The Effect of CO 2 Administration Upon Parathyroid Tetany.

Abstract

It has been known for some years that certain mineral acids such as HCl, and acid producing salts such as CaCl₂ and NH₄Cl are effective agents in the treatment of infantile tetany, and have also been successfully employed in cases of experimental tetany.

The effect of injecting HCl and CaCl₂ or NH₄Cl is the production of an acidosis. It seems from a survey of the literature on the subject, that the gross manifestations of tetany, even the most violent convulsions, are rather promptly relieved by slight changes in the reaction of the blood toward the acid side, and that such changes influence in some manner the calcium content of the blood.

In view of these facts it was considered worthwhile to test the effect of administering CO₂ to dogs in tetany, (1) in relation to relief of symptoms and (2) the effect upon the serum calcium level.

Small rat and fox terriers were used as experimental animals. They were thyroparathyroidectomized and permitted to develop tetany. When the animals were prostrate they were bled and the serum Ca, CO₂ capacity, CO₂ content and pH determined. Following bleeding, the dogs were immediately placed in a specially constructed CO₂ chamber and sufficient gas administered over a 20 to 40 minute interval to produce unconsciousness.

The rapidity with which the muscle tremors, jerks and convulsions disappear following CO₂ treatment is remarkable. Within a few minutes following treatment the animal shows a complete return to norm. The length of the recovery period varies considerably. Some animals do riot again exhibit tetany symptoms for 12 hours, others show tetany within a few hours. If such animals are again placed in the CO₂ chamber they again temporarily recover. No effort was made to keep the animals alive indefinitely, since we were primarily interested in the effects produced by the acid intoxication.