Lab Value


A 58-year-old woman without any significant past medical history presents to her primary care physician for her routine yearly physical. She has had some vague complaints of fatigue, but has otherwise been in good health. Her calcium level was noted to be elevated on her blood work.

Which of the following is the most likely etiology of her disease?

Hypercalcemia occurs in 0.1–0.5% of the population, with the most common etiology in the outpatient setting being primary hyperparathyroidism (PHPT), present in approximately 1% of the population (incidence increases to 2% over the age of 55).

Hyperparathyroidism and resulting hypercalcemia affect several organ systems in the body. Renal symptoms develop because hypercalcemia leads to an increase in urinary calcium excretion and PTH increases the excretion of phosphate and produces urinary alkalosis. This combination increases risk of stone formation. Bone disease is a direct effect of PTH, causing bone resorption and resulting in osteopenia/osteoporosis. Gastrointestinal manifestations are general nonspecific complaints of nausea, constipation, and abdominal pain. In addition, although nonspecific, neurocognitive symptoms include fatigue, lethargy, confusion, memory loss, concentration issues, and depression. Cardiac effects can be seen on electrocardiogram showing shortened QT interval and widening of the T wave. When calcium levels are extremely elevated, bradycardia and complete heart block can be seen.
The only definitive treatment of primary hyperparathyroidism is surgical resection of the affected gland(s).