Health Encyclopedia

Hyperparathyroidism

Definition

Hyperparathyroidism is excessive production of parathyroid hormone by the parathyroid glands.

Causes, incidence, and risk factors

The parathyroid glands are located in the neck, near or attached to the back side of the thyroid gland. They produce parathyroid hormone, which controls calcium, phosphorus, and vitamin D levels within the blood and bone.

When calcium levels are too low, the body responds by increasing production of parathyroid hormone. This increase in parathyroid hormone causes more calcium to be taken from the bone and more calcium to be reabsorbed by the intestines and kidney. When the calcium level returns to normal, parathyroid hormone production slows down.

There are two types of hyperparathyroidism.

Primary hyperparathyroidism is caused by enlargement of one or more of the parathyroid glands. This leads to too much parathyroid hormone, which raises the level of calcium in the blood. The term "hyperparathyroidism" generally refers to primary hyperparathyroidism.

Secondary hyperparathyroidism is when the body produces extra parathyroid hormone because the calcium levels are too low. This is seen when vitamin D levels are low or when calcium is not absorbed from the intestines. Correcting the calcium level and the underlying problem will bring the parathyroid levels in the normal range.

If the parathyroid glands continue to produce too much parathyroid hormone even though the calcium level is back to normal, the condition is called "tertiary hyperthyroidism." It occurs especially in patients with kidney problems.

Symptoms

Fatigue
Back pain
Joint pain
Fractures of long bones
Decreased height
Increased urine output
Increased thirst
Upper abdominal pain
Loss of appetite
Nausea
Muscular weakness
Muscle pain
Depression
Personality changes
Stupor and possibly coma
Itching of the skin
Blurred vision (because of cataracts)
Bone pain or tenderness

Signs and tests

Blood tests will be done to check for increased levels of parathyroid hormone (PTH), calcium, and alkaline phosphatase, and lower levels of serum phosphorus.

Additional tests include:

24-hour urine collection may show increased calcium in urine.
Bone x-ray shows bone reabsorption or fractures.
X-rays, ultrasound, or CT scans of the kidneys or ureters may show calcification or obstruction.
Bone density test may show reduced bone mineral density, particularly of the forearm.

Treatment

Treatment depends upon the severity and cause of the condition. If you have mild hypercalcemia due to primary hyperparathyroidism and no symptoms, you may just need regular check ups with your doctor.

If symptoms are present or your calcium level is very high, surgery may be necessary to take out the gland that is overproducing the hormone.

Secondary hyperparathyroidism is treated by giving calcium and vitamin D alone or together, depending on the underlying disorder.

Expectations (prognosis)

The outlook depends on the specific type of hyperparathyroidism.

Complications

Complications that result from excess calcium deposits within the body:

Skeletal damage
Urinary tract infection due to kidney stones and obstruction
Peptic ulcer disease and pancreatitis
Pseudogout

Surgery for hyperparathyroidism may lead to low blood calcium levels, which causes tingling and muscle twitching. This requires immediate treatment.

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.

Prevention

Getting the proper amount of calcium in your diet or through supplements may reduce your risk of secondary hyperparathyroidism.

Review Date:8/11/2006
Reviewed By:Robert Hurd, MD, Department of Biology, College of Arts and Sciences, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.

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