The parathyroid glands are four small glands that sit in the lower part of the front of the neck. Each of them is normally about the size of a pea. The parathyroid glands sit immediately next to the thyroid gland but are otherwise unrelated. They are simply neighbors. The parathyroid glands produce a hormone called parathyroid hormone which is involved in controlling the calcium level in your blood stream. Calcium is absorbed in the intestines from the foods that we eat and used to build bone density as well as other chemical reactions that occur in the body. The calcium level in the blood should stay in a defined range, and this is regulated by parathyroid hormone. Increased production of parathyroid hormone from the parathyroid glands will result in increasing the calcium level in the blood stream. As the calcium in the blood is used up and the level begins to decrease, the parathyroid glands will sense this and produce more parathyroid hormone. This will raise the calcium level in the blood in three important ways. It will pull calcium out from the bones and deposit it in the blood stream. It will also work on the intestines and the kidneys to increase calcium absorption from the foods that we eat.
In primary hyperparathyroidism one or more of the parathyroid glands becomes overgrown and overactive. This is virtually always benign. Parathyroid cancer is extraordinarily rare. As the abnormal parathyroid gland becomes overactive it produces high levels of parathyroid hormone which results in high levels of calcium in the blood. Normally if the blood calcium level were high, perhaps from consuming high levels of calcium containing foods, the parathyroid glands would sense this and temporarily shut down. However, in primary hyperparathyroidism instead of shutting down in the face of high calcium levels, the abnormal parathyroid gland continues to produce high levels of parathyroid hormone. The result is high levels of parathyroid hormone and high levels of calcium in the blood.
The symptoms of primary hyperparathyroidism can vary. Bone loss, or osteoporosis, can occur. This weakening of the bones can result in easy fracture from even minor trauma. Kidney stones and kidney damage can result from the high levels of calcium circulating in the blood that is ultimately filtered through the kidneys. Patient may also experience gastrointestinal symptoms such as nausea and bloating. There are also may be psychiatric symptoms such as anxiety, fatigue, depression, and mental fogginess. However, many patients may be completely asymptomatic. They may only become aware of the diagnosis on routine blood testing with their primary care physician.
The treatment for primary hyperparathyroidism is surgery to remove the abnormal gland or glands. Unfortunately, there is no medication to treat this condition. Not everyone with primary hyperparathyroidism needs to have surgery. Patients with obvious symptoms such as easy fractures or kidney stones should clearly have surgery. Patients who are under 50 years old should have surgery because it is felt that they body will be subject to the disorder for so long that inevitably they will develop problems. Patients with very high blood calcium (>1mg/dl above normal) or urine calcium (>400 mg in a 24-hour urine collection) should have surgery. Patients with osteoporosis, even without factures, should have surgery to prevent future weakening of the bones. And patients with the beginnings of kidney damage and dysfunction should have surgery to prevent further damage. In patients who are asymptomatic and do not meet any of these criteria, observation is a reasonable option. Yearly testing to monitor progression of the disorder is done to identify problems as they arise. An asymptomatic person may also choose to have surgery, in an effort to avoid the problems that may occur.
The goal of surgery is to remove the abnormal gland or glands and leave the normal ones behind. In approximately 80% of cases the problem is being caused by a single abnormal gland. This means that about 15 to 20% of the time there may be more than one gland that needs to be removed. As many as three or even three and a half of the glands can be removed safely. We cannot remove all of the parathyroid glands, or else the calcium levels will become too low.
Parathyroidectomy is done through a horizontal incision in the lower part of the front of the neck. It is performed in an operating room with the patient under anesthesia. The surgery time can range from as short as an hour, to as long as four or five hours, depending on how many glands need to be removed. In most cases patients are sent home on the day of surgery, however there may be times when an overnight observation is indicated. The success rate for the surgery is approximately 98%.