Paper II — 2024 December (Supplementary) (2019 Scheme) — Qxvi
3 min read
Paper II
2024 December (Supplementary) (2019 Scheme) · 100 marks · 180 min
Question
Assertion (A): Lactulose is used in hepatic encephalopathy.
Reason (R): Lactulose is neither digested not absorbed in the small intestine, therefore retains water
and produces soft formed stools by osmotic action.
a) Both A and R are true, and R is the correct explanation of A
c) A is true, but R is false
b) Both A and R are true, and R is not the correct explanation of A
d) A is false, but R is true
Qxvi1 marksMCQs
Answer
Correct answer: b) Both A and R are true, and R is not the correct explanation of A
Both statements are factually true, but R does not correctly explain A. R correctly describes lactulose’s osmotic laxative mechanism, but this is not why it is used in hepatic encephalopathy specifically — the actual reason is that colonic bacteria ferment lactulose to lactic/acetic acid, acidifying the colon and trapping absorbable ammonia (NH3) as non-absorbable ammonium (NH4+) for excretion, lowering blood ammonia. The laxative effect (faster transit) is a secondary contributor, not the primary explanation for A.
