Prognosis of Japanese encephalitis patients with dystonia compared to those with parkinsonian features only

Abstract

Objectives: A number of movement disorders have been reported in Japanese encephalitis (JE). The prognostic significance of these movement disorders, however, has not been evaluated. The present study reports the prognostic significance of parkinsonian features and dystonia in JE. Patients and methods: During 1992 and 1998, 50 JE patients were managed; 35 of them developed movement disorders (the study group). The diagnosis of JE was based on clinical, radiological, and serological criteria. Parkinsonian features were rated by the unified Parkinson's disease rating scale and dystonia by the dystonia rating scale. The patients with parkinsonian features only were classified into group I and those with additional dystonia or dyskinesia into group II. The outcome was defined at the end of three months into poor, partial, and complete recovery depending on how the patients coped with daily living activities. Results: The patients' ages ranged from 2 to 64 years and 11 were females. The admission mean Glasgow coma scale score was 6.9 (range 4-13). The movement disorders were noted after 1-4 weeks of ictus. There were 16 patients in group I and 19 in group II. The parkinsonian features were more pronounced in group II than in group I. At three months of follow up, fewer patients had parkinsonian features in group I than group II. Hypophonia, however, persisted in 12 patients in group I and 16 in group II until the three month follow up. In group II, the mean dystonia score was 3.2 which regressed to 1.8 at three months. Tremor was present in five patients in groups I and eight in group II. Cranial computed tomography was abnormal in six and magnetic resonance imaging abnormal in 15 patients in group I and in nine and 12 patients respectively in group II. The thalamus was most frequently involved (11 patients in each group), basal ganglia (four in group I and six in group II), and midbrain (six in group I and one in group II). Group II patients had poorer recovery compared with group I. In group I, at the end of three months functional recovery was complete in 10, partial in two, and poor in three patients. In group II, four patients had complete, seven partial, and eight poor recovery. Conclusion: JE results in a transient form of parkinsonian syndrome, which is associated with a lower frequency of tremor and prominent hypophonia. The presence of dystonia suggests more severe illness and poorer prognosis.