An unrecognized cause of recurrent hypercalcemia: immobilization.

We report a 66-year-old Chinese man with chronic renal insufficiency (creatinine 1.7 mg/dL) and gout suffering from slurred speech and right hemiplegia for 3 days. Acute cerebral infarction was confirmed by computed tomography. Conscious disturbance occurred on the tenth hospital day without significant changes on imaging study when compared with a previous scan. Hypercalcemia (total calcium 14.1 mg/dL) and acute exacerbation of chronic renal failure (serum creatinine 2.5 mg/dL) were noticed. Hypercalciuria (FECa 3.2%), and low serum levels of intact parathyroid hormone and 1,25(OH)2D3 suggested nonparathyroidal hypercalcemia. An extensive workup failed to identify any etiology of hypercalcemia. Hypercalcemia and renal failure were temporarily ameliorated after aggressive volume expansion and loop diuretic treatment but recurred 2 weeks later. Immobilization hypercalcemia was considered after the exclusion of other discernible causes and was successfully treated with rehabilitative exercises and bisphosphonates without further recurrence during a 2-year follow-up. Clinical alertness to immobilization as a possible cause of hypercalcemia may avoid unnecessary and invasive examinations, life-threatening complications and annoying recurrences.