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HYPOPARATHYROIDISM

What is Hypoparathyroidism ?

The parathyroids are four tiny glands, each the size of a rice grain. They are situated, two on each side, behind the thyroid gland which sits low in the neck. Their function is to regulate the calcium level in the blood. They do this by producing a hormone (parathormone) which withdraws calcium both from the bones as well as from food in the bowel. In hypoparathyroidism (hypo = deficient, parathyroidism = parathyroid activity), an absence or underactivity of these glands allows the calcium level in the blood to fall too low. This may produce no symptoms at all if it is only mild. In more severe cases, a low calcium level makes the nerves of the body very irritable. There may be tingling in the fingers or in the mouth, and spasms may occur in the hands so that the fingers cannot be straightened.

Why does Hypoparathyroidism occur ?

In some people, the parathyroid glands undergo an early decay (auto-immune destruction). This disorder is sometimes found in patients who have other endocrine gland damage. The commonest of these is an underactive thyroid gland or adrenal glands. The tendency to this type of glandular damage is inherited. More commonly, the parathyroid glands are damaged at the time of an operation. This may be because they are caught up with the thyroid gland at the time that this is removed by a surgeon for a variety of different reasons. The condition may also occur because the parathyroid glands need to be removed for an overactive parathyroid state. Some patients with this disorder have several glands affected: therefore all of them may need to be removed completely.

Treatment Involved with Hypoparathyroidism

Unfortunately, parathormone cannot be given by mouth. It would be destroyed by the enzymes in the stomach juices. It can be given by injection, but this is generally unnecessary. Vitamin D is a substance which has some similar actions to parathormone. It increases the absorption of calcium from the food in the bowel. Also, it can be given by mouth which makes it more convenient. Sometimes it needs to be given with calcium-containing tablets. Sometimes it is effective by itself but must usually be given either every day or every second day. The doctor will decide which type of vitamin D and what dose is best for your treatment and will measure the calcium level to ensure that the treatment dose is correct.

During Treatment for Hypoparathyroidism

At regular intervals, the doctor will check the calcium level in your blood. This will help him or her to decide whether the dose needs to be changed. To start with, this may mean tests every 1 to 2 weeks. After this, tests every 2 to 6 months are usually sufficient. Any symptoms which were present rapidly disappear, once the calcium level in the blood returns to normal. Because there are various types of vitamin D available, it is your responsibility to double check with the pharmacy that exactly the same preparation and strength continues to be supplied. It is important to emphasize that treatment must usually be given for the rest of your life, unless the parathyroids were just bruised at the time of an operation on your neck.

If Hypoparathyroidism is Left Untreated

In more severe cases, the symptoms of tingling and spasms in the hands would become unbearably painful. Mild cases of hypoparathyroidism produce only slight reductions in the blood-calcium level. In the absence of symptoms, the only area known to suffer under these circumstances is the lens of the eye. Cataracts are likely to form as a result of the calcium disturbance. This produces haloes around light objects and ultimately reduced vision. Some patients with long-standing hypoparathyroidism also develop calcium deposits in other tissues in the body, particularly parts of the brain. Here it can result in damage which in turn produces abnormal muscle movements of the hands.

Effects on Family of Hypoparathyroidism

Rare cases do run in families. If there has been no operation on the neck to cause the hypoparathyroidism, it is likely that it falls into this inherited category. It is then a good idea for close relatives to have their calcium level checked, and perhaps screening tests for other hormone deficiencies. Remember: once vitamin D has been commenced for permanently damaged or absent parathyroid glands, it must be continued lifelong.