Hypercalcemia worsened after vitamin D supplementation in a sarcoidosis patient: A case report

There are many causes of hypercalcemia, with hyperparathyroidism and malignancy accounting for 90% of cases. Sarcoidosis and the intake of vitamin D supplements may also cause hypercalcemia, although the occurrence rate is low if only one is involved. We herein report a sarcoidosis patient who developed hypercalcemia after taking cholecalciferol (vitamin D supplement) for a year.

A 62-year-old Japanese man presented with hypercalcemia and acute kidney injury along with symptoms of fatigue and appetite loss while being followed up for sarcoidosis.

We determined that a combination of cholecalciferol supplementation and sarcoidosis had led to hypercalcemia for several reasons. First, hypercalcemia had not been noted when this patient had first been admitted due to sarcoidosis-related respiratory failure several years earlier, which we presumed that was the highest sarcoidosis disease activity. Second, low serum 25-OH Vit.D3 and high 1,25-(OH)2 Vit.D3 levels were noted despite cholecalciferol supplementation for a year, suggesting that 1-α-hydroxylase overexpression caused by sarcoidosis accelerated the conversion from 25-OH Vit.D3 to 1,25-(OH)2 Vit.D3.

Although initially resistant to preservative management, the hypercalcemia promptly improved after starting corticosteroid treatment.

Hypercalcemia and acute kidney injury were normalized after corticosteroid treatment.

We should be aware of patients' medications, especially in patients with granulomatosis disease. The concomitant measurement of 25-OH Vit.D3 and 1,25-(OH)2 Vit.D3 levels is useful for determining the cause of hypercalcemia.