Primary hyperparathyroidism

Definition

Primary hyperparathyroidism involves excessive production of parathyroid hormone, caused by enlargement of one or more of the parathyroid glands.

Causes, incidence, and risk factors

The parathyroid glands are located at the front and base of the neck at the 4 corners of the thyroid gland. The glands produce parathyroid hormone (PTH), which regulates calcium and phosphorus balance in the body.

In primary hyperparathyroidism, increased secretion of parathyroid hormone occurs because one or more of the glands have become enlarged. 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 distinctly unusual.

Rarely, the disease is caused by parathyroid carcinoma.

Symptoms

• 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

Signs and tests

• Radioimmunoassay of parathyroid hormone shows an increased level.
• Serum calcium is increased.
• Serum phosphorus may be decreased.
• Serum alkaline phosphatase may be increased.
• Bone x-ray may show bone reabsorption or fractures.
• Imaging of the kidneys or ureters may show calcification or obstruction.
• ECG may show abnormalities.

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

Treatment

Treatment depends upon the severity and cause of the condition. Mild hypercalcemia may be monitored -- rather than treated -- unless impaired renal function, kidney stones or bone demineralization occur.

Treatment may include:

• Encouraging fluids given by mouth to prevent kidney stone formation
• Avoiding sedentary lifestyle or immobilization
• Avoiding thiazide-type diuretics
• Using estrogen therapy (for postmenopausal women)

For symptomatic, severe hypercalcemia, hospitalization may be required. Rehydration using intravenous fluids may be started. Medications to quickly bring down the calcium may be given, such as bisphosphonates and calcitonin

Surgical removal of a tumor or excess parathyroid tissue from hyperplasia is indicated if hypercalcemia is more severe or if one or more of the following complications are present: kidney stones (nephrolithiasis), pancreatitis, psychiatric disease, or bone demineralization.

Surgery is also recommended for younger patients (less than 50 years old).

Expectations (prognosis)

The prognosis is good for mild cases, which are in the majority.

Complications

Complications that result from excess calcium deposits within the body:

• Skeletal damage
• Urinary tract infection due to kidney stones and obstruction
• Pancreatitis
• Pseudogout

Calling your health care provider

Call for an appointment with your health care provider if symptoms indicate that primary hyperparathyroidism may be present.

Call your health care provider if signs of complications develop.

Illustrations

Endocrine glands

Parathyroid glands

Page Content:

Parathyroid-related hypercalcemia