Hyperparathyroidism
What is Hyperparathyroidism?
Primary hyperparathyroidism is a hormonal problem due to one or more parathyroid glands producing too much parathyroid hormone. Parathyroid glands, four small glands located in the neck near the thyroid gland, keep blood calcium from falling below normal.
In 80 to 85 percent of patients with primary hyperparathyroidism, a single gland is affected. In 15 to 20 percent of patients, two or more glands are affected. The affected gland(s) enlarge and produce too much parathyroid hormone. As a result, blood calcium becomes high, bones may lose calcium, and kidneys may excrete too much calcium.
Hyperparathyroidism Risk Factors
- Gender. Women outnumber men 3 to 1 in developing the disease.
- Age. Risk of developing the disease increases with age.
- Radiation. Previous exposure to radiation in the facial or neck area and certain medications (including thiazide diuretics and lithium) may cause primary hyperparathyroidism.
- Family history. In some families the disease is inherited.
Hyperparathyroidism Diagnosis
Primary hyperparathyroidism is usually diagnosed through a routine blood test. Once suspected, the following additional tests are done:
- Blood test. For calcium, phosphorus, alkaline phosphatase, 25-hydroxyvitamin D, 1,25-dihydroxy-vitamin D, and parathyroid hormone to determine the activity of the disease.
- Urine test. For calcium, kidney function, and "bone markers" that indicate whether a patient is likely to be losing bone calcium.
- Urinalyses and kidney X-rays. In some cases these are needed to check on kidney stone formation.
- Bone density test. This test is the only way to measure bone density.
Hyperparathyroidism Early Detection
Even in patients who have no symptoms, primary hyperparathyroidism can cause bones to become less dense and can also lead to kidney stones. When the blood calcium exceeds the routine elevations seen in primary hyperparathyroidism, symptoms can include:
- Loss of appetite
- Thirst
- Frequent urination
- Lethargy
- Fatigue
- Muscle weakness
- Joint pain
- Constipation
When the blood calcium becomes very high, more severe symptoms include:
- Nausea
- Vomiting
- Abdominal pain
- Memory loss
- Depression
Hyperparathyroidism Treatment
At present, the only known cure for primary hyperparathyroidism is surgical removal of the affected gland(s). Experts have developed guidelines to help determine who should have surgery. The decision requires careful evaluation and individual assessment.
An experienced surgeon often does not require imaging tests to locate the affected gland(s). However, if needed, several non-invasive tests may be used including ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and the Sestamibi scan.
Recently three surgical techniques termed "minimally invasive parathyroidectomy" have been developed. These new techniques are generally performed in select medical centers, such as John Wayne Cancer Institute, by experienced parathyroid surgeons. The Sestamibi scan is used for these procedures.
- Removal of a single gland using local anesthesia. During the operation, the blood parathyroid hormone level is measured. After the gland is removed, the hormone level is tested again. A normal hormone level indicates a successful operation.
- Use of a detector to measure abnormal activity before and after surgery. Following a Sestamibi scan, the detector is passed over the area of the operation to further identify the overactive gland(s) and measure abnormal activity. The detector is used again following removal of the gland(s) to ensure that all abnormal activity has been eliminated.
- Removal of the affected gland by an endoscope, an instrument used for examination of a body cavity.
Patients should drink enough fluid to avoid dehydration, which leads to an increase in blood calcium. To avoid worsening calcium levels, patients should get regular exercise and avoid immobilization. A diet including approximately 1200 mg of calcium is recommended.