Jaundice Flashcards
What is jaundice
Yellow pigmentation of the skin, sclerae and mucosa due to raised bilirubin
How is bilirubin normally produced
Created by the breakdown of haemoglobin
Conjugated with glucuronic acid by hepatocytes, making it water soluble.
Secreted in bile into the small intestine
Most bile is reabsorbed into the enterohepatic circulation, the rest converted by gut bacteria into urobilinogen
What normally happens to urobilinogen
Reabsorbed and excreted by kidneys
What happens to urobilinogen that isn’t reabsorbed
Converted to stercobilinogen
Excreted in faeces
How do you classify jaundice
Prehepatic jaundice
Hepatocellular jaundice
Obstructive jaundice
What are the features of prehepatic jaundice
Unconjugated hyperbilirubinaemia
Excess bilirubin production
Water insoluble so not in urine
What are some causes of prehepatic jaundice
Physiological (neonatal)
Haemolysis - sickle cell, thalassaemia
Gilbert’s syndrome - bilirubin increased on fasting
What are the features of hepatocellular jaundice
Due to hepatocyte damage
Usually some cholestasis
What are some causes of hepatocellular jaundice
Hepatitis - viral, alcoholic, drug-induced, ischaemic, autoimmune Non-alcoholic steatohepatitis Cirrhosis Metastatic disease Infection - septicaemia, liver abscesses Haemochromatosis Wilson's disease
What are the features of obstructive jaundice
Blockage of common bile ducts
Conjugated bilirubinaemia
Dark urine and pale stool - water soluble so more is excreted in urine than stool
Pruritus
What are some causes of obstructive jaundice
Biliary obstruction - gallstones
Malignancies - pancreatic, cholangiocarcinoma
Autoimmune - PBC, primary sclerosing cholangitis
Drugs - antibiotics (co-amoxiclav, chlorpromazine, prochlorperazine)
What is the differential for a patient with jaundice and signs of chronic liver disease?
ETOH, viral hepatitis, NAFLD
What is the differential for splenomegaly with jaundice?
Haemolysis
Chronic liver disease (causing portal hypertension)
Viral hepatitis e.g. EBV
What is the differential for hepatomegaly with jaundice?
hepatitis
CLD
What is the differential for jaundice without signs of CLD or organomegaly?
biliary obstruction
haemolysis
drugs: fluclox, OCP
Gilbert’s syndrome
