Gastroenterology & Hepatology · NEET PG Preparation Medicine
A 60-year-old male with long-standing cirrhosis of the liver presents with confusion, slurred speech, and inverted sleep-wake cycle. On examination,…
Practice question from Gastroenterology & Hepatology (NEET PG Preparation Medicine), with the correct answer and a step-by-step solution.
easy · MCQ · Q-1795E4
A 60-year-old male with long-standing cirrhosis of the liver presents with confusion, slurred speech, and inverted sleep-wake cycle. On examination, he has grade 2 hepatic encephalopathy and asterixis. Serum ammonia is significantly elevated. Which of the following is the primary mechanism of action of lactulose in the management of this condition?
- A.Acidification of the colonic lumen converting NH3 to NH4+Correct answer
- B.Direct systemic inhibition of urease-producing bacteria in the stomach
- C.Competitive inhibition of GABA receptors in the central nervous system
- D.Chelation of circulating blood ammonia in the portal circulation
Solution
Lactulose is a non-absorbable disaccharide that is metabolized by colonic bacteria into short-chain fatty acids, acidifying the gut lumen. This converts freely diffusible ammonia (NH3) into the ionized, non-absorbable form (NH4+), which is then excreted in the feces.
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