B. Pathogenesis of HE hE is a neuropsychical disturbance The following features may Imply hE is mainly caused by the metabolic and functional disturbance of the brain Reversibility of symptoms 2) Dissemination of disease region 3)No clear evidence of morphologic alteration 4) Accompanied with biochemical abnormalit9 B. Pathogenesis of HE HE is a neuropsychical disturbance. The following features may imply HE is mainly caused by the metabolic and functional disturbance of the brain: l ) Reversibility of symptoms 2) Dissemination of disease region 3) No clear evidence of morphologic alteration 4) Accompanied with biochemical abnormality