The curative effect of vitamin D or ultraviolet irradiation on rickets in infants is one of the most constant phenomena in pediatric practice. In infants with tetany, for whom the influence of treatment on the serum calcium can be readily measured, the rise in the serum calcium level after adequate doses of viosterol or ultraviolet radiation occurs at a fairly regular rate of about 0.4 mg. per day. Exceptions are unusual.
After the second year of life the effect of antirachitic therapy is much less constant. The amounts necessary for cure are often considerably larger than during infancy, and the rate of healing is much slower. However, cases such as that to be described, in which extremely large amounts of vitamin D are necessary for cure, are extremely rare.
REPORT OF A CASE
W. D., a boy of 8 years, was first seen in April 1931 because of difficulty and