What Are Common Disorders of the Parathyroid Glands and How Are They Treated?

What is a parathyroid gland?

Parathyroid glands are tiny glands located next to the thyroid gland. The parathyroid glands are named for their location next to the thyroid. The thyroid gland and parathyroid glands sound the same but have very different roles.

“Para” is Latin for “next to” and thus the parathyroid gland means “the gland next to the thyroid.” Most people have four parathyroid glands located directly behind the thyroid gland. However, their exact number and location can vary from person to person. In approximately 1 in 10 people, these small glands are located higher up in the neck or even down in the chest region. 

The parathyroid glands make parathyroid hormone (PTH), which is a completely different hormone from the thyroid hormone that the thyroid gland makes.

What is the function of the parathyroid glands?

Parathyroid glands play an important role in regulating the calcium level in the blood.  Parathyroid glands can regulate calcium levels by adjusting the amount of parathyroid hormone (PTH) they produce.

Parathyroid glands work like a thermostat for calcium levels. If the amount of calcium in the blood dips too low, the parathyroid glands release the exact amount of PTH needed to restore a normal calcium level. Once the calcium is normalized, the parathyroid glands stop making PTH, and the PTH levels decrease.

How do the parathyroid glands maintain a normal calcium level?

The parathyroid glands monitor the calcium level in the blood. Parathyroid hormone (PTH) is released by the parathyroid glands in response to low calcium. When extra PTH is released, it circulates through the blood and targets the bones, kidneys and intestines. 

PTH acts on the bones to release calcium to increase the calcium level. PTH also goes to the kidneys and exchanges calcium for phosphorus to increase the calcium level in the blood and release phosphorus in the urine. With the help of vitamin D, PTH helps your intestines absorb calcium from the foods that you eat. 

Why is calcium important?

Calcium is an essential electrolyte, and all your cells, nerves and muscles need calcium in just the right amount. A normal calcium level is maintained by complex interactions between the parathyroid glands, the bones, the kidneys and the intestines.

Most of the body’s calcium is stored in the bones and the rest circulates in the blood.  Too much calcium can lead to abnormal heart rhythms, frequent urination and excessive thirst, and may contribute to mood changes or concentration difficulties. 

What are common disorders of the parathyroid glands and how are they treated?

There are several types of hyperparathyroidism:

• Primary hyperparathyroidism is a disorder defined by inappropriate PTH and calcium levels. It is most often caused by a parathyroid adenoma. A parathyroid adenoma is a growth on one or more of the parathyroid glands. Adenomas are not cancerous, but they produce extra PTH and this leads to elevated calcium levels. The standard treatment for primary hyperparathyroidism is surgery, which is the only potential cure.
• Hyperparathyroidism can also arise from secondary causes including:
  • low vitamin D
  • kidney disease
  • malabsorption of calcium
  • very low dietary calcium intake

Secondary hyperparathyroidism is managed by treating the underlying cause.  Tertiary hyperparathyroidism occurs after the underlying cause of the secondary hyperparathyroidism is treated, but the parathyroid glands still produce extra PTH.

What are common symptoms of hyperparathyroidism?

Many people with hyperparathyroidism have no symptoms or very vague symptoms. Primary hyperparathyroidism can lead to frequent urination, excessive thirst, bone and joint pain, fatigue, depression or constipation. Untreated primary hyperparathyroidism can lead to:

• significant elevation of calcium levels
• osteopenia and osteoporosis
• increased fracture risk
• elevated levels of calcium in the urine
• heart disease
• kidney disease

How is hyperparathyroidism diagnosed?

A combination of blood and urine tests, as well as a thorough review of your history and medications, are used to make the diagnosis of hyperparathyroidism. Primary hyperparathyroidism is the most common cause of high calcium, however there are many potential causes of elevated calcium or PTH levels, so it is important to make the right diagnosis, so the appropriate treatment is planned.

Parathyroid hormone levels are also monitored in patients with end-stage kidney disease and in patients undergoing kidney transplants. 

Should I be screened for hyperparathyroidism?

Since parathyroid glands play such an important role in the regulation of calcium, you should be screened for hyperparathyroidism if you have high calcium levels. Medications and other diseases can also cause high calcium, so it is important to have the appropriate workup to determine the cause of the high calcium levels.

You may also be screened for hyperparathyroidism if you have osteoporosis or if you have kidney disease and are on dialysis. 

What role does surgery play?

Parathyroid surgery is a low-risk outpatient procedure and offers the only potential cure for parathyroid disease. Primary hyperparathyroidism is treated by surgically removing the abnormal parathyroid glands. Most often in primary hyperparathyroidism, there is one abnormal parathyroid gland (a parathyroid adenoma), and the disease is cured when this abnormal gland is removed. 

Sometimes, two or three glands are abnormal (multi-gland disease), the disease is cured by removing these abnormal parathyroid glands. If all four parathyroid glands are abnormal (four-gland hyperplasia), three and a half glands are removed leaving a parathyroid remnant that is about the size of one normal gland. 

To have normal calcium and normal parathyroid function, you need at least one normal parathyroid gland or a remnant of a parathyroid gland of normal size. Sometimes a remnant of a parathyroid gland is put into a muscle in the arm or neck as a backup parathyroid gland.

Is there such thing as hypoparathyroidism?

Hypoparathyroidism, or parathyroid hormone (PTH) levels, is most commonly caused by accidental damage or removal of parathyroid glands during thyroid or neck surgeries. Hypoparathyroidism can be temporary or permanent. 

Because parathyroid glands are essential for calcium regulation, hypoparathyroidism leads to low calcium levels. The calcium level is too low it can cause symptoms including numbness or tingling, muscle cramps, and severe cases of extremely low calcium can lead to seizures or severe muscle spasms. 

Hypoparathyroidism is treated dietary adjustments, supplementation of calcium and vitamin D, and other medications to improve calcium absorption and increase calcium levels in the blood.

Learn more about the expert endocrine surgeons at Ochsner.