Jaundice

Question 1

when does it clinically manifest?

Answer 1

when serum billirubin >3mg/dL

Question 2

outline billirubin metabolism

Answer 2

Unconjugated = indirect bilirubin

• RBCs break down in spleen. Haem –> bilirubin –> bound w albumin = unconjugated bilirubin ie INDIRECT bilirubin
• High molecular weight & water insoluble, therefore cannot be filtered by kidneys

Conjugated= Direct bilirubin

• Unconjugated then travels to liver where it is conjugated to glucuronic acid in hepatocytes, then secreted through hepatic ducts into gall bladder where forms part of bile. When food enters SI, bile secreted through CBD and goes into SI. In SI, converted into urobilinogen then stercobilin, which gives faeces characteristic brown colour
• Conjugated bili has low molecular weight so is water soluble

Question 3

Causes of pre-hepatic jaundice?

Answer 3

• haemolytic anaemia
• haemolysis post-massive transfusion

Question 4

what picture is seen on LFTs in pre-hepatic jaundice?

Answer 4

• rise in unconjugated bilirubin
• ALT & AST: normal
• ALP: normal
• urine & stools normal

Question 5

pathophysiology of Hepatocellular jaundice- 2 options.

Answer 5

1. sub optimal function of hepatocytes –> build up of unconjugated billirubin
2. hepatocytes swollen –> bile ducts compressed –> degree of intrahepatic biliary obstruction–> rise in conjugated billirubin

Question 6

causes of hepatocellular jaundice?

Answer 6

• viral hepatitis
• liver cirrhosis & liver failure
• drug induced & liver toxins

Question 7

what picture is seen on LFTs in hepatocellular jaundice?

Answer 7

• bilirubin- direct & indirect
• ALT & AST: markedly increased
• ALP: mild increase
• urine dark
• stool depends on degree of biliary obstruction

Question 8

causes of post-hepatic jaundice?

Answer 8

• CBD stones
• CBD strictures
  
  • usually malignant (cholangiocarcinoma)
• other malignancies
  
  • periampullary & carcinoma of head of pancreas

Question 9

what picture is seen on LFTs in post-hepatic jaundice?

Answer 9

• conjugated billirubin raised
• ALT & AST: mild increase
• ALP: markedly raised
• urine: dark
• stools: pale

Question 10

how do you investigate someone w jaundice?

Answer 10

1. USS
   
   • shows whether biliary tree dilated / non-dilated
     
     • dilated: in diagram shown
     • non-dilated & no gallstone: liver biopsy

Question 11

purposes of an ERCP?

Answer 11

diagnostic AND therapeutic

• diagnostic: filling defects, biliary stricture, dilated biliary tree, biopsy
• therapeutic: sphincterotomy, biliary stent

Question 12

complications of ERCP?

Answer 12

• bleeding
• perforation
• cholangitis
• pancreatitis

Question 13

indications for pancreato-biliary endoscopic US?

Answer 13

• small pancreatic tumour <3cm
• small <4mm bile duct stones that would miss w MRCP

Question 14

risk factors for operative Mx?

Answer 14

• bleeding tendency
  
  • bile needed for vit K absorption, so need to correct this by giving IV vit K prior to intervention
• infections - give prophylactic Abx
• renal failure- hepatorenal syndrome
• hepatic failure