ie raised blood bilirubin.

First decide if conjugated or unconjugated.  Conjugated suggests a biliary problem, ie obstruction to bile flow, usually associated with raised gamma glucuronyl transferase (gamma GT).  Unconjugated (as measured in split bilirubin) implies haemolysis or else hepatocellular damage (transaminases also go up ie AST, ALT).  Unconjugated can also go up in conjugated disease, presumably competition for conjugation sites, or else because of secondary or mixed hepatocellular damage.

History – maternal if baby, immunisations, transfusions, outdoor activities, pets, holidays, drugs, tattoos. Family history (haemolytic conditions, in particular).

Look for signs of liver failure, lymphadenopathy, eyes (Wilsons – best with slit lamp), dysmorphic (Alagille’s).

Consider:

• Infection (viral hepatitis, leptospirosis, Q fever etc)
• Autoimmune – can be acute
• Gilbert’s syndrome is unconjugated.
• Reye’s – metabolic but precipitated by infection eg varicella
• biliary disease eg sclerosing cholangitis, Caroli disease/syndrome, veno-occlusive disease.
• Haemolysis
• Haemophagocytic lymphohistiocytosis – acutely unwell, coagulopathy, transfusion dependent
• Poisoning esp paracetamol but also herbal remedies, mushrooms
• Alpha 1 antitrypsin deficiency
• Alagille’s syndrome
• Inherited Metabolic conditions

So do:

• USS abdo – exclude obstruction.  Common bile duct stones can be obscured on USS by bowel gas.
• FBC, U&Es, LFTs (including GGT, AST if not routinely done), CRP
• Prothrombin time, glucose, ammonia, lactate – to monitor for failure
• Amylase
• Coombs test and reticulocytes – haemolytic anaemia seen in Wilsons
• Paracetamol level
• Cholesterol/TGs
• Urate
• ANA, anti SMA/LKM ab’s, Immunogloblulins
• Ca/Phosph/Mg
• Copper, caeruloplasmin (but not great for Wilsons if acute)
• COVID, HHV6, HSV, HCV, CMV, EBV PCR
• HBsAg
• Hep A&E, Parvo B19, CMV, EBV Serology incl HIV, IM test
• Viral throat swab (extended screen)
• Alpha 1 AT if chronic
• Slit lamps examination – (Wilson’s, also Alagille’s (posterior embryotoxin)
• CXR to look for butterfly vertebrae (Alagille’s)
• TTG ab
• C3/4
• Alfa fetoprotein
• Urine amino/organic acids if under 5

If PT>15, give IV vitamin K (0.3mg/kg, max 10mg) and check daily. If resistant then refer.