A liver which is failing cannot carry out its functions of inactivating and detoxifying certain substances, nor can it metabolize other substances. The hepatic encephalopathy that results brings about changes in consciousness behavior and neurological status. Ammonia is formed predominantly in the gastro intestinal tract as a result of protein break down and gastro intestinal bleeding and preoduction by gut bacteria. The ammonia crosses the blood brain barrier to bring about changes.
Hepatic encephalopathy is a worsening of brain function that occurs when the liver is no longer able to remove toxic substances in the blood. Hepatic encephalopathy is caused by disorders that affect the liver. These include disorders that reduce liver function (such as cirrhosis or hepatitis) and conditions in which blood circulation does not enter the liver.