A Study of the Allergic Phenomena in the Central Nervous System.

Abstract

These experiments were designed to study the allergic response of the central nervous system and to determine what part this phenomena might play in certain types of meningitis and encephalitis. Tuberculous animals were first employed because it is known that their tissues are sensitive to tuberculin.

Guinea pigs were inoculated subcutaneously in the groin with a known quantity of virulent human tubercle bacilli sufficient to give rise to an extensive generalized tuberculosis within 3 to 6 weeks. At varying intervals, up to 5 weeks, following the initial inoculation different animals had injected in their subarachnoid spaces by the way of the basal cisterns 0.3 cc. of a 1/10, 1/100, and 1/1000 dilution of old tuberculin. If the animals failed to develop fatal central nervous system disturbances they were killed by means of decapitation under ether anesthesia. Gross and microscopic studies were made of the brain and viscera. Cultures were prepared of the brains for the presence of the tubercle bacilli and other pathogenic organisms. As controls, both tuberculous and non-tuberculous animals were employed in each experiment. In this investigation 112 guinea pigs were employed, 42 of which were controls.

Following the subarachnoid injection of tuberculin the animals with advanced visceral tuberculosis showed definite and constant clinical central nervous system manifestations as well as a striking histological response in the leptomeninges. Restlessness, ruffled hair, progressive weakness, twitching and loss of sphincter control occurred 3 to 4 hours after the inoculation of tuberculin. Death usually occurred within 6 to 12 hours. Histological studies of the brains revealed an extensive polymorphonuclear exudate in the subarachnoid space. In the more advanced cases there was a definite perivascular extension and some glial proliferation around the vessels of the cerebral parenchyma.