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Hepatic encephalopathy

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Definition:

Hepatic encephalopathy is brain and nervous system damage that occurs as a complication of liver disorders. It causes different nervous system symptoms including changes in reflexes, changes in consciousness , and behavior changes that can range from mild to severe.

Alternative Names:

Hepatic coma; Encephalopathy - hepatic

Causes, incidence, and risk factors:

Hepatic encephalopathy is caused by disorders affecting the liver. These include disorders that reduce liver function (such as cirrhosis or hepatitis ) and conditions where blood circulation does not enter the liver. The exact cause of hepatic encephalopathy is unknown.

However, when the liver cannot properly metabolize and and turn poisons into harmless substances in the body, these poisons build up in the bloodstream. One substance believed to be particularly harmful to the central nervous system is ammonia , which is produced by the body when proteins are digested. Ammonia is normally made harmless by the liver. Many other substances may also accumulate in the body if the liver is not working well. They add to the damage done to the nervous system.

In people with otherwise stable liver disorders, hepatic encephalopathy may be triggered by gastrointestinal bleeding, eating too much protein, infections, renal disease, procedures that bypass blood past the liver, and electrolyte abnormalities (especially a decrease in potassium). A potassium decrease may result from vomiting, or treatments such as paracentesis or taking diuretics ("water pills").

Hepatic encephalopathy may also be triggered by any condition that results in alkalosis , low oxygen levels in the body, use of medications that suppress the central nervous system (such as barbiturates or benzodiazepine tranquilizers), surgery, and sometimes by co-occurring illness.

Disorders that mimic or mask symptoms of hepatic encephalopathy include alcohol intoxication , sedative overdose, complicated alcohol withdrawal , Wernicke-Korsakoff syndrome , subdural hematoma , meningitis , and metabolic abnormalities such as low blood glucose .

Hepatic encephalopathy may occur as an acute , potentially reversible disorder or as a chronic , progressive disorder associated with chronic liver disease.

• Review Date: 10/13/2006
• Reviewed By: Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-Torresdale Hospital, Jefferson Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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