ICU · Hepatobiliary / neurocritical care

Hepatic Encephalopathy — Ammonia, Lactulose, Rifaximin & the Precipitant

Also known as Hepatic encephalopathy · HE · Portosystemic encephalopathy · Ammonia · Asterixis · West Haven grade · Lactulose · Rifaximin · L-ornithine L-aspartate · LOLA · Astrocyte swelling · Cerebral oedema · Acute liver failure

The hepatic encephalopathy (HE) is a reversible syndrome of the impaired brain function in the patient with the advanced liver failure and the portosystemic shunting. The pathophysiology centres on the ammonia (the gut-derived ammonia bypasses the liver, crosses the blood-brain barrier, and is converted to the glutamine in the astrocytes, causing the astrocyte swelling and the cerebral oedema). In the chronic liver disease, the HE is precipitated (the GI bleed, the infection, the constipation, the hypokalaemia and the alkalosis, the dehydration, the sedatives); finding and treating the precipitant is the most important step. The treatment: the lactulose (the first-line, titrated to soft stools), the rifaximin (550 mg BD, the add-on for the recurrent), the L-ornithine L-aspartate; the adequate protein (1.2 to 1.5 g/kg/day, NOT the restriction — an old myth); and the avoidance of the sedatives and the benzodiazepines. In the acute liver failure, the HE is from the acute necrosis, the cerebral oedema is the major threat, and the emergency transplant is the consideration. The West Haven classification grades the HE from I (the mild confusion) to IV (the coma).

Checked against its sources on 3 Sept 2026