Arsenic penetration of the meninges during the treatment of neurosyphilis

Abstract

It is difficult to estimate from clinical results the relative values of the different methods of treating neuro-syphilis. The amount of arsenic that reaches the cerebrospinal fluid may, however, be estimated quantitatively with reasonable accuracy, and the effectiveness of the treatment may be assumed to parallel this amount of penetration.

Quantitative estimations of arsenic penetrating the meninges was made in about 100 spinal fluids. These were divided into the following groups:

Group A—44 cases in which spinal drainage was performed one hour after simple intravenous injection of 0.6 arsphenamine. Of this number 43 per cent. gave positive test for arsenic, averaging .036 m.mg. of arsenic per c.c.

Group B-23 cases in which the intravenous injection of 0.6 arsphenamine was followed in half an hour by complete drainage of spinal fluid. One hour later a second lumbar puncture was done to determine if complete drainage tended to increase the amount of arsenic penetrating. In 32 per cent. arsenic penetrated in half an hour; in 23 per cent. it had penetrated following drainage. Quantitatively, the average amount of penetrations in the first half hour was .009 and after one hour, .0043 m.mg. per c.c.

Group C-Of 5 cases in which complete drainage was done one hour before the intravenous injection of 0.6 arsphenamine none showed arsenic penetration an hour afterwards.

Group D-In 40 cases the patient's own serum was injected into the subarachnoid space followed in 6 to 8 hours by an intravenous injection of 0.6 arsphenamine. Of the spinal fluid obtained one hour later 92 per cent. showed positive test for arsenic. Quantitatively, these cases averaged .103 mmg. per C.C.

From these figures it is apparent that the simple withdrawal of spinal fluid either before or after the intravenous administration of arsphenamine does not increase the amount of arsenic which penetrates into the spinal fluid.