ASA :: Parathyroid Disease

Parathyroid Disease Parathyroid glands are small glands of the endocrine system which are normally about the size and shape of a grain of rice. The sole purpose of the parathyroid glands is to regulate the calcium level in our bodies within a very narrow range so that the nervous and muscular systems can function properly. Although they are neighbors and both part of the endocrine system, the thyroid and parathyroid glands are otherwise unrelated. The single major disease of the parathyroid glands is overactivity of one or more of the parathyroid glands, which make too much parathyroid hormone causing a potentially serious calcium imbalance. This is called hyperparathyroidism.

Hyperparathyroidism:

The primary disease of parathyroid glands is overactivity -- when too much parathyroid hormone is produced. This is called hyperparathyroidism. Under this condition one or more of the parathyroid glands behaves inappropriately by making excess hormone regardless of the level of calcium. In other words, the parathyroid glands continue to make large amounts of parathyroid hormone even when the calcium level is normal and they should not be making hormone at all. Remember as you read these pages, it’s a hormone problem, not a cancer problem.

Treatment:

Since 1925, the standard treatment for parathyroid disease (primary hyperparathyroidism) has been to surgically remove the parathyroid gland (or glands). Again, the concept is really quite simple: Find which parathyroid gland has become a tumor and is making too much parathyroid hormone and take it out — leaving the other normal parathyroids alone. The normal parathyroid glands will take over and you will be cured. You don’t need all four parathyroid glands. The standard parathyroid operation is performed by putting the patient to sleep under general anesthesia. An incision is made in the neck, the muscles of the neck retracted sideways and the thyroid gland is mobilized to allow the surgeon to identify the four parathyroid glands which reside moderately deep in the neck behind the thyroid. Patients usually stay in the hospital overnight to be sure the calcium level does not drop too low. During the surgery the surgeon will try to identify all four parathyroid glands and remove whichever one(s) is enlarged. Approximately 95% of the time there is one large parathyroid gland (an adenoma which is a benign parathyroid tumor) and three normal parathyroid glands. In this situation the one large gland (parathyroid adenoma) would be removed leaving the three normal ones to function in a normal fashion indefinitely. If the surgeon found all four parathyroid glands to be enlarged (found in only 3-4% of patients and called: parathyroid hyperplasia), he would typically take out 3-1/2 of these glands leaving some parathyroid tissue behind to function normally in the future (you only need ½ of a parathyroid gland to function normally).

The principle of parathyroid surgery is simple but the parathyroid glands can be hard to find. There are four parathyroid glands and they can be located all over the neck. The key to successful operation is for the surgeon to find the bad parathyroid gland. Parathyroid glands have the most un-predictable anatomy in the human body. Parathyroid glands are typically found on the back side of the thyroid gland. In fact, about 85% of parathyroid glands are found here. The picture shows the back side of the thyroid gland, showing that the four parathyroid glands are closely associated with the back of the thyroid.

Parathyroid glands are only the size of a grain of rice (half a pea) when the are normal and get to be about the size of a grape when they develop into a tumor (parathyroid adenoma).

The important thing to remember is that this is a benign tumor and surgery with removal of the tumor will cure 95% of all patients.

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