化膿性髓膜炎における髓液酸塩基平衡の障害

ACID-BASE DISTURBANCE OF CEREBROSPINAL FLUID IN PURULENT MENINGITIS

I．はじめに

　われわれは以前から脳外傷，脳出血などの急性脳疾患を対象として，脳脊髄液（以下髄液と略する）の呼吸ガス分圧，酸塩基平衡に関する一連の臨床的研究を行なつてきた。その間，たまたま髄膜炎を併発した患者で，とくに髄液中に多核白血球の増加したいわゆる化膿性髄膜炎に際して，特異的な髄液酸塩基平衡障害が出現することを経験したので，ここに若干の文献的考察を加えて報告する。

Changes of cerebrospinal fluid (CSF) PH, PCO₂,HCO₃^- and PO₂ were investigated in seven patientswith purulent meningitis.

The results obtained were as follows:

1) The most significant changes concerned CSFHCO₃^- concentration, which was reduced invariablyduring purulent meningitis. The decrease in CSFHCO₃^- was fairly paralleled with increased cellcount and with decreased sugar content in CSF.But in a few instances of early meningitic stageand of convalescence, the fall of CSF HCO₃^- wasobserved without significant changes in cell numbersor sugar concentrations.

2) Except for two cases, there was a lack ofCSF PH changes, despite the fact that CSF HCO₃^-was reduced to 14-18 mEq/l. The another twopatients showed extraordinary fall in CSF HCO₃^-,PH (below than 7.27) and PO₂, and rise in CSFPCO₂. It was suggested in them that there wasa blockade of CSF comminucation in one patient,and severe circulatory disturbance of cerebral tissuein the other.

3) CSF PCO₂ was mostly below normal at therange from 30 to 40 mmHg. It might be well cor-related to hypocapnea in arterial blood.

4) CSF/arterial PO₂ ratio was significantly re-duced at the severest stages of meningitis, com-pared with that of recoverd period.

The chemical changes such as CSF acid-basedisturbance could not be pathognomonic, and theeventual diagnosis of meningitis is to be confirmedby cell count, sugar content and bacterial exam-ination of CSF. But it should be emphasized thatCSF acid-base status is easily and immediatelydetermined at the first, and, at the second, it sug-gests the prognosis of the patients more exactly,since it would reflect the metabolic changes ofbrain tissue, not only of CSF.