Hypoparathyroidism

What Is It?

Hypoparathyroidism is a rare disorder in which the body produces too little or no parathyroid hormone. This hormone, together with vitamin D and another hormone called calcitonin, regulates the amount of calcium in the blood. Hypoparathyroidism can result in an abnormally low level of calcium in the blood, called hypocalcemia.

Parathyroid hormone is produced by the parathyroid glands, four small glands located behind the thyroid gland in the neck.

Doctors classify hypoparathyroidism as either hereditary or acquired. In hereditary hypoparathyroidism, the parathyroid glands are either absent at birth or fail to function properly for some unknown reason. Hereditary hypoparathyroidism sometimes occurs with other developmental defects, or as part of a syndrome of abnormalities that also affects the thyroid gland and adrenal cortex. It generally causes symptoms before age 10, although occasionally it will appear later.

Acquired hypoparathyroidism most commonly occurs when the parathyroid glands are removed during surgery. This can occur during thyroid surgery to treat hyperthyroidism or a thyroid tumor, or during surgery on the parathyroid glands themselves to treat an overproduction of parathyroid hormone (hyperparathyroidism). Acquired hypoparathyroidism is less common than it once was because surgeons have recognized the importance of preserving the parathyroid glands during surgery, and because nonsurgical treatments for hyperthyroidism have become more common.

Symptoms

The symptoms of hypoparathyroidism result from the low levels of calcium in the body. The most common symptom is muscle cramps or tightness and tingling of the lips or fingers. This condition is known as tetany, which causes twitching and painful spasms in muscles of the face, hands, arms, throat and, sometimes, the feet. Seizures also can occur, but they are rare.

In addition to tetany, symptoms accompanying hereditary hypoparathyroidism can include:

• Hair loss
• Dry skin
• Yeast infection (candidiasis), typically of the fingers, toenails, skin, mouth (thrush) or vagina

Undetected hypoparathyroidism in children also can lead to:

• Vomiting
• Headaches
• Poor tooth development
• Mental retardation

Diagnosis

Your doctor will ask you about unexplained twitching or spasms of muscles, dry skin, hair loss or yeast infections. In children, your doctor will ask about tooth development and about the timing of developmental milestones (ages at which your child first rolled over, sat up, crawled, walked and spoke).