Hepatic encephalopathy
A disturbance of brain function caused by liver failure, in which toxins the liver would normally clear — especially ammonia — build up and affect the brain. It ranges from subtle confusion and drowsiness to a characteristic hand-flap and, at its most severe, coma, and needs prompt treatment.
What it is
Hepatic encephalopathy is a decline in brain function that happens when the liver can no longer clear toxins from the blood. Normally the liver removes substances absorbed from the gut, chief among them ammonia; when the liver is severely damaged (as in cirrhosis or acute liver failure), or when blood bypasses it through abnormal channels, these toxins accumulate and reach the brain, disturbing how it works. It occurs across a spectrum. In its mildest form the changes are subtle — poor concentration, altered sleep, small changes in personality. As it worsens, there is confusion, disorientation, daytime sleepiness and drowsiness, a distinctive flapping tremor of the outstretched hands (asterixis), and slurred speech; at its most severe it progresses to marked confusion, unresponsiveness and coma. In people with chronic liver disease, an episode is often set off by a trigger: an infection, gastrointestinal bleeding, constipation, dehydration, certain medications (especially sedatives), or an electrolyte disturbance. It is diagnosed clinically, in the context of known or suspected liver disease; a raised blood ammonia supports it but is not essential and does not track severity reliably. Treatment targets the trigger and lowers ammonia — most commonly with lactulose (which clears the gut) and sometimes the antibiotic rifaximin. It is usually reversible when treated, but signals advanced liver disease.
Key lab markers
- Ammonia — often raised; supports the diagnosis, though it does not reliably reflect severity and is not needed to diagnose.
- Bilirubin — raised, reflecting the underlying liver failure.
- Albumin — low, reflecting poor liver synthetic function.
- INR / prothrombin time — prolonged, another sign of failing liver function.
- Sodium, potassium and kidney function — electrolyte disturbances are common triggers.
- Full blood count and CRP — look for infection, a frequent trigger.
Symptoms
- Confusion and disorientation
- Difficulty concentrating and changes in personality or mood
- Daytime sleepiness, drowsiness and reversed sleep pattern
- A flapping tremor of the outstretched hands (asterixis)
- Slurred speech and clumsiness
- In severe cases, marked confusion, unresponsiveness and coma
- Usually in someone with known chronic liver disease, often with a trigger (infection, bleeding, constipation)
Related symptoms
Related lab panels
When to discuss with a doctor
Hepatic encephalopathy is a serious complication of liver failure and needs prompt medical attention. In someone with known liver disease, new confusion, marked drowsiness, a change in behaviour or a flapping hand tremor should be treated as a possible episode and assessed urgently, because it is usually reversible when the trigger (such as an infection, bleeding or constipation) is found and treated and ammonia is lowered. Increasing drowsiness, unresponsiveness or coma is an emergency. Because sedative medications and dehydration can precipitate it, these are reviewed. The appearance of encephalopathy also signals advanced liver disease that needs specialist care, including consideration of transplantation. Mediora.AI can surface the failing-liver pattern (a raised bilirubin, low albumin, prolonged INR and raised ammonia) that provides the backdrop, but new confusion or drowsiness in someone with liver disease needs urgent in-person assessment.