The Lactic Acid Content of Cerebrospinal Fluid.

Abstract

The lactic acid content of a series of normal and pathological specimens of spinal fluid was investigated, and in a number of cases compared with the blood lactic acid of the same patient after one-half hour of absolute rest following the lumbar puncture. Analyses were made by the sulphuric acid method of Clausen. 1

A spinal fluid was considered normal if it was clear and colorless, under normal pressure, had 10 or less cells per cm., gave a Pandy test plus one or less, a negative Wasserman and a Lange curve not rising over 2. Of 13 spinal fluids which could be considered normal, using this standard, the lactic acid content varied from 11 to 27 mg. per 100 cc., with an average of 19 mg. In 9 cases in which the lactic acid of the blood was also examined, the value for lactic acid in the spinal fluid was found to be 60 to 100 per cent of that in the blood. The average was 75 per cent. Killian 2 reported a lactic acid content of 8 to 15 mg. per 100 cc. in 5 normal cases and in 15 miscellaneous cases found a percentage ratio of spinal fluid lactic acid to blood lactic acid of 80 to 90 per cent. In our series a number of cases of syphilis of the central nervous system, of old hemiplegia, of epilepsy (between convulsions), and of amyotrophic lateral sclerosis, the values for lactic acid in the spinal fluid were within normal limits. In 2 cases of acute meningitis the lactic acid content was found to be greatly increased. A case of influenza1 meningitis had a lactic acid content of 91 mg. per cent and one case of Streptococcus meningitis 150 mg. per cent.