診断困難であった難治性，結核性髄膜炎の1例

A Case Report of Tuberculous Meningitis :： Limits of Detection Using Polymerase Chain Reaction（PCR） and Treatments

要旨　患者は40歳男性。原因不明の水頭症を伴う難治性髄膜炎のため発症6週間後に他院より転院となった。結核性髄膜炎を疑い，抗結核剤による治療を開始したが，11日後に脳幹部虚血性病変により死亡した。全経過中数回にわたる髄液塗抹，培養，polymerase chain reaction(PCR)法では結核菌は検出されず，死後，脳幹部組織の培養5週間後より抗酸菌が発育し，PCR法にて結核菌が同定された。PCR法は高感度な検査であるが，結核性髄膜炎では偽陰性を生じる可能性が比較的高く，その診断には総合的判断が重要である。治療は虚血性変化をきたさない早期に開始し，両側深部虚血性病変をきたしたものにはステロイドの使用を考慮すべきである。

A 40-year-old man with intractable meningitis was transferred to our hospital 6 weeks after onset. On admission, he showed consciousness disturbance, meningeal signs and right oculomotor nerve palsy. MRI demonstrated prominent cisternal enhancement and hydrocephalus. We suspected tuberculous meningitis as the diagnosis, and treated with antituberculotics, though he died of midbrain infarction day 11 of the treatment. Before and during the admission, bacterial cultures, PCR, smear examination of cerebrospinal fluid（CSF） were repeated. But no evidence of tuberculosis was obtained. Cultures of the brainstem fragments detected mycobacterium, which was finally confirmed by a PCR method after his death.

　PCR provides a rapid and reliable diagnosis of tuberculous meningitis, although there is a potential for false-negative. Thus the clinical, radiological and CSF findings should be stressed. Corticosteroids treatment should be considered in cases with ischemic lesions.