Primary hyperparathyroidism: epidemiology, diagnosis and clinical picture.

Primary hyperparathyroidism (HPT) is a common disorder that mainly afflicts elderly women. It can be diagnosed in at least 1% of all postmenopausal females and autopsy studies indicate an even higher frequency. Although the widespread use of automated serum calcium analyses has increased the awareness of HPT, only 10% of all cases seem to be identified. The diagnosis relies on the demonstration of an inappropriately elevated serum concentration of parathyroid hormone (PTH) relative to the serum calcium value, which need not be markedly raised. Measurements of intact PTH with immunometric methods have considerably improved the diagnostic precision but it is still difficult to evaluate patients with only marginal hypercalcemia. Few patients with diagnosed HPT are completely without symptoms. Symptoms commonly encountered are psychiatric and neuromuscular disturbances. Subclinical bone disease might be relevant but there is insufficient information about its importance in otherwise asymptomatic individuals. Various cardiovascular risk factors appear more commonly in patients with HPT and untreated disease is associated with an increased risk of premature death.