Recurrent or Persistent Hyperparathyroidism

Approximately 90% of patients with primary hyperparathyroidism (PHPT) are cured by parathyroidectomy at the initial neck exploration. Those not cured either remain hypercalcemic in the immediate postoperative period or develop hypercalcemia after a long period of normocalcemia. Almost all cases of hypercalcemia after neck exploration for PHPT are evident early in the postoperative period and are caused either by an overlooked parathyroid adenoma or an incomplete resection of hyperplastic parathyroid tissue. Less commonly, the surgeon has failed to recognize, and adequately treat, parathyroid carcinoma, or the diagnosis of PHPT was incorrect and there is another cause of the hypercalcemia. A successful neck exploration for PHPT is primarily dependent on the experience of the operating surgeon, the anatomic location of the parathyroid glands, either in "normal" or "ectopic" sites, and the presence of a single enlarged parathyroid gland as opposed to multiglandular disease or parathyroid carcinoma. In cases where an enlarged parathyroid gland is not identified at operation, noninvasive or invasive radiographic imaging procedures are useful in localizing the gland. Currently, the most reliable and practical procedure is technetium 99m sestamibi scanning. This technique identifies an enlarged parathyroid gland in 65-80% of cases. Single photon emission computed tomography (SPECT) in association with sestamibi scanning increases the sensitivity of the procedure to 85%. These imaging procedures are least reliable in patients with multiglandular disease. Ultrasound and computed tomographic scanning are less sensitive; however, they are commonly used as confirmatory tests in association with sestamibi scanning. When noninvasive imaging procedures fail to identify an enlarged parathyroid gland, invasive procedures, such as selective arteriography, are performed. Whereas invasive procedures are useful, they are associated with significant morbidity. Reoperations for persistent or recurrent hyperparathyroidism, compared with the initial operations, are associated with higher complication rates. In 90% of cases, the abnormal pathology can be reached through a cervical incision. The success rate of the reoperation depends primarily on the results of the localization procedure and whether the patient has a single enlarged parathyroid gland or multiglandular disease. Resection of a single enlarged gland is curative in virtually all patients. If, however, the patient has multiple gland disease, the operation is successful less often, especially in those with certain familial endocrinopathies.