The parathyroid glands are four or more small collections of tissue that sit on either side of the thyroid gland in the neck. Their primary function is to control calcium levels in the blood and they do this by releasing a hormone called parathyroid hormone (PTH).
Calcium is one the most important elements required for function of the nervous system (including the brain), muscles and bones. As the blood filters through the parathyroid glands, they detect the amount of calcium present in the blood and react by making more or less parathyroid hormone (PTH). When the calcium level in the blood is too low, the cells of the parathyroid glands sense it and make more parathyroid hormone. Once the parathyroid hormone is released into the blood, it circulates to act in a number of places to increase the amount of calcium in the blood (like removing calcium from bones). When the calcium level in the blood is too high, the cells of the parathyroid glands make less parathyroid hormone (or stop making it altogether), thereby allowing calcium levels to decrease. This feed-back mechanism runs constantly, thereby maintaining calcium (and parathyroid hormone) in a very narrow "normal" range
In patients with hyperparathyroidism, one of the four parathyroid glands grows into a tumor and behaves inappropriately by constantly making excess parathyroid hormone regardless of the level of calcium. This leads to excessively high levels of calcium. What causes this excess hormone production? The most common cause of excess hormone production (hyperparathyroidism) is the development of a benign growth (tumor) in one of the parathyroid glands. This enlargement of one parathyroid gland is called a parathyroid adenoma which accounts for about 94 percent of all patients with hyperparathyroidism. Other causes include hyperplasia (enlargement) of all four glands, or very rarely, a cancerous tumor of the parathyroid.
Symptoms of hyperparathyroidism :
- Loss of energy. Don't feel like doing much. Tired all the time.
- Just don't feel well; don't quite feel normal. Hard to explain but just feel kind of bad.
- Can't concentrate, or can't keep your concentration like in the past.
- Gastric acid reflux
- Inability to concentrate or not like you used to
- Not sleeping well
- Thinning hair
- High blood pressure
- Kidney stones
- Heart palpitations
Imaging of the Parathyroids
- Sestamibi scan: this is a specialized scan done in a nuclear medicine facility. Sestamibi is a small protein which is labeled with the radio-pharmaceutical technetium-99. This very mild and safe radioactive agent is injected into the veins of a patient with parathyroid disease (hyperparathyroidism) and is absorbed by the overactive parathyroid gland. This gland alone will absorb the radioactive tracer and “light up” on the scan. In this way, the sestamibi scan help your doctor figure out which parathyroid gland has become the adenoma.
- Ultrasound: this technique is uses sound waves to detect masses in the neck and does not involve the use of contrast material or radioactivity. This technique is often used to identify abnormalities in the thyroid gland and can be very useful to differentiate parathyroid growths from the thyroid gland itself.
Treatment of hyperparathyroidism
85-95% of patients with hyperparathyroidism will have this disorder due to an adenoma. The most appropriate treatment for this in most cases is removal of the adenoma. You do not need all your parathyroid glands, and once the overactive adenoma is removed, the remaining glands will take over to keep your blood levels of calcium normal.
The surgery involves making an incision in the neck just above the collarbones. The muscles of the neck are moved to the side and the thyroid gland is identified. Often, the sestamibi scan and/or ultrasound will help your surgeon to know which side of the neck to start the surgery on. The essence of the surgery is to remove the offending gland while leaving the other structures of the neck intact. Important structures in the area of the parathyroid glands include the recurrent laryngeal nerve which allows you to move you to move your vocal cords.
What to expect: The surgery can take 1-3 hours on average. Often, your surgeon will place a small drain in your neck for the first 24 hours to collect any fluid that your body may weep after surgery. You may stay overnight in the hospital to check your calcium levels after surgery.
Risks of parathyroid surgery:
- Wound infection: after surgery, you may develop an infection of your incision. This is most commonly treated with a short course of antibiotics
- Hematoma: this is collection of blood under the skin. This is prevented by making sure all bleeding has stopped before closing the patient’s incision and applying some pressure to the neck after surgery. If a hematoma occurs, the blood can be sucked out with a needle in the office. Very rarely, the blood collection can be so large that the patient has trouble breathing. In this very rare case, the patient must be taken to the operating room to re-open the incision and remove the blood collection
- Injury to the recurrent laryngeal nerve: this nerve allows for proper movement of the vocal cords with speech. This nerve runs just below the thyroid gland to enter the voice box. This nerve is generally identified as it runs along the thyroid however, very rarely, this nerve can be injured. The result of injury can be hoarseness and vocal cord paralysis.
- Hypocalcemia (low calcium levels): it is not uncommon for patients to have temporary low calcium for the first 3-4 days after surgery as the remaining glands begin to take over controlling calcium levels. You may be discharged on calcium supplementation for the first week after surgery. However, there is a small risk of inadvertent removal of all parathyroid glands while searching for the adenoma. This can result in permanent low calcium levels and requirement for lifelong calcium supplementation.