Hepatic encephalopathy

The association between liver disease and mental disorders has been recognized since the time of Hippocrates. Galen, a Roman physician of the 2nd century, described neurologic and psychiatric symptoms resulting from brain diseases and from diseases of other organs, including the liver. Morgagni, the father of pathologic anatomy, described the relation between liver failure and mental disorder in the 18th century. In one of his case reports, Morgagni described an alcoholic man with a history of abdominal pain and delirium who died in coma. Autopsy showed liver cirrhosis, but the brain was grossly normal. Further studies of hepatic encephalopathy continued in the 19th century. The works in which the modern concepts of hepatic encephalopathy are based were published in the 1950s.^[1]

Hepatic encephalopathy is not an inherited condition, so an individual who has it cannot pass it on to his/her children. It is brought on by chronic liver failure, particularly in alcoholics with cirrhosis.^[2]

Although there are many theories and possibilities regarding what exactly causes hepatic encephalopathy, it is thought that one of the main causes is the accumulation of ammonia in the blood, which the liver, damaged by alcoholic liver disease, cannot remove. Researchers have found that ammonia alters the expression of certain genes; the genes that may be affected carry instructions for brain proteins.^[2] When the instructions in these genes are not "followed" correctly by the body due to the altered expression of the genes, the cells in the brain can no longer function normally, which may contribute to the signs and symptoms of the disease. However, the genes themselves are not changed in such a way that these changes are passed down to an individual's children.