急性小脳失調症を主徴とした伝染性単核症—症例報告と文献的考察

ACUTE CEREBELLAR ATAXIA ASSOCIATED WITH INFECTIOUS MONONUCLEOSIS:A CASE REPORT AND REVIEW OF THE LITERATURE

　抄録　症例は20歳の男子で，発熱・喉頭炎・頸部リンパ腺腫大および肝障害で発症し，1ヵ月後より歩行障害が始まった。神経学的には構音障害，企図振戦，躯幹性失調症の他Babinski反射が陽性で，末梢血には異型リンパ球が認められた。Epstein-Barr virus （EBV）に対する血清抗体価はVCA-IgG抗体：640倍，EA抗体：160倍，EBNA抗体：10倍以下でありEBVの初感染と診断された。髄液中のEBV抗体は陰性であった。ステロイド剤の投与をおこない，入院6週間後に神経症状は完全に消失した。伝染性単核症の神経合併症が神経系へのウイルス侵襲によるものか，あるいは免疫異常によるものかについては議論も多いが，今回の症例は定型的なpost-infectionとしての発症様式を示した点に特徴があり，immuno—allergicな過程の関与が考えられた。

A 20-year-old man, a college student, was admit-ted to Kochi Municipal Central Hospital with a month's history of slurring of speech and unstea-diness of gait.

He had developed fever, sore throat and cervi-cal 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) anti-body 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. Treat-ment 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 litera-ture. It was postulated that the neurological symp-toms complicating infectious mononucleosis were possibly caused by infectious and immuno-allergic mechanisms.