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What are the parathyroid glands?

The parathyroid glands are very small glands (about the size of a grain of rice) situated in the neck just behind the thyroid gland.  There are usually four parathyroid glands – two on each lobe of the thyroid gland – which produce a hormone called parathyroid hormone.1

What do they do?

The parathyroid glands control calcium levels in the bloodstream to make sure you don’t have too little or too much calcium.

If calcium levels drop, the parathyroid glands release parathyroid hormone into the blood which then causes the bones to release calcium.  Parathyroid hormone also causes the kidneys to stop releasing calcium into the urine and stimulates the kidneys to increase vitamin D metabolism. Vitamin D then increases calcium absorption from the gut.

If calcium or vitamin D levels are low, the parathyroid glands produce more parathyroid hormone to bring levels up to normal.1

Primary hyperparathyroidism

The most common form of hyperparathyroidism (and the third most common endocrine disorder in men and women)2 is called primary hyperparathyroidism.   Similar to hypothyroidism, it is more common in women, and most commonly seen in women aged 50-60.3

The parathyroid glands can make too much parathyroid hormone hyperparathyroidism.  This causes high calcium levels (hypercalcaemia).1

What causes primary hyperparathyroidism?

In 75-85% of cases, the cause is a single benign (non-cancerous) growth or nodule (adenoma) in one gland.  Growths in more than one gland are not very common and cancer in the parathyroid glands is very rare (less than 1%).2

In rare cases, primary hyperparathyroidism can have genetic causes.

What are the symptoms of hyperparathyroidism?

Some people have no symptoms1,2,3 and the condition is found via a routine blood test.  Symptoms can vary depending on the length of time you have had the problem:

      • increased thirst

      • increased urine production

      • abdominal pain

      • constipation

      • aches and pains

      • mood changes

      • nausea

      • loss of appetite

      • tiredness

      • poor concentration

      • confusion

      • depression

    It may take some time for hyperparathyroidism to be diagnosed because the symptoms are similar to symptoms of other conditions so other potential causes need to be excluded.

    If the condition has gone on a long time undetected, calcium in the bones can be lost to the blood and urine hence high blood and urine levels of calcium.  This can eventually cause osteoporosis, calcium stones in the kidneys, peptic ulcers and pancreatitis (inflammation of the pancreas).

    This can then cause further symptoms:3

        • vomiting

        • drowsiness

        • dehydration

        • muscle spasms

        • bone pain or tenderness

        • joint pain

        • irregular heartbeat

        • high blood pressure (hypertension)

      In very severe cases hyperparathyroidism can cause high calcium levels to lead to:

          • kidney failure

          • loss of consciousness

          • coma

          • heart rhythm abnormalities

        How is it diagnosed?

        It is important that hyperparathyroidism is diagnosed quickly.  It is diagnosed by looking at calcium and parathyroid hormone levels in the blood and urine. Phosphorus levels can also be checked for low levels.

        It is also recommended to have a bone density scan (DEXA), X-rays, CT scans or ultrasound scans of the kidneys to check for osteoporosis and kidney stones.

        How is hyperparathyroidism treated?

        Depending on the severity of the condition, conservative management only may be required, or another option is to remove the affected parathyroid gland/s.1,2 Medication may be given to lower calcium levels as a short-term treatment to stabilise levels.

        Secondary hyperparathyroidism

        Secondary hyperparathyroidism is due to a condition outside of the glands such as kidney failure or vitamin D deficiency which lowers calcium levels which in turn causes the parathyroid glands to make extra parathyroid hormone.3

        Treatment for secondary hyperparathyroidism depends on whether it is caused by vitamin D deficiency or kidney disease.

        Vitamin D deficiency is treated with oral vitamin D.3

        Tertiary hyperparathyroidism

        This is long-standing secondary hyperparathyroidism usually associated with very advanced kidney failure.3


        The prognosis of treating conditions of the parathyroid gland depends on the cause of the condition.

        If you have mild hyperparathyroidism, not needing surgery, you may not develop any problems or need any treatment in the future.  However, some people will find that their calcium levels will slowly rise so you may need further treatment.

        If you have had surgery and it was successful, things should return to normal although some generalised symptoms may remain such as fatigue.2

        If you have hyperparathyroidism, you need to ensure that you eat a healthy, balanced diet.  There is no need to avoid calcium as this may cause osteoporosis although you should avoid a high-calcium diet and avoid becoming dehydrated.3

        For more support check out our online community:

        Further information

        Visit Parathyroid UK’s website for further information


        1. You and Your Hormones
          Parathyroid Glands

        2. You and Your Hormones
          Primary Hyperparathyroidism

        3. NHS

        Date updated: 10.05.21 (V1.5)
        Review date: 17.12.22

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