Hypoparathyroidism

DEFINITION

Hypoparathyroidism is an uncommon condition in which your body secretes abnormally low levels of parathyroid hormone (PTH). PTH plays a key role in regulating and maintaining a balance of your body’s levels of two minerals — calcium and phosphorus.

The low production of PTH in hypoparathyroidism leads to abnormally low ionized calcium levels in your blood and bones and to an increase of serum phosphorus.

Treatment for hypoparathyroidism consists of taking supplements to normalize your calcium and phosphorus levels. Depending on the cause of your hypoparathyroidism, you’ll likely need to take supplements for life.

CAUSES

Hypoparathyroidism occurs when your parathyroid glands don’t secrete enough parathyroid hormone. You have four parathyroid glands — each normally about the size of a grain of rice — situated in your neck, adjacent to your thyroid gland.

The low production of PTH leads to abnormally low calcium levels (hypocalcemia) in your blood and bones and to increased levels of serum phosphorus (hyperphosphatemia).
Factors that can cause hypoparathyroidism include:

• Acquired hypoparathyroidism. This most common cause of hypoparathyroidism develops after accidental damage to or removal of the parathyroid glands during surgery. This surgery may be a treatment for diseases of the nearby thyroid gland, or for throat cancer or neck cancer. Today, surgeons are more careful to avoid injuring the parathyroid glands during surgery.
• Autoimmune disease. In this condition, your immune system creates antibodies against the parathyroid tissues, trying to reject them as if they were foreign bodies. In the process, the parathyroid glands stop manufacturing their hormone.
• Hereditary hypoparathyroidism. In this form, either the parathyroid glands aren’t present at birth, or they don’t work properly. Some types of hereditary hypoparathyroidism are associated with deficiencies of other hormone-producing glands.
• Extensive cancer radiation treatment of your face or neck. Radiation can result in destruction of your parathyroid glands, as can radioactive iodine treatment for hyperthyroidism, occasionally.
• Low levels of magnesium in your blood, which can affect the function of your parathyroid glands. Normal serum magnesium levels are required for optimum secretion of parathyroid hormone.

SYMPTOMS

Signs and symptoms of hypoparathyroidism can include:

• Tingling or burning (paresthesias) in your fingertips, toes and lips
• Muscle aches or cramps affecting your legs, feet, abdomen or face
• Twitching or spasms of your muscles, particularly around your mouth, but also in your hands, arms and throat
• Fatigue or weakness
• Painful menstruation
• Patchy hair loss, such as thinning of your eyebrows
• Dry, coarse skin
• Brittle nails
• Headaches
• Depression, mood swings
• Memory problems

When to see a doctor

If you have any of the signs and symptoms associated with hypoparathyroidism, make an appointment with your doctor for an evaluation. Contact your doctor immediately if you have a seizure or have difficulty breathing, both of which can be complications of hypoparathyroidism.