6 Hepatic Encephalopathy

Recognizing hepatic encephalopathy

Hepatic encephalopathy (HE) is brain dysfunction associated with liver impairment or portosystemic shunting. It is a clinical diagnosis: altered mental status in a person with cirrhosis should prompt assessment for HE, while also prompting consideration of other causes.

Management brings together appropriate triage, investigation and treatment of precipitating factors, and HE-directed therapy.

Grading severity

The West Haven criteria help describe severity. Grade II or higher is generally considered overt HE.

Disorientation to time, lethargy, and asterixis are typical of grade II. Asterixis is a useful clue, but it is not specific to HE. Grade III involves marked confusion or somnolence with gross disorientation; grade IV is coma.

Prioritizing urgent assessment

When a patient with cirrhosis is difficult to arouse and responds only to strong stimulation, treat the presentation as severe HE, likely grade III. Urgently assess airway protection and the appropriate level of care; high-grade HE may require step-down or intensive care. Also evaluate for other urgent causes of altered consciousness.

In acute confusion, use severity to guide triage, but do not assume HE is the only possible explanation.

Finding and treating precipitants

Look for and address factors that can precipitate or worsen overt HE. Examples include:

• Infection, including spontaneous bacterial peritonitis

• Gastrointestinal bleeding

• Constipation

• Dehydration or excessive diuresis

• Electrolyte or renal abnormalities

• Sedating medications such as opioids or benzodiazepines

• Missed HE medication

If a patient with cirrhosis and ascites develops new confusion and fever, promptly evaluate for infection. Diagnostic paracentesis is important in a patient with ascites. Infection is a common precipitant, so treating it is part of treating the HE episode; assess for other infections and contributing factors as well.

Address the cause rather than treating mental-status changes with lactulose alone.

Interpreting ammonia results

An elevated serum ammonia level alone should not establish the diagnosis of HE, grade its severity, or guide treatment. A normal ammonia result in a confused patient should prompt careful consideration of alternative or additional causes.

Applying treatment principles

Lactulose is a core treatment for overt HE. Titrate it to about 2–3 soft bowel movements daily, avoiding excessive diarrhea because it can cause dehydration.

If HE recurs despite maintenance treatment, reassess adherence and search again for precipitating factors. Rifaximin may be added for recurrence despite lactulose and is also used to help prevent further episodes.