OBJECTIVES: 1. To present seven cases of Japanese B encephalitis in different age groups with different neurologic presentations; 2. To present the different involuntary movements as manifestations of Japariese B encephalitis patients; 3. To present the pathogenesis, diffetential diagnosis, management, and prognosis of Japanese B encephalitis.
DESIGN: Case series study.
PATIENTS/PARTICIPANTS: Seven patients who were admitted and managed as Japanese B encephalitis from January 2011 April 2012 in the Neurology ward were included in the study. The number of patients included at the start of the study is the same number of patients at the end of the study (no attrition).
SETTING: Neurology ward, Philippine Children's Medical Center.
DISCUSSION: The patients ages range from 1.4 to 15 years old. Five were females and 2 were males. All of the patients are free Luzon in which 6 were from rural areas and live near ricefields. One patient had history of travel in an endemic area. Febrile illness were noted to all the patients followed by headache, poor appetite, vomiting and chills. Six of the patients had depressed sensorium and aphasia. Four patients showed increased tone 3 patients had seizures and 2 patients presented with involuntar movements such as choreoathetoid and orofacial dyskinesias. The presence of nuchal rigidity, clonus and extensor toe sign are noted in 6 of the patients. Cerebrospinal fluid analysis with viral studies were done to all the patients and showed pleocytosis, normal sugar and normal protein. Routine gram stain with culture and sensitivities are negative. Japanese B antigen were all positive and confirmed by the serum Japanese B Immunoglobulin M. Electroencephalogram of the 6 patients showed generalized slowing of the background activity while 1 patient had normal result. The 2 patients with involuntary movements had an MRI findings of bilateral thalamic infarcts with some involvement in the basal ganglia and brainstem while 3 patients had CT scan showing bilateral cerebral low density in the thalamo-capsulo-ganglionic region who presented as spasticity. There is no specific treatment for Japanese B encephalitis. Supportive care was only given to the patients. On follow up after 2 weeks, the sensorium of the patients improved, muscle tone are normal and with resolution of involuntary movements.
CONCLUSION: The incidence of Japanese B encephalitis is increasing in the Philippines causing severe neurologic complications like impaired consciousness, seizures and involuntary movements. But as one of the affected countries, there are limited data up to date.