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Obstructive Jaundice

  • Jaundice – yellow staining of the skin, sclera and mucous membranes by bilirubin
  • Normal level of bilirubin is <1.0 mg/dl
  • Jaundice manifests when levels are 2.5-3.0 mg/dl

Metabolism of bilirubin

  • Bilirubin is a bile pigment produced by the breakdown of red blood cells
  • Bilirubin is conjugated within the liver by the enzyme UDP-glucuronyl transferase
    • Conjugated bilirubin is water soluble
  • It is then secreted into bile
  • Bilirubin enters the intestinal tract via bile
    • The intestinal bacteria converts it into urobilinogen
  • 80% of urobilinogen is then converted to stercobilinogen
  • 20% of urobilinogen is reabsorbed by enterocytes
    • Most of it is transported back to the liver – enterohepatic circulation
    • Some of it is filtered into the kidney

Causes of jaundice

Pre-hepatic

  • Jaundice is due to excessive hemolysis which overwhelms the liver’s ability to conjugate bilirubin
  • Leads to unconjugated hyperbilirubinemia
  • Examples
    • Haemolytic anemia
    • Gilbert’s syndrome – decreased glucuronyl transferase
    • Criggler-Najjar syndrome – absent glucuronyl transferase

Hepatocellular

  • Jaundice is due to dysfunction of the hepatocytes – the liver loses its ability to conjugate bilirubin
  • In a cirrhotic liver, there is also compression of the intra-hepatic biliary tree – leading to obstruction
  • For this reason, there is increase in both unconjugated and conjugated bilirubin in the blood
  • Examples
    • Alcoholic liver disease
    • Viral and autoimmune hepatitis
    • Primary sclerosing cholangitis
    • Hepatocellular carcinoma

Post-hepatic (obstructive)

  • Obstruction of biliary drainage
  • Because the liver has already conjugated the bilirubin there will be conjugated hyperbilirubinemia
  • Examples
    • Intraluminal – gallstones
    • Intramural – cholangiocarcinoma, strictures
    • Extramural – pancreatic cancer, lymphomas
  • Causes ↑ALP and GGT

Clinical features

  • Yellowish discolouration of the sclera and skin
  • Dark urine
  • Pale, fatty stools
  • Itchiness

Investigations

Blood markers

  • AST:ALT ratio – over 2 indicates alcoholic liver disease; ratio of 1 indicates viral hepatitis
  • ALP – raised in biliary obstruction
    • Isolated rise in ALP without GGT elevation – indicates malignancies
  • GGT – more specific for biliary obstruction than ALP

Liver screen

  • Hepatitis – A, B, C, E
  • CMV, EBV

Imaging

  • Ultrasound abdomen
  • MRCP – to visualise biliary tree
  • Liver biopsy

Treatment

  • Depends on the underlying cause

Obstructive jaundice

  • ERCP – to remove gallstone
  • Stenting of the common bile duct
  • Symptomatic treatment for itching – cholestyramine, antihistamine
  • Manage coagulopathy – vitamin K, fresh frozen plasma
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