Primary and secondary cerebrospinal fluid acidosis as a manifestation of cerebral lesions.

Abstract

This paper deals with the problems of metabolic acidosis and lesions of the CNS. It is necessary to divide the results into two categories: one summarizing acid base dysregulations in the blood with secondary impairment of the functions of the CNS, the other discussing primary CNS lesions and consequent CSF acidosis. It is important that in the first category there is a strong regulation between the HCO 3 − concentrations in the blood and those in the CSF over the wide range from acidosis to alkalosis. In the second category there is a very marked CSF bicarbonate deficiency while in the blood the acid-base balance can be within the normal range. In these cases of primary metabolic CSF acidosis (PMA(CSF)) there is no relation between blood and CSF HCO 3 − concentrations. In the presence of a primary cerebral lesion, the CSF acidosis is often combined with rise in the level of lactic acid and pyruvic acid in the CSF and an elevation of the lactate/pyruvate ratio reflecting cerebral hypoxia. But it is necessary to point out that in a special group of PMA(CSF) the disturbances are caused directly by intracranial infections with organisms producing lactic acid, for instance in the case of pneumococcal meningitis. The possible complications and the therapy of acid-base disturbances in both categories are discussed.