Abstract
Severe hypercalcemia is often caused by primary hyperparathyroidism (PHP), which is not commonly seen in patients with systemic lupus erythematosus (SLE). In this case report a 77 years old woman with a history of SLE develops mild hypercalcemia secondary to unrecognized PHP that leads to a hypercalcemic crisis with a prolonged recovery. Therefore, early diagnostic evaluation of persistent hypercalcemia in patients with SLE is important for detection and appropriate treatment of PHP to avoid a hypercalcemic crisis and associated prolonged morbidity.