FURTHER OBSERVATIONS ON ELECTROLYTE CHANGE IN TUBERCULOUS MENINGITIS

Abstract

The investigation of the disturbance of the electrolytes of the serum in 8 patients with tuberculous meningitis again demonstrates the frequent presence of metabolic alkalosis, hypochloremia and hyponatremia, a normal total content of chloride in the body and hypotonic expansion of the extracellular fluid (chloride space). Total content of water is normal or decreased in some instances (on the basis of total weight) so that the expansion of the chloride space can be considered as being occasionally, if not frequently, at the expense of water from the cells. The instances in which total content of water is increased could be explained on a malnutrition basis. The findings of metabolic alkalosis and hypotonic expansion of the chloride space are not the rule in purulent meningitis. The penetration by bromide of the blood-spinal fluid barrier has been investigated in 7 cases of tuberculous meningitis and in 5 cases of purulent meningitis. In the former instance, bromide, penetrated the spinal fluid almost completely within 8 hours of injection, giving a [See equation in source pdf] ratio of about one. In purulent meningitis the degree of penetration was also increased in some instances, and it is not possible to differentiate tuberculous meningitis from purulent meningitis by the above method. While the initial cause of the coexisting metabolic alkalosis remains obscure, it is pointed out that requirements for potassium should be more than fulfilled, and loads of sodium should not exceed maintenance requirements in the presence of this persistent metabolic alkalosis.