoidosis, fungal infectionsInfectionsInvasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases.Chronic Granulomatous Disease, toxoplasmosisToxoplasmosisToxoplasmosis is an infectious disease caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. Felines are the definitive host, but transmission to humans can occur through contact with cat feces or the consumption of contaminated foods. The clinical presentation and complications depend on the host’s immune status. Toxoplasma/Toxoplasmosis, histiocytosis, hemochromatosisHemochromatosisA disorder of iron metabolism characterized by a triad of hemosiderosis; liver cirrhosis; and diabetes mellitus. It is caused by massive iron deposits in parenchymal cells that may develop after a prolonged increase of iron absorption.Hereditary Hemochromatosis, lymphocytic hypophysitisLymphocytic HypophysitisAdrenal Insufficiency and Addison Disease
Traumatic brain injuryTraumatic brain injuryA form of acquired brain injury which occurs when a sudden trauma causes damage to the brain.Le Fort Fractures with injury to the pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types stalk
Stroke, subarachnoid hemorrhageSubarachnoid HemorrhageSubarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most SAHs originate from a saccular aneurysm in the circle of Willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage
Sheehan’s syndrome (postpartum pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and TypesnecrosisNecrosisThe death of cells in an organ or tissue due to disease, injury or failure of the blood supply.Ischemic Cell Damage).
Checkpoint inhibitor–induced hypophysitis or other drug-induced cause
Effects of surgery or radiationRadiationEmission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles).Osteosarcoma therapy for brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification tumors or other disorders
Ischemic or hemorrhagic strokeHemorrhagic strokeStroke due to rupture of a weakened blood vessel in the brain (e.g., cerebral hemispheres; cerebellum; subarachnoid space).Subarachnoid Hemorrhage
Hypothalamic–pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types–thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy axis[2]
HormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types involved:
TRH from the hypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus
TSH from the anterior pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types gland
T4 and T3 from the thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland:
T4 > T3 released
T4 is converted to T3 peripherally, predominantly in the liverLiverThe liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy (but also in other tissues).
Total thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyhormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types = bound + free T3/free T4 (FT3/FT4)
Bound T3 and T4:
Bound to thyroxine-binding globulins (TBGs) (cannot freely diffuse into cells)
99% of hormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types released into circulationCirculationThe movement of the blood as it is pumped through the cardiovascular system.ABCDE Assessment
FT4 and FT3:
Bioavailable
Can bindBINDHyperbilirubinemia of the Newborn to tissue thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyreceptorsReceptorsReceptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.Receptors and exert their effects
Regulation of hormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types:
HypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus releases TRH → pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types gland releases TSH (prolactinProlactinA lactogenic hormone secreted by the adenohypophysis. It is a polypeptide of approximately 23 kd. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation.Breasts: Anatomy release is also stimulated) → thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland produces T3/T4:
↑ Level of FT3/FT4 → ↓ TSH and TRH
↓ Level of FT3/FT4 → ↑ TSH and TRH
Normal function of thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyhormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types:
Increased metabolism:
Increased transcriptionTranscriptionTranscription of genetic information is the first step in gene expression. Transcription is the process by which DNA is used as a template to make mRNA. This process is divided into 3 stages: initiation, elongation, and termination. Stages of Transcription of cell membraneCell MembraneA cell membrane (also known as the plasma membrane or plasmalemma) is a biological membrane that separates the cell contents from the outside environment. A cell membrane is composed of a phospholipid bilayer and proteins that function to protect cellular DNA and mediate the exchange of ions and molecules. The Cell: Cell Membrane Na+/K+adenosineAdenosineA nucleoside that is composed of adenine and d-ribose. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.Class 5 Antiarrhythmic Drugs triphosphatase (ATPase) → oxygen consumption
Enhanced fatty acid oxidation and heatHeatInflammation generation
GluconeogenesisGluconeogenesisGluconeogenesis is the process of making glucose from noncarbohydrate precursors. This metabolic pathway is more than just a reversal of glycolysis. Gluconeogenesis provides the body with glucose not obtained from food, such as during a fasting period. The production of glucose is critical for organs and cells that cannot use fat for fuel. Gluconeogenesis, glycolysisGlycolysisGlycolysis is a central metabolic pathway responsible for the breakdown of glucose and plays a vital role in generating free energy for the cell and metabolites for further oxidative degradation. Glucose primarily becomes available in the blood as a result of glycogen breakdown or from its synthesis from noncarbohydrate precursors (gluconeogenesis) and is imported into cells by specific transport proteins. Glycolysis, lipolysisLipolysisThe metabolic process of breaking down lipids to release free fatty acids, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the digestive tract, circulating lipids in the blood, and stored lipids in the adipose tissue or the liver. A number of enzymes are involved in such lipid hydrolysis, such as lipase and lipoprotein lipase from various tissues.Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD)
Regulates cholesterolCholesterolThe principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Cholesterol Metabolism and triglyceride metabolism
Affects brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification, reproductive system, and bone developmentBone developmentThe process of bone formation is called ossification. The 2 types of ossification are intramembranous ossification, in which bone is developed directly from mesenchyme cells, and endochondral ossification, in which a hyaline cartilage model is created 1st and then later replaced with bone. Bones: Development and Ossification and growth
Interrelated actions with catecholaminesCatecholaminesA general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Adrenal Hormones:
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyhormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types enhance responsiveness to catecholaminesCatecholaminesA general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Adrenal Hormones (producing inotropic and chronotropic cardiac effects)
↑ Expression of catecholamine receptorsReceptorsReceptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.Receptors
Schematic diagram of the hypothalamic–pituitary–thyroid axis: The hypothalamus produces TRH, which stimulates the pituitary gland to synthesize and secrete TSH, which then stimulates the synthesis and secretion of T3 and T4 by the thyroid gland. T4 is converted to T3 in the liver and other tissues. A fraction of T4 and T3 is conjugated with glucuronide and sulfate in the liver, excreted in the bile, and partially hydrolyzed in the intestine; some of this fraction in the intestine may be reabsorbed. If the hypothalamus senses low FT3 and FT4, there will be an increase in TRH and subsequently, TSH; conversely, in this negative feedback loop, T3 and T4 inhibit the release of TSH from the hypothalamus and the pituitary once normal levels are achieved.
↓ Metabolic rate: slow organ function and metabolic processes
MyxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema: deposition and accumulation of connective tissueConnective tissueConnective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix.Connective Tissue: Histology elements such as glycosaminoglycans with water retention
Congenital hypothyroidismCongenital hypothyroidismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism[1,10]
Initially asymptomatic:
Due to maternal thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyhormonesHormonesHormones are messenger molecules that are synthesized in one part of the body and move through the bloodstream to exert specific regulatory effects on another part of the body. Hormones play critical roles in coordinating cellular activities throughout the body in response to the constant changes in both the internal and external environments. Hormones: Overview and Types
Weight and length within normal range, partly due to myxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema
General symptoms:
Poor growth and weight gain
Poor feeding
Decreased activity/excessive sleeping
ConstipationConstipationConstipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
Dry skinSkinThe skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue.Skin: Structure and Functions
Prolonged jaundiceJaundiceJaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice
Head and neckNeckThe part of a human or animal body connecting the head to the rest of the body.Peritonsillar Abscess:
MacroglossiaMacroglossiaThe presence of an excessively large tongue, which may be congenital or may develop as a result of a tumor or edema due to obstruction of lymphatic vessels, or it may occur in association with hyperpituitarism or acromegaly. It also may be associated with malocclusion because of pressure of the tongue on the teeth.Wilms Tumor
Coarse facial features
GoiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter may be noted.
Abdomen:
Umbilical herniaUmbilical HerniaA hernia due to an imperfect closure or weakness of the umbilical ring. It appears as a skin-covered protrusion at the umbilicus during crying, coughing, or straining. The hernia generally consists of omentum or small intestine. The vast majority of umbilical hernias are congenital but can be acquired due to severe abdominal distention.Abdominal Hernias
Protuberant abdomen
MyxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema
Central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism can present with microgenitalism.
CretinismCretinismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism:
Severe intellectual disabilityDisabilityDetermination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits.ABCDE Assessment resulting from iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones deficiency–related maternal hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
Maternal iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones intake, especially in the first 12 weeks of gestation, is needed for brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification development.
Intellectual disabilityDisabilityDetermination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits.ABCDE Assessment
Short stature
HypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
Intellectual disabilityDisabilityDetermination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits.ABCDE Assessment
No hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism (when iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones intake is increased in the newbornNewbornAn infant during the first 28 days after birth.Physical Examination of the Newborn)
CretinismCretinismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism, remember the 6 PsPSInvasive Mechanical Ventilation:
Pale
Puffy face
Protuberant tongueTongueThe tongue, on the other hand, is a complex muscular structure that permits tasting and facilitates the process of mastication and communication. The blood supply of the tongue originates from the external carotid artery, and the innervation is through cranial nerves.Lips and Tongue: Anatomy
Poor brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification development
Pot-bellied
Protruding umbilicus
Infant with congenital hypothyroidism displaying typical signs and symptoms, such as hypotonia (A), myxedematous facies and macroglossia (B), and an umbilical hernia (C)
Image: “Infant with congenital hypothyroidism” by Department of Pediatrics, Division of Endocrinology, Oregon Health & Science University, 707 SW Gaines Street, Portland, OR, USA. License: CC BY 2.0
Acquired hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
Common signs and symptoms:[8,9]
General:
Tiredness, weakness
Weight gain with poor appetite
Cold intolerance
Slow movement
Integumentary:
Dry skinSkinThe skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue.Skin: Structure and Functions
Hair loss
Decreased sweating
Neurologic and musculoskeletal:
Difficulty concentrating and poor memoryMemoryComplex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Psychiatric Assessment
Carpal tunnelCarpal TunnelThe carpal tunnel is formed by the transverse carpal ligament (flexor retinaculum) superiorly and the carpal bones inferiorly.Carpal Tunnel Syndrome syndrome
Cardiac:
BradycardiaBradycardiaBradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea.Bradyarrhythmias
Pericardial effusionPericardial effusionFluid accumulation within the pericardium. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of thoracic duct. Severe cases can lead to cardiac tamponade.Pericardial Effusion and Cardiac Tamponade
Decreased cardiac outputCardiac outputThe volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat).Cardiac Mechanics
Pulmonary:
DyspneaDyspneaDyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea on exertion
Pleural effusionPleural EffusionPleural effusion refers to the accumulation of fluid between the layers of the parietal and visceral pleura. Common causes of this condition include infection, malignancy, autoimmune disorders, or volume overload. Clinical manifestations include chest pain, cough, and dyspnea. Pleural Effusion
Gastrointestinal:
ConstipationConstipationConstipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
InfertilityInfertilityInfertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility
Decreased libido
Erectile dysfunctionErectile DysfunctionErectile dysfunction (ED) is defined as the inability to achieve or maintain a penile erection, resulting in difficulty to perform penetrative sexual intercourse. Local penile factors and systemic diseases, including diabetes, cardiac disease, and neurological disorders, can cause ED. Erectile Dysfunction
Other:
Nonpitting edemaEdemaEdema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema (myxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema)
PeriorbitalPeriorbitalOrbital and Preseptal CellulitisedemaEdemaEdema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
MacroglossiaMacroglossiaThe presence of an excessively large tongue, which may be congenital or may develop as a result of a tumor or edema due to obstruction of lymphatic vessels, or it may occur in association with hyperpituitarism or acromegaly. It also may be associated with malocclusion because of pressure of the tongue on the teeth.Wilms Tumor
Because prolactinProlactinA lactogenic hormone secreted by the adenohypophysis. It is a polypeptide of approximately 23 kd. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation.Breasts: Anatomy also can increase, effects can include:
Sexual dysfunctionSexual dysfunctionPhysiological disturbances in normal sexual performance in either the male or the female.Sexual Physiology and infertilityInfertilityInfertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility (males)
In the elderly:
Depression
Psychosis/delusions/hallucinationsHallucinationsSubjectively experienced sensations in the absence of an appropriate stimulus, but which are regarded by the individual as real. They may be of organic origin or associated with mental disorders.Schizophrenia
Severe hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism is characterized by slowing function of multiple organs.
A medical emergency:
Can lead to shockShockShock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock and death
Illness (e.g., infection, surgery, myocardial infarctionMyocardial infarctionMI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms.Myocardial Infarction)
Decreased mental status
HypothermiaHypothermiaHypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
HypoglycemiaHypoglycemiaHypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia
HyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia
HypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
Hypoventilation
BradycardiaBradycardiaBradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea.Bradyarrhythmias
Diagram of the most common signs and symptoms of hypothyroidism
Congenital hypothyroidismCongenital hypothyroidismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism
Measurement of TSH and/or T4 24–48 hours after birth
Sample obtained via heel prick
Elevated TSH → confirm with venous TSH and T4
↑ TSH, ↓ FT4: confirms diagnosis
NBS TSH > 40 mIU/L → initiate L-thyroxineL-ThyroxineThyroid Replacement Therapy treatment after drawing the confirmatory serum sample (without waiting for the results).
NBS TSH ≤ 40 mIU/L → can wait for the confirmatory serum sample results (preferably with a 24-hour turnaround time)
Special categories:
Some groups of patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship have a false-negative NBS, including prematurePrematureChildbirth before 37 weeks of pregnancy (259 days from the first day of the mother’s last menstrual period, or 245 days after fertilization).Necrotizing Enterocolitis babies, low birthweight and/or sick infants, monozygotic twin.
Consider collection of a second specimen at 2 to 4 weeks of age.
Monitor serum TSH and FT4 every 1 to 2 weeks without treatment. Initiate treatment:
If FT4 becomes low, or
If TSH remains >10 mIU/L beyond 4 weeks of age
Serum TSH is normal or low and serum FT4 is low → evaluate for central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
There is insufficient evidence to provide recommendation in infants with TSH > 5 mIU/L but ≤ 10 mIU/L. Consult a pediatric endocrinologist for a management plan.
Imaging:[10,11]
Not routine
Ultrasonography or radionuclide uptake imaging are options.
Performed if results are borderline and indication for treatment is unclear (e.g., if imaging shows thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: AnatomyagenesisAgenesisTeratogenic Birth Defects, treatment is initiated)
Performed if transient hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism is suspected
Early diagnosis and treatment can prevent long-term mental disabilityDisabilityDetermination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits.ABCDE Assessment.
Acquired hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism[2,5,8,9]
Consistent with autoimmune hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
Not routinely measured in typical cases of hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, unless active thyroiditisThyroiditisThyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel’s thyroiditis). Thyroiditis is suspected, since > 90% of cases of hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism are due to “burned-out” Hashimoto’s thyroiditisThyroiditisThyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel’s thyroiditis). Thyroiditis in non–iodine-deficient regions.
Obtain TPOAb inpatients with a diffuse, firm goiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter (identifies autoimmune thyroiditisAutoimmune thyroiditisInflammatory disease of the thyroid gland due to autoimmune responses leading to lymphocytic infiltration of the gland. It is characterized by the presence of circulating thyroid antigen-specific T-cells and thyroid autoantibodies. The clinical signs can range from hypothyroidism to thyrotoxicosis depending on the type of autoimmune thyroiditis.Thyroiditis).[5]
Helpful in subclinical hypothyroidismSubclinical HypothyroidismHypothyroidism or goiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter or in recurrent unexplained miscarriageMiscarriageSpontaneous abortion, also known as miscarriage, is the loss of a pregnancy before 20 weeks’ gestation. However, the layperson use of the term “abortion” is often intended to refer to induced termination of a pregnancy, whereas “miscarriage” is preferred for spontaneous loss.Spontaneous Abortion:
AntibodiesAntibodiesImmunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution.Immunoglobulins: Types and Functions (indicating immunologically mediated disease) may predict the progression to overt hypothyroidismOvert HypothyroidismHypothyroidism.
Monitoring TSH regularly in these cases helps assess the need for pharmacotherapy.
Imaging studies:
Ultrasonography:
Rarely used but can help in distinguishing asymmetric goiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter in Hashimoto’s thyroiditisThyroiditisThyroiditis is a catchall term used to describe a variety of conditions that have inflammation of the thyroid gland in common. It includes pathologies that cause an acute illness with severe thyroid pain (e.g., subacute thyroiditis and infectious thyroiditis) as well as conditions in which there is no clinically evident inflammation and the manifestations primarily reflect thyroid dysfunction or a goiter (e.g., painless thyroiditis and fibrous Riedel’s thyroiditis). Thyroiditis from a noduleNoduleChalazion/multinodular goiterMultinodular goiterAn enlarged thyroid gland containing multiple nodules (thyroid nodule), usually resulting from recurrent thyroid hyperplasia and involution over many years to produce the irregular enlargement. Multinodular goiters may be nontoxic or may induce thyrotoxicosis.Goiter
Nuclear medicineNuclear medicineA specialty field of radiology concerned with diagnostic, therapeutic, and investigative use of radioactive compounds.Nuclear Imaging scan:
Consider in workup of thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy nodules or goiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter
Radioactive tracer activity is decreased.
BrainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification imaging:
CT or MRI
Part of workup for central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
Assess pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types gland, hypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus, and surrounding areas.
Obtain cortisolCortisolGlucocorticoids level (as adrenal insufficiencyAdrenal InsufficiencyConditions in which the production of adrenal corticosteroids falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the adrenal glands, the pituitary gland, or the hypothalamus.Adrenal Insufficiency and Addison Disease needs to be treated).
Obtain metabolic panel (may show low sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia) and electrocardiogramElectrocardiogramAn electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) (bradycardiaBradycardiaBradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea.Bradyarrhythmias).
In central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism: Obtain other pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types hormone levels, especially in cases suspicious for hypopituitarismHypopituitarismHypopituitarism is a condition characterized by pituitary hormone deficiency. This condition primarily results from a disease of the pituitary gland, but it may arise from hypothalamic dysfunction. Pituitary tumors are one of the most common causes. The majority of cases affect the anterior pituitary lobe (adenohypophysis), which accounts for 80% of the gland. Hypopituitarism.
Congenital hypothyroidismCongenital hypothyroidismA condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. Endemic cretinism is the result of iodine deficiency. Clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.Hypothyroidism (CH)[10,11]
Patient should be evaluated and followed by a pediatric endocrinologist.
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy replacement therapy:
L-thyroxineL-ThyroxineThyroid Replacement Therapy: synthetic form of T4 that is peripherally converted to T3; should be initiated as soon as the diagnosis is confirmed
Oral (preferred): initially 10–15 µg/kg/day, given at the same time each day (crush tablet and mix into 2‒5 mL of human milk, non–soy-containing formula, or water)
Parenteral: Reduce oral dose by 75%.
AbsorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption reduced by antacids, ironIronA metallic element with atomic symbol fe, atomic number 26, and atomic weight 55. 85. It is an essential constituent of hemoglobins; cytochromes; and iron-binding proteins. It plays a role in cellular redox reactions and in the transport of oxygen.Trace Elements, calciumCalciumA basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Electrolytes, soy formula
For central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy replacement
Treat other concomitant hormone deficiencies, if present.
Monitoring:
Repeat TSH and FT4 at 2 weeks of age and adjust dose accordingly.
Lifelong L-thyroxineL-ThyroxineThyroid Replacement Therapy treatment is recommended in confirmed permanent hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
Cases of thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy dysgenesis, or
Serum TSH increases > 10 mIU/L after 1 year of age.
Inconclusive: TSH > age-specific range, but ≤ 10 mIU/L and FT4 is normal → repeat in labs in 4‒8 weeks
Severe intellectual impairment does not typically occur in patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship who are treated with L-thyroxineL-ThyroxineThyroid Replacement Therapy in a timely and appropriate manner.
In endemic areas, where iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones deficiency is common, iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones supplementation is advised; iodized salt is commonly used in the United States but is not mandated, as in some other countries.
Acquired hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism[5–7,12,13]
Reduce goiterGoiterA goiter is a chronic enlargement of the thyroid gland due to nonneoplastic growth occurring in the setting of hypothyroidism, hyperthyroidism, or euthyroidism. Morphologically, thyroid enlargement can be diffuse (smooth consistency) or nodular (uninodular or multinodular). Goiter size (if present)
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy replacement therapy:
1.6 µg/kg of body weight per day in young and healthy patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship
Take 30–60 minutes before breakfast, caffeine-containing liquids, or other medication.
May also take at bedtime (4 hours after the last meal, on an empty stomachStomachThe stomach is a muscular sac in the upper left portion of the abdomen that plays a critical role in digestion. The stomach develops from the foregut and connects the esophagus with the duodenum. Structurally, the stomach is C-shaped and forms a greater and lesser curvature and is divided grossly into regions: the cardia, fundus, body, and pylorus. Stomach: Anatomy)
Starting dose of 25 µg per day in the elderly and those with cardiovascular disease
Pregnant women: Additional doses may be required to satisfy increased demand.
Dose adjustments:
Measure TSH after 4–6 weeks and adjust the dose as necessary.
Adjust in increments of 25 µg.
Dose adjustments should also be considered in cases of large changes in body massMassThree-dimensional lesion that occupies a space within the breastImaging of the Breast, pregnancyPregnancyThe status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth.Pregnancy: Diagnosis, Physiology, and Care, and aging.
Schematic diagram of the management of Hashimoto’s thyroiditis:
Note that the adjustments depend on TSH levels.
Image by Lecturio.
Case-specific treatments[5,16]
Drug-induced hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism:
Discontinuation of medication depends on the medical necessity.
In some cases, such as in amiodarone- or lithium-induced hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, the medication can be continued and L-thyroxineL-ThyroxineThyroid Replacement Therapy is given to the patient.
Surgery for pituitaryPituitaryA small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum.Hormones: Overview and Types–hypothalamic tumors in secondary and tertiary hypothyroidismTertiary HypothyroidismHypothyroidism
In central hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, monitoring serum free T4T4The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form triiodothyronine which exerts a broad spectrum of stimulatory effects on cell metabolism.Thyroid Hormones should guide therapy.
American ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy Association
TSH > 10 mIU/L: Consider treatment.
TSH ≤ 10 mIU/L: Consider treatment if symptoms of hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, if TPO antibody–positive, or if there are risk factors/evidence of atherosclerotic
cardiovascular disease, or heart failureHeart FailureA heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.Total Anomalous Pulmonary Venous Return (TAPVR).
European ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy Association
Age < 65 years:
TSH > 10 mIU/L: Treat.
TSH 4–10 mIU/L with symptoms: Start trial.
TSH < 10 mIU/L without symptoms: watchful waiting
Age ≥ 65 years:
TSH < 10 mIU/L: watchful waiting
TSH ≥ 10 mIU/L: Consider treatment if hypothyroid symptoms or high cardiovascular risk are present.
See the full list of symptoms in the thyrotoxicosisThyrotoxicosisA hypermetabolic syndrome caused by excess thyroid hormones which may come from endogenous or exogenous sources. The endogenous source of hormone may be thyroid hyperplasia; thyroid neoplasms; or hormone-producing extrathyroidal tissue. Thyrotoxicosis is characterized by nervousness; tachycardia; fatigue; weight loss; heat intolerance; and excessive sweating.Thyrotoxicosis and Hyperthyroidism and hyperthyroidismHyperthyroidismHypersecretion of thyroid hormones from the thyroid gland. Elevated levels of thyroid hormones increase basal metabolic rate.Thyrotoxicosis and Hyperthyroidism page
2 of the most deleterious side effects are:
Arrhythmias, especially atrial fibrillationAtrial fibrillationAtrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation
OsteoporosisOsteoporosisOsteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis (in postmenopausal women)
Reversible cardiomyopathyCardiomyopathyCardiomyopathy refers to a group of myocardial diseases associated with structural changes of the heart muscles (myocardium) and impaired systolic and/or diastolic function in the absence of other heart disorders (coronary artery disease, hypertension, valvular disease, and congenital heart disease). Cardiomyopathy: Overview and Types
Congestive heart failureHeart FailureA heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction.Total Anomalous Pulmonary Venous Return (TAPVR)
Drugs reducing absorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption:
CalciumCalciumA basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Electrolytes salts
A 4-hour separation between levothyroxineLevothyroxineThyroid Replacement Therapy and other medication interfering with absorptionAbsorptionAbsorption involves the uptake of nutrient molecules and their transfer from the lumen of the GI tract across the enterocytes and into the interstitial space, where they can be taken up in the venous or lymphatic circulation.Digestion and Absorption is traditional but untested.
Consider workup for gastrointestinal disorders including:
Helicobacter pyloriHelicobacter pyloriA spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus campylobacter, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus Helicobacter. It has been officially transferred to Helicobacter gen.Helicobacter–related gastritisGastritisGastritis refers to inflammation of the gastric mucosa. Gastritis may occur suddenly (acute gastritis) or slowly over time (chronic gastritis). Gastritis may be asymptomatic or with symptoms, including burning abdominal pain (which either worsens or improves with eating), dyspepsia, nausea, and vomiting. Gastritis
Atrophic gastritisAtrophic gastritisGastritis with atrophy of the gastric mucosa, the gastric parietal cells, and the mucosal glands leading to achlorhydria. Atrophic gastritis usually progresses from chronic gastritis.Gastritis
Celiac diseaseCeliac diseaseCeliac disease (also known as celiac sprue or gluten enteropathy) is an autoimmune reaction to gliadin, which is a component of gluten. Celiac disease is closely associated with HLA-DQ2 and HLA-DQ8. The immune response is localized to the proximal small intestine and causes the characteristic histologic findings of villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis. Celiac Disease
If these disorders are detected and effectively managed, reevaluation of thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy function and L-thyroxineL-ThyroxineThyroid Replacement TherapydosageDosageDosage Calculation is recommended.
Myxedema coma
Definition[4,7]
Severe hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism is characterized by slowing function of multiple organs.
Myxedema comaMyxedema ComaHypothyroidism is a misnomer because patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship typically do not exhibit myxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema (non-pitting edemaNon-pitting edemaEdema caused by excess colloid without excess fluidEdema) or comaComaComa is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma.
A medical emergency:
Can lead to shockShockShock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock and death
MyxedemaMyxedemaA condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. It is caused by a deficiency of thyroid hormones. The skin becomes puffy around the eyes and on the cheeks. The face is dull and expressionless with thickened nose and lips.Edema face:
MacroglossiaMacroglossiaThe presence of an excessively large tongue, which may be congenital or may develop as a result of a tumor or edema due to obstruction of lymphatic vessels, or it may occur in association with hyperpituitarism or acromegaly. It also may be associated with malocclusion because of pressure of the tongue on the teeth.Wilms Tumor
PeriorbitalPeriorbitalOrbital and Preseptal CellulitisedemaEdemaEdema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
Coarse, sparse hair
HypothermiaHypothermiaHypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia
HypoglycemiaHypoglycemiaHypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia
HyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia
HypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension (late stage)
Hypoventilation
BradycardiaBradycardiaBradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea.Bradyarrhythmias
A man with myxedema due to hypothyroidism: Note the expressionless face, periorbital puffiness, pallor, peripheral edema, and massive ascites. Because it is curable, myxedema should be considered in every patient with conspicuous ascites, except perhaps those with widespread or terminal malignancy. The patient shown received thyroid replacement therapy, and all of his physical abnormalities resolved. If ascites persists after treatment, a coexisting cause should be sought.
Image: “57-year-old bartender” by Herbert L. Fred, MD and Hendrik A. van Dijk. License: CC BY 2.0
Precipitating event (anything which disrupts homeostatic mechanisms)[4,6,7]
InfectionsInfectionsInvasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases.Chronic Granulomatous Disease (particularly pneumoniaPneumoniaPneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy.Pneumonia and urosepsis)
Myocardial infarctionMyocardial infarctionMI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms.Myocardial Infarction
BurnsBurnsA burn is a type of injury to the skin and deeper tissues caused by exposure to heat, electricity, chemicals, friction, or radiation. Burns are classified according to their depth as superficial (1st-degree), partial-thickness (2nd-degree), full-thickness (3rd-degree), and 4th-degree burns. Burns
GI hemorrhage
Medications:
AmiodaroneAmiodaroneAn antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting potassium channels and voltage-gated sodium channels. There is a resulting decrease in heart rate and in vascular resistance.Pulmonary Fibrosis
AnestheticsAnestheticsAgents that are capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general anesthesia, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.Anesthesiology: History and Basic Concepts
Beta blockers
LithiumLithiumAn element in the alkali metals family. It has the atomic symbol li, atomic number 3, and atomic weight [6. 938; 6. 997]. Salts of lithium are used in treating bipolar disorder.Ebstein’s Anomaly
HypoglycemiaHypoglycemiaHypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia
HyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia (due to decreased free water clearance)
HypercapniaHypercapniaA clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.Neonatal Respiratory Distress Syndrome + respiratory acidosisAcidosisA pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up.Respiratory Acidosis
ECGECGAn electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)/cardiac enzymesEnzymesEnzymes are complex protein biocatalysts that accelerate chemical reactions without being consumed by them. Due to the body’s constant metabolic needs, the absence of enzymes would make life unsustainable, as reactions would occur too slowly without these molecules. Basics of Enzymes: rule out myocardial infarctionMyocardial infarctionMI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms.Myocardial Infarction
Management[4–7]
Urgent transfer to an intensive care unit for continuous cardiopulmonary monitoring and support.
Supportive therapy:
Correct hypovolemiaHypovolemiaSepsis in Children, electrolyte abnormalities, hypothermiaHypothermiaHypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia, and hypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension.
Mechanical ventilationVentilationThe total volume of gas inspired or expired per unit of time, usually measured in liters per minute.Ventilation: Mechanics of Breathing may be required.
If possible, pressors and inotropesInotropesHypoplastic Left Heart Syndrome (HLHS) should be avoided owing to the risk of arrhythmia with concomitant IV thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy replacement.
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy replacement:
Intravenous thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy hormone replacement
100–500 µg IV once daily followed by 75–100 µg IV once daily
Switch to oral replacement as soon as tolerated.
Lower initial dose in the elderly or those with cardiovascular disease
SteroidsSteroidsA group of polycyclic compounds closely related biochemically to terpenes. They include cholesterol, numerous hormones, precursors of certain vitamins, bile acids, alcohols (sterols), and certain natural drugs and poisons. Steroids have a common nucleus, a fused, reduced 17-carbon atom ring system, cyclopentanoperhydrophenanthrene. Most steroids also have two methyl groups and an aliphatic side-chain attached to the nucleus.Benign Liver Tumors:
HydrocortisoneHydrocortisoneThe main glucocorticoid secreted by the adrenal cortex. Its synthetic counterpart is used, either as an injection or topically, in the treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.Immunosuppressants: 100 mg IV every 8 hours (given before levothyroxineLevothyroxineThyroid Replacement Therapy)
Administered until adrenal insufficiencyAdrenal InsufficiencyConditions in which the production of adrenal corticosteroids falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the adrenal glands, the pituitary gland, or the hypothalamus.Adrenal Insufficiency and Addison Disease has been ruled out.
Failure to do so may precipitate an adrenal crisisAdrenal crisisAdrenal crisis is the acute decompensation of adrenal function that can be triggered by another disease, surgery, stress, or increased glucocorticoid inactivation.Adrenal Insufficiency and Addison Disease.
Some guidelines advocate empiric broad-spectrumBroad-SpectrumFluoroquinolones antibiotic therapy while awaiting blood and urine cultures and a chest radiograph.
EuthyroidEuthyroidThyroiditis sick syndrome: abnormal thyroid function testsThyroid Function TestsBlood tests used to evaluate the functioning of the thyroid gland.Ion Channel Myopathy in the setting of nonthyroidal illness in clinically euthyroidEuthyroidThyroiditispatientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship: Low T3 with normal FT4 and TSH is commonly noted. There is impaired T4 conversion to T3 (removal of iodineIodineA nonmetallic element of the halogen group that is represented by the atomic symbol I, atomic number 53, and atomic weight of 126. 90. It is a nutritionally essential element, especially important in thyroid hormone synthesis. In solution, it has anti-infective properties and is used topically.Thyroid Hormones atom normally in the outer ring, occurs in the inner ring). This produces reverse T3 (rT3), which is an inactive form of T3. Monitoring thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy function until recovery is recommended.
ResistanceResistancePhysiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.Ventilation: Mechanics of Breathing to TSH or thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy hormone: will have an elevated serum TSH level: This disorder may be associated with 1 or more abnormalities in the TSH receptorsReceptorsReceptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.Receptors, and the patient may be euthyroidEuthyroidThyroiditis or hypothyroid. The thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland is not enlarged. The diagnosis is made in infancy if a child is symptomatic, especially if other family members are affected. Finding an inactivating mutationMutationGenetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations in the TRH receptorReceptorReceptors are proteins located either on the surface of or within a cell that can bind to signaling molecules known as ligands (e.g., hormones) and cause some type of response within the cell.Receptors confirms the diagnosis.
Recovery from nonthyroidal illness: will have an elevated serum TSH level but only elevated during recovery period: Repeat measurement of TSH and FT4 should be performed 4–6 weeks after recovery; rarely true hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism.
Adrenal insufficiencyAdrenal InsufficiencyConditions in which the production of adrenal corticosteroids falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the adrenal glands, the pituitary gland, or the hypothalamus.Adrenal Insufficiency and Addison Disease (AI): will have an elevated serum TSH level, usually caused by prolonged treatment with exogenous corticosteroidsCorticosteroidsChorioretinitis: Adrenal insufficiencyAdrenal InsufficiencyConditions in which the production of adrenal corticosteroids falls below the requirement of the body. Adrenal insufficiency can be caused by defects in the adrenal glands, the pituitary gland, or the hypothalamus.Adrenal Insufficiency and Addison Disease may coexist with hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism but should be suspected if symptoms (lethargyLethargyA general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction.Hyponatremia, hypotensionHypotensionHypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension) persist after treatment with thyroxineThyroxineThe major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood.Thyroid Hormones and/or if there are associated laboratory findings of AI, such as hyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia, hyperkalemiaHyperkalemiaHyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia, or hypoglycemiaHypoglycemiaHypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia. Diagnosis involves a multistep approach, which includes the determination of low cortisolCortisolGlucocorticoids levels, measuring ACTH, and determining if it is primary or secondary.
Billing and Coding
Diagnosis Codes:
These codes are used to diagnose hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, an underactive thyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy gland. The codes can specify the cause, such as postsurgical, or be left unspecified.
Coding System
Code
Description
ICD-10-CM
E03.9
HypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, unspecified
ICD-10-CM
E89.0
Postprocedural hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism
SNOMED CT
40930008
HypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism (disorder)
Evaluation & Workup:
These laboratory tests are used to diagnose hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism: a Thyroid-Stimulating HormoneThyroid-stimulating hormoneA glycoprotein hormone secreted by the adenohypophysis. Thyrotropin stimulates thyroid gland by increasing the iodide transport, synthesis and release of thyroid hormones (thyroxine and triiodothyronine).Thyroid Hormones (TSH) level (which will be high) and a Free ThyroxineThyroxineThe major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood.Thyroid Hormones (Free T4T4The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form triiodothyronine which exerts a broad spectrum of stimulatory effects on cell metabolism.Thyroid Hormones) level (which will be low).
Coding System
Code
Description
CPT
84443
ThyroidThyroidThe thyroid gland is one of the largest endocrine glands in the human body. The thyroid gland is a highly vascular, brownish-red gland located in the visceral compartment of the anterior region of the neck.Thyroid Gland: Anatomy stimulating hormone (TSH)
CPT
84439
ThyroxineThyroxineThe major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood.Thyroid Hormones; free (FT4)
Medications:
This code is for levothyroxineLevothyroxineThyroid Replacement Therapy, a synthetic T4T4The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (monoiodotyrosine) and the coupling of iodotyrosines (diiodotyrosine) in the thyroglobulin. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form triiodothyronine which exerts a broad spectrum of stimulatory effects on cell metabolism.Thyroid Hormones hormone, which is the standard-of-care replacement therapy for hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism.
This code is for myxedema comaMyxedema ComaHypothyroidism, a rare, life-threatening complication of severe, longstanding, untreated hypothyroidismHypothyroidismHypothyroidism is a condition characterized by a deficiency of thyroid hormones. Iodine deficiency is the most common cause worldwide, but Hashimoto’s disease (autoimmune thyroiditis) is the leading cause in non-iodine-deficient regions. Hypothyroidism, characterized by profound lethargyLethargyA general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction.Hyponatremia, hypothermiaHypothermiaHypothermia can be defined as a drop in the core body temperature below 35°C (95°F) and is classified into mild, moderate, severe, and profound forms based on the degree of temperature decrease. Hypothermia, and organ failure.
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