Jaundice and LFTs.

Question 1

Define jaundice. (5)

Answer 1

A clinical manifestation of raised bilirubin. It is a breakdown product of haem and exists in an unconjugated state bound to albumin until the liver can conjugate it and excrete it in this soluable form.

Question 2

Describe pre-hepatic jaundice. (4)

Answer 2

Caused by too much haem breakdown. Livers ability to conjugate is fine, there’s just too much - raised levels of unconjugated bilirubin.
Common in sickle-cell, thalassaemias.

Question 3

Describe hepatic jaundice. (5)

Answer 3

Reduced ability of the liver to conjugate haem due to damage to hepatocytes, leading to a mixed picture of conjugated and unconjugated.
Can be caused by cirrhosis (alcoholic liver disease, autoimmune hep, Wilson’s) or acutely (paracetamol toxicity, acute hep infection).

Question 4

Describe post-hepatic jaundice. (6)

Answer 4

Obstruction to the outflow pathway (gallstones), so raised conjugated bilirubin.
Can cause dark urine and pale stools (no bile entering duodenum, all existing in the blood).
Commonly caused by gallstones but also malignancy pressing on the bile duct, biliary strictures.

Question 5

Describe albumin as a liver function test. (3)

Answer 5

Used to assess the synthetic function of the liver as important for oncotic capillary pressure.
Remember the liver could be fine but there could be severe albuminuria like in nephrotic syndrome.

Question 6

Describe ALT and AST as liver function tests. (5)

Answer 6

Alanine transaminase and aspartate transaminase indicate damage to helpatocytes.
ALT>AST rise in acute damage.
AST>ALT rise in chronic damage esp alcohol.

Question 7

Describe ALP as a liver function test. (5)

Answer 7

Alkaline phosphatase
Indicates damage to cells lining the bile duct so go up in bile obstruction (ie post hepatic).
Also an indicator of bone turnover - need to specify a liver cause of raised ALP with a Gamma GT.

Question 8

Describe a clinical picture seen in pre-hepatic. (3)

Answer 8

High unconjugated bilirubin
Other LFTs normal
Assocaited anaemia

Question 9

Describe a clinical picture seen in hepatic. (3)

Answer 9

Mispxed bilirubin.
High AST and ALT
Normal ALP

Question 10

Describe a clinical picture seen in post-hepatic. (2)

Answer 10

High conjugated bilirubin

Raised ALP with Gamma GT.