neonatal jaundice

Question 1

Physiological neonatal jaundice

Answer 1

Always unconjugated hyperbilirubinemia
Peak total serum bilirubin : < 15 mg/dL (in the case of a full-term, breastfed infant)
Daily rise in bilirubin levels < 5 mg/dL/day

Question 2

Pathological neonatal jaundice

Answer 2

Can be either conjugated or unconjugated hyperbilirubinemia
Peak total serum bilirubin can rise > 15 mg/dL
Daily rise in bilirubin levels > 5 mg/dL/day

Risk factors for pathological jaundice:
Prematurity
Low birth weight
History of previously affected sibling
Fetal-maternal blood group incompatibility
Birth trauma

Question 3

Etiology of conjugated hyperbilirubinemia

Answer 3

Decreased bilirubin excretion
Intrahepatic cholestasis
Sepsis
Hepatitis A
Hepatitis B
TORCH infections
Cystic fibrosis
Extrahepatic cholestasis
Biliary atresia
Choledochal cyst
Tumors/strictures
Intrahepatic pathologies
Infectious hepatitis
Metabolic diseases
Dubin-Johnson syndrome
Rotor syndrome
Galactosemia
Alpha-1-Antitrypsin deficiency
Hypermethioninemia
Idiopathic neonatal hepatitis
Alagille syndrome

Question 4

Etiology of unconjugated hyperbilirubinemia

Answer 4

Hemolytic
Infection or sepsis (infections in the newborn)
Hematomas (e.g., from vacuum-assisted delivery, vitamin K deficiency bleeding)
Hemolytic disease of the newborn (ABO incompatibility , Rhesus incompatibility)
RBC structural defects (spherocytosis, hereditary elliptocytosis)
Ineffective erythropoiesis (thalassemias)
Glucose-6-phosphate dehydrogenase deficiency
Nonhemolytic
Hyperbilirubinemia syndromes (e.g., Crigler-Najjar syndrome, Gilbert’s syndrome)
Glucuronyl transferase deficiency
Increased enterohepatic circulation: e.g., high GI obstruction (pyloric stenosis, bowel obstruction)
Other causes: medication, hypothyroidism, malnutrition, polycythemia

Question 5

Pathophysiology of physiological and pathological bilirubinemia

Answer 5

Physiological hyperbilirubinemia
Short lifespan of erythrocytes in the newborn + impaired bilirubin metabolism + ↑ enterohepatic circulation of bilirubin → unconjugated hyperbilirubinemia

Pathological hyperbilirubinemia
Can be caused by multiple mechanisms:
Increased production of bilirubin
Decreased hepatic uptake
Decreased conjugation
Impaired excretion
Increased enterohepatic circulation

Question 6

subtypes and variants

Answer 6

Breastfeeding jaundice
Pathophysiology: insufficient breast milk intake; inadequate quantities of bowel movements to remove bilirubin from the body → ↑ enterohepatic circulation → increased reabsorption of bilirubin from the intestines
Clinical features: onset within 1 week
Treatment: increase breastfeeding sessions, rehydration
Breast milk jaundice
Pathophysiology: increased concentration of β-glucuronidase in breast milk → ↑ deconjugation and reabsorption of bilirubin → persistence of physiologic jaundice
Clinical features: onset within 2 weeks after birth; lasts for 4–13 weeks
Treatment
Continued breastfeeding

Question 7

Physiological neonatal jaundice

Answer 7

Asymptomatic, except for transient icterus
Does not manifest until 3rd day of life, resolves by 8th day (in term infants)
Pathological hyperbilirubinemia
Onset of jaundice: can appear < 24 hours after birth; can persist > 1 week in term infants and > 2 weeks in preterm infants
In rare cases
Acute bilirubin encephalopathy
Kernicterus/chronic bilirubin encephalopathy (develop over first years of life)
Cerebral paresis; vertical gaze palsy
Movement disorder (athetosis)

Question 8

Diagnostics

Answer 8

Physical examination for icterus
Bilirubin tests
Transcutaneous bilirubin measurement
Serum bilirubin measurement
Differentiation of direct (conjugated) and indirect (unconjugated) bilirubin
Assessment of degree of jaundice based on nomogram → infants > 95th percentile must be evaluated for pathological jaundice (see tests below)
Other laboratory tests
Complete blood count (including reticulocyte count)
Blood grouping
Direct and indirect Coombs’ test (see Rh incompatibility)

Question 9

Treatment

Answer 9

Phototherapy: primary treatment in neonates with unconjugated hyperbilirubinemia.
Indications
Increase of total serum bilirubin above the threshold for phototherapy (children > 95th percentile on nomogram (e.g., > 15 mg/dL in a 48-hour-old term infant, > 20 mg/dL in 96-hour-old infant))
Contraindication: ↑ direct (conjugated) bilirubin
Procedure
Exposure to blue light; wavelength: 420–480 nm; → conversion of unconjugated (hydrophobic) bilirubin in skin to water-soluble form → excretion of water-soluble form in urine and/or bile
Side effects
Changes in skin hue (bronzing) and skin rashes
Exchange transfusion
Most rapid method for lowering serum bilirubin concentrations
Indications
Threshold in a 24-hour-old term baby is a total serum bilirubin value > 20 mg/dL
Inadequate response to phototherapy
Acute bilirubin encephalopathy
Hemolytic disease, severe anemia
Implementation
Use ABO-matched and Rh-negative erythrocyte concentrate
IV immunoglobulin
Used in cases with immunologically mediated conditions, or in the presence of Rh, ABO, or other blood group incompatibilities that cause significant neonatal jaundice

Question 10

prevention

Answer 10

Interruption of enterohepatic circulation through adequate enteral nutrition
Frequent feeds with breast milk