A progressive decline in alertness eventually leads to coma of varying degree. A majority of patients become totally unresponsive or responsive only to pain. Generalized hypertonia and hyperreflexia are the most common motor abnormalities, but focal motor deficits, including paresis and hemi- and tetraplegia, cranial nerve deficits and abnormal reflexes may also be present. Central hyperpnea, hypertension, pulmonary edema and urinary retention may also complicate the illness. Signs of extrapyramidal involvement, including tremor, mask-like facies, rigidity, and choreoathetoid movements are characteristics of JE, but these signs may be obscured by generalized weakness.
Treatment is supportive.
Overall, approximately one third of surviving patients exhibit serious, residual neurological disability. Principal sequelae include memory loss, impaired cognition, behavioral disturbances, convulsions, motor weakness or paralysis, and abnormalities of tone and coordination. Persistent EEG abnormalities are common in children. Clinical laboratory examination shows moderate peripheral leucocytosis with neurophilia and mild anemia. Neutrophils may predominate in early CSF samples but a lymphocytic pleocytosis is typical.