A syndrome characterized by central nervous system dysfunction in association with liver failure, including portal-systemic shunts. Clinical features include lethargy and confusion (frequently progressing to coma); ASTERIXIS; nystagmus, pathologic; brisk oculovestibular reflexes; decorticate and decerebrate posturing; muscle spasticity; and bilateral extensor plantar reflexes (see reflex, babinski). electroencephalography may demonstrate triphasic waves. (From Adams et al., Principles of neurology, 6th ed, pp1117-20; Plum & Posner, diagnosis of stupor and coma, 3rd ed, p222-5)