The reasons for persistent hypercalcaemia after cervical exploration for presumed primary hyperparathyroidism

Of 500 consecutive patients who underwent cervical exploration for presumed primary hyperparathyroidism, 461 (92.2 per cent) were cured, as judged by an immediate return of serum calcium levels to normal. Thirty-nine patients (7.8 per cent) had persistent hypercalcaemia after the initial operation. The clinical profiles, operative and pathologic findings, surgical procedures performed and subsequent management of these 39 patients were reviewed. At reevaluation, 4 patients were noted to have been cured of their hyperparathyroidism. Twenty-one patients had persistent hyperparathyroidism: in 6, all 4 parathyroid glands had not been identified at the initial operation and in 15, hypercalcaemia persisted after the identification of 4 glands. One patient had recurrent hyperparathyroidism after the removal of a 720 mg adenoma and the identification of 3 normal parathyroid glands. Nine patients had nonparathyroid causes for the hypercalcaemia: 2 had occult malignant neoplasms, 6 had benign familial hypocalciuric hypercalcaemia and 1 had immobilization hypercalcaemia. In 4 patients the reason for the persistent hypercalcaemia remained unclear. We suggest a schema that may be used as a guideline in the investigation and management of patients with persistent hypercalcaemia after primary neck exploration for presumed hyperparathyroidism.