Hyperbilirubinemia of the Newborn

Overview

Definition

Hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice of the newborn Newborn An infant during the first 28 days after birth. Physical Examination of the Newborn is defined as a yellow discoloration of the 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 and sclera Sclera The white, opaque, fibrous, outer tunic of the eyeball, covering it entirely excepting the segment covered anteriorly by the cornea. It is essentially avascular but contains apertures for vessels, lymphatics, and nerves. Eye: Anatomy of the newborn Newborn An infant during the first 28 days after birth. Physical Examination of the Newborn usually due to the tissue deposition of unconjugated bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism, the end product of heme-protein catabolism.

Epidemiology

• 60% of term infants and 80% of preterm infants have visible jaundice Jaundice Jaundice 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 after birth.
• More common in East Asians and Native Americans

Etiology

Increased indirect (unconjugated) bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism

Positive Coombs test: isoimmunization

• ABO incompatibility ABO incompatibility Hemolytic Disease of the Fetus and Newborn
• Rh incompatibility Rh Incompatibility Hemolytic Disease of the Fetus and Newborn
• Other alloimmunization

Negative Coombs test

• Polycythemia Polycythemia An increase in the total red cell mass of the blood. Renal Cell Carcinoma:
  • Twin-to-twin transfusion
  • Maternal-fetal transfusion
  • Delayed cord clamping
  • Small for gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care
• Low/normal hemoglobin:
  • Increased reticulocyte Reticulocyte Immature erythrocytes. In humans, these are erythroid cells that have just undergone extrusion of their cell nucleus. They still contain some organelles that gradually decrease in number as the cells mature. Ribosomes are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic ‘reticulum’ (not the same as the endoplasmic reticulum), hence the name reticulocytes. Erythrocytes: Histology count with abnormal morphology:
    • Glucose-6-phosphate Glucose-6-phosphate An ester of glucose with phosphoric acid, made in the course of glucose metabolism by mammalian and other cells. It is a normal constituent of resting muscle and probably is in constant equilibrium with fructose-6-phosphate. Gluconeogenesis dehydrogenase ( G6PD G6PD Pentose Phosphate Pathway) deficiency
    • Pyruvate Pyruvate Derivatives of pyruvic acid, including its salts and esters. Glycolysis kinase (PK) deficiency
    • Other enzyme deficiency
    • Disseminated intravascular coagulation Disseminated intravascular coagulation Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation
    • Spherocytosis
    • Elliptocytosis
    • Stomatocytosis
    • Pyknocytosis
  • Increased/normal reticulocyte Reticulocyte Immature erythrocytes. In humans, these are erythroid cells that have just undergone extrusion of their cell nucleus. They still contain some organelles that gradually decrease in number as the cells mature. Ribosomes are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic ‘reticulum’ (not the same as the endoplasmic reticulum), hence the name reticulocytes. Erythrocytes: Histology count with normal morphology:
    • Enclosed hemorrhage (cephalhematoma)
    • Increased enterohepatic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment (delayed stooling, bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis)
    • Inadequate caloric intake Inadequate Caloric Intake Failure to Thrive
    • Asphyxia Asphyxia A pathological condition caused by lack of oxygen, manifested in impending or actual cessation of life. Drowning
    • 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
    • Breastfeeding Breastfeeding Breastfeeding is often the primary source of nutrition for the newborn. During pregnancy, hormonal stimulation causes the number and size of mammary glands in the breast to significantly increase. After delivery, prolactin stimulates milk production, while oxytocin stimulates milk expulsion through the lactiferous ducts, where it is sucked out through the nipple by the infant. Breastfeeding
    • Gilbert’s syndrome
    • Crigler-Najjar syndrome Crigler-Najjar Syndrome A familial form of congenital hyperbilirubinemia transmitted as an autosomal recessive trait. It is characterized by icterus and brain damage caused by a glucuronyl transferase deficiency in the liver and faulty bilirubin conjugation. Jaundice

Increased direct (conjugated) bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism

• Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock
• Intrauterine infection
• Bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy duct disorders
• Bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy obstruction
• Severe hemolytic disease
• Choledochal cyst
• Cystic Cystic Fibrocystic Change fibrosis Fibrosis Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury. Bronchiolitis Obliterans
• Galactosemia Galactosemia Galactosemia is a disorder caused by defects in galactose metabolism. Galactosemia is an inherited, autosomal-recessive condition, which results in inadequate galactose processing and high blood levels of monosaccharide. The rare disorder often presents in infants with symptoms of lethargy, nausea, vomiting, diarrhea, and jaundice. Galactosemia
• Alpha-1 antitrypsin Alpha-1 antitrypsin Plasma glycoprotein member of the serpin superfamily which inhibits trypsin; neutrophil elastase; and other proteolytic enzymes. Alpha-1 Antitrypsin (AAT) Deficiency deficiency
• Tyrosinemia Tyrosinemia A group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. Type I tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. Type II tyrosinemia features intellectual disability, painful corneal ulcers, and keratosis of the palms and plantar surfaces and is caused by a deficiency of the enzyme tyrosine transaminase. Type III tyrosinemia features intellectual disability and is caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase. Renal Tubular Acidosis
• Alagille syndrome
• Hepatitis

Risk Factors

Major risk factors

• Predischarge high-risk clinical features or serum bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels based on the Bhutani nomogram
• Jaundice Jaundice Jaundice 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 in the first 24 hours of life
• Maternal/fetal blood group incompatibility and positive antiglobulin test
• Gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care 35–36 weeks
• Prior phototherapy in siblings
• Cephalohematoma Cephalohematoma Von Willebrand Disease or significant bruising
• Exclusive breastfeeding Breastfeeding Breastfeeding is often the primary source of nutrition for the newborn. During pregnancy, hormonal stimulation causes the number and size of mammary glands in the breast to significantly increase. After delivery, prolactin stimulates milk production, while oxytocin stimulates milk expulsion through the lactiferous ducts, where it is sucked out through the nipple by the infant. Breastfeeding, particularly if nursing is not going well and weight loss Weight loss Decrease in existing body weight. Bariatric Surgery is excessive
• Known hemolytic disorder in the child
• East Asian ethnicity ( G6PD deficiency G6PD Deficiency Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a type of intravascular hemolytic anemia. The condition is inherited in an X-linked recessive manner. Patients have episodic hemolysis due to an oxidative stressor that causes damage to red blood cells, which lack sufficient NADPH to protect them from oxidative injury. Glucose-6-phosphate Dehydrogenase (G6PD) Deficiency)

Minor risk factors

• Having the last bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism reading prior to discharge high-intermediate-risk area based on the Bhutani nomogram
• Gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care 37–38 weeks
• Jaundice Jaundice Jaundice 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 observed before discharge
• Sibling with prior jaundice Jaundice Jaundice 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
• Diabetes-induced macrosomia
• Maternal age ≥ 25 years
• Male sex Sex The totality of characteristics of reproductive structure, functions, phenotype, and genotype, differentiating the male from the female organism. Gender Dysphoria

Additional risk factors

• Dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration
• Infection
• Delay in passage of meconium Meconium The thick green-to-black mucilaginous material found in the intestines of a full-term fetus. It consists of secretions of the intestinal glands; bile pigments; fatty acids; amniotic fluid; and intrauterine debris. It constitutes the first stools passed by a newborn. Prenatal and Postnatal Physiology of the Neonate
• Drugs and substance: oxytocin (in mother), phenolic detergents (in nursery)
• Polycythemia Polycythemia An increase in the total red cell mass of the blood. Renal Cell Carcinoma 
• Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock 
• Acidosis Acidosis A 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
• Low serum albumin Albumin Serum albumin from humans. It is an essential carrier of both endogenous substances, such as fatty acids and bilirubin, and of xenobiotics in the blood. Liver Function Tests

Factors that decrease risk

• Predischarge low-risk clinical or serum bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels
• Gestational age Gestational age The age of the conceptus, beginning from the time of fertilization. In clinical obstetrics, the gestational age is often estimated as the time from the last day of the last menstruation which is about 2 weeks before ovulation and fertilization. Pregnancy: Diagnosis, Physiology, and Care ≥ 41 weeks
• Exclusive bottle-feeding
• African American
• Discharge from hospital after 72 hours

Classification

Indirect hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice

• → unconjugated
• Physiologic (always unconjugated or indirect): due to increased production of bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism caused by fetal erythrocyte breakdown and transient limitation of the 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 to conjugate bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism
  • Expected to appear after the 1st 24 hours and peak by day 2–4 at 5–6 mg/dL and then fall to < 2 mg/dL by the end of the 1st week
  • Normal bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels by 10–14 days is < 1 mg/dL
• Exaggerated physiologic jaundice Jaundice Jaundice 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 (always unconjugated or indirect):
  • May reach high total serum bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism (TSB) levels (> 15 mg/dL) in the presence of risk factors  
• Increased enterohepatic circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment of bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism
  • Breast milk jaundice Jaundice Jaundice 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: unclear etiology, seen in exclusively breastfed infants
• Breastfeeding Breastfeeding Breastfeeding is often the primary source of nutrition for the newborn. During pregnancy, hormonal stimulation causes the number and size of mammary glands in the breast to significantly increase. After delivery, prolactin stimulates milk production, while oxytocin stimulates milk expulsion through the lactiferous ducts, where it is sucked out through the nipple by the infant. Breastfeeding ( lactation Lactation The processes of milk secretion by the maternal mammary glands after parturition. The proliferation of the mammary glandular tissue, milk synthesis, and milk expulsion or let down are regulated by the interactions of several hormones including estradiol; progesterone; prolactin; and oxytocin. Breastfeeding failure) jaundice Jaundice Jaundice 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: secondary to inadequate nutrition and hydration
• Genetic causes leading to increased RBC hemolysis
  • Structural: hereditary spherocytosis Hereditary Spherocytosis Hereditary spherocytosis (HS) is the most common type of hereditary hemolytic anemia. The condition is caused by a cytoskeletal protein deficiency in the RBC membrane. This results in loss of membrane stability and deformability of the RBC, giving the cell its spherical shape (spherocyte). Hereditary Spherocytosis and elliptocytosis
  • Enzymatic: G6PD deficiency G6PD Deficiency Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a type of intravascular hemolytic anemia. The condition is inherited in an X-linked recessive manner. Patients have episodic hemolysis due to an oxidative stressor that causes damage to red blood cells, which lack sufficient NADPH to protect them from oxidative injury. Glucose-6-phosphate Dehydrogenase (G6PD) Deficiency, PK deficiency
• Genetic causes leading to decreased clearance
  • Crigler-Najjar syndrome Crigler-Najjar Syndrome A familial form of congenital hyperbilirubinemia transmitted as an autosomal recessive trait. It is characterized by icterus and brain damage caused by a glucuronyl transferase deficiency in the liver and faulty bilirubin conjugation. Jaundice
  • Gilbert’s syndrome
• Sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock

Direct hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice

• → conjugated 
• Obstructive causes
  • Biliary atresia Atresia Hypoplastic Left Heart Syndrome (HLHS)
  • Biliary cyst
  • Neonatal sclerosing cholangitis
• Infectious causes
  • Congenital Congenital Chorioretinitis 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 (TORCH pathogens)
  • Acquired perinatal 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
• Genetic causes
  • Alagille syndrome
  • Alpha-1 antitrypsin Alpha-1 antitrypsin Plasma glycoprotein member of the serpin superfamily which inhibits trypsin; neutrophil elastase; and other proteolytic enzymes. Alpha-1 Antitrypsin (AAT) Deficiency deficiency
• Metabolic causes
  • Galactosemia Galactosemia Galactosemia is a disorder caused by defects in galactose metabolism. Galactosemia is an inherited, autosomal-recessive condition, which results in inadequate galactose processing and high blood levels of monosaccharide. The rare disorder often presents in infants with symptoms of lethargy, nausea, vomiting, diarrhea, and jaundice. Galactosemia
  • Tyrosinemia Tyrosinemia A group of disorders which have in common elevations of tyrosine in the blood and urine secondary to an enzyme deficiency. Type I tyrosinemia features episodic weakness, self-mutilation, hepatic necrosis, renal tubular injury, and seizures and is caused by a deficiency of the enzyme fumarylacetoacetase. Type II tyrosinemia features intellectual disability, painful corneal ulcers, and keratosis of the palms and plantar surfaces and is caused by a deficiency of the enzyme tyrosine transaminase. Type III tyrosinemia features intellectual disability and is caused by a deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase. Renal Tubular Acidosis

Diagnosis

History

• Family history Family History Adult Health Maintenance
  • Sibling with jaundice Jaundice Jaundice 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, splenectomy Splenectomy Surgical procedure involving either partial or entire removal of the spleen. Rupture of the Spleen 
  • Bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy stones in family suspicious for sickle cell disease Sickle cell disease Sickle cell disease (SCD) is a group of genetic disorders in which an abnormal Hb molecule (HbS) transforms RBCs into sickle-shaped cells, resulting in chronic anemia, vasoocclusive episodes, pain, and organ damage. Sickle Cell Disease
• Pregnancy Pregnancy The 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/perinatal history
  • Maternal 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
  • Illicit drug use or herbal remedy use during pregnancy Pregnancy The 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
  • History of trauma to the infant during delivery
• Postnatal history
  • Acholic stool
  • Abnormal weight loss Weight loss Decrease in existing body weight. Bariatric Surgery, especially when exclusively breastfed 
  • RhoGAM^® administration
  • Signs of infection

Physical examination

• General 
  • Note for tone and level of activity of the neonate Neonate An infant during the first 28 days after birth. Physical Examination of the Newborn
  • Infants with hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice are often drowsy.
• 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 exam
  • Evaluating jaundice Jaundice Jaundice 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 can be challenging under fluorescent lighting.
  • Must account for a child’s natural pigmentation
  • Neonatal jaundice Jaundice Jaundice 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 progresses cephalocaudally:
    • Rule of thumb:
      • Jaundice Jaundice Jaundice 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 to face (approximately 5 mg/dL)  
      • Jaundice Jaundice Jaundice 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 to mid abdomen (approximately 15 mg/dL) 
      • Jaundice Jaundice Jaundice 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 to soles (approximately 20 mg/dL)
  • Also evaluate for
    • Cephalohematoma Cephalohematoma Von Willebrand Disease
    • Petechiae Petechiae Primary Skin Lesions
• Neurologic exam
  • Signs requiring immediate phototherapy:
    • Decreased muscle tone Muscle tone The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. Skeletal Muscle Contraction
    • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures 
    • Altered cry
• Other important findings: hepatosplenomegaly Hepatosplenomegaly Cytomegalovirus, microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder, congenital Congenital Chorioretinitis malformations, signs of dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration, infection, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever

Indications for laboratory testing

• Jaundice Jaundice Jaundice 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 in 1st 24 hours or jaundice Jaundice Jaundice 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 appearing excessive for infant’s age: check TSB
• Consider risk assessment Risk assessment The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. Preoperative Care based on the Bhutani nomogram
• If TSB rising rapidly or infant requiring phototherapy, check:
  • CBC and smear
  • Blood type and Coombs test
  • Direct bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism and repeat TSB within 24 hours
  • Reticulocyte Reticulocyte Immature erythrocytes. In humans, these are erythroid cells that have just undergone extrusion of their cell nucleus. They still contain some organelles that gradually decrease in number as the cells mature. Ribosomes are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic ‘reticulum’ (not the same as the endoplasmic reticulum), hence the name reticulocytes. Erythrocytes: Histology count, G6PD G6PD Pentose Phosphate Pathway, albumin Albumin Serum albumin from humans. It is an essential carrier of both endogenous substances, such as fatty acids and bilirubin, and of xenobiotics in the blood. Liver Function Tests, end-tidal carbon monoxide Carbon monoxide Carbon monoxide (CO). A poisonous colorless, odorless, tasteless gas. It combines with hemoglobin to form carboxyhemoglobin, which has no oxygen carrying capacity. The resultant oxygen deprivation causes headache, dizziness, decreased pulse and respiratory rates, unconsciousness, and death. Carbon Monoxide Poisoning in breath (ETCO) (if available), blood gases ( acidosis Acidosis A 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)
• Elevated direct bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism: perform urinalysis Urinalysis Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically. Urinary Tract Infections (UTIs) in Children, urine culture Urine culture Urinary tract infections (UTIs), and sepsis Sepsis Systemic inflammatory response syndrome with a proven or suspected infectious etiology. When sepsis is associated with organ dysfunction distant from the site of infection, it is called severe sepsis. When sepsis is accompanied by hypotension despite adequate fluid infusion, it is called septic shock. Sepsis and Septic Shock workup
• Jaundice Jaundice Jaundice 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 present > 3 weeks: check 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 and galactosemia Galactosemia Galactosemia is a disorder caused by defects in galactose metabolism. Galactosemia is an inherited, autosomal-recessive condition, which results in inadequate galactose processing and high blood levels of monosaccharide. The rare disorder often presents in infants with symptoms of lethargy, nausea, vomiting, diarrhea, and jaundice. Galactosemia screen and check direct bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism

Management

• The goal of therapy in unconjugated neonatal hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice is to avoid neurotoxicity and prevent kernicterus. 
• Phototherapy:
  • First-line therapy for unconjugated hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice
  • Considered when indirect bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels reach 50%–70% of maximum
  • Provokes conformational changes that turn bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism into the soluble form lumirubin, which is excreted in urine and bile Bile An emulsifying agent produced in the liver and secreted into the duodenum. Its composition includes bile acids and salts; cholesterol; and electrolytes. It aids digestion of fats in the duodenum. Gallbladder and Biliary Tract: Anatomy
  • 420–470 nm are the light frequencies that produce the best results.
  • Complications include:
    • Dehydration Dehydration The condition that results from excessive loss of water from a living organism. Volume Depletion and Dehydration
    • Thermal environmental changes → hyperthermia (more common) or hypothermia Hypothermia Hypothermia 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 (from exposure)
    • Bronze baby syndrome (in the presence of direct hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice)
    • Corneal damage (if eyes not appropriately covered)
• Intravenous immune globulin ( IVIG IVIG Dermatomyositis): in isoimmune hemolytic anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types not responsive to phototherapy and reaching maximum levels of indirect bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism
• Exchange transfusion: 
  • When phototherapy fails to control hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice
  • When there are signs of kernicterus regardless of bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels
  • At bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism levels approaching the maximum for that infant, especially during the 1st 48 hours
  • In cases of severe hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice, severe anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types, and hydrops Hydrops Cholecystitis (used when phototherapy and IVIG IVIG Dermatomyositis fail)
• Adjunct treatment: enteral feeding is encouraged, fluid resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome in dehydrated babies

Complications

Bilirubin-induced neurologic dysfunction (BIND):

• Occurs when bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism crosses the blood-brain barrier Blood-brain barrier Specialized non-fenestrated tightly-joined endothelial cells with tight junctions that form a transport barrier for certain substances between the cerebral capillaries and the brain tissue. Systemic and Special Circulations, causing tissue damage
• Subtle long-term effects causing disorders in:
  • Vision Vision Ophthalmic Exam
  • Hearing
  • Speech
• Acute bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism encephalopathy Encephalopathy Hyper-IgM Syndrome:
  • 1st 48 hours: lethargy Lethargy A 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, poor feeding, loss of Moro reflex Moro Reflex Primitive Reflexes, increasingly ill appearance, respiratory distress 
  • Middle of 1st week: extensor hypertonia Hypertonia Abnormal increase in skeletal or smooth muscle tone. Skeletal muscle hypertonicity may be associated with pyramidal tract lesions or basal ganglia diseases. Neurological Examination, opisthotonos, and fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever
  • After 1st week: hypertonia Hypertonia Abnormal increase in skeletal or smooth muscle tone. Skeletal muscle hypertonicity may be associated with pyramidal tract lesions or basal ganglia diseases. Neurological Examination  
• Chronic bilirubin Bilirubin A bile pigment that is a degradation product of heme. Heme Metabolism encephalopathy Encephalopathy Hyper-IgM Syndrome (kernicterus):
  • 1st year: hypotonia Hypotonia Duchenne Muscular Dystrophy, increased deep tendon reflexes Deep Tendon Reflexes Neurological Examination, delayed motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology skills
  • After 1st year: choreoathetosis, ballismus, tremor Tremor Cyclical movement of a body part that can represent either a physiologic process or a manifestation of disease. Intention or action tremor, a common manifestation of cerebellar diseases, is aggravated by movement. In contrast, resting tremor is maximal when there is no attempt at voluntary movement, and occurs as a relatively frequent manifestation of parkinson disease. Myotonic Dystrophies, upward gaze, sensorineural hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss