The parathyroid glands in the neck help regulate calcium absorption, use, and removal by the body. They do this by producing parathyroid hormone, or PTH. PTH helps regulate calcium, phosphorus, and vitamin D levels in the blood and bone. It is important for healthy bones.

Parathyroid adenomas are common. Most parathyroid adenomas do not have an identified cause. Sometimes a genetic problem is the cause. This is more common if the diagnosis is made when you are young.

Parathyroid adenomas may occur in people without a family history of the disease, or as part of 3 inherited syndromes:

• Multiple endocrine neoplasia (MEN) I
• Multiple endocrine neoplasia (MEN) IIA
• Isolated familial hyperparathyroidism

In people with an inherited syndrome, a changed (variant) gene is passed down through the family. You only need to get the gene from one parent to develop the condition.

• In MEN I, problems in the parathyroid glands occur, as well as tumors in the pituitary gland and pancreas.
• In MEN IIA, overactivity of the parathyroid glands occurs, along with tumors in the adrenal or thyroid gland.

Conditions that stimulate the parathyroid glands to get bigger can also cause an adenoma. These include:

• Genetic disorders
• Taking the medicine lithium
• Chronic kidney disease

Women over age 60 have the highest risk for developing this condition. Radiation to the head or neck also increases the risk.

Many people have no symptoms. The condition is often discovered when blood tests are done for another medical reason.

Parathyroid adenomas are the most common cause of hyperparathyroidism (overactive parathyroid glands), which leads to an increased blood calcium level. Symptoms may include any of the following:

• Confusion
• Constipation
• Lack of energy (lethargy)
• Muscle pain
• Nausea or decreased appetite
• Urinating more often at night
• Weak bones or fractures

Blood tests may be done to check levels of:

• PTH
• Calcium
• Creatinine, BUN (kidney function tests)
• Magnesium
• Phosphorus
• Vitamin D
• 24-hour urine test - done to determine how much calcium is being filtered out of the body into the urine
  
• Alkaline phosphatase

Other tests include:

• Bone density exam
• Kidney ultrasound or CT scan (may show kidney stones or calcification)
• Kidney x-rays (may show kidney stones)
• MRI
• Neck ultrasound
• Sestamibi neck scan (to identify the location of the parathyroid adenoma)

Surgery is the most common treatment, and it often cures the condition. But, some people choose to only have regular checkups with their health care provider if the condition is mild.

To help improve the condition, your provider may ask you to stop taking calcium and vitamin D supplements. Women who have gone through menopause may want to discuss treatment with estrogen or other medicines to prevent bone loss.

When treated, outlook is generally good.

Osteoporosis and the increased risk for bone fractures is the most common concern.

Other complications are less common, but may include:

• Calcium deposits in the kidneys that can reduce kidney function (nephrocalcinosis)
• Softened, weak areas in the bones (osteitis fibrosa)

Complications from surgery include:

• Damage to a nerve that controls your voice
• Damage to the parathyroid glands, which causes hypoparathyroidism (lack of enough parathyroid hormone) and low calcium level

Contact your provider if you have symptoms of this condition.

Hyperparathyroidism - parathyroid adenoma; Overactive parathyroid gland - parathyroid adenoma; Osteoporosis - parathyroid adenoma; Bone thinning - parathyroid adenoma; Osteopenia - parathyroid adenoma; High calcium level - parathyroid adenoma; Chronic kidney disease - parathyroid adenoma; Kidney failure - parathyroid adenoma

Reid LM, Kamani D, Randolph GW. Management of parathyroid disorders. In: Flint PW, Francis HW, Haughey BH, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 123.

Thakker RV. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 227.

Walker MD, Bilezikian JP. Primary hyperparathyroidism. In: Robertson RP, ed. DeGroot's Endocrinology. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 54.

Updated by: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.