Immobilization hypercalcaemia with severe bone mineral loss and hypogonadism

Abstract
Summary: Moderate hypercalcaemia occurred in a 17-year-old male who was immobilized with abdominal and right hip sepsis for 9 months after a motor vehicle accident. The hypercalcaemia was due to bone resorption, with a urine hydroxyproline:creatinine ratio of 0.203 (normal less than 0.017) and a urine calcium loss of 22.9 mmol/24 hr, associated with impaired renal function. There was radiological evidence of severe bone demineralization in the pelvis over 42 weeks. Radiocalcium absorption, using 47Ca, was decreased (0.17, normal range 0.35–1.30), renal tubular maximum for calcium reabsorption was decreased (1.61 mmol/1 glomerular filtrate, normal range 1.8-2.2), the serum parathyroid hormone concentration was in the low normal range (3.2, 3.6 u/l, normal range 2-6) and the plasma 1,25-dihydroxy-vitamin D concentration was decreased despite a normal 25-hydroxy-vitamin D concentration, indicating suppression of the parathyroid, 1,25-dihydroxy-vitamin D axis. The patient was found to be hypogonadal at 41 weeks after admission and testosterone therapy was begun, with associated improvement in mobilization and a reduction of the hypercalcaemia.