A Case of Severe Hypercalcemia and Hyperphosphatemia Concomitant to Hyperthyroidism

ABSTRACT

Changes of serum electrolytes in patients with hyperthyroidism are often disregarded. Hypercalcemia has been reported in 17% to 50% of patients with hyperthyroidism. However, severe and symptomatic hypercalcemia is rare among patients with hyperthyroidism. We report a rare case of symptomatic hypercalcemia and hyperphosphatemia in a 31-year-old male patient who was diagnosed with hyperthyroidism. He visited our hospital with nausea, vomiting, and tremor. Thyroid function test showed severe thyrotoxicosis and serum calcium and phosphorus were elevated but parathyroid hormone was low, excluding primary hyperparathyroidism as the cause of hypercalcemia. Saline hydration with diuretics to lower serum calcium and antithyroid medication with lugol solution were administered for six days. But symptoms persisted and he was treated with intravenous pamidronate. Symptoms were relieved after resolution of hypercalcemia and hyperphosphatemia. The case suggests that severe and symptomatic hypercalcemia and hyperphosphatemia can complicate hyperthyroidism and early correction of hypercalcemia can relieve symptoms.