Parathyroid Glands and Calcium Regulation

Thyroid Surgery - Indications

There are four parathyroid glands in the neck, two on each side. Most commonly they sit immediately behind the thyroid gland and adjacent to the recurrent laryngeal nerve. Rarely the glands can be found in unusual locations such as the chest, within the thyroid gland, or higher up in the neck.

The parathyroid glands make parathyroid hormone (PTH). This hormone controls blood calcium levels. Calcium is very important for proper functioning of bones, muscles and nerves. In the normal state, PTH is secreted whenever blood calcium gets too low. PTH helps absorb calcium from the gut and releases it from bones. This helps to raise blood calcium and prevent low body calcium (hypocalcemia).


Too much parathyroid hormone, a condition called hyperparathyroidism, causes the level of calcium in the blood to rise outside of the normal range with subsequent negative effects on the body. Increased calcium release from bones can cause osteoporosis and increased risk of bone fractures. High blood calcium is filtered by the kidneys which can become overloaded leading to impaired kidney function and kidney stones. The calcium also affects muscles, joints and nerves causing muscle aches and cramps, irritability, weakness, fatigue, depression, and – in extreme cases – heart arrhythmias.

Hyperparathyroidism affects women more commonly than men. Rarely, it can run in families.  Most people with hyperparathyroidism have a single abnormal parathyroid gland that is secreting too much hormone. This overactive gland is referred to as a ‘parathyroid adenoma’. In about 15% of people, more than one gland is enlarged (‘multigland disease’). 

Other symptoms of hyperparathyroidism can include:
  • Blood pressure elevation
  • Abdominal discomfort
  • Nighttime urination and increased thirst
  • Constipation
  • Psychiatric problems
  • Menory loss
  • Headaches
  • Loss of libido
These symptoms improve in the majority of patients after parathyroid surgery.
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