Movement disorders in Japanese encephalitis

Abstract

Movement disorders in Japanese encephalitis (JE), although reported, have not been analyzed systematically. In this study, we report an analysis of movement disorders in 14 out of 17 JE patients, correlated with the radiological findings. All patients had at least a four fold rise of IgG antibodies against JE in a haemagglutination inhibition test. The patients' ages ranged between 2 and 54 years and 4 of them were women. Extrapyramidal signs, such as hypokinesia, hypophonia and masking of the face, were present in all patients by the first month as the patients came out of the coma - except for 1 patient. Eight patients had axial and 3 tongue dyskinesia; rigidity was present in 6 and tremor in 2 patients. At 3 months, these symptoms improved considerably in 6 patients. Cranial CT scan revealed thalamic involvement in 10, which was bilateral in 9 patients. Two patients had brain stem and one had cerebellar involvement. Cranial MRI was carried out in 9 patients and revealed additional findings in lentiform nucleus, midbrain and pons in 3 each and cerebellum in 4 patients. Bilateral thalamic involvement on MRI was seen in all the patients, including two patients whose CT scans were normal. SPECT studies using ^99mTc-ECD revealed bilateral thalamic hypoperfusion in all (n = 7) and frontal hypoperfusion in 3 patients. In JE, movement disorders are common and may be due to thalamic involvement in isolation or in combination with basal ganglia or midbrain or both.