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The Parathyroid Gland: Disease, Diagnosis and Treatment

By Douglas W. Klotch, M.D.

The parathyroid is a small gland that migrates into the central neck in close proximity to the thyroid. It can also be found in the mediastinum (thymus gland) or within the thyroid itself.

Authors have reported there to be between two and nine of these glands with the average number being four. As an experienced thyroid and parathyroid surgeon I frequently find more than four glands. In my practice this is seen about 26% of the time which is corroborated in the literature.

The Parathyroid glands are responsible for the regulation of calcium in the body. The majority of the calcium resides in the bone. Circulating ionized calcium is responsible for a variety of reactions in the body as well as nerve and cardiac function. The parathyroid regulates the absorption of calcium by the GI tract, the turn over of calcium in the bone, and the excretion by the kidneys. Vitamin D helps to increase the absorption. A variety of medicines and some medical disorders may affect the absorption and excretion of calcium. Understanding of these processes is important before considering parathyroid treatment.

Low parathyroid function is uncommon and generally is related to previous surgery in the thyroid region. Elevated parathyroid function (hyperthyroidism) is generally secondary to benign disease. Parathyroid cancers are uncommon and generally recognized before surgical intervention by excessively elevated parathyroid hormone levels.

The diagnosis of hyperthyroidism is made with laboratory tests. Essentially the presence of elevated parathorme (PTH) in the face of elevated ionized calcium is diagnostic for hyperparathyroidism. In the younger population this is more commonly secondary to a single enlarged gland (a benign adenoma). In the older population there is a higher percentage involvement of multiple glands. Patients with long standing renal disease may have elevated calcium either with hyperplasia (secondary hyperparathyroid ) or multiple adenomas (tertiary hyperparathyoid). Fortunately the majority of patients have single adenomas. When this is the case removal of the parathyroid is uniformly easy and with minimal risk in all age groups.

Elevated Parathyroid function may cause: (bones, stones, and psychic moans)

  • Osteoporosis: diminishing bone density possibly leading to fractures
  • Mental confusion
  • Kidney stones
  • Constipation
  • Itching: pruritis
  • Cardiac arrhythmia

Lab tests:

  • Repeated serum calcium (ionized)
  • Parathormone assay

If only calcium is elevated other causes must be excluded such as: metastatic cancer, familial hypercalcemia/ hypercalcuria, sarcoidosis, multiple myeloma etc.

A small group of patients have multiple endocrinopathies (MEN syndromes). Patients who have elevated calciums with thyroid masses, ulcers or other endocrine disorders need further evaluation. These associations are well known to all competent head and neck and endocrine surgeons. Only the most experienced surgeons should manage these cases.

A sonogram may localize the parathyroid as may MRI scans, but the standard localizing test is the Sestimibi scan. This scan may also be used immediately before surgery (1-4 hours) so that a localizing device (neoprobe) may be used to help localize the diseased gland. Likewise intraoperative PTH assays can help to assure that all diseased glands are removed.

Despite some surgeon’s claims, all good endocrine and head and neck surgeons have similar results performing parathyroid surgery. The tests and techniques are available to all surgeons. Complications include potential injury to the nerves to the voice box, possible bleeding, infection, and airway difficulties are rare since this is a limited surgery for most patients.

Patients with isolated solitary adenomas represent greater than 85% of patients presenting with primary hyperparathyroidism. When the sestimibi scan localizes the diseased gland the operation take approximately fifteen minutes. I generally verify by sampling at least one additional gland to assure the possibility of multiple gland hyperplasia. Multiple gland exploration is mandated when the scan fails to localize a single enlarged gland. Interoperative PTH assays are useful in assuring adequate removal. This is especially important when remembering that at least 25% of patients have more than four glands.

In older patients it is important to perform sequential calcium assays since it is not uncommon for them to have hyperplasia and to develop a secondary gland involvement months to years after presumed successful parathyroid surgery.