Experimental tetany and diet.

Abstract

In 1922 Dragstedt 1 and his co-workers were successful for the first time in preventing the onset of tetany in thyroparathyroid-ectomized dogs, their method being to add to the diet large amounts of lactose—from 50 to 100 grams—daily.

It has been our plan to repeat Dragstedt's work and do it more exactly and systematically, taking advantage of Cowgill's 2 method of feeding. In doing so we have been able to vary the foodstuff components in any way we like, keeping the total caloric value nearly the same.

After the animals were fed on a certain diet for 6 to 7 days, they were operated upon and the diet was continued. Severe tetany when it occurred usually developed on the second or the third day following the operation. When animals developed tetany, various attempts were made to cure them and special attention was paid to the efficacy of lactose in the treatment. If the animal did not show tetany under the experimental conditions, the diet was changed until symptoms of tetany appeared; this was done in order to exclude any possible action of accessory glands in the experiments.

In the table are given results obtained with various diets. In each case all constituents except casein and carbohydrate were kept constant.

As will be seen in this table, in a diet relatively low in casein, the amount of lactose which may prevent the onset of tetany is comparatively small, and when casein is increased, more lactose is needed.

The dextrin experiments are significant. It is niuch easier to prevent the appearance of tetany or depression in thyropara-thyroidectomized animals than it is to cure it, once it has become established. Although lactose administration at the time severe symptoms of tetany develop appears to give much relief after a few hours, it has never ken so successful as the administration of calcium salts which cure almost all symptoms in a short time. However, by stopping the symptoms of tetany by calcium administration and then changing the diet to a lactose food mixture, we have been able usually, without giving any more calcium, to save the animals from the recurrence of tetany. Furthermore, in mild cases, we were often convinced that lactose administration alone by stomach was effective enough to cure the symptoms.