[Acute cerebellar ataxia associated with infectious mononucleosis--a case report and review of the literature].

A 20-year-old man, a college student, was admitted to Kochi Municipal Central Hospital with a month's history of slurring of speech and unsteadiness of gait. He had developed fever, sore throat and cervical lymphadenopathy. On admission, the throat was mildly injected, and enlarged lymph nodes were palpable in the lateral cervical regions. His speech was slightly slurred. Bilateral dysmetria, dyssynergia and intention tremor were noted in both extremities. The gait was grossly ataxic. Plantar responses were extensor. Examination of his peripheral blood revealed atypical lymphocytes, and the titer of Paul-Bunnell was 1:16. The CSF protein was 25 mg/dl with normal cell count. Epstein-Barr virus (EBV) antibody titers by indirect immunofluorescence in the serum of the second hospital day were as follows: VCA-IgG was 1:640, VCA-IgM less than 1:10, EBV-EA 1:160, and EBNA less than 1:10, while the CSF-EBV antibody titer was negative. Treatment with prednisolone was started and within 7 days he began to recover. Six weeks after admission he was completely free of neurological symptoms and signs. We also reviewed 18 cases of acute cerebellar ataxia with infectious mononucleosis in the literature. It was postulated that the neurological symptoms complicating infectious mononucleosis were possibly caused by infectious and immuno-allergic mechanisms.