Patient information and resources
The Parathyroid Glands:
WHAT ARE THE PARATHYROID GLANDS?
Each person has, in general, four separate parathyroid glands that lie in close proximity to the thyroid gland and trachea (windpipe). The parathyroid glands secrete hormones that regulate the calcium level in the blood. The correct amount of calcium in the bloodstream is important for many bodily functions including the musculoskeletal and nervous systems.
Too much parathyroid hormone (PTH) can cause multiple problems. We remember the outward symptoms of hyperparathyroidism as "stones, bones, groans, and moans" because too much PTH can cause kidney stones, decreased bone density (osteopenia or osteoporosis) and bone fractures, pancreatitis, increased acid production and ulcers, and psychiatric manifestations such as depression, difficulty concentrating or with memory, and fatigue. Other symptoms include generalized musculoskeletal aches and pains, constipation, insomnia, and anxiety.
Each parathyroid gland is usually about the size of a grain of rice (about 3-5 millimeters in diameter and around 30 - 60 milligrams in weight). Although the thyroid and parathyroid glands are physically near each other, and are both part of your body's endocrine system, their functions are not related.
The relationship of the blood calcium level to PTH level is complex. In general, PTH is released from the parathyroid glands when the body senses that the calcium level in the blood stream is too low. PTH acts on several different sites in the body - mainly the bones, kidneys, and indirectly on the GI tract (intestines). If the blood calcium level is low, the parathyroid glands are stimulated to release PTH. PTH then acts on the bones to allow release of calcium into the bloodstream. PTH also acts on the kidneys to reabsorb calcium passing through the kidneys. PTH release indirectly causes the GI tract to absorb more calcium. When the blood calcium levels are high, the parathyroid glands should not be releasing very much PTH if they are functioning correctly. When the parathyroid glands lose the ability to appropriately regulate the secretion of parathyroid hormone, this allows continuous release of PTH and leads to the development of inappropriately high calcium levels. A high calcium level with an elevated PTH level is termed "hyperparathyroidism".
WHAT IS HYPERPARATHYROIDISM?
There are three types of Hyperparathyroidism (HPTH) - primary, secondary and tertiary.
- Primary HPTH is by far the most common type, and in 85% of patients it is caused by a single abnormal gland. The calcium level is high and the PTH level is usually elevated above normal, although in some patients with HPTH, we see PTH levels in the "normal range", however their PTH level is higher than it should be relative to the elevated calcium level.
- Secondary HPTH is usually found in patients with renal (kidney) failure and involves all four parathyroid glands. The excess function of the parathyroid glands is stimulated by the abnormal function of the kidney. Calcium levels are usually in the normal range and PTH levels can be markedly elevated.
- Tertiary HPTH also involves all four glands and is usually seen in patients who have undergone a kidney transplant for renal failure. Instead of parathyroid gland function returning to normal after a new kidney is transplanted and normal renal function returns, the parathyroid glands fail to respond to the normal signals for PTH secretion and regulation of calcium levels. In these patients, the PTH level is high and the calcium level is high.
WHEN IS AN OPERATION RECOMMENDED?
Surgery is the only cure for hyperparathyroidism.
Surgery for hyperparathyroidism is very low risk and very well tolerated. It can even be done under local anesthetic (numbing medicine) with intravenous medication for sedation.
Since primary hyperparathyroidism is by far the most common type of hyperparathyroidism, we will discuss the operative indications for this type only.
Any patient with symptomatic disease should undergo parathyroidectomy.
In 1990 and 2002, the NIH (National Institutes of Health) published guidelines for operative intervention with "asymptomatic disease". It is still debatable what constitutes an "asymptomatic" patient. The guidelines include patients with marked elevation of blood calcium levels, history of an episode of life-threatening hypercalcemia, reduced creatinine clearance (an indicator of kidney function), presence of kidney stones, markedly elevated calcium in the urine, age less than 50, and substantially reduced bone mass as determined by a bone density study. "Asymptomatic" patients should be followed closely (every six months) to look for any changes.
Many feel that the above indications are too limited and should be broadened. In several studies, it has been noted that "asymptomatic" patients treated conservatively (without surgery) have no frame of reference to validate whether or not they are truly asymptomatic. In one study, of the 9% of patients thought to be "asymptomatic", 81% of those patients reported improvement from their preoperative state. Only after their operation did they realize they really were symptomatic. Many of these symptoms that were relieved are vague, non-specific complaints, but nonetheless are real manifestations of the disease (aches, pains, fatigue, depression, insomnia, etc.). Some feel that any patient with any significant remaining life span should undergo surgery once primary hyperparathyroidism has been confirmed by lab work. Surgery has been shown to be very safe, even in patients into their 80's and beyond.
WHAT TYPES OF OPERATIONS ARE THERE?
A parathyroid operation takes place in the operating room. If you have primary HPTH and we feel we have located the abnormal gland by imaging studies, we may offer you an operation performed under local anesthesia with IV sedation. You may also choose to have it done under general anesthesia. The final decision will be based on a discussion between you and your surgeon.
For many years, the standard operation for parathyroid surgery involved looking at all four parathyroid glands and removing the abnormal appearing gland/glands. Over the past fifteen years, the approach has changed significantly to a more minimally invasive type of surgery (smaller incisions, less time in the hospital, faster recovery). By using various imaging techniques (ultrasound or nuclear sestamibi scans), we attempt to locate the abnormal gland/s. In 85% of cases, only one gland is abnormal. If we can visualize it on imaging obtained before surgery, then we consider the patient to be a candidate for a "minimally invasive" operation. If it is believed that all four glands are abnormal, or a likely candidate for an abnormal gland on imaging studies cannot be located, then the operation will be performed under general anesthesia and all four glands will be evaluated. Each patient is individually considered for the minimally invasive approach.
Minimally invasive or "directed" parathyroidectomy entails a small one-inch (2.5cm) incision at the base of the neck versus the standard 3-4cm incision for a "four gland exploration". After making an incision, the muscles in the front of the neck are separated and the thyroid is moved out of the way. The offending parathyroid gland(s) is removed. Intraoperative PTH monitoring is used in all "minimally invasive" cases as an adjunct to confirm removal of all hyperfunctioning parathyroid tissue. The muscles are closed and the skin is reapproximated using a material similar to "super glue". Small cloth "Steri Strips" are placed over the incision as a dressing.
If only one gland is removed, patients are discharged home the same day. Otherwise, they are admitted to the hospital overnight to monitor calcium levels and the incision site. They are discharged home the next morning.