The liver acts like the body's filtration plant, clearing many substances from the blood. One of its key jobs is handling waste products such as ammonia, which is made when gut bacteria break down protein. When the liver's capacity falls — because of cirrhosis, major liver surgery, or a tumour — these substances are no longer fully filtered and build up in the blood. When they reach the brain and cloud thinking and awareness, the condition is called hepatic encephalopathy, sometimes described as "hepatic coma."
Symptoms range widely, from very mild to severe. Early on, a person may reverse day and night, speak less than usual, struggle to concentrate, or become clumsy with numbers or handwriting. If they hold their arms out with the wrists cocked back, a flapping tremor of the hands (asterixis) may appear. As it progresses, they may fail to recognise people, say things that don't make sense, grow increasingly sleepy, and in severe cases barely respond even when woken.
These changes are easy to mistake for ageing or dementia, but hepatic encephalopathy differs in that it fluctuates — improving and worsening within a single day — and tracks with liver function and triggers. Constipation, dehydration, infection, gastrointestinal bleeding, certain medicines, electrolyte imbalance, or a sudden large protein intake can all act as triggers that make it worse quite suddenly.
The main principle of treatment is to reduce the ammonia that has built up in the body. This is why a hospital may give an enema or a laxative such as lactulose. These make the bowel acidic and increase bowel movements, helping ammonia leave the body before it is absorbed. When needed, an antibiotic such as rifaximin may be used to reduce the gut bacteria that produce ammonia, alongside correcting triggers such as constipation or infection. When the cause is well managed, many people recover substantially — though it is also a sign that the liver is under real strain.
If you are caring for someone at home or on the ward and they suddenly slur their words, become confused about the time or place, or grow unusually sleepy and hard to wake, it is worth telling the care team. Sharing what they have eaten, how many days since their last bowel movement, and whether there has been any fever or other new symptom can help find the cause.
This article is for general information and does not replace an individual's diagnosis or treatment. Symptoms and responses differ from person to person, so please discuss any specific decisions with your treating doctor.