Quick version
Calcium is a vital mineral for many functions in the body, from building strong bones and teeth to regulating muscle contractions and heartbeats. However, when calcium levels in the blood become too high, it can lead to a condition known as hypercalcemia. This condition can cause a range of symptoms and health problems affecting everything from the kidneys to the nervous system.
What is elevated calcium?
Elevated calcium levels in the blood, also known as hypercalcemia, mean that calcium levels exceed the normal reference range, which is between 2.1 and 2.7 mmol/L for P-calcium. When calcium levels exceed the upper limit Ca >3.4 mmol/L, the body may respond with various symptoms depending on how much the calcium levels have risen. Mildly elevated calcium levels may be asymptomatic and often detected incidentally during routine blood testing, such as during a health check. However, when calcium levels are significantly elevated, it can cause more pronounced problems affecting several organs, including the kidneys, muscles, and nervous system.
Symptoms of hypercalcemia
Symptoms of hypercalcemia can vary depending on how high the calcium levels are and how quickly they have risen. Common symptoms include:
- Fatigue and muscle weakness, as elevated calcium concentrations in the blood can affect muscles and nerves, making one feel tired or weak.
- Nausea and loss of appetite, caused by digestive issues that can be an early sign of hypercalcemia.
- Increased thirst and urination, as kidney function may be affected, leading to frequent urination and increased thirst due to hypercalcemia.
- Constipation, as too much calcium can impact the gastrointestinal tract and cause constipation.
- Confusion and concentration difficulties, as severely elevated calcium levels can affect the brain, leading to cognitive issues.
What causes elevated calcium levels?
There are several causes of elevated calcium levels, and it is important to identify the underlying cause to treat hypercalcemia appropriately.
- Overactive parathyroid glands (hyperparathyroidism): The most common cause of elevated calcium levels is the overproduction of parathyroid hormone (PTH) from the parathyroid glands. This leads to too much calcium being released from the bones into the bloodstream.
- Medications and vitamin D intoxication: Excessive use of vitamin D supplements can cause the body to absorb too much calcium from the intestines, leading to dangerously high levels of calcium in the blood.
- High intake of calcium-rich foods: Temporary increases in calcium levels can occur with excessive intake of calcium-rich foods or supplements, although this rarely causes prolonged hypercalcemia in healthy individuals with normal kidney function.
- Cancer: Certain types of cancer, such as breast, lung, and kidney cancer, can raise calcium levels by stimulating the release of calcium from bone tissue or through the production of substances that mimic PTH.
Vitamin D intoxication and hypercalcemia
Vitamin D is essential for maintaining the body’s calcium balance, but excessive use can lead to vitamin D intoxication. This usually occurs when taking too high doses of vitamin D supplements over a long period. Excessive intake of vitamin D increases calcium absorption from the intestines and can cause hypercalcemia. It is important to follow recommended dosages and avoid prolonged high intake without medical supervision.
Symptoms of vitamin D intoxication include the classic signs of hypercalcemia, such as fatigue, nausea, constipation, as well as kidney issues, which can lead to kidney stones or, in severe cases, kidney failure.
Diagnosis and treatment of hypercalcemia
Hypercalcemia is diagnosed through blood tests that measure calcium levels as well as related values such as parathyroid hormone (PTH) and vitamin D. If hypercalcemia is suspected, the doctor may also examine kidney function and bone health. Treatment depends on the underlying cause and the severity of the condition. For mild hypercalcemia, it may be sufficient to stop taking calcium and vitamin D supplements and monitor the condition. In more severe cases, more extensive treatment may be necessary, such as intravenous fluids to help the kidneys flush out excess calcium, as well as medications to lower calcium levels in the blood.
Preventive measures
To avoid hypercalcemia, it is important to:
- Avoid excessive intake of supplements, particularly vitamin D and calcium, without medical guidance.
- Follow up with regular blood tests if you have an underlying condition that affects calcium regulation, such as hyperparathyroidism.
- Discuss with a doctor before taking long-term high doses of vitamins and minerals.
