What is hyperparathyroidism?

Dr. Jack Merendino, MD
Endocrinology Diabetes & Metabolism
Under normal circumstances, parathyroid hormone (PTH) is released when the blood calcium starts to fall. PTH helps to raise the blood calcium back to an appropriate level. When the calcium level is high enough, PTH production falls. If the calcium level is too high, PTH production is almost completely turned off. In this way the calcium levels may fluctuate somewhat but are generally kept within the normal range. 

In primary hyperparathyroidism, the parathyroid glands are overactive and are producing too much PTH. This results in a rise in blood calcium, often to a level higher than normal. This can result in a variety of symptoms and problems, including increased urine calcium loss, an increased risk of kidney stones, osteoporosis, physical symptoms including muscle and joint discomfort, and neuro-psychiatric problems including difficulty with focus and concentration and a depressed mood. In general, the higher the blood calcium the worse the symptoms tend to be. 

Typically one has four parathyroid glands. Primary hyperparathyroidism is usually the result of a benign tumor called an adenoma involving one of the parathyroid glands, though sometimes more than one of the glands is involved. Sometimes the condition is hereditary, either as a solitary problem or as part of a condition called multiple endocrine neoplasia. The best treatment is surgery to remove the overactive gland or glands. There are medications for those people who cannot undergo surgery for some reason. Not everyone needs surgery, but those with symptoms or a very high calcium level usually should be treated. 

Secondary hyperparathyroidism is a condition is which PTH levels are high as compensation for another problem. I have addressed this condition in a separate answer.
Howard E. Lewine, MD
Hyperparathyroidism (hi-per-par-a-thi-royd-izm) occurs when the parathyroid glands make more parathyroid hormone than they should. There are 4 of these small (normally about the size of a half of a pea) glands. They are in the lower part of the neck behind the thyroid gland.

Parathyroid hormone acts on bone to release calcium into the blood stream. The amount of hormone made by the glands changes to keep the calcium blood level within the normal range. (The range is 9.0 to 10.5 mg/dL in adults, and 7.6 to 10.8 mg/dL in children.)

If the blood calcium level starts to drop, the parathyroid gland makes more of the hormone. If the calcium level rises, the glands make less hormone. If the calcium level is higher than normal, the parathyroid glands pretty much shut down.

In hyperparathyroidism, one or more of the four parathyroid glands doesn't pay attention to the calcium blood level and continues to make parathyroid hormone. The excess hormone is released into the blood stream. The result is an abnormally high blood calcium level and also a higher than normal parathyroid hormone level. (When the blood calcium level is higher than normal, the parathyroid hormone level should be very low.)

Many people with hyperparathyroidism have no symptoms. Others have fatigue, muscle aches and/or mild weakness. In some cases, when calcium blood levels are very high, symptoms include:
  • Frequent urination
  • Excessive thirst
  • Constipation
  • Difficulty concentrating
Mild hyperparathyroidism might not need immediate treatment. But it should not be ignored. You would need periodic blood tests to measure your calcium blood level. You will also need bone density tests to make sure your bones are not getting thinner because parathyroid hormone leaches calcium out of bones.

If you have symptoms, your doctor will order tests to determine if just one parathyroid gland is overactive or if all of them are overactive. Your treatment plan will depend upon the test results.
Harvard Medical School Thyroid Disease: Understanding hypothyroidism and hyperthyroidism

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.