| Abstract: | A woman with hyperthyroidism, hypercalcemia, and a parathyroid adenoma is described. Various studies indicate that in hypothyroid subjects given an acute dose of calcium, the serum calcium levels remain elevated for longer periods than in control subjects. In part, this may be due to diminished bone uptake. Despite these studies which would tend to support the contention that hypothyroid patients "have a propensity to hypercalcemia" (Lowe et al), overt and significant hypercalcemia is unusual. Hypothyroidism is listed as a possible cause of hypercalcemia. This does not seem to be warranted by a review of the literature. The reference most often cited is that of Lowe et al. In their particular case, the hypercalcemia improved with thyroid replacement therapy. This also happened in our case. However, the measurement of IPTH levels led to the correct diagnosis. IPTH levels were not available at the time of Lowe's report and hyperparathyroidism was not completely excluded. Therefore, at this time, the reported association of hypercalcemia with adult hypothyroidism needs further examination to determine if this association is real. |
