On the bromide test of permeability of the barrier between blood and cerebrospinal fluid—an assessment

Abstract

The publication of Walter's monograph (1929) on the blood/cerebrospinal-fluid barrier was followed by the widespread use ofthe bromide test in diseased conditions of the brain and spinal cord. The bromide test consists in the administration of bromide to the patient; after allowing 24 hr. for equilibration with the cerebrospinal fluid (c.s.f.), the content of bromide in the serum and c.s.f. is determined. The permeability of the barrier is then judged by the magnitude of the ratio (bromide/unit vol. serum)/(bromide/unit vol. c.s.f.). Walter found normal control ratios to lie in the range 2-90-3-30 (mean 3-10). In pathological states causing the greatest increase in permeability (syphilitic or tuberculous meningitis) the ratio was near 2-0, although a few values as low as 1-50 have been recorded. On the other hand, ratios over 3-50 were found in a number of conditions.

Clinical pharmacology of hypnotics and sedatives

“…20 Equi-Hypnotics and sedatives 333 librium between human plasma and erythrocytes in vitro occurs rapidly, and the ratio plasma/erythrocytes approximates but is slightly less than 1. 98 Except for brain, the bromide/chloride ratio in the extracellular fluid in cats and dogs is the same as that for serum.l"4 In man at least 24 hours is required for the establishment of equilibrium between plasma and cerebrospinal fluid,ns and the ratio cerebrospinal fluid bromide/ serum bromide, at equilibrium, is approximately 0.4. 39 This ratio is essentially the same in a number of mental disorders, schizophrenia, affective disorders, senile dementia, puerperal psychosis, and general paresis.…”

Encephalomyelitis and the Clinical Pathologist

“…For this the intravenous bromide test, recently elaborated by Hunter, Smith, and Taylor (1954), has, in their hands, proved of considerable value.…”