Lecture 13 Jaundice

Question 1

Jaundice

Answer 1

Yellow discolouration to eyes and skin due to raised bilirubin in blood

Question 2

Bilirubin

Answer 2

Breakdown product of haem

Question 3

Uncojugated bilirubin

Answer 3

Not water soluble therefore to travel in blood it must bind to albumin

Question 4

Excretion of bilirubin

Answer 4

Via urination and mostly defecation [makes faeces brown]

Question 5

Conjugation

Answer 5

Occurs in liver

Make bilirubin more water soluble

Question 6

Pre - hepatic jaundice

Answer 6

Increased degradation of Hb

Too much haem - increased demand on liver beyond conjugation capacity

• Raised blood bilirubin - unconjugated

Question 7

Hepatic jaundice

Answer 7

Reduced hepatocyte function due to damage

• reduced conjugating ability of the liver

Mix of unconjugate and conjugated bilirubin in blood

Question 8

Post- hepatic jaundice

Answer 8

Obstruction in bilirubin excretion pathway

Raised conjugated bilirubin in blood

Question 9

Causes pre-hepatic jaundice

Answer 9

Sickle cell anaemia
Thalassaemia
Spherocytosis

Haemolysis

Question 10

Neonatal jaundice

Answer 10

Unconjugated haem passes through the blood brain barrier to the brain causing brain damage

Question 11

Causes of hepatic jaundice

Answer 11

Cirrhosis:

• Alcoholic fatty liver disease
• Hepatitis B and C
• NAFLD
• Haemachromatosis
• Wilson’s disease
• Autoimmune

Acute liver damage:

• paracetamol toxicity
• acute viral hepatitis

Question 12

Signs of post hepatic jaundice

Answer 12

Conjugated bilirubin is water soluble therefore more is excreted by the kidneys

• dark urine
• pale stool

Question 13

Causes of post hepatic jaundice

Answer 13

Gall stones blocking cystic duct
Biliary stricture
Pathology of the head of the pancreas - carcinoma

Intrahepatic pathology compressing the intrahepatic bile ducts

• inflammation and oedema
• Primary or metastatic growth of tumour
• Scarring - cirrhosis

Question 14

Albumin

Answer 14

Marker for liver function

If liver function is reduced, less albumin is produced

• Low albumin causes ascites

Can also use INR to test liver function and liver produces clotting factors

Question 15

ALT

Answer 15

Hepatic enzyme
Hepatocyte damage increases ALT
More specific to the liver

If ALT rises more than AST - acute liver damage

Question 16

AST

Answer 16

Hepatic enzyme
Hepatocyte damage releases AST and ALP Therefore increases AST
Found in liver, cardiac muscle, skeletal muscle and RBCs

AST more than ALT - seen in cirrhosis and alcoholic hepatitis - chronic

Question 17

ALP

Answer 17

Alkaline phosphate

Found in cells lining the bile ducts

Increases in cholestasis - bile duct obstruction

High bone turnover in children can raise ALP

Question 18

Gamma GT

Answer 18

Used to specify source of raised ALP as liver

High ALP and gamma GT - post hepatic jaundice

Question 19

Presentation of prehepatic jaundice

Answer 19

Raised unconjugated bilirubin
Associated anaemia
No raised LFTs

Question 20

Presentation of hepatic jaundice

Answer 20

Mixed bilirubin
High ALT and AST
Normal ALP

Question 21

Presentation of post hepatic jaundice

Answer 21

Raised conjugated bilirubin
Raised ALP and Gamma GT
Normal ALT and AST