Which intervention is primarily used to prevent further uptake of ammonia in patients with hepatic encephalopathy?

• A. Diamox
• B. Lactulose
• C. Allopurinol
• D. Acyclovir

Answer: (B)

In patients with hepatic encephalopathy, lactulose is primarily used to prevent further uptake of ammonia. Hepatic encephalopathy occurs due to the accumulation of ammonia and other toxins in the bloodstream, which the impaired liver is unable to detoxify.

Lactulose is a synthetic disaccharide that is not absorbed in the intestine and acts as an osmotic laxative. When administered, it is metabolized by colonic bacteria into short-chain fatty acids, which decreases the pH of the colon. This acidic environment promotes the conversion of ammonia (NH3), which is more readily absorbed, into ammonium (NH4+), which cannot easily cross the intestinal mucosa. Consequently, this process reduces the serum ammonia levels by trapping ammonia in the form of ammonium, allowing for its elimination through the feces.

Thus, lactulose effectively reduces the absorption of ammonia from the gut and helps alleviate the neurological symptoms associated with hepatic encephalopathy. Its role is critical in the management of this condition, and its use is supported by clinical guidelines.