Hepatic Encephalopathy (HE) is a neuropsychiatric disorder resul t ing from liver failure. HE may be associated with fulminant (acute) hepatic failure or chronic liver disease with portal-systemic shunting. The latter condition is characterized neuropathologically by astro cytic rather than neuronal changes (Alzheimer Type II astrocytosis). The former is frequently accompanied by cerebral edema. Several hypotheses have been proposed to explain the pathogene sis of HE. These include: 1. A toxic action of a substance (or substances) such as ammonia on brain function 2. A deficit of cerebral...