Is there more than one kind of rickets? 1

Abstract

I. CLINICAL OBSERVATIONS SUGGESTING THE EXISTENCE OF MORE THAN ONE KIND OF RICKETS.

For at least two years our attention has been attracted to the possibility that there might be more than one kind of rickets. We were led to think of this possibility as the result of the consideration of certain peculiar manifestations of the disease and associations with other diseases. The facts are as follows: Rickets occurs with great frequency in premature children, even when breast fed. It seems to affect the head more than the extremities or ribs. In a group of cases of rickets the disease shows an especial tendency to involve the shafts of the long bones declaring itself clinically by the occurrence of multiple fractures from trivial causes. There is a curious association between rickets and certain forms of secondary anemia (the so-called alimentary anemias and the anemias of the von Jaksch type). The rachitic involvement of the head in the children suffering from the combined conditions appears to be out of all proportion to the involvement of the extremities. Rickets is associated with the most severe forms of chronic interstitial nephritis or developmental defects of the kidney in which there is the most extreme degree of disturbance in renal function. Curiously, tetany sometimes occurs with rickets and sometimes not. Since the conception that there might be more than one kind of rickets was supported solely by clinical observations of at most a suggestive character, we did not feel at liberty to express it as a definite hypothesis. Recently, however, our experiments have yielded results which indicate that there may be two distinct forms of the disease.

II. THE EXPERIMENTAL EVIDENCE.

In previous publications 1 we have described certain defective diets which, when fed to the young rat, produced marked disturbances in the growth and calcification of the skeleton.