Excess blood calcium; high blood calcium level; raised blood calcium; hypercalcemia
Hypercalcaemia is the presence of abnormally high calcium levels in the blood.
Calcium metabolism is affected by three hormones. They are parathyroid hormone, vitamin D and calcitonin (which only has a minor effect). Parathyroid hormone and vitamin D increase circulating calcium, whereas calcitonin acts to reduce it. Calcium is introduced to the body through the diet and is found particularly in dairy products. Most diets will contain a sufficient daily intake of calcium. The body’s main calcium stores are in the bones, although calcium can be found to some degree in most parts of the body.
Hypercalcaemia has several common causes, including:
Rarer causes of hypercalcaemia include:
A mild rise in calcium levels will generally cause very few symptoms or none at all.
Moderate hypercalcaemia can cause a number of symptoms including nausea, vomiting, constipation, lethargy, depression, weakness, vague joint pains, feeling excessively thirsty, increased frequency of urination, abdominal pain and kidney stones, which might cause lower back pain.
Severe hypercalcaemia can cause headaches, heart rhythm disturbances, confusion and, ultimately, coma.
Hypercalcaemia is fairly common in adults, with primary hyperparathyroidism being the commonest cause. Three times as many women as men are affected by hypercalcaemia. It affects approximately 25 in every 100,000 general patients and 75 in every 100,000 hospitalised patients. The peak for the start of hypercalcaemia is between 50 and 60 years of age.
In patients with cancer, 20–40% will develop hypercalcaemia at some stage.
Most cases of hypercalcaemia are not inherited. One very rare cause of hypercalcaemia, which runs in families, is familial hypocalciuric hypercalcaemia and is a condition associated with passing less calcium in the urine. Hypercalcaemia as a result of hyperparathyroidism can be inherited as part of multiple endocrine neoplasia type 1 syndrome as well as other rare inherited conditions.
Hypercalcaemia is generally diagnosed through a series of tests including:
In addition, chest X-rays, electrocardiogram (ECG), computerised tomography scans of the chest, and nuclear medicine scans (‘MIBI’ or ‘SPECT-CT’) of the parathyroid glands, as well as ultrasound scans of the parathyroids, may also be employed.
All these tests can be undertaken as an outpatient unless the patient is too unwell, in which case they will be carried out as a hospital inpatient.
Management of hypercalcaemia depends on the patient’s physical state, including levels of hydration, mental state, the severity of the hypercalcaemia and the results of a kidney function test. It also depends on the cause of the hypercalcaemia.
Mild to moderate hypercalcaemia can be managed as an outpatient.
Moderate to severe hypercalcaemia, where the patient shows signs of dehydration and confusion, needs treatment as an inpatient. The following measures can help in managing more serious cases of hypercalcaemia:
If hypercalcaemia is caused by primary hyperparathyroidism, it is important to treat this condition in order to improve symptoms and prevent long-term problems such as osteoporosis or kidney stones. Primary hyperparathyroidism requires an early specialist opinion to determine if symptoms are related to the hyperparathyroidism. Expertise is required to identify whether a parathyroid swelling (adenoma) is present before surgical removal. If an adenoma is identified, the aims of surgical removal are reversal of symptoms, prevention of long-term complications and normalisation of calcium levels. In patients where an operation is not possible, specialist medication may be needed to lower parathyroid hormone levels.
The majority of patients do not suffer from any side-effects to the treatment. Medical management of hypercalcaemia can lead to a number of side-effects in rare cases:
Side-effects following parathyroid surgery may include a reduction in calcium levels. Levels usually return to normal but occasionally remain low for the rest of the patient’s life.
The longer-term implications of hypercalcaemia depend on the underlying cause of the condition. Many patients, particularly those with only a mild case of hypercalcaemia that is successfully treated, can make a full recovery. However, the ongoing presence of hypercalcaemia can lead to a number of conditions, specifically osteoporosis, kidney stones and kidney failure, and patients should be monitored for this.
Last reviewed: May 2021