The incidence is 6 out of 100,000 people. A biopsy of the parathyroid gland shows tumor or hyperplasia . A radioimmunoassay of parathyroid hormone that shows an increased level. Serum calcium is increased. Serum chloride may be increased.
Serum phosphorus is decreased.
Serum alkaline phosphatase may be increased. Bone X-ray shows bone reabsorption or fractures . Imaging of the kidneys or ureters shows calcification or obstruction. ECG may show abnormalities. Mild hypercalcemia may be followed medically unless impaired renal function, bone demineralization, or high blood pressure is present.