肺炎球菌感染により後咽頭膿瘍から頸椎化膿性脊椎炎，髄膜脳炎に進展した糖尿病の1例

A Case of Diabetes Mellitus Associated with Cervical Pyogenic Spondylitis and Meningoencephalitis Secondary to Retropharyngeal Abscess Caused by Streptococcus Pneumoniae

はじめに

　化膿性脊椎炎の起炎菌は，従来黄色ブドウ球菌の頻度が高く，先行感染としては尿路感染が多く，次いで肺炎，皮下膿瘍，胆囊炎，心内膜炎がみられる^1）。しかしながら，最近では，高齢化や糖尿病などの生活習慣病の増加，薬剤耐性菌の出現により病態が変化しつつある。成人の市中肺炎で最も分離頻度の高い肺炎球菌は，浸潤性感染としても重要な起炎菌の1つであり，細菌性髄膜炎を引き起こす^2）。肺炎球菌による後咽頭膿瘍が，頸椎化膿性脊椎炎へと進展し，髄膜脳炎を合併したと考えられる糖尿病患者を経験したので報告する。

Abstract

　A 63-year-old man with diabetes mellitus had undergone insulin therapy for 10 years.　He developed symptoms of upper respiratory tract infection and neck pain.　After 5 days, he suddenly experienced high fever and consciousness disturbance.　Neurological examination detected drowsiness and neck stiffness.　Cerebrospinal fluid (CSF) examination revealed pleocytosis with low glucose level.　Gram staining and a latex agglutination test of his CSF revealed Streptococcus pneumoniae to be the causative organism of meningoencephalitis in the patient.　Gadolinium-enhanced T1-weighted images obtained from a cervical spine MRI showed ring enhancement in the anterior clivus and thickening in the anterior dura matter with specific thickening at the dens of the axis.　Based on the diagnosis of cervical pyogenic spondylitis and meningoencephalitis secondary to retropharyngeal abscess caused by Streptococcus pneumoniae, the patient was administered panipenem/betamipron and dexamethasone, following which his neurological symptoms and signs gradually improved.　Diabetes mellitus is a factor that predisposes patients to invasive pneumococcal infection.　Thus, we conclude that physicians need to be aware of the possible development of cervical pyogenic spondylitis and meningoencephalitis subsequent to Streptococcus pneumoniae infection, and symptoms such as fever and neck pain should be carefully examined.