Coexisting hyperthyroidism and primary hyperparathyroidism with vitamin D-deficient osteomalacia in a Vietnamese...

To present the first report of concurrent hyperthyroidism, primary hyperparathyroidism (PHP), and vitamin D-deficient osteomalacia.

We describe the complicated clinical course in a 65-year-old Vietnamese immigrant, and underlying factors potentially contributing to her condition are discussed.

Our patient, who had hyperthyroidism and hypercalcemia, was found to have an inappropriately high level of intact parathyroid hormone (PTH) because of a parathyroid adenoma, detected on a parathyroid scan. With propranolol treatment, however, improvement was noted in both laboratory data--intact PTH, ionized calcium, serum total calcium, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and urinary cyclic adenosine monophosphate--and findings on ultrasonography and nuclear parathyroid scanning. Later, the adenoma was removed surgically. The improvement of PHP after administration of a beta-adrenergic blocker suggested that the parathyroid adenoma in this patient was not completely autonomous. The patient also had vitamin D-deficient osteomalacia that was confirmed by a low serum level of 25-hydroxyvitamin D3 (25OHD3) and by bone histomorphometry. This coexisting condition was caused by the long-term increase in conversion of 25OHD3 to 1,25(OH)2D3 from hyperparathyroidism in a patient with low stores of vitamin D (which were ascribed to aging, liver dysfunction in hyperthyroidism, a vegetarian diet, deprivation of sunlight, and avoidance of dairy products).

The complex concurrence of hyperthyroidism, PHP, and vitamin D-deficient osteomalacia is rare but possible.