Hyperparathyroidism is marked by overactivity of one or more of the parathyroid glands, the four pea-size glands located at the corners of the thyroid gland. These glands produce parathyroid hormone (PTH), a chemical that, along with vitamin D and calcitonin (a hormone), regulates blood calcium levels.
Inappropriate production of PTH due to hyperparathyroidism results in unusually high levels of blood calcium (hypercalcemia), most of which is released from the calcium stores in the bones. Eventually, this calcium loss may lead to weakened bones and fractures.
Excess calcium in the blood may also lead to calcinosis—the deposition of calcium salts in various body tissues, including the kidneys, skin, tendons, and cartilage—resulting in kidney disorders, arthritis, or other problems.
Excess blood levels of calcium also results in excretion of large amounts of calcium in the urine, which can, over time, cause kidney stones or renal damage. Other problems associated with hyperparathyroidism are peptic ulcers and pancreatitis.
A sudden attack of severe hypercalcemia can be a life-threatening emergency. However, in many cases, mild hyperparathyroidism causes few if any symptoms and is only discovered during a routine blood test. This relatively rare disorder is most common among women over age 40.
What Causes Hyperparathyroidism?
- Most often, a benign tumor (adenoma) on one or more of the parathyroid glands is the cause.
- Hyperparathyroidism may run in families with a history of multiple endocrine tumors, such as those of the pituitary or pancreas.
- The disorder may be due to generalized enlargement (hyperplasia) of all four parathyroid glands.
- Other disorders, including chronic renal failure and vitamin D deficiency (rickets), result in low blood calcium. This triggers a rise in parathyroid hormone, known as secondary hyperparathyroidism.
- Long-term use of certain drugs such as laxatives, lithium, and phenytoin may play a role.
Symptoms of Hyperparathyroidism
- Generalized discomfort
- Muscle aches or weakness; arthritic joint pain
- Heartbeat irregularities
- Constipation, nausea, vomiting, loss of appetite, weight loss
- Fatigue, lethargy, confusion, depression, psychosis, or other mental changes, possibly resulting in coma (due to hypercalcemia)
- Increased thirst and urine output (due to kidney involvement)
- Frequent or unexplained bone fractures
- Chronic low back pain or upper abdominal pain (due to peptic ulcer or pancreatitis)
- Kidney stones
- Blurred vision (because of cataracts), bone pain or tenderness, decreased height, increased urine output, itchy skin, joint pain, muscle weakness and pain and personality changes
- There is no way to prevent hyperparathyroidism.
- Neck ultrasound determines the existence of parathyroid tumor (adenoma) in the neck.
- Abdominal x-ray reveals the presence of kidney stones caused by high calcium levels.
- Patient history and physical examination are needed.
- Calcium levels in the urine are measured.
- High blood levels of calcium and low levels of phosphorous indicate primary hyperparathyroidism.
- Measuring blood levels of PTH confirms diagnosis.
- Bone densitometry may be taken to assess bone loss.
How Hyperparathyroidism Is Treated
- In cases producing no obvious symptoms, careful, regular monitoring may be all that is required.
- High fluid intake is recommended in patients with high levels of calcium in their blood or urine.
- In symptomatic cases, surgical removal of abnormal parathyroid tissue usually cures the disorder. If more than one gland is enlarged or if the parathyroid abnormal growth cannot be located, all but half of one of the four parathyroid glands may be removed. (The remaining parathyroid tissue may produce insufficient amounts of PTH, requiring treatment for hypoparathyroidism.) Surgery is indicated if blood calcium levels are too high or if there is evidence of bone or kidney damage.
When to Call a Doctor
- See a doctor for regular checkups or if you experience symptoms of hyperparathyroidism.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media