Clinical and experimental aspects of hepatic encephalopathy

Hepatic encephalopathy (HE) is a neuropsychiatnc syndrome associated with severe liver disease. Clinical symptoms range from minimal changes in mental state and neuromuscular defects to unresponsive coma. 1-' The syndrome of HE can be divided into three major groups: HE associated with liver cirrhosis, HE associated with acute liver necrosis and HE associated with errors of metabolism (table I). HE is most often observed in patients with cirrhosis of the liver, either as a result of decreased hepatic parenchymal function or as a result of increasing portal-systemic shunting without liver insufficiency (also defined as portal-systemic encephalopathy 1 - ')_ In patients with cirrhosis, HE can be induced or aggravated by a number of precipitating factors (table 2). ' HE associated with acute liver necrosis has a dramatic clinicaJ course, leading to acute liver failure in most patients. Apart from jaundice, HE can be the first alarming symptom of acute liver failure. The degree of HE is a strong predictor of outcome in acute liver failure~ patients who only reach grade II HE have a possibility of spontaneous recovery of 65 - 70 %; with grade III HE it is 40 - 50 % and in grade IV HE it is only 20 %. In the majority of patients with grade III HE cerebral edema is present, which can evolve to an increase in intracranial pressure, cerebral herniation and death. '