Calcium supplement necessary to correct hypocalcemia after total parathyroidectomy for renal osteodystrophy

Prediction of the extent of calcium supplement will facilitate safe and efficient management of hypocalcemia in the early postoperative stage of total parathyroidectomy with autotransplantation (PTXa) in patients with renal osteodystrophy.

The correlation between the extent of calcium deficiency, estimated by the amount of calcium supplement over 48 h after PTXa and using various parameters such as carboxy terminal parathyroid hormone (c-PTH), intact PTH (i-PTH), alkaline phosphatase (ALP), serum calcium, serum phosphorus, duration of hemodialysis, total weight of resected parathyroid glands and degree of subperiosteal resorption of the middle phalanx was examined in 49 patients who underwent PTX with subcutaneous autotransplantation. Bone mineral density (BMD) was also determined before, 3 months and 1 year after PTXa with dual energy X-ray absorptiometry (DEXA) in 13 patients.

There was a positive correlation between pre-operative i-PTH level (r=0.56, P<0.0005) or ALP level (r=0.50, P<0.0005) and the amount of calcium supplement over 48 h after PTXa in these patients. Furthermore, the degree of subperiosteal resorption, determined by Jensen's classification, was significantly correlated with the amount of calcium supplement after PTX (P<0.05). Bone mineral density 3 months after (P<0.0005) and 1 year after PTXa (P<0.001) significantly increased compared with BMD before PTXa in all patients examined.

These findings suggest that the pre-operative determination of i-PTH, ALP levels and degree of subperiosteal resorption allow the management of hypocalcemia safely and efficiently in renal osteodystrophy patients after PTXa.