Primary hyperparathyroidism is an endocrine disorder in which the body has too much parathyroid hormone (PTH).

The parathyroid glands are located at the front and base of the neck at the four corners of the thyroid gland. The glands produce parathyroid hormone, which controls the amount of calcium and phosphorus in the body.

In primary hyperparathyroidism, enlargement of one or more of the parathyroid glands causes extra parathyroid hormone to be released. This increases calcium levels. The effects of increased calcium are seen in several body systems including the skeletal, gastrointestinal, renal (kidney), muscular, and central nervous system.

The disease is most common in people over 60, but can also be seen in younger adults. Women are more likely to be affected than men. Radiation to the head and neck increases risk. Hyperparathyroidism in childhood is very unusual.

Rarely, the disease is caused by parathyroid cancer.

• Fatigue
• Fractures
• Decreased height
• Upper abdominal pain
• Loss of appetite
• Nausea
• Muscular weakness
• Muscle pain
• Depression
• Personality changes
• Stupor and possibly coma
• Kidney stones
• Increased urination

• A test called radioimmunoassay shows an increased level of PTH.
• Serum calcium is increased.
• Serum phosphorus may be decreased.
• Serum alkaline phosphatase may be increased.
• Bone x-ray may show bone reabsorption (the body breaks down the bone), or fractures.
• Imaging of the kidneys or ureters may show calcification or blockage.
• ECG may show abnormalities.

This disease may cause changes in the results of the following tests:

• Calcium - urine
• Calcium (ionized)
• Bone density
• Markers of bone resorption (N-telopeptide, pyridinoline, and deoxypyridinoline)