Gastroenterology

Question 1

What drugs cause a mixed LFT derangement with a R factor 2-5?

Answer 1

Carbamazepine
Lamotrigine
Phenytoin
Sulphonamides

Question 2

What drugs cause a hepatocellular pattern of LFT derangement with R factor > 5?

Answer 2

Paracetamol
Statins
Isoniazid
Rifampicin
Lamotrigine, diclofenac, disulfram, pyrazinamide

Question 3

What are the causes of an acute transaminitis which would result in ALT / AST rise >1000?

Answer 3

1. Ischaemic hepatitis - typically associated pre-renal AKI and elevated LDH
2. Viral hepatitis
3. Drug induced hepatitis - paracetamol
4. Hepatic vein thrombosis

Question 4

How is the R factor calculated and what does it indicate?

Answer 4

R factor = ALT / ULN divided by ALP / ULN

Ratio <2 suggests a cholestatic pattern of injury
Ratio > 5 suggests hepatocellular injury
Ration 2-5 - mixed

Question 5

What causes an AST: ALT ratio of 2:1?

Answer 5

AST: ALT ratio >2 suggestive of alcoholic liver disease, especially if GGT also elevated. If ratio >3, highly suspicious for alcoholic liver disease.

AST : ALT ratio occassionally also elevated in patients with non-alcoholic steatohepatitis
AST: ALT ratio elevated (although not greater than 2) in patients with hepatitis C who develop cirrhosis
Patients with Wilson’s disease or cirrhosis due to viral hepatitis may also have AST > ALT (although ratio not typically >2)

Question 6

What drugs cause a cholestatic pattern of LFT derangement with R factor <2?

Answer 6

Augmentin
Flucloxacillin
Penicillins
Cephalosporins
Androgens
OCP
Erythromycin