PROLONGED VITAMIN D INTOXICATION IN A PATIENT WITH HYPOPARATHYROIDISM

Pitfalls in the management of hypoparathyroidism are illustrated by the case of a patient who developed hypervitaminosis D while receiving doses of calciferol and of calcium in amounts commonly recommended for treatment. Either the patient was very slow to obtain maximum vitamin D effect or else her sensitivity to vitamin D increased, because she did not become hypercalcemic until two years after treatment was started. The dose of vitamin D was halved to 50,000 units per day and the dose of calcium was lowered to 0.26 g. daily. She failed to remain under medical supervision for the next four years and presented with hypercalcemia and evidence of renal impairment. After vitamin D was discontinued she remained hypercalcemic for nine months.These findings are discussed in the light of current knowledge concerning the actions of parathyroid hormone and vitamin D. The influence of adrenocortical hormones on calcium metabolism is considered. The need to follow up hypoparathyroid patients closely, and to check the level of calcium in the serum, is emphasized.