[Hepatic encephalopathy]

Hepatic encephalopathy (HE) is a neuropsychiatric complication of acute and chronic liver disease. Its etiology and pathogenesis are thought to be a complex, metabolically induced, and therefore potentially reversible disturbance in brain functions. The diagnosis is based on demonstrating both a disorder of the central nervous system and a concomitant liver disease as well as the exclusion of any neurological or psychiatric disorder of other etiology. The diagnosis of HE is clinical and displays a wide spectrum of neuropsychiatric symptoms in different degrees of severity. Ancillary diagnostic workup includes laboratory tests, neuroimaging, and neurophysiological exams such as electroencephalography and evoked potentials. The therapy of HE mainly consists of treatment and avoidance of any precipitating conditions such as high protein intake, infections, and gastrointestinal bleeding. Other therapeutic approaches modulate metabolic processes such as ammonium synthesis and excretion, formation of neurotransmitters, and as a last resort liver transplantation. The prognosis depends ultimately on the course of the liver disease.