嫌気性菌Fusobacterium nucleatum感染による小脳膿瘍の1例

Cerebellar Abscess Due to Infection with the Anaerobic Bacteria Fusobacterium Nucleatum:A Case Report

Ⅰ．はじめに

　小脳膿瘍は，脳膿瘍の中でも3.8〜12%とテント上の脳膿瘍（大脳膿瘍）と比べて頻度は少ない^2,8,9,23)．また，その病態は大脳膿瘍と異なり，急速に閉塞性水頭症や小脳扁桃ヘルニアを来しやすく^8,9,22)，致死率も10〜15%と高いといわれてている^16,17)．治療に関しても，穿頭による持続排膿ドレナージが行いにくいなど，大脳膿瘍に対する外科的管理と異なる点が多い²⁴⁾．今回，嫌気性菌であるFusobacterium nucleatum感染による硬膜下膿瘍を伴った稀な小脳膿瘍に対し，2回の開頭手術による排膿に加えて，高圧酸素療法併用下の抗生剤治療を行い，良好な転帰を得た1例を報告する．

　We report a rare case of cerebellar abscess produced by anaerobic bacteria. A 76-year-old man was admitted to our hospital with a history of fever, vomiting, and dizziness lasting 14 days. Computed tomography（CT）scan and magnetic resonance images showed the presence of a multiloculated cerebellar abscess with a right subdural abscess. The patient underwent aspiration of the abscess through a suboccipital craniotomy. Fusobacterium nucleatum, which is an anaerobic bacteria naturally present in the human oral cavity, was detected in cultures of the aspirated abscess. The patient was administered antibiotic treatment combined with hyperbaric oxygen therapy（HBO). The symptoms were briefly relieved but the cerebellar abscess recurred, which required a second aspiration. The combined treatment with antibiotics and HBO was maintained after the second operation. After 6 weeks of treatment, the cerebellar abscess was completely controlled.

　We conclude that antibiotic treatment combined with HBO is useful for treatment of cerebellar abscesses caused by infection with anaerobic bacteria.