Loss of brain function occurs when the liver is unable to remove toxins from the blood. This is called hepatic encephalopathy (HE). This problem may occur suddenly or it may develop slowly over time.
An important function of the liver is to make toxic substances in the body harmless. These substances may be made by the body (ammonia), or substances that you take in (medicines).
When the liver is damaged, these "poisons" can build up in the bloodstream and affect the function of the nervous system. The result may be HE.
HE can occur suddenly and you may become ill very quickly. Causes of HE may include:
People with severe liver damage often suffer from HE. The end result of chronic liver damage is cirrhosis. Common causes of chronic liver disease are:
Once you have liver damage, episodes of worsening brain function may be triggered by:
Disorders that can appear similar to HE may include:
In some cases, HE is a short-term problem that can be corrected. It may also occur as part of a long-term (chronic) problem from liver disease that gets worse over time.
Symptoms of HE are graded on a scale of grades 1 to 4. They may begin slowly and worsen over time.
Early symptoms may be mild and include:
Severe symptoms may include:
People with HE can become unconscious, unresponsive, and possibly enter a coma.
People are often not able to care for themselves because of these symptoms.
Signs of nervous system changes may include:
Tests done may include:
Treatment of HE depends upon the cause.
If changes in brain function are severe, a hospital stay may be needed. In the hospital:
Medicines are given to help lower ammonia level and improve brain function. Medicines given may include:
You should avoid:
Your health care provider may suggest other medicines and treatments. These may have varying results.
The outlook of HE depends on the management of cause of HE. Chronic forms of the disorder often continue to get worse and come back.
The first two stages of the disease have a good prognosis. Stage three and four have a poor prognosis.
Call your provider if you or people around you notice any problems with your mental state or nervous system function. This is important for people who already have a liver disorder. HE can get worse quickly and become an emergency condition.
Treating liver problems may prevent HE. Avoiding heavy drinking and intravenous drug use can prevent many liver disorders.
Reviewed By: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.