Gastrointestinal & Hepatic · Topic 7 of 26

Hepatic Encephalopathy

Hepatic · complication of cirrhosis

Hepatic Encephalopathy

A clinical diagnosis: exclude mimics, fix the precipitant and give lactulose to 2–3 soft stools — the ammonia level does not guide care.

Key numbers

Find and treat the precipitant~90% resolve with it

Lactulose to 2–3 soft stools daily2–3 soft stools/day

Add rifaximin 550 mg twice dailyrifaximin 550 mg BID

01 · CauseFind and treat the precipitant

Almost every episode has a trigger — infection, GI bleeding, hypokalemia or other electrolyte disorder, dehydration or overdiuresis, constipation, sedatives or alcohol; correcting it alone resolves about 90% of episodes.

02 · GiveLactulose to 2–3 soft stools daily

Lactulose is first-line for overt HE: 25 mL every 1–2 hours until at least 2 soft stools, then titrate to 2–3 soft bowel movements daily (by nasogastric tube or enema if the patient cannot swallow).

03 · The ruleAmmonia does not guide HE care

A high blood ammonia adds no diagnostic, staging or prognostic value in chronic liver disease and should not guide therapy; a normal ammonia in suspected overt HE calls the diagnosis into question.

What it is

Core idea

Covert HE needs psychometric testingCovert HE (minimal HE plus grade 1) has no disorientation or asterixis and is found by psychometric or neurophysiological tests; treatment is individualized (ACG 2026 conditionally suggests lactulose) — counsel the patient about driving.

Presentation

What you'll see

Asterixis: negative myoclonus, not HE-specificAsterixis is a flapping loss of postural tone elicited with arms outstretched and wrists dorsiflexed; it appears in early-to-middle stages of HE but also occurs in uremia, so it is not pathognomonic.

Diagnosis & monitoring

Work-up

Clinical diagnosis after excluding mimics must knowHepatic encephalopathy is a clinical diagnosis of exclusion in a patient with liver failure or portosystemic shunting: rule out hypoglycemia, intoxication or sedatives, hyponatremia, infection and subdural hematoma before attributing confusion to HE.

West Haven grades 1–4; overt starts at 2West Haven grading: 1 — sleep disturbance, short attention, mild tremor; 2 — lethargy, disorientation, asterixis; 3 — somnolence, gross confusion; 4 — coma. Disorientation or asterixis marks overt HE (grade 2 or higher).

Do right now

In this order

First moves

Grade 3–4 HE: ICU and airway protection

→

Clinical diagnosis after excluding mimics

→

Find and treat the precipitant~90% resolve with it

→

Lactulose to 2–3 soft stools daily2–3 soft stools/day

Why each step

Grade 3–4 HE: ICU and airway protectionPatients with high-grade HE who cannot protect their airway need ICU-level monitoring and airway protection; give oral therapy by nasogastric tube if aspiration risk prevents swallowing.

Clinical diagnosis after excluding mimicsHepatic encephalopathy is a clinical diagnosis of exclusion in a patient with liver failure or portosystemic shunting: rule out hypoglycemia, intoxication or sedatives, hyponatremia, infection and subdural hematoma before attributing confusion to HE.

Find and treat the precipitantAlmost every episode has a trigger — infection, GI bleeding, hypokalemia or other electrolyte disorder, dehydration or overdiuresis, constipation, sedatives or alcohol; correcting it alone resolves about 90% of episodes.

Lactulose to 2–3 soft stools dailyLactulose is first-line for overt HE: 25 mL every 1–2 hours until at least 2 soft stools, then titrate to 2–3 soft bowel movements daily (by nasogastric tube or enema if the patient cannot swallow).

Management

Orders

Add rifaximin 550 mg twice daily must knowAdd rifaximin 550 mg orally twice daily to lactulose when overt HE recurs despite lactulose (AASLD/EASL: after the second episode); ACG 2026 also suggests adding it during an acute overt episode.

Lactulose prophylaxis after the first episodeAfter a first overt episode continue lactulose as secondary prophylaxis; primary prophylaxis is not routinely needed, and prophylaxis may stop once precipitants are controlled or liver function improves.

Recurrent intractable HE: refer for transplantRecurrent intractable overt HE together with liver failure is an indication for liver transplant evaluation.

Red flags & don'ts

Avoid harm

Lactulose overuse: dehydration and hypernatremia complicationOverdosing lactulose causes aspiration, dehydration, hypernatremia and perianal skin breakdown and can itself precipitate HE; nonresponse calls for a search for missed precipitants, not ever-larger doses.

The rules

Know these

Do not restrict protein: 1.2–1.5 g/kg/dayDo not restrict protein: give 1.2–1.5 g/kg/day protein and 35–40 kcal/kg/day as small frequent meals with a late-evening snack — restriction worsens the malnutrition common in cirrhosis.

Covert or overt hepatic encephalopathy?

Commonly confused

Findings	Abnormal psychometric tests or subtle attention and sleep changes
How it is diagnosed	Psychometric or neurophysiological testing
Treatment	Individualized; lactulose may be offered

More detail

Reference

Show 5 reference facts

Neomycin and metronidazole are alternative agents for overt HE, but rifaximin is preferred because neomycin, an aminoglycoside, causes ototoxicity and nephrotoxicity.

High-volume (4 L) polyethylene glycol is an alternative to lactulose in acute overt HE; IV L-ornithine L-aspartate, oral branched-chain amino acids or zinc (if low) may be added for nonresponders.

Overt HE follows TIPS in 10–50% within a year; ACG 2026 recommends starting rifaximin 14 days before elective TIPS and continuing it at least 6 months; refractory cases may need shunt reduction.

HE types: A — acute liver failure (risk of cerebral edema and raised ICP); B — portosystemic shunting without liver disease; C — cirrhosis. Recurrent HE means episodes within 6 months.

Portosystemic shunting lets gut-derived toxins, chiefly ammonia, bypass hepatic clearance and reach the brain; lactulose acts as an osmotic cathartic and lowers colonic pH to reduce ammonia production.

Pearl

Treat the patient, not the ammonia: find the trigger, titrate lactulose to 2–3 soft stools, and add rifaximin after a recurrence.

Sources · Vilstrup H et al. Hepatic Encephalopathy in Chronic Liver Disease: 2014 Practice Guideline by the AASLD and EASL. Hepatology 2014;60:715–735 · Merck Manual Professional — Portosystemic Encephalopathy · Xifaxan (rifaximin) prescribing information — DailyMed (550 mg twice daily to reduce risk of overt HE recurrence) · Bajaj JS et al. ACG Clinical Guideline: Hepatic Encephalopathy. Am J Gastroenterol 2026;121(3):588–618 · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).