Synopsis
Recognise overt hepatic encephalopathy, protect the deteriorating patient, identify reversible precipitants, and prevent recurrence without mistaking a clinical syndrome for an ammonia result.
- Hepatic encephalopathy is a clinical neuropsychiatric syndrome caused by liver insufficiency or portosystemic shunting after competing explanations have been considered.
- Asterixis supports metabolic encephalopathy but is neither specific to liver disease nor reliably present in deep coma.
- Search actively for infection, gastrointestinal bleeding, constipation, dehydration, acute kidney injury, electrolyte disturbance and medicines that depress cognition.
- A venous ammonia concentration does not confirm, exclude or grade overt encephalopathy; a normal result should prompt diagnostic reconsideration.
- Lactulose is titrated to regular soft stools, not profuse diarrhoea, because over-treatment can worsen dehydration, hypokalaemia and encephalopathy.
- Rifaximin is used with specialist oversight to reduce recurrent overt episodes, commonly alongside lactulose, rather than to replace precipitant treatment.
- Avoid routine protein restriction; provide adequate energy and protein with dietetic help because sarcopenia reduces extrahepatic ammonia handling.
- Recurrent or persistent encephalopathy should trigger review of adherence, constipation, sedating medicines, large spontaneous shunts, TIPSS and transplant suitability.
Key red flags
Disorientation to time or place, inappropriate behaviour, lethargy and asterixis suggest overt encephalopathy, but fever, focal signs, head injury or meningism should redirect urgent investigation.
Marked somnolence, absent protective reflexes, recurrent vomiting or coma creates aspiration risk. Escalate early for airway protection and monitored care rather than repeatedly giving oral treatments.
A focal deficit, unequal pupils, seizure, sudden severe headache, trauma or prolonged failure to improve is atypical and may justify urgent brain imaging or neurological review.
Investigation priorities
Detect immediately reversible coma and quantify acute physiological compromise.
Management branches
A person with cirrhosis or portosystemic shunting develops new disorientation, somnolence or coma.
- Perform ABCDE assessment, check glucose, record Glasgow Coma Scale and West Haven features, obtain intravenous access, and call for senior help if airway protection is doubtful.
- Stop or withhold non-essential sedatives and nephrotoxic or volume-depleting medicines while assessing bleeding, sepsis, renal injury, electrolyte imbalance and recent alcohol or drug exposure.
- Start enteral lactulose when the airway and route are safe, using local guidance for an alternative route if swallowing is unsafe, while treating each identified precipitant in parallel.
- Escalate grade III–IV disease, shock, respiratory compromise, acute liver failure or failure to improve to critical care and the regional hepatology or transplant service.