Physiological is because Long chain FAs in breast milk compete with Glucuronyl transferase! Dehydration and poor feeding contribute (jaundice FOLLOWS, does not cause). But can also be seen in bottle fed babies.
Prolonged jaundice defined as 21/7 if well, term according to American Academy of Pediatrics. After that, investigation probably appropriate.
Unconjugated vs Conjugated bilirubin is important – do direct bilirubin. Conj bili >20 may indicate significant disease, esp if unconj not high. Low albumin suggests prenatal onset.
- Haemolysis (so liver function tests normal): eg rhesus disease (diagnosis: Direct Coombs Test Positive), ABO, irregular antibodies (Kell, Duffy; varying significance), hereditary sphero/elliptocytosis, G6PD deficiency, DIC. G6PD in baby can be precipitated by maternal drugs/infection. Enzyme assay false negative because of high retic count, so test mother for carrier status.
- Crigler Najjar is unconjugated. Uridine Di Phos Glucuronyl transferase deficiency (Dubin Johson/Rotor only present >2 yr). Recessive form is severe, assoc with kernicterus; dominant can be treated with phenobarb.
- Galactosaemia – in the first week of life can be unconjugated but always features liver dysfunction cf Crigler Najjar so unlikely to be any confusion.
Suggests hepatitis. Note that Alk phos in normal neonates is often high in isolation. See BSPGHAN protocol.
- Congenital Biliary Atresia
- Choledochal cyst: assoc with East Asians, PKD (Caroli’s disease). Cystic mass below liver. Can rupture and cause ascites, cause obstruction +/or cholangitis. Late carcinoma risk.
- Spont CBD perforation – discoloured umbilicus, paracentesis diagnostic. Rx Surg
- Gallstones – possible!
- Congenital viral infection (TORCH), enteroviruses (esp ECHO, assoc with fulminant hepatitis), sepsis (eg UTI, listeria assoc with hepatic abscesses).
- Cystic fibrosis and bile plug syndrome
- Inherited Metabolic Disorders: galactosaemia, Zellweger’s, haemochromatosis, etc.
- Alpha -1 antitrypsin deficiency
- Alagille’s syndrome
- Endocrine disorders: congenital hypothyroidism (1 in 60 000), pituitary/adrenal underactivity.