Secondary hyperparathyroidism after removal of a parathyroid adenoma

To report a case of secondary hyperparathyroidism after successful extirpation of a single parathyroid adenoma.

We present the clinical, pathologic, and laboratory findings in a 29-year-old woman with primary hyperparathyroidism. Serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations, bone turnover, and results of densitometry studies before and after parathyroidectomy were evaluated.

A young woman had noted fatigue, nervousness, weight loss, back pain, and polyuria for 3 months. She had hypercalcemia, hypophosphatemia, high PTH concentrations, and increased markers of bone turnover. Subperiosteal bone resorption of the distal phalanges, femoral and spine osteopenia, and osteoporosis in the radius were found. A nodule was palpated in the right side of the neck and localized by ultrasonography, nuclear medicine imaging studies, and computed tomography. A single parathyroid adenoma was removed; no other parathyroid lesions were found. Postoperatively, hypoparathyroidism developed. Supplementation with intravenously and orally administered calcium and vitamin D relieved her symptoms and normalized the serum calcium and phosphate concentrations. Subsequently, however, PTH levels were high and remained above the upper normal range for 27 weeks of follow-up, while calcium concentrations remained normal. These findings were consistent with physiologic secondary hyperparathyroidism due to "hungry bone syndrome," in the setting of normal renal function. Postoperatively, markers of bone resorption declined faster than those of bone formation, and sequential densitometry studies showed increments in bone mineral density.

This patient with primary hyperparathyroidism fulfilled the criteria for surgical extirpation of the neck mass. The prolonged postoperative increase in PTH level was indicative of physiologic secondary hyperparathyroidism that resolved gradually, along with the normalization of the increased bone turnover and bone mineral density during the 40-week observation period.