[Changes in calcium metabolism after parathyroidectomy in primary hyperparathyroidism].

Introduction: Primary hyperparathyroidism causes elevated serum calcium level and osteopenia in most patients.

Aims: The authors measured the changes of calcium and bone mineral metabolism after parathyroidectomy in patients with primary hyperparathyroidism.

Patients: From 1995 to 2000, osteopenia was detected in 34 patients with primary hyperparathyroidism before surgery. There were 26 females (16 women were post-menopausal) and 8 males. The mean age of the patients was 54 years (range 19 to 64). The serum levels of calcium, phosphorus, alkaline phosphatase and the parathyroid hormone were measured before the operation and every year thereafter. Bone densitometry was performed at the lumbar spine (L II-IV) during the same period.

Results: The mean levels of calcium and parathyroid hormone rapidly decreased and varied in the normal range after the operation. The mean alkaline phosphatase concentrations also decreased after surgery, but in most cases the difference was not statistically significant. Bone densitometry showed increased bone mineral density at the lumbar spine (L II-IV) after the parathyroidectomy. One, 2, 3, 4 and 5 years after surgery the bone mineral density increased with 8.5%, 12.5%, 14.1%, 13.5% and 11.3% compared to the preoperative value respectively. The changes in bone mineral density values were not statistically significant 1 year after parathyroidectomy. The increase in the bone mineral density was significant two years after the operation. Nine patients had T-scores less than -2.5 before parathyroidectomy.

Conclusion: The authors conclude, that the serum levels of calcium and parathyroid hormone significantly decreased after the parathyroidectomy in primary hyperparathyroidism. After successful surgical treatment the bone mineral density significantly increases and the osteopenia decreases or resolves.