Hyperparathyroidism (HPT) is a hormonal disorder that occurs when one or more of your four parathyroid glands become enlarged and overactive, causing them to produce excessive amounts of parathyroid hormone (PTH).
Your parathyroid glands, which are about the size of a pea, are located behind the thyroid gland at the front of your neck. They produce PTH, the hormone that maintains the correct levels of calcium in your blood and bones, helps absorb calcium from food and prevents you from losing too much calcium in your urine.
If you have HPT, too much calcium leaves your bones and collects in your blood. This can result in excess bone loss or osteoporosis as well as other problems such as kidney stones and kidney malfunction.
In 85 percent of people with HPT, a benign tumor, called an adenoma, has formed on one of the parathyroid glands, causing it to become overactive. In most other cases, the excess hormone comes from two or more enlarged parathyroid glands, a condition called hyperplasia.
Very rarely, hyperparathyroidism is caused by cancer of a parathyroid gland. About 28 out of 100,000 Americans develop HPT each year. Twice as many women develop this disease and the incidence increases with age.
Often people with hyperparathyrodism do not experience any symptoms or attribute them to other causes. Excessive parathyroid hormone can cause bones to become weak from loss of calcium. Skeletal weakening is one of the classic effects of hyperparathyroidism and may make people susceptible to broken bones. A high blood calcium level also can lead to kidney stones and kidney malfunction. Other common symptoms of hyperparathyroidism include:
Hyperparathyroidism is diagnosed by a simple blood test that measures the amount of parathyroid hormone and calcium in your blood. Once the diagnosis is established, other tests may be done to determine if other problems are present. For example, a bone density measurement test may be performed to calculate bone loss or asses the risk of fractures. Abdominal radiographs may detect kidney stones and a 24-hour urine collection may provide information on kidney damage and the risk of stone formation.
Surgery to remove the enlarged gland(s) is the only treatment for hyperparathyroidism (HPT) and cures 95 percent of cases. The growth typically does not return and symptoms disappear after the first month of surgery. For a short time after surgery, your blood calcium level may be too low, which is easily treated with medicine.
If surgery is not recommended because of other medical conditions, medicines are available to treat some of the symptoms of HPT. Some patients who have a mild form of the disease, are symptom-free, only have slightly elevated blood calcium levels and whose kidneys and bones are normal may not need surgery. In these cases, patients require monitoring of their calcium and kidney functions ever six months as well as abdominal X-rays and bone mass measurements after one to two years.
Reviewed by health care specialists at UCSF Medical Center.