What are parathyroids and what can go wrong?
The parathyroid glands are actually four tiny glands that sit in the lower neck. They are found very near another gland in the neck called the thyroid gland. Although the parathyroid glands may lie very close to the thyroid or even be found inside of it, they have a very different function. While the thyroid regulates energy levels and growth, the parathyroid glands regulate calcium levels in your system.
The parathyroid glands regulate calcium in your body by making more or less of a hormone called parathormone (or PTH as it is also called). The parathyroid glands constantly measure calcium levels in the blood as it flows through them. If the calcium level gets high and is unsafe for your body, the normal glands sense this and decrease or stop their hormone production. This in turn lowers the calcium in your body and all returns to normal. Abnormal glands are unable to do this. They make too much hormone and continue to raise the blood calcium even when it is already very high.
What can go wrong with your parathyroid glands?
When one or more of your parathyroid glands become abnormal it is called hyperparathyroidism. In this situation, your gland (or glands) make too much (“hyper”) parathyroid hormone. Too much hormone raises blood calcium to unsafe levels. High blood calcium causes many symptoms and problems for your body including brittle bones, premature fractures, bone pain, general loss of energy or fatigue, depression, gastric reflux, kidney stones, and high blood pressure. In short, the bodily system has a major malfunction.
Instead of stopping the rising calcium as it should, the parathyroid gland only makes it go higher. This problem occurs because one (more rarely more) of the parathyroid glands stops working with the rest of the body. It develops a growth (also called an adenoma) and swells to a larger size. It no longer senses calcium levels in the blood and instead of listening to what the body needs, just keeps raising the calcium level. Like a “runaway train” the calcium level gets higher and higher and the symptoms and problems you experience get worse and worse. 97% of the time only one of the glands is the culprit. It develops a benign growth called a parathyroid adenoma.
Less commonly (2-2.5% of the time), a person will develop enlargement of all four glands. This is not an adenoma but is called hyperplasia. Even more rare is a condition where an individual will develop enlargement of just two glands, which is called “multiple adenomas”. And finally, much less than 1% of the time, a malignant growth may be found in the abnormal parathyroid.
What are the symptoms of parathyroid gland disease and what is the best treatment?
How do we identify the abnormal parathyroid glands?
Cervical Ultrasound and Nuclear Scintigraphy (Sestamibi Scan)
The traditional methods for parathyroid imaging are cervical ultrasound (US) and nuclear scintigraphy (sestamibi scan). These two imaging modalities are often used together to allow for identification and localization of the abnormal parathyroid gland. US enables precise anatomic localization and may be very accurate for normally positioned parathyroid adenomas. While the spatial resolution of a sestamibi scan is lower than that of US, it is able to identify parathyroid glands located outside of their normal position (i.e. upper neck or chest) that can be missed with US.
4D CT Parathyroid Scan
Four-dimensional CT has advantages in common to both US and scintigraphy. It provides excellent detail for preoperative localization, while the multiple phases show uptake characteristics that help to differentiate parathyroid lesions from lymph nodes and thyroid nodules.
How is parathyroid surgery usually performed?
Minimally Invasive Parathyroidectomy
Minimally invasive parathyroid surgery refers to the utilization of a small incision on the anterior neck, usually less than 2.5 cm. To select patients for minimally invasive parathyroidectomy surgery, the surgeon needs precise localization of the parathyroid adenoma and to exclude multiglandular disease.
The advantage of pre-operative localization is that it allows the surgeon to directly target a single gland for removal. Some surgeons may also use radio-guided (sestimibi detection with a gamma probe) to aid in adenoma localization during surgery.
Once the abnormal gland has been removed, intraoperative parathyroid hormone levels can be measured to determine if all abnormal glands have been resected. Further gland exploration is usually not needed.
The cure rates of minimally invasive parathyroidectomy surgery and four gland exploration are similar, but minimally invasive parathyroidectomy surgery has the advantages of better cosmetic results, shorter operating time and reduced complication rates.
Four Gland Parathyroid Exploration
Parathyroid glands can sometimes be difficult to find. Additionally, 30 percent of people can have more than one parathyroid adenoma that may not be identified with pre-operative imaging. If your affected parathyroid gland(s) cannot be located prior to surgery, all four of the glands (two on each side of the neck) will be explored during surgery with identification and removal of the abnormal gland(s). While this approach may require a larger incision, in most cases patients are discharged home the same day.