Rapid Homologous Radioimmunoassay for Human Parathyroid Hormone (Residues 53–84) as a Diagnostic Aid in Hypercalcemic Crisis

Abstract

The most frequent cause of hypercalcemia is primary hyperparathyroidism (HPT). Primary HPT is found in 55% of all hypercalcemic patients, while 35% of them suffer from malignancy [1]. Malignancies, which are occasionally associated with hypercalcemia, are divided into three groups: (a) hematopoetic malignancies, (b) solid tumors with bone metastases and (c) solid tumors without bone metastases [2]. Less frequent causes of hypercalcemia are sarcoidosis, vitamin D intoxication, thiazide intake, hyperthyroidism, Addison’s disease, and familial hypocalciuric hypercalcemia. There is some variation in reports of the frequency of disease which causes hypercalcemia [3]. The underlying disease in patients who develop hypercalcemic crisis (serum calcium > 4.0 mmol/liter) is most often primary HPT [3]. However, another group has reported somewhat different data [4]. Hypercalcemic crisis is an acute disease with high lethality. Therefore, rapid diagnostic procedures are mandatory. The search for a malignancy must parallel measures to reveal hyperparathyroidism (anamnesis, laboratory results, hand and skull X-rays). It is important to perform surgery in a patient with primary HPT while therapy of other causes of hypercalcemic crisis does not include surgery of the parathyroid glands.