Primary hyperparathyroidism: changes in the pattern of clinical presentation.

207 hypercalcaemic patients, discovered in an urban area of 1 million people over a period of 5 months, were examined to determine the current incidence and mode of presentation of primary hyperparathyroidism. Primary hyperparathyroidism was diagnosed in 111 patients and those most at risk were women over the age of 70 (55% of all patients). In 57% of all patients the initial indication of primary hyperparathyroidism was hypercalcaemia found unexpectedly on biochemical screening of the serum. The next most common mode of presentation was an acute hypercalcaemic syndrome in elderly patients, characterised by confusion and dehydration (14% of all patients). Modern diagnostic methods and routine estimations of serum calcium can be expected to yield at least 250 new cases of primary hyperparathyroidism per million population per year.