Hepatic Encephalopathy
A cirrhosis patient suddenly can't write their name legibly — this isn't dementia or a stroke. The ammonia building up in their blood is hijacking their brain, and your interventions determine whether it reverses.
Core Concept
Hepatic encephalopathy (HE) occurs when the failing liver cannot convert ammonia to urea for renal excretion. Ammonia crosses the blood-brain barrier and disrupts neurotransmission, producing a spectrum of neuropsychiatric changes graded Stage I through Stage IV. Stage I presents as mild confusion, sleep-wake reversal, and irritability — easy to miss. Stage II brings asterixis (liver flap), lethargy, and disorientation. Stage III shows somnolence, gross confusion, and hyperreflexia. Stage IV is unresponsive coma. Serum ammonia levels above 35–45 mcg/dL support the diagnosis, but severity correlates poorly with the exact number — clinical staging guides management more than the lab value. First-line treatment is lactulose, an osmotic laxative that traps ammonia in the colon as ammonium and promotes its excretion in stool. The dose is titrated to produce 2–3 soft stools per day. Rifaximin, a non-absorbable antibiotic, is added to reduce ammonia-producing gut bacteria. Nursing priorities include monitoring neurological status serially, instituting fall and aspiration precautions, and restricting dietary protein only in acute episodes — chronic protein restriction is no longer recommended because it worsens malnutrition.
Watch Out For
Don't confuse asterixis (flapping tremor elicited with wrists dorsiflexed) with a seizure or essential tremor — it is characteristic of metabolic encephalopathies, including hepatic. Students assume high-protein diets cause HE; actually, common triggers are GI bleeding, infection, constipation, and hypokalemia/alkalosis. Lactulose's goal is 2–3 stools/day — diarrhea beyond this causes dehydration and worsens encephalopathy, not improves it.
Clinical Pearl
Lactulose = laxative for the brain. If the patient isn't having 2–3 soft stools daily, ammonia isn't leaving — titrate accordingly.
Test Your Knowledge
3 quick questions — see how well you understood Hepatic Encephalopathy