[Definitions and criteria for acute and chronic portal systemic encephalopathy]

Hepatic encephalopathy is a neuropsychiatric syndrome that develops secondary to acute or chronic liver disease. Three variants have been recognized: acute, chronic and subclinical. Acute encephalopathy occurs in fulminant liver failure and in chronic liver disease which is decompensated by external or internal factors. Chronic encephalopathy is associated with terminal liver disease. The encephalopathy that is not identified by ordinary clinical studies and requires specific psychometric tests and visual evoked potentials is called subclinical encephalopathy. Some clinical, biochemical and pathological features distinguishing acute from chronic encephalopathy are reviewed.