Hyperparathyroidism (primary)

In patients with primary hyperparathyroidism, one or more parathyroid glands become enlarged and make too much parathyroid hormone. Eighty percent of the time, only one of the four glands is affected. This form of hyperparathyroidism is called a single adenoma. In about 10 percent of the cases, either two to three glands are affected, which is called double or triple adenoma. In the remaining 10 percent of cases, all four glands are affected, and the disease is often called four-gland hyperplasia. 

Hyperparathyroidism can lead to other serious health conditions because high levels of PTH cause calcium to be taken out of the bones (which then leads to osteoporosis) and the gastrointestinal tract. This raises the amount of calcium in the blood, which needs to be filtered by the kidneys. The kidneys are then exposed to high levels of calcium, which can cause kidney stones and kidney damage. 

Parathyroid cancer is very rare, and causes hyperparathyroidism in less than 1 percent of patients.

Causes of Hyperparathyroidism

The main function of the parathyroid glands is to maintain proper levels of both calcium and phosphorus in your body by regulating the amount of parathyroid hormone (PTH) released into the blood stream. 

When calcium levels in your blood are too low, the parathyroid glands secrete more PTH, since this hormone raises calcium levels by releasing calcium from your bones and increasing calcium absorption in from your small intestine. If there is too much calcium in the blood, the parathyroid glands produce less PTH.

In cases of hyperparathyroidism, one or more of the parathyroid glands produce too much PTH, which leads to high levels of calcium and low levels of phosphorus in the blood. 

This disorder can be caused by an issue with the parathyroid or by another disease process that affects the parathyroid. 

When the cause is due to the parathyroid itself, the condition is called primary hyperparathyroidism. The main causes of primary hyperparathyroidism are: 
  • Enlargement (hyperplasia) of two or more parathyroid glands 
  • A noncancerous growth (adenoma) 
  • A cancerous (malignant) tumor

Risk Factors

A risk factor is anything that increases a person's chance of getting a disease. Different diseases have different risk factors. Some risk factors can be controlled with lifestyle changes. Other risk factors cannot be changed.

Women are at a higher risk for developing hyperparathyroidism than men, and most people diagnosed with the disease are older than 45, with an average age of 65 at diagnosis. 

The following risk factors are associated with hyperparathyroidism: 
  • Menopause 
  • Prolonged, severe calcium or vitamin D deficiency 
  • Certain inherited disorders that affect multiple glands, such as MEN 1 and MEN 2
  • Past radiation treatments for cancer that have exposed the head, chest, or neck to radiation 
  • Taking lithium 
Having one or more of the above risk factors does not mean that you will develop hyperparathyroidism. Understanding your risk factors will help you determine, what, if any, precautions and special screening you should consider.


If you have hyperparathyroidism, you may experience a range of symptoms from mild to non-specific, or you may experience severe symptoms.

Some of the signs of hyperparathyroidism include: 
  • Kidney stones 
  • Fragile bones that easily fracture (osteoporosis) 
  • Excessive urination 
  • Abdominal pain 
  • Tiring easily or weakness 
  • Depression or forgetfulness 
  • Bone and joint pain 
  • Frequent complaints of illness with no apparent cause 
  • Nausea, vomiting, or loss of appetite
Having one or more of the above symptoms does not mean that you have a form of hyperparathyroidism. If you think you have this condition, please call your doctor.


The only treatment for a hyperparathyroidism and tumors of the parathyroid glands is surgery to remove the affected glands. This surgery is referred to as a parathyroidectomy. Once the affected glands are removed, symptoms of hyperparathyroidism resolve. 

Minimally Invasive Parathyroidectomy (MIP)
This surgery is performed as a treatment for hyperparathyroidism under local analgesia with sedation, with a small incision to remove the enlarged parathyroid gland(s). While removing the gland(s), the surgeon talks with the patient to ensure that the recurrent laryngeal nerve is not affected by the surgery. After removal of the affected gland(s), and while the patient is still under sedation, the surgeon performs a blood test to check the patient's parathyroid hormone level in the operating room. This blood test will allow the surgeon to confirm that all enlarged parathyroid glands have been removed before the patient leaves the operating room. Patients will recover in the hospital for 24 to 72 hours so that blood calcium levels can continue to be monitored.

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Yale Endocrine/General Surgery
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New Haven, CT 06510

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