15 Jaundice

Definitions
Jaundice (also called icterus) is defined as yellowing of the skin and sclera from accumulation of the pigment bilirubin in the blood and tissues. The bilirubin level has to exceed 35–40 mmol/l before jaundice is clinically apparent.
KEY POINTS
• Jaundice can be classified simply as pre-hepatic (haemolytic), hepatic (hepatocellular) and post-hepatic (obstructive).
• Most of the surgically treatable causes of jaundice are post-hepatic (obstructive).
• Painless progressive jaundice is highly likely to be due to malignancy.
Differential diagnosis
The following list explains the mechanisms behind the causes of jaundice.
Pre-hepatic/haemolytic jaundice
Haemolytic/congenital hyperbilirubinaemias
Excess production of unconjugated bilirubin exhausts the capacity of the liver to conjugate the extra load, e.g. haemolytic anaemias (e.g. hereditary spherocytosis, sickle cell disease, hypersplenism, thalassaemia).
Hepatic/hepatocellular jaundice
Hepatic unconjugated hyperbilirubinaemia
• Failure of transport of unconjugated bilirubin into the cell, e.g.Gilbert’s syndrome.
• Failure of glucuronyl transferase activity, e.g. Crigler–Najjar syndrome.
Hepatic conjugated hyperbilirubinaemia
Hepatocellular injury. Hepatocyte injury results in failure of excretion of bilirubin, e.g. infections: viral hepatitis; poisons: CCl4, aflatoxin; drugs: paracetamol, halothane.
Post-hepatic/obstructive jaundice
Post-hepatic conjugated hyperbilirubinaemia
Anything that blocks the release of conjugated bilirubin from the hepatocyte or prevents its delivery to the duodenum.
Courvoisier’s law
‘A palpable gallbladder in the presence of jaundice is unlikely to be due to gallstones.’ It usually indicates the presence of a neoplastic stricture (tumour of pancreas, ampulla, duodenum, CBD), chronic pancreatitic stricture or portal lymphadenopathy.
KEY INVESTIGATIONS
• FBC: haemolysis.
• LFTs: alkaline phosphatase (cholestasis), g-GT and transaminases (hepatocellular).
• Clotting: PT (elevated in cholestatic and hepatocellular jaundice).
• Urinary urobilinogen
→
Haemolytic
• Blood film
• Reticulocyte count
• Autoantibody screen
Obstructive
U/S CBD and gallbladder
CBD dilated
Gallstones
ERCP
Surgery
→
Hepatocellular
• Viral titres: including hepatitis
A/B/C, CMV, EBV
• Ultrasound: details of hepatic
parenchyma.
• Liver biopsy: hepatocellular
disease
→
→
CBD dilated
No gallstones
?Ca pancreas/CBD
ERCP +/– stent
CT scan/MRCP
→→
Other cause found
ERCP
CT scan
Surgery