Immobilization hypercalcemia associated with Landry-Guillain-Barré syndrome. Successful therapy with combined calcitonin and etidronate.

Two patients with immobilization hypercalcemia associated with Landry-Guillain-Barré syndrome had marked hypercalciuria (890 and 1136 mg/d [22.2 and 28.3 mmol/d]) and radiologic evidence of generalized osteopenia. Parathyroid hormone levels were either low or normal by C-terminal radioimmunoassay. Subtotal parathyroidectomy was performed in the one patient, with no improvement in serum or urinary calcium levels. A bone biopsy specimen revealed decreased cellular activity in the first patient and increased bone resorption in the second patient. Treatment with intravenous saline, furosemide, oral phosphate supplementation, mithramycin, and calcitonin alone was ineffective in lowering serum or urinary calcium levels. However, when subcutaneous calcitonin combined with oral etidronate disodium was used, a reduction in the serum calcium level was observed within two days of therapy. Within one week of the start of this combined therapy, the calcium level returned to normal and urinary calcium excretion was substantially reduced.