HYPERCALCEMIA ASSOCIATED WITH WEGENER GRANULOMATOSIS AND HYPERPARATHYROIDISM - ETIOLOGY AND MANAGEMENT

We report a case of hypercalcemia in a patient with coexisting hyperpa rathyroidism and Wegener's granulomatosis. Parathyroidectomy with remo val of an adenoma resulted in a low parathyroid hormone level but high calcitriol levels and hypercalcemia persisted. In various granulomato us diseases, hypercalcemia has been shown to be the result of overprod uction of 1,25-dihydroxyvitamin D by disease-activated macrophages. Ch loroquine has been demonstrated to effectively reduce the extrarenal s ynthesis of 1,25-dihydroxy-vitamin D and serum calcium concentration i n hypercalcemic patients with sarcoidosis. Hypothesizing that a simila r mechanism would explain hypercalcemia in Wegener's granulomatosis as well, a therapeutic trial of chloroquine was initiated. The patient r esponded to chloroquine 500 mg twice daily with significant decreases in serum 1,25-dihydroxyvitamin D and calcium levels. This report exten ds previous observations of hypercalcemia associated with other granul omatous diseases to Wegener's granulomatosis and demonstrates an effec tive reduction of serum calcitriol and calcium levels in response to c hloroquine therapy.