細菌性髄膜炎および脳炎における認知機能障害

Cognitive Impairment in Patients with Bacterial Meningitis and Encephalitides

細菌性髄膜炎や脳炎は神経学的な緊急対応を要する疾患である。これらの疾患では急性の認知機能障害で発症する場合がある。また，後遺症として認知症を含む各種認知機能障害を高頻度に認める。したがって，急性の認知機能障害を認めた場合，これらの疾患も念頭に置いて対応すること，後遺症としての認知機能障害を可能な限り回避するために，急性期に適切な治療対応をすることが極めて重要である。本論では細菌性髄膜炎，単純ヘルペス脳炎，ヒトヘルペス6型脳炎，および抗N-メチル-D-アスパラギン酸受容体脳炎について概説する。

Abstract

Cognitive impairments, including dementia, can present as first symptoms at the acute stage, and/or as sequelae in the chronic stages, in some patients with bacterial meningitis (BM) or encephalitides. BM and encephalitides are lifethreatening neurological emergencies, and early recognition, efficient decision-making, and rapid commencement of therapy can be lifesaving. Empirical therapy should be initiated promptly whenever BM or encephalitides are a probable diagnosis. In this article cognitive impairments, including dementia, presenting in patients with BM, Herpes simplex virus encephalitis (HSVE), Human herpesvirus-6 (HHV-6) encephalitis, and Anti N-methyl-d-aspartate (NMDA) receptor encephalitis are reviewed. In the above mentioned diseases, cognitive impairment without fever might be observed at the time of disease onset. cognitive impairment has been also noted in some aged or immunocompromised patients at the onset of BM. Immediate memory disturbance as one of the first symptoms of HHV-6 encephalitis presented in 74% of patients with this disease. Cognitive impairment, including dementia as sequela, was also found in 10-27% of patients with BM, 54-69% of patients with HSVE, 33% of HHV-6 encephalitis patients, and 39% of patients with anti-NMDA receptor encephalitis. Suitable therapeutic management of these diseases at the acute stage is thus required in order to avoid these sequelae.