Hypoparathyroidism

Parathyroid-related hypocalcemia

There are 4 tiny parathyroid glands in the neck, located near or attached to the back side of the thyroid gland.

The parathyroid glands help control calcium use and removal by the body. They do this by producing parathyroid hormone (PTH). PTH helps control calcium, phosphorus, and vitamin D levels in the blood and bone.

Hypoparathyroidism occurs when the glands produce too little PTH. The blood calcium level falls, and the phosphorus level rises.

The most common cause of hypoparathyroidism is injury to the parathyroid glands during thyroid or neck surgery. It may also be caused by any of the following:

• Radioactive iodine treatment for hyperthyroidism
• Very low magnesium level in the blood
• Autoimmune attack on the parathyroid glands

DiGeorge syndrome is a childhood disease in which hypoparathyroidism occurs because all the parathyroid glands are missing at birth. This disease includes other health problems besides hypoparathyroidism.

Familial hypoparathyroidism occurs with other endocrine diseases such as adrenal insufficiency in a syndrome called type I polyglandular autoimmune syndrome (PGA I).

Symptoms may include any of the following:

• Abdominal pain
• Brittle nails
• Cataracts
• Calcium deposits in some tissues
• Decreased consciousness
• Dry hair
• Dry, scaly skin
• Muscle cramps
• Muscle spasms called tetany (can affect the larynx, causing breathing difficulties)
• Pain in the face, legs, and feet
• Painful menstruation
• Seizures
• Teeth that do not grow in on time, or at all
• Tingling lips, fingers, and toes
• Weakened tooth enamel (in children)

The health care provider will do a physical exam and ask about symptoms.

Tests that will be done include:

• PTH blood test
• Calcium blood test
• Magnesium
• 24-hour urine test

Other tests that may be ordered include:

• ECG to check for an abnormal heart rhythm
• CT scan to check for calcium deposits in the brain

The goal of treatment is to reduce symptoms and restore the calcium and mineral balance in the body.

Treatment involves calcium carbonate and vitamin D supplements. These usually must be taken for life. Blood levels are measured regularly to make sure that the dose is correct. A high-calcium, low-phosphorous diet is recommended.

Injections of PTH may be recommended for some people. Your doctor can tell you if this medicine is right for you.

People who have life-threatening attacks of low calcium levels or prolonged muscle contractions are given calcium through a vein (IV). Precautions are taken to prevent seizures or larynx spasms. The heart is monitored for abnormal rhythms until the person is stable. When the life-threatening attack has been controlled, treatment continues with medicine taken by mouth.

The outcome is likely to be good if the diagnosis is made early. But changes in the teeth, cataracts, and brain calcifications cannot be reversed in children who have undiagnosed hypoparathyroidism during development.

Hypoparathyroidism in children may lead to poor growth, abnormal teeth, and slow mental development.

Too much treatment with vitamin D and calcium can cause high blood calcium (hypercalcemia) or high urine calcium (hypercalciuria). Excess treatment may sometimes interfere with kidney function, or even cause kidney failure.

Hypoparathyroidism increases the risk of:

• Addison disease (only if the cause is autoimmune)
• Cataracts
• Parkinson disease
• Pernicious anemia (only if the cause is autoimmune)

Call your provider if you develop any symptoms of hypoparathyroidism.

Seizures or breathing problems are an emergency. Call 911 or your local emergency number right away.