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A: Primary hyperparathyroidism occurs when the body produces too much parathyroid hormone (PTH), the hormone that controls the amount of calcium in the body. PTH is produced by the parathyroids, four pea-sized glands located behind the thyroid (see Picturing the parathyroid glands). Normally, PTH maintains the serum calcium level at 8.4 to 10.5 mg/dL (2.1 to 2.6 mmol/L). But in primary hyperparathyroidism, enlargement of one or more of the parathyroid glands causes extra PTH to be secreted, which increases the calcium level (hypercalcemia). Too much calcium in the body may affect the skeletal, gastrointestinal, renal, muscular, and central nervous systems, as well as possibly cause a decreased phosphate level (normal phosphate is 2.5 to 4.5 mg/dL).


Primary hyperparathyroidism is usually caused by a benign tumor or overgrowth. Cancer of the parathyroid glands is rare but should be considered, especially if the patient presents with a palpable neck mass and severe hypercalcemia. Primary hyperparathyroidism can be seen in patients over age 30, but it's most common in patients over age 60 and in those who have had radiation to the head or neck. It affects women and men equally and is rarely seen in children.

Figure. Q: Whats pri... - Click to enlarge in new windowFigure. Q: What's primary hyperparathyroidism?

A patient with primary hyperparathyroidism may be asymptomatic, especially if her calcium level is only slightly elevated. Symptoms of hypercalcemia include muscle weakness, fatigue, constipation, nausea, fractures, kidney stones, hypertension, and cardiac dysrhythmias.

Figure. Picturing th... - Click to enlarge in new windowFigure. Picturing the parathyroid glands

Diagnosis consists of a radioimmunoassay for PTH. The double-antibody PTH test is used to distinguish between primary hyperparathyroidism and malignancy. A nuclear parathyroid scan is used to localize a growth. Ultrasound, magnetic resonance imaging, thallium scan, and fine-needle biopsy can also be used to evaluate parathyroid function and localize cysts, tumors, or overgrowth.


Parathyroidectomy is the treatment of choice. A minimally invasive procedure may be done if the tumor can be localized preoperatively. Normal parathyroid function usually returns within a week of surgery. Monitor the patient for hypocalcemia; if present, she may need to take calcitriol and oral calcium supplements.


If the patient isn't a surgical candidate due to age or comorbidities, her calcium level must be closely monitored. Bisphosphonate therapy (alendronate [Fosamax] or risedronate [Actonel]) may be prescribed for patients with documented bone loss to reduce the serum calcium and urine calcium levels. Other conservative treatments include increasing fluid intake and exercise.


Most cases of primary hyperparathyroidism are mild, so the patient should make a full recovery.


Learn more about it


MedlinePlus. Primary hyperparathyroidism. Accessed January 31, 2006.


Smeltzer SC, Bare B. Brunner & Suddarth's Textbook of Medical-Surgical Nursing, 11th edition. Philadelphia, Pa., Lippincott Williams & Wilkins, 2007.