Lab Value


A 47-year-old woman develops symptomatic hypercalcemia, and further workup demonstrates primary hyperparathyroidism. Surgical treatment shows the following gross and permanent histologic sections (see the image).

What is the most likely etiology of her disease?

Primary hyperparathyroidism (PHPT) is defined as the autonomous secretion of PTH, resulting in hypercalcemia. This is the most common cause of hypercalcemia in the outpatient population. Women are two-thirds more likely to have PHPT.

The systemic manifestations of PHPT are due to hypercalcemia. Bone pain, fragility fractures, nephrolithiasis, proximal muscle weakness, depression, nausea, vomiting, concentration issues, irritability, and gastrointestinal symptoms can all result from elevated levels of calcium (see the image).

Laboratory tests will be able to reliably diagnose primary hyperparathyroidism. Elevated calcium levels along with elevated or inappropriately normal PTH levels confirm the diagnosis. Ionized calcium levels are useful in determining an accurate calcium level in patients with albumin fluctuations. Creatinine and vitamin D levels should be evaluated to exclude secondary hyperparathyroidism. All patients with hypercalcemia should have a 24-hour urinary calcium/ creatinine ratio measured to rule out familial hypocalciuric hypercalcemia (FHH). This distinction is essential in making sure patients with FHH do not undergo parathyroidectomy, because surgery is not indicated.
The most common etiology of primary hyperparathyroidism is a single adenoma, which is found in 80–85% of patients.