Spectrum of movement disorders in Japanese encephalitis: a systematic review of case reports, case series, and cohort studies

Movement disorders are common, disabling sequelae of Japanese encephalitis (JE) survivors yet remain poorly characterized. This review synthesizes their epidemiology, clinical spectrum, radiological correlates and outcomes to inform early diagnosis and treatment.

We searched PubMed, Scopus, Embase and Google Scholar data bases for reports of JE with subsequent movement disorders. We included case reports, case series and cohort studies. Extracted data on demographics, timing and type of movement disorder, magnetic resonance imaging findings, treatment and follow-up outcomes were recorded.

In this review of 72 isolated JE cases, the mean age was 20.8 years (range < 1-66), with 39 males (54.2%). Most cases (60%) were from India. The most frequent movement disorder was parkinsonism (18, 25%), followed by rigidity (13, 18.1%), bradykinesia (8, 11.1%), and hypomimia (7, 9.7%). Dystonia occurred in 28 (38.9%), including generalized (6.7%), oromandibular (2.2%), and opisthotonus (4.5%). Neuropsychiatric features were noted in 22 (30.6%), bulbar-autonomic signs in 14 (19.4%), and long-term sequelae in 11 (15.3%). Abnormal cerebrospinal fluid was found in 44 (61.1%), and bilateral thalamic hyperintensities on MRI in 49 (68.1%). Symptomatic treatment was given in 15 (20.8%) and immunotherapy in 7 (9.7%). Outcomes included partial improvement in 20 (27.8%), complete in 12 (16.7%), and death in 1 (1.4%). Two Indian retrospective cohorts (n = 209, n = 50) showed similar spectrum of movement disorders with predominant thalamic-basal ganglia involvement.

Movement disorders following JE are common, predominantly parkinsonism and dystonia, often with bilateral thalamic involvement and variable recovery.