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Obesity

Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue Adipose tissue Adipose tissue is a specialized type of connective tissue that has both structural and highly complex metabolic functions, including energy storage, glucose homeostasis, and a multitude of endocrine capabilities. There are three types of adipose tissue, white adipose tissue, brown adipose tissue, and beige or "brite" adipose tissue, which is a transitional form. Adipose Tissue: Histology. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Several conditions are associated with obesity, including diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, and heart disease, all of which contribute to significant healthcare costs. Diagnosis is most commonly based on BMI measurement, wherein obesity is defined as BMI > 30. Management includes lifestyle changes, medications, or, in severe cases, bariatric surgery Bariatric surgery Bariatric surgery refers to a group of invasive procedures used to surgically reduce the size of the stomach to produce early satiety, decrease food intake (restrictive type) and/or alter digestion, and artificially induce malabsorption of nutrients (malabsorptive type). The ultimate goal of bariatric surgery is drastic weight loss. Bariatric Surgery.

Last updated: Jul 18, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

Obesity is a condition associated with excess body weight, specifically with excessive adipose tissue Adipose tissue Adipose tissue is a specialized type of connective tissue that has both structural and highly complex metabolic functions, including energy storage, glucose homeostasis, and a multitude of endocrine capabilities. There are three types of adipose tissue, white adipose tissue, brown adipose tissue, and beige or “brite” adipose tissue, which is a transitional form. Adipose Tissue: Histology deposition.

Obesity measurements

  • Obesity can be precisely defined by BMI or body fat percentage.
  • Waist circumference is a measure of abdominal obesity and is associated with increased cardiovascular risks.
  • BMI is calculated as weight (kg)/height² (m²).
  • BMI classification:
    • Underweight < 18.5
    • Normal weight: 18.5–24.9 
    • Overweight: 25–29.9
    • Obesity: 30–39.9
    • Morbid obesity: > 40
  • Body fat percentage = 1.2(BMI) + 0.23(age) – 10.8( sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria) – 5.4:
    • Normal:
      • Men ( sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria = 1): 15%–20%
      • Women ( sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria = 0): 25%–30%
    • Obesity:
      • Men: > 25%
      • Women: > 33%
  • Waist circumference indicating increased cardiac risk:
    • Men: > 102 cm
    • Women: > 88 cm
Body mass index calculation

Body mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast index chart

Image by Lecturio.

Epidemiology

  • ⅓ or more adults in the United States suffer from obesity.
  • Prevalence Prevalence The 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 appears to be steadily increasing and shows a slightly increased prevalence Prevalence The 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 in women compared to men.
  • There was an increase in the prevalence Prevalence The 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 of obesity from 19.4% in 1997 to 31.4% in 2017.
  • About 17% of children and adolescents are affected.
  • In 2015, approximately 108 million children and 604 million adults globally were obese.

Etiology

The nature of obesity is believed to be multifactorial. Sedentary lifestyle and increased caloric intake appear to be the most common causes.

Causes can be further categorized by:

  • Dietary factors: overeating, high-fat diets
  • Social/behavioral factors: socioeconomic factors, psychological factors, night eating, binge eating Binge eating Binge eating is defined as consuming an amount of food in a specified amount of time (e.g., 1 hour) that greatly exceeds what most people would consume in that same amount of time. Binge Eating Disorder
  • Sedentary lifestyle: poor exercise habits and sedentary jobs; inactivity due to surgery, disability Disability Determination 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, or aging
  • Iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome: due to certain medications or hypothalamic surgery
  • Genetic conditions
  • Underlying neuroendocrine disorders: Cushing’s syndrome, hypothyroidism Hypothyroidism 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. Hypothyroidism, growth hormone deficiency, hypogonadism Hypogonadism Hypogonadism is a condition characterized by reduced or no sex hormone production by the testes or ovaries. Hypogonadism can result from primary (hypergonadotropic) or secondary (hypogonadotropic) failure. Symptoms include infertility, increased risk of osteoporosis, erectile dysfunction, decreased libido, and regression (or absence) of secondary sexual characteristics. Hypogonadism

Medications associated with weight gain include:

  • Steroids Steroids A 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 ( prednisone Prednisone A synthetic anti-inflammatory glucocorticoid derived from cortisone. It is biologically inert and converted to prednisolone in the liver. Immunosuppressants)
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus medications ( insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin, sulfonylureas Sulfonylureas Sulfonamides and Trimethoprim, thiazolidinediones Thiazolidinediones Thiazoles with two keto oxygens. Members are insulin-sensitizing agents which overcome insulin resistance by activation of the peroxisome proliferator activated receptor gamma (ppar-gamma). Non-insulinotropic Diabetes Drugs)
  • Antipsychotics ( risperidone Risperidone A selective blocker of dopamine D2 receptors and serotonin 5-HT2 receptors that acts as an atypical antipsychotic agent. It has been shown to improve both positive and negative symptoms in the treatment of schizophrenia. Second-Generation Antipsychotics, quetiapine Quetiapine A dibenzothiazepine and antipsychotic agent that targets the serotonin 5-HT2 receptor; histamine h1 receptor, adrenergic alpha1 and alpha2 receptors, as well as the dopamine d1 receptor and dopamine D2 receptor. It is used in the treatment of schizophrenia; bipolar disorder and depressive disorder. Second-Generation Antipsychotics, olanzapine Olanzapine A benzodiazepine derivative that binds serotonin receptors; muscarinic receptors; histamine h1 receptors; adrenergic alpha-1 receptors; and dopamine receptors. It is an antipsychotic agent used in the treatment of schizophrenia; bipolar disorder; and major depressive disorder; it may also reduce nausea and vomiting in patients undergoing chemotherapy. Second-Generation Antipsychotics)
  • Antidepressants ( paroxetine Paroxetine A serotonin uptake inhibitor that is effective in the treatment of depression. Serotonin Reuptake Inhibitors and Similar Antidepressants, citalopram Citalopram A furancarbonitrile that is one of the serotonin uptake inhibitors used as an antidepressant. The drug is also effective in reducing ethanol uptake in alcoholics and is used in depressed patients who also suffer from tardive dyskinesia in preference to tricyclic antidepressants, which aggravate dyskinesia. Serotonin Reuptake Inhibitors and Similar Antidepressants, amitriptyline Amitriptyline Tricyclic antidepressant with anticholinergic and sedative properties. It appears to prevent the reuptake of norepinephrine and serotonin at nerve terminals, thus potentiating the action of these neurotransmitters. Amitriptyline also appears to antagonize cholinergic and alpha-1 adrenergic responses to bioactive amines. Tricyclic Antidepressants, mirtazapine)
  • Mood stabilizers/neurological agents ( carbamazepine Carbamazepine A dibenzazepine that acts as a sodium channel blocker. It is used as an anticonvulsant for the treatment of grand mal and psychomotor or focal seizures. It may also be used in the management of bipolar disorder, and has analgesic properties. First-Generation Anticonvulsant Drugs, valproate Valproate A fatty acid with anticonvulsant and anti-manic properties that is used in the treatment of epilepsy and bipolar disorder. The mechanisms of its therapeutic actions are not well understood. It may act by increasing gamma-aminobutyric acid levels in the brain or by altering the properties of voltage-gated sodium channels. First-Generation Anticonvulsant Drugs, lithium Lithium An 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, gabapentin Gabapentin A cyclohexane-gamma-aminobutyric acid derivative that is used for the treatment of partial seizures; neuralgia; and restless legs syndrome. Second-Generation Anticonvulsant Drugs)
  • Hormonal agents/ progestins Progestins Compounds that interact with progesterone receptors in target tissues to bring about the effects similar to those of progesterone. Primary actions of progestins, including natural and synthetic steroids, are on the uterus and the mammary gland in preparation for and in maintenance of pregnancy. Hormonal Contraceptives (medroxyprogesterone)
  • Beta-blockers Beta-blockers Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety. Class 2 Antiarrhythmic Drugs (Beta Blockers) ( propranolol Propranolol A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for myocardial infarction; arrhythmia; angina pectoris; hypertension; hyperthyroidism; migraine; pheochromocytoma; and anxiety but adverse effects instigate replacement by newer drugs. Antiadrenergic Drugs)
  • Alpha-blockers Alpha-blockers Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma. Antiadrenergic Drugs ( terazosin Terazosin Antiadrenergic Drugs)

Pathophysiology and Obesity-related Morbidity

Pathophysiology

  • Obesity may be hypertrophic (increased size of adipocytes Adipocytes Cells in the body that store fats, usually in the form of triglycerides. White adipocytes are the predominant type and found mostly in the abdominal cavity and subcutaneous tissue. Brown adipocytes are thermogenic cells that can be found in newborns of some species and hibernating mammals. Adipose Tissue: Histology) or hypercellular (increased number of cells):
    • The hypertrophic variant is typical of android (abdominal) obesity.
    • The hypercellular variant is frequently associated with childhood and very severe obesity.
  • A number of hormones Hormones Hormones 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 are involved in the regulation of appetite, satiety, metabolism, and fat distribution.
  • Orexigenic hormones Hormones Hormones 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 in appetite stimulation include ghrelin Ghrelin A 28-amino acid, Acylated, orexigenic peptide that is a ligand for growth hormone secretagogue receptors. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin. Glucagonoma, endocannabinoid, and neuropeptide Y.
  • Anorexigenic hormones Hormones Hormones 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 in appetite suppression Suppression Defense Mechanisms include leptin Leptin A 16-kda peptide hormone secreted from white adipocytes. Leptin serves as a feedback signal from fat cells to the central nervous system in regulation of food intake, energy balance, and fat storage. Adipose Tissue: Histology, GLP-1 GLP-1 A peptide of 36 or 37 amino acids that is derived from proglucagon and mainly produced by the intestinal l cells. Glp-1(1-37 or 1-36) is further n-terminally truncated resulting in glp-1(7-37) or glp-1-(7-36) which can be amidated. These glp-1 peptides are known to enhance glucose-dependent insulin release, suppress glucagon release and gastric emptying, lower blood glucose, and reduce food intake. Insulinomas, and peptide YY.
  • 2 hormones Hormones Hormones 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 that likely play the biggest role in regulation of appetite and body weight are ghrelin Ghrelin A 28-amino acid, Acylated, orexigenic peptide that is a ligand for growth hormone secretagogue receptors. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin. Glucagonoma and leptin Leptin A 16-kda peptide hormone secreted from white adipocytes. Leptin serves as a feedback signal from fat cells to the central nervous system in regulation of food intake, energy balance, and fat storage. Adipose Tissue: Histology
    • Ghrelin Ghrelin A 28-amino acid, Acylated, orexigenic peptide that is a ligand for growth hormone secretagogue receptors. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin. Glucagonoma:
      • Mainly produced in the stomach Stomach The 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
      • Sends signals to the lateral nucleus Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. The Cell: Organelles of the hypothalamus Hypothalamus The 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 (hunger center) to ↑ appetite and stimulate hunger 
      • Levels ↑ during starvation/fasting and sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep deprivation
      • Levels ↓ after food intake
    • Leptin Leptin A 16-kda peptide hormone secreted from white adipocytes. Leptin serves as a feedback signal from fat cells to the central nervous system in regulation of food intake, energy balance, and fat storage. Adipose Tissue: Histology:
      • Primarily produced by adipose tissue Adipose tissue Adipose tissue is a specialized type of connective tissue that has both structural and highly complex metabolic functions, including energy storage, glucose homeostasis, and a multitude of endocrine capabilities. There are three types of adipose tissue, white adipose tissue, brown adipose tissue, and beige or “brite” adipose tissue, which is a transitional form. Adipose Tissue: Histology
      • Sends signals to the ventromedial nucleus Nucleus Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (cell nucleolus). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the endoplasmic reticulum. A cell may contain more than one nucleus. The Cell: Organelles of the hypothalamus Hypothalamus The 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 (satiety center) to decrease appetite
      • Opposes ghrelin Ghrelin A 28-amino acid, Acylated, orexigenic peptide that is a ligand for growth hormone secretagogue receptors. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin. Glucagonoma by signaling the sense of satiety to the hypothalamus Hypothalamus The 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
      • Levels ↑ with food intake and with ↑ in weight and body fat due to increasing leptin Leptin A 16-kda peptide hormone secreted from white adipocytes. Leptin serves as a feedback signal from fat cells to the central nervous system in regulation of food intake, energy balance, and fat storage. Adipose Tissue: Histology resistance Resistance Physiologically, 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
      • Levels ↓ with starvation, sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep deprivation, and exercise

Obesity-associated morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status

Obesity is associated with increased mortality Mortality All deaths reported in a given population. Measures of Health Status and negatively impacts almost every organ system. Abdominal obesity is specifically associated with increased cardiovascular risks.

Commonly observed effects include:

  • Cardiovascular:
    • Coronary artery Coronary Artery Truncus Arteriosus syndrome
    • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Cardiomyopathy Cardiomyopathy Cardiomyopathy 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
    • Ventricular hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation
    • Heart failure Heart Failure A 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)
    • Varicose veins Varicose veins Enlarged and tortuous veins. Chronic Venous Insufficiency
    • Deep vein thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus
  • Respiratory:
    • Obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea
    • Asthma Asthma Asthma is a chronic inflammatory respiratory condition characterized by bronchial hyperresponsiveness and airflow obstruction. The disease is believed to result from the complex interaction of host and environmental factors that increase disease predisposition, with inflammation causing symptoms and structural changes. Patients typically present with wheezing, cough, and dyspnea. Asthma
    • Respiratory infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease
    • Obesity hypoventilation syndrome Obesity hypoventilation syndrome Hypoventilation syndrome in very obese persons with excessive adipose tissue around the abdomen and diaphragm. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic hypoxia; hypercapnia; polycythemia; and long periods of sleep during day and night (hypersomnolence). It is a condition often related to obstructive sleep apnea but can occur separately. Obstructive Sleep Apnea
  • Neurological:
    • Increased risk of hemorrhagic and ischemic stroke Ischemic Stroke An ischemic stroke (also known as cerebrovascular accident) is an acute neurologic injury that occurs as a result of brain ischemia; this condition may be due to cerebral blood vessel occlusion by thrombosis or embolism, or rarely due to systemic hypoperfusion. Ischemic Stroke in men
    • Meralgia paresthetica Meralgia Paresthetica Mononeuropathy and Plexopathy ( compression Compression Blunt Chest Trauma of the lateral cutaneous nerve of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy)
  • Genitourinary/reproductive:
    • Polycystic ovarian syndrome Polycystic ovarian syndrome Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%-10% of women in the age group. It is characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction. Polycystic Ovarian Syndrome ( PCOS PCOS Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%-10% of women in the age group. It is characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction. Polycystic Ovarian Syndrome)
    • Macrosomic babies and subsequent pelvic dystocia
    • Stress incontinence Stress incontinence Involuntary discharge of urine as a result of physical activities that increase abdominal pressure on the urinary bladder without detrusor contraction or overdistended bladder. The subtypes are classified by the degree of leakage, descent and opening of the bladder neck and urethra without bladder contraction, and sphincter deficiency. Urinary Incontinence
  • Skin Skin The 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:
    • Increased risk of infection and cellulitis Cellulitis Cellulitis is a common infection caused by bacteria that affects the dermis and subcutaneous tissue of the skin. It is frequently caused by Staphylococcus aureus and Streptococcus pyogenes. The skin infection presents as an erythematous and edematous area with warmth and tenderness. Cellulitis due to poor circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment
    • Acanthosis nigricans Acanthosis nigricans A circumscribed melanosis consisting of a brown-pigmented, velvety verrucosity or fine papillomatosis appearing in the axillae and other body folds. It occurs in association with endocrine disorders, underlying malignancy, administration of certain drugs, or as in inherited disorder. Diabetes Mellitus secondary to metabolic changes
  • Endocrine/metabolic:
    • Type 2 Type 2 Spinal Muscular Atrophy diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Metabolic syndrome Metabolic syndrome Metabolic syndrome is a cluster of conditions that significantly increases the risk for several secondary diseases, notably cardiovascular disease, type 2 diabetes, and nonalcoholic fatty liver. In general, it is agreed that hypertension, insulin resistance/hyperglycemia, and hyperlipidemia, along with central obesity, are components of the metabolic syndrome. Metabolic Syndrome
    • Dyslipidemia
    • Hypercholesterolemia Hypercholesterolemia A condition with abnormally high levels of cholesterol in the blood. It is defined as a cholesterol value exceeding the 95th percentile for the population. Lipid Disorders
  • GI: 
    • Gallbladder Gallbladder The gallbladder is a pear-shaped sac, located directly beneath the liver, that sits on top of the superior part of the duodenum. The primary functions of the gallbladder include concentrating and storing up to 50 mL of bile. Gallbladder and Biliary Tract: Anatomy disease
    • GERD GERD Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD)
  • Musculoskeletal: knee osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis
  • Hematology/oncology:
    • Lymphadenopathy Lymphadenopathy Lymphadenopathy is lymph node enlargement (> 1 cm) and is benign and self-limited in most patients. Etiologies include malignancy, infection, and autoimmune disorders, as well as iatrogenic causes such as the use of certain medications. Generalized lymphadenopathy often indicates underlying systemic disease. Lymphadenopathy
    • ↑ Risk for lung, pancreatic, renal, and gastric cancers in both genders
    • ↑ Risk for endometrial, ovarian, and breast cancers in women
    • ↑ Risk for prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. , colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy, and rectal cancer in men
Complications of obesity

A sample of complications of obesity

Image by Lecturio.

Diagnosis

History

  • Identify factors contributing to obesity:
    • Lifestyle (occupation, exercise)
    • Diet/caloric intake
    • Duration of a problem/age of onset
    • Previous weight-loss attempts
    • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation (may stimulate increased caloric intake)
    • Family history Family History Adult Health Maintenance
  • Rule out secondary causes:
    • Medications (e.g., steroids Steroids A 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, antipsychotics)
    • Diseases:
      • Hypothyroidism Hypothyroidism 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. Hypothyroidism
      • Cushing’s syndrome

Physical exam

  • Individuals should be screened to obtain BMI measurements.
  • There are some caveats in using BMI: 
    • BMI does not account for the percentage of weight that is muscle versus fat, and may overestimate adiposity in muscular individuals (i.e., athletes, bodybuilders).
    • BMI may underestimate adiposity in individuals, such as the elderly, who may have lost muscle mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast secondary to aging.
    • BMI does not take into account the distribution of body fat, such as abdominal obesity, which is a risk factor in itself.
  • Body-fat percentage may be a more accurate tool to evaluate muscular individuals.
  • Waist circumference should be measured in individuals having BMI ranging from 25–35 to assess abdominal adiposity.
Belly of an obese teenage boy

Abdominal obesity

Image: “Belly of an obese teenage boy” by OctoMocto. License: Public Domain

Laboratory workup

  • Fasting glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance and/or HbA1c HbA1c Products of non-enzymatic reactions between glucose and hemoglobin a, occurring as a minor fraction of the hemoglobin components of human erythrocytes. Hemoglobin a1c is hemoglobin a with glucose covalently bound to the terminal valine of the beta chain. Glycated hemoglobin a is used as an index of the average blood sugar level over a lifetime of erythrocytes. Diabetes Mellitus
  • Thyroid-stimulating hormone Thyroid-stimulating hormone A 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)
  • Liver Liver The 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 enzymes Enzymes Enzymes 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
  • Fasting lipids Lipids Lipids are a diverse group of hydrophobic organic molecules, which include fats, oils, sterols, and waxes. Fatty Acids and Lipids
  • Cholesterol Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Cholesterol Metabolism
  • Further tests should be performed if history, exam findings, or initial labs raise suspicion of secondary causes:
    • Growth hormone levels
    • Adrenocorticotropic hormone Adrenocorticotropic hormone An anterior pituitary hormone that stimulates the adrenal cortex and its production of corticosteroids. Acth is a 39-amino acid polypeptide of which the n-terminal 24-amino acid segment is identical in all species and contains the adrenocorticotropic activity. Upon further tissue-specific processing, acth can yield alpha-msh and corticotropin-like intermediate lobe peptide (clip). Adrenal Hormones/ cortisol Cortisol Glucocorticoids

Management

Goals of treatment

  • To prevent, treat, or reverse obesity-related morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status
  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery of 5%–7% of body weight is associated with reducing the risk of diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, and dyslipidemia.
  • In individuals with BMI > 30, weight loss Weight loss Decrease in existing body weight. Bariatric Surgery of approximately 25 lbs is associated with a reduced risk of cardiovascular disease, cancer, and overall mortality Mortality All deaths reported in a given population. Measures of Health Status.

Lifestyle/behavior modifications

  • 1st step in the management of obesity 
  • Dietary changes:
    • Decreasing caloric intake relative to caloric expenditure
    • Recommended caloric intake for weight loss Weight loss Decrease in existing body weight. Bariatric Surgery: 800–1200 kcal/day
    • Specific type of diet not as important, but overall healthier food choices should be recommended
  • Increase physical activity/exercise 
  • Behavior therapy/modification:
  • Patient education:
    • Educate the patient about the risks and benefits associated with their weight and lifestyle habits.
    • Counsel patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship on healthier nutrition habits and choices of physical activity.

Medications

Weight-loss medications are reserved for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who have:

  • Failed to lose > 5% total body weight within 3–6 months after modifications in lifestyle behavior alone, AND have
  • BMI of ≥ 27 with comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus 
  • BMI of 30 with or without comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus

Considerations and results:

  • Use of medications for weight loss Weight loss Decrease in existing body weight. Bariatric Surgery typically results in a weight loss Weight loss Decrease in existing body weight. Bariatric Surgery of 4%–8% of body weight over a period of 6–12 months.
  • Combining lifestyle/behavioral changes with weight-loss medications results in greater weight loss Weight loss Decrease in existing body weight. Bariatric Surgery than with medications alone.
  • Choice of the anti-obesity agent is based on the comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus and relative contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation relevant to the patient.
  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, blood pressure, and heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology of the patient should be closely monitored for the duration of medical management.
  • Discontinuation of weight-loss medications has been associated with regaining weight.

Duration: 

  • If the patient does not lose 4%–5% baseline body weight by 12 weeks at the maximum tolerated dose, the medication should be tapered and discontinued.
  • Continuation of weight-loss medications for long-term use may be considered if:
    • Medication has been well-tolerated
    • At least 5% of weight reduction from baseline has occurred and lasted 6 months after starting medication
  • The following medications are approved for short-term use (< 12 weeks):
    • All noradrenergic sympathomimetic Sympathomimetic Sympathomimetic drugs, also known as adrenergic agonists, mimic the action of the stimulators (α, β, or dopamine receptors) of the sympathetic autonomic nervous system. Sympathomimetic drugs are classified based on the type of receptors the drugs act on (some agents act on several receptors but 1 is predominate). Sympathomimetic Drugs agents
    • Controlled substances with amphetamine-like effects and potential for abuse:
      • Phentermine Phentermine A central nervous system stimulant and sympathomimetic with actions and uses similar to those of dextroamphetamine. It has been used most frequently in the treatment of obesity. Stimulants
      • Benzphetamine
      • Diethylpropion Diethylpropion A appetite suppressant considered to produce less central nervous system disturbance than most drugs in this therapeutic category. It is also considered to be among the safest for patients with hypertension. Stimulants
      • Phendimetrazine Phendimetrazine Stimulants
    • The following medications are approved for long-term use in weight-loss management:
      • Glucagon-like peptide-1 ( GLP-1 GLP-1 A peptide of 36 or 37 amino acids that is derived from proglucagon and mainly produced by the intestinal l cells. Glp-1(1-37 or 1-36) is further n-terminally truncated resulting in glp-1(7-37) or glp-1-(7-36) which can be amidated. These glp-1 peptides are known to enhance glucose-dependent insulin release, suppress glucagon release and gastric emptying, lower blood glucose, and reduce food intake. Insulinomas) agonists: Semaglutide or liraglutide
      • Orlistat
      • Phentermine-topiramate
      • Naltrexone-bupropion

Medications may also be needed to manage comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus such as hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, hyperlipidemia, and depression:

  • If possible, avoid medications associated with weight gain.
  • Select medications that may also result in weight loss Weight loss Decrease in existing body weight. Bariatric Surgery.
  • Examples of medications that may aid weight loss Weight loss Decrease in existing body weight. Bariatric Surgery:
    • Metformin Metformin A biguanide hypoglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus not responding to dietary modification. Metformin improves glycemic control by improving insulin sensitivity and decreasing intestinal absorption of glucose. Non-insulinotropic Diabetes Drugs or semaglutide (Ozempic) used in the management of diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
    • Fluoxetine Fluoxetine The first highly specific serotonin uptake inhibitor. It is used as an antidepressant and often has a more acceptable side-effects profile than traditional antidepressants. Serotonin Reuptake Inhibitors and Similar Antidepressants (Prozac) used in the management of psychiatric disorders

Bariatric surgery Bariatric surgery Bariatric surgery refers to a group of invasive procedures used to surgically reduce the size of the stomach to produce early satiety, decrease food intake (restrictive type) and/or alter digestion, and artificially induce malabsorption of nutrients (malabsorptive type). The ultimate goal of bariatric surgery is drastic weight loss. Bariatric Surgery

  • Weight loss Weight loss Decrease in existing body weight. Bariatric Surgery of up to 40% of baseline weight may be seen at 12–18 months after the procedure.
  • Indications:
    • BMI > 40 kg/m2
    • BMI > 35 kg/m2 with co-morbidities of obesity ( hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, severe diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea, osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis)
    • BMI > 30 kg/m2 with type 2 Type 2 Spinal Muscular Atrophy diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus, refractory to treatment measures or dysmetabolic syndrome X
    • Failure of conservative attempts at weight loss Weight loss Decrease in existing body weight. Bariatric Surgery 
  • Psychological screening Screening Preoperative Care recommended before undergoing surgery
  • Best means to cure obesity-related complications ( hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus)
  • Surgical options:
    • Sleeve gastrectomy 
    • Roux-en-Y gastric bypass Gastric bypass Surgical procedure in which the stomach is transected high on the body. The resulting small proximal gastric pouch is joined to any parts of the small intestine by an end-to-side surgical anastomosis, depending on the amounts of intestinal surface being bypasses. This procedure is used frequently in the treatment of morbid obesity by limiting the size of functional stomach, food intake, and food absorption. Gastroesophageal Reflux Disease (GERD) 
    • Laparoscopic gastric band
    • Intragastric balloon

Clinical Relevance

Secondary causes of obesity

  • Hypothyroidism Hypothyroidism 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. Hypothyroidism: a condition caused by the deficiency of T3 T3 A 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 and T4 T4 The 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. Clinical features of hypothyroidism Hypothyroidism 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. Hypothyroidism reflect the effects of decreased metabolic rate and include fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia, bradycardia Bradycardia Bradyarrhythmia 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, cold intolerance, and weight gain. Diagnosis is based on thyroid function tests Thyroid Function Tests Blood tests used to evaluate the functioning of the thyroid gland. Ion Channel Myopathy. Elevated thyroid Thyroid The 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 and low free thyroxine Thyroxine The 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 ( T4 T4 The 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) are noted. Treatment is with synthetic T4 T4 The 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.
  • Cushing’s syndrome: a disorder that occurs due to hypercortisolism Hypercortisolism Cushing’s syndrome or hypercortisolism is a disorder characterized by features resulting from chronic exposure to excess glucocorticoids. Cushing’s syndrome may be exogenous, due to chronic glucocorticoid intake, or endogenous, due to increased adrenal secretion of cortisol or adrenocorticotropic hormone (ACTH) production from the pituitary gland or ectopic sources. Cushing Syndrome. Cushing’s syndrome may result from the excessive use of corticosteroids Corticosteroids Chorioretinitis or something in the body that produces excess cortisol Cortisol Glucocorticoids. Clinical features include central obesity Central Obesity Cushing Syndrome, round moon face, hump of fatty tissue on the upper back/ neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess, abdominal striae, and easy bruising Easy bruising Chédiak-Higashi Syndrome. Cushing’s syndrome is associated with hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension and hyperglycemia Hyperglycemia Abnormally high blood glucose level. Diabetes Mellitus. Diagnosis is based on the measurement of cortisol Cortisol Glucocorticoids levels. Treatment depends on the cause of the excess level of cortisol Cortisol Glucocorticoids
  • Prader-Willi syndrome Prader-Willi syndrome Prader-Willi syndrome (PWS) is a rare autosomal neurodevelopmental genetic disorders mapped to a specific region of chromosome 15 attributed to genomic imprinting. A paternally derived chromosome 15 with this deletion results in 15q11-13 paternal deletion syndrome, or PWS. Prader-Willi Syndrome and Angelman Syndrome: a rare genetic neurodevelopmental disorder. Prader-Willi syndrome Prader-Willi syndrome Prader-Willi syndrome (PWS) is a rare autosomal neurodevelopmental genetic disorders mapped to a specific region of chromosome 15 attributed to genomic imprinting. A paternally derived chromosome 15 with this deletion results in 15q11-13 paternal deletion syndrome, or PWS. Prader-Willi Syndrome and Angelman Syndrome is associated with hypotonia Hypotonia Duchenne Muscular Dystrophy, short stature, intellectual disability Disability Determination 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, and obesity. Extremely high ghrelin Ghrelin A 28-amino acid, Acylated, orexigenic peptide that is a ligand for growth hormone secretagogue receptors. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin. Glucagonoma levels in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are hypothesized to be culpable for obesity, hyperphagia, and voracious appetite. Genetic testing Genetic Testing Detection of a mutation; genotype; karyotype; or specific alleles associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing. Myotonic Dystrophies confirms the diagnosis. A multidisciplinary treatment approach includes weight management, a range of therapies (i.e., physical, language, behavioral), and condition-specific treatments. 

Disorders related to obesity

  • PCOS PCOS Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%-10% of women in the age group. It is characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction. Polycystic Ovarian Syndrome: a common endocrine disorder affecting reproductive-aged women. Polycystic ovarian syndrome Polycystic ovarian syndrome Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%-10% of women in the age group. It is characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction. Polycystic Ovarian Syndrome is characterized by hyperandrogenism Hyperandrogenism A condition caused by the excessive secretion of androgens from the adrenal cortex; the ovaries; or the testes. The clinical significance in males is negligible. In women, the common manifestations are hirsutism and virilism as seen in patients with polycystic ovary syndrome and adrenocortical hyperfunction. Potassium-sparing Diuretics, irregular menstrual cycles, and metabolic dysfunction, and is known to increase the risk of infertility Infertility Infertility 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 and cardiovascular disease. Etiology is uncertain but genetics Genetics Genetics is the study of genes and their functions and behaviors. Basic Terms of Genetics and excess hormone levels are believed to play a role. Diagnosis is based on exclusion. Management includes attempting to restore normal ovulation Ovulation The discharge of an ovum from a rupturing follicle in the ovary. Menstrual Cycle through weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, oral contraceptive Oral contraceptive Compounds, usually hormonal, taken orally in order to block ovulation and prevent the occurrence of pregnancy. The hormones are generally estrogen or progesterone or both. Benign Liver Tumors pills, and assistance with fertility.
  • Metabolic syndrome Metabolic syndrome Metabolic syndrome is a cluster of conditions that significantly increases the risk for several secondary diseases, notably cardiovascular disease, type 2 diabetes, and nonalcoholic fatty liver. In general, it is agreed that hypertension, insulin resistance/hyperglycemia, and hyperlipidemia, along with central obesity, are components of the metabolic syndrome. Metabolic Syndrome: a group of health problems that includes hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, impaired fasting glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance levels, dyslipidemia, and a large waist circumference. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are characteristically overweight with predominant central (abdominal)-fat distribution. Diagnosis is made based on the presence of the above conditions after exam and blood tests. Management involves lifestyle changes and medications to manage associated health problems. 
  • Diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus type 2 Type 2 Spinal Muscular Atrophy: a metabolic disorder characterized by chronic hyperglycemia Hyperglycemia Abnormally high blood glucose level. Diabetes Mellitus with elevated urine sugar. Type 2 Type 2 Spinal Muscular Atrophy diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus results from insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin resistance Resistance Physiologically, 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 in tissues and/or the inability of the pancreas Pancreas The pancreas lies mostly posterior to the stomach and extends across the posterior abdominal wall from the duodenum on the right to the spleen on the left. This organ has both exocrine and endocrine tissue. Pancreas: Anatomy to synthesize adequate insulin Insulin Insulin is a peptide hormone that is produced by the beta cells of the pancreas. Insulin plays a role in metabolic functions such as glucose uptake, glycolysis, glycogenesis, lipogenesis, and protein synthesis. Exogenous insulin may be needed for individuals with diabetes mellitus, in whom there is a deficiency in endogenous insulin or increased insulin resistance. Insulin. Symptoms include increased thirst, frequent urination, increased hunger, fatigue Fatigue The state of weariness following a period of exertion, mental or physical, characterized by a decreased capacity for work and reduced efficiency to respond to stimuli. Fibromyalgia, and paresthesias Paresthesias Subjective cutaneous sensations (e.g., cold, warmth, tingling, pressure, etc.) that are experienced spontaneously in the absence of stimulation. Posterior Cord Syndrome. Blood tests are used to confirm the diagnosis. Management involves lifestyle changes and medications. 
  • Obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea: a condition characterized by episodic apnea or cessation of breathing during sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep, wherein the period of apnea lasts > 10 seconds. Obstructive sleep apnea Sleep apnea Repeated cessation of breathing for > 10 seconds during sleep and results in sleep interruption, fatigue, and daytime sleepiness. Obstructive Sleep Apnea results from a partial or complete collapse of the upper airway Airway ABCDE Assessment and is associated with snoring, restlessness, daytime headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, and somnolence. A sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep study is used to confirm the diagnosis. Management involves weight loss Weight loss Decrease in existing body weight. Bariatric Surgery and the use of devices, such as a continuous positive airway pressure Continuous positive airway pressure A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. Noninvasive Ventilation ( CPAP CPAP A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. Noninvasive Ventilation) machine, which helps keep the airway Airway ABCDE Assessment open. 
  • Meralgia paresthetica Meralgia Paresthetica Mononeuropathy and Plexopathy: a condition caused by compression Compression Blunt Chest Trauma of the lateral femoral cutaneous nerve, which supplies sensation to the upper lateral thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy. Meralgia paresthetica Meralgia Paresthetica Mononeuropathy and Plexopathy is marked by tingling Tingling Posterior Cord Syndrome, numbness, and burning pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the outer part of the upper lateral thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy and is common in individuals with high BMI. Diagnosis is based on history and exam, although tests may be conducted to rule out other conditions. Management involves weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, drug therapy, steroid injections, and in rare cases, surgical decompression.

References

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  2. Gonzalez-Campoy, J.M. (2015). Pharmacological Management of Obesity: Agents and Mechanisms of Action. https://www.endocrineweb.com/professional/obesity/pharmacological-management-obesity-agents-mechanisms-action 
  3. Perreault, L. (2020). Obesity in adults: Prevalence, screening, and evaluation. UpToDate. Retrieved February 24, 2021, from https://www.uptodate.com/contents/obesity-in-adults-prevalence-screening-and-evaluation
  4. Perreault, L. (2020). Obesity in adults: Drug therapy. UpToDate. Retrieved February 25, 2021, from https://www.uptodate.com/contents/obesity-in-adults-drug-therapy
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  6. Lim, R.B. (2020). Bariatric procedures for the management of severe obesity: Descriptions. UpToDate. Retrieved February 25, 2021, from https://www.uptodate.com/contents/bariatric-procedures-for-the-management-of-severe-obesity-descriptions
  7. Ellsmere, J.C. (2019). Late complications of bariatric surgical operations. UpToDate. Retrieved February 25, 2021, from https://www.uptodate.com/contents/late-complications-of-bariatric-surgical-operations
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