CLINICAL FINDINGS IN PATIENTS WITH HYPERCALCAEMIA A Final Investigation Based on Biochemical Screening

Ninety patients with hypercalcaemia (serum calcium 5.6 mEq/l or more) found in the course of 9 months in 1970‐71, when a multiphasic procedure was applied for the first time, have been reexamined 2 1/2 years later. According to clinical data the patients were divided into six groups: 1) verified primary hyperparathyroidism, 2) probable primary hyperparathyroidism, 3) possible primary hyperparathyroidism, 4) hypercalcaemia of other known cause, 5) hypercalcaemia of unknown cause, and 6) no disturbance of calcium metabolism. The frequency of hyperparathyroidism seems to be higher than in other studies probably because biochemical profiling was applied for the first time to the population in this area. Hyperparathyroidism was the most common cause of hypercalcaemia (28/100 000 in‐hab./y.), closely followed by thiazides (21/100 000 in‐hab./y.) and malignant diseases (16/100000 inhab./y.). Of patients treated with thiazides 0.44% have been found to have hypercalcaemia. When screening procedure is used regularly over a longer period, it seems likely that the most common cause of hypercalcaemia will be found to be thiazides. However, from a clinical point of view the diagnosis of hyperparathyroidism remains the main problem.