There are four parathyroid glands: two on each side of the neck, behind the thyroid gland. The parathyroid glands regulate the amount of calcium in the blood. When calcium levels are low, the parathyroid glands release parathyroid hormone (PTH), which takes calcium from the bones.
The parathyroid glands stop production of PTH when there is a sufficient amount of calcium in the blood. This feedback system keeps calcium levels within normal ranges when the parathyroid glands are healthy.
Hypercalcemia is when blood calcium levels are abnormally high. The most common cause of hypercalcemia is an overproduction of PTH in one or more glands. This is a form of hyperparathyroidism called primary hyperparathyroidism.
According to the American Association of Enocrine Surgeons, primary hyperthyroidism is twice as common in women as it is in men. Most people diagnosed with primary hyperthyroidism are at least 45 years old. The average age of diagnosis is 65 (AAES, 2012).
When diseased parathyroid glands are the cause of high blood calcium levels, you may need surgery to remove them. However, the surgeon must determine how many of the four glands are diseased and which should be removed. Surgeons who perform 50 or more such operations per year have the most successful outcomes.
Symptoms can be vague in the early stages of hypercalcemia. They include fatigue, depression, and muscle aches. As the condition progresses, a person may also experience:
- loss of appetite
- nausea and vomiting
- excessive thirst
- frequent urination
- abdominal pain
- muscle weakness
- kidney stones
- bone fractures
The most serious consequences of hypercalcemia are kidney failure, hypertension, arrhythmia coronary artery disease, and an enlarging heart. This may due to the buildup of calcium in the arteries and heart valves.
Primary hyperparathyroidism is most often caused by tumors in the parathyroid glands. These tumors are usually benign and are called adenomas. Parathyroid tumors are rarely cancerous. A parathyroid adenoma produces PHT like the parathyroid glands.
Unlike the parathyroid glands, they do not shut down in response to high blood calcium levels. Calcium blood levels can rise even if only one gland is affected. In about 80 percent of cases, only one parathyroid gland is involved (AAES, 2012).
Parathyroid hyperplasia is a condition in which all four parathyroid glands are enlarged. According to UCLA Endocrine Surgery, it’s responsible for about 15 percent of all cases of primary hyperparathyroidism (UCLA, 2012).
Hyperparathyroidism may initially be diagnosed through blood and urine tests. If the tests show high levels of both calcium and high levels of PHT, it is an indication of primary hyperthyroidism.
Patients with no symptoms may only need monitoring. Mild cases can be managed medically. However, only surgery that removes the affected glands will provide a cure. The surgery to remove the diseased gland or glands is called a parathyroidectomy.
There are different approaches to locating and removing the diseased parathyroid glands.
In the traditional method, the surgeon explores all four glands visually to see which are diseased and should be removed. This is called a bilateral neck exploration. An incision is made in the middle to lower portion of the neck. Sometimes a surgeon will remove both glands on a single side. This approach has been shown to be safe and effective.
However, since the great majority of patients have only one diseased gland, a more limited approach has been developed. This is called a minimally invasive parathyroidectomy.
Examples of this class of minimally invasive methods include:
- radio-guided parathyroidectomy
- video-assisted parathyroidectomy
- endoscopic parathyroidectomy
The radio-guided approach uses a scan called a sestamibi scan. This uses radioactive material that only the diseased glands will absorb. A special probe can locate the source of the radiation. The surgeon will only need to make a small incision to remove the diseased gland.
The accuracy rate for these scans is not 100 percent, and it may depend on the institution where the scan is performed. Sometimes a person with a negative scan will have a positive one when the test is repeated at a more experienced institution. Other forms of radiology, such as ultrasound, can also be used to locate diseased glands.
The video-assisted method uses a small video camera. The surgeon will make two small incisions in the neck: one for the camera and one for the instruments.
The endoscopic method uses two or three small incisions in the neck and one near the breastbone. This minimizes visible scarring. This technique is similar to the video-assisted surgery.
These minimally invasive methods allow for a quicker recovery. However, if not all of the diseased glands are discovered and removed, the high calcium levels will continue and there may be need for a second surgery.
Patients with parathyroid hyperplasia will usually have three and a half parathyroid glands removed. The doctor will leave the remaining tissue to control calcium levels. However, the tissue will be implanted in an accessible place, like the forearm, in case it needs to be removed later.
The success rate for this surgery is less than that for removal of an adenoma. Hypercalcemia reoccurs in about 20 percent of cases of hyperplasia (UCLA, 2012).
You will need to stop taking medications that interfere with the ability of the blood to clot about a week before surgery. These include aspirin, ibuprofen, and naproxen, as well as medications that contain them. Patients taking prescription medications such as warfarin and clopidogrel, will need to discontinue them under the supervision of their doctors.
The anesthesiologist will review the patient’s medical history and decide what form of anesthesia to use. Most methods require the patient to fast before surgery.
Most parathyroidectomies are done under general anesthesia. There are some risks to general anesthesia, which include breathing problems and allergic reactions to the medicines used.
Risks from any surgery include excessive bleeding and infection. The risks from this particular surgery include injuries to the thyroid gland and vocal cords. In rare cases, you may experience breathing problems that usually go away in several weeks or months after surgery.
Calcium levels normally drop after surgery. It is called hypocalcemia if they drop to abnormally low levels. This can be dangerous. However, this condition quickly responds to supplementation. Hypocalcemia is not permanent for most patients.
Surgeons who perform at least 50 parathyroidectomies per year have the lowest rates of surgery complications (AAES, 2012).
Patients may return home the same day of surgery or spend the night in the hospital. There is normally some pain or discomfort after surgery, like a sore throat or a bad cold. Most patients are able to return to their normal activities in several days.
Calcium levels will fall quickly after surgery. Some people will experience numbness or tingling in the fingertips, toes, or lips. This is easily treated with calcium supplementation. A patient’s blood calcium levels will be monitored for at least six months after surgery. Some doctors keep their patients on supplementation for a year after surgery to rebuild bones that have been robbed of calcium.