Introduction: We describe a 31-year-old man with sarcoidosis found having concomitant primary hyperparathyroidism and vitamin D deficiency. Although hypercalcaemia is common in sarcoidosis, when accompanied by hypophosphatemia and resistance to steroids, should suggest coexisting primary hyperparathyroidism\.. Associated vitamin D deficiency presented management difficulties.
Case report: A 31-year-old bodybuilder presented with dyspnoea. Sarcoidosis was suspected on the basis of bi-hilar lyphadenapathy on chest X-ray. The diagnosis was confirmed by biopsy from a large axillary lymph node. Further investigations confirmed systemic respiratory and liver involvement. He had hypercalcemia with serum calcium 3.06 mmol/l and phosphate of 0.84. He was treated with oral prednislone with good symptomatic relief. However, his calcium remained high despite steroid treatment. His PTH ranged between 8.6 and 11.8 in the presence of high Ca confirming coexisting hyperparathyroidism. His vitamin D was <10. He was treated with vitamin D with close monitoring of Calcium, though his vitamin D is still only 43 mmol/l. He is arranged to have parathyroid adenoma localization scan in order to proceed for parathyroidictomy.
Discussion: Hypercalcaemia accompanying sarcoidosis is due to rise in circulating active vitamin D 1,25-dihydroxycholecalciferol. Serum PTH concentration is generally low or normal. PTH remains high when there is co-existent primary hyperparathyroidism. Corticosteroid administration produces a simultaneous decline in serum calcium and 1,25-DHCC concentrations in sarcoidosis and can be used to distinguish between sarcoidosis-related hypercalcaemia and primary hyperparathyroidism. Our patient had low vitamin D which presented management difficulties as treatment with vitamin D may aggravate hypercalcaemia. The clinician, when confronts a patient with hypercalcaemia because of sarcoidosis should consider the possibility of coexistent hyperparathyroidism in the presence of high PTH and inadequate response to steroids.