Hepatic Encephalopathy

Alternative names:

encephalopathy - hepatic; hepatic coma

Definition:

A group of symptoms that may occur when there is damage to the brain and nervous system as a complication of liver disorders, characterized by various neurologic symptoms including changes in consciousness, behavior changes, and personality changes.

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 bypasses the liver. The exact cause of the disorder is unknown. The liver cannot properly metabolize and detoxify substances in the body. Accumulation of toxic substances causes metabolic abnormalities that lead to damage in the central nervous system (brain and spinal cord). The most common toxic substance is ammonia, which is produced by the body when proteins are digested, but normally is detoxified by the liver. Many other substances also accumulate in the body and damage the nervous system.

In people with otherwise stable liver disorders, hepatic encephalopathy may be triggered by episodes of gastrointestinal bleeding, excessive dietary protein, or electrolyte abnormalities (especially decrease in potassium, which may result from vomiting or treatments such as diuretics or paracentesis). The disorder may also be triggered by any condition that results in alkalosis (alkaline blood pH), low oxygen levels in the body, use of medications that suppress the central nervous system (such as barbiturates or Benzodiazepine tranquilizers), infections including viral hepatitis, bile duct obstruction, surgery, or any coincidental illness.

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

Hepatic encephalopathy occurs in approximately 4 out of 100,000 people. It may occur as an acute, potentially reversible disorder or as a chronic, progressive disorder.