Hyperparathyroidism: primary or secondary disease?

Primary hyperparathyroidism (PHPT) is characterized by the autonomous production of parathyroid hormone (PTH), in which there is hypercalcemia or normal-high serum calcium levels in the presence of elevated or inappropriately normal serum PTH concentrations. Exceptionally in symptomatic patients, a diagnostic can be established on the basis of clinical data. PHPT must always be evaluated in patients with clinical histories of nephrolithiasis, nephrocalcinosis, osseous pain, subperiosteal resorption, and pathologic fractures, as well as in those with osteoporosis-osteopenia, a personal history of neck irradiation, or a family history of multiple endocrine neoplasia syndrome (types 1 or 2). Diagnosis of PHPT is biochemical. Asymptomatic hypercalcemia without guiding signs or symptoms is the most frequent manifestation of the disease. For differential diagnosis, PTH must be measured, as well as phosphate, chloride, 25-hydroxyvitamin D, 1,25 dyhidroxyvitamin D and calcium-to-creatinine clearance. The diagnosis and differential diagnosis of primary hyperparathyroidism will be discussed here.