Hypercalcemia is when calcium levels in your blood are too high. It can have a variety of negative effects on your body, including renal failure. Once kidney damage has happened, it cannot be reversed.

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Calcium is the most abundant mineral in your body. It’s needed for a variety of vital bodily functions. Some of these include bone and tooth structure maintenance, muscle movement, and nerve signaling.

More than 99% of calcium in your body is stored in your bones. The remaining calcium is found in your blood in various forms. Several hormones tightly regulate blood calcium levels to prevent health problems.

In rare cases, calcium levels in your blood can be too high. When this happens, it can cause renal (kidney) problems and potentially renal failure. Sometimes, renal failure can boost calcium levels in the blood as well. Keep reading to learn more.

Hypercalcemia is when there’s too much calcium in your blood.

Blood calcium levels typically range from 8.5–10.5 milligrams (mg) per deciliter (dL). Calcium levels above this generally mean you have hypercalcemia.

The symptoms of hypercalcemia typically don’t come on until blood calcium levels are higher than 12 mg/dL. Some potential symptoms include:

The most common causes of hypercalcemia are hyperparathyroidism, in which your body makes too much parathyroid hormone (PTH), and cancer. Together, these two causes account for 80–90% of all hypercalcemia diagnoses.

Some other less common causes of hypercalcemia include:

Renal failure happens when your kidneys can no longer filter wastes and excess fluid from your blood. It can be acute or chronic.

Acute renal failure is a sudden episode of renal failure that develops over a period of hours or days. Renal failure from chronic kidney disease (CKD) develops over a longer period.

Some symptoms common to both types of kidney failure are:

People with CKD may also have:

Serious illness or injury, certain medications, and blockage of the urinary tract are all examples of things that can cause acute renal failure.

Diabetes and high blood pressure are two of the most common causes of CKD.

Yes. Hypercalcemia can damage the kidneys and lead to renal failure. Excess calcium in the blood can reduce the filtering ability of the kidneys.

Increases in blood calcium can cause it to build up in kidney tissue, a condition called nephrocalcinosis. Over time, this can lead to damage and potentially renal failure.

The effects of hypercalcemia also increase the risk of kidney stones. Kidney stones may block urine flow and can increase the risk of infection, both factors that can contribute to kidney damage.

Yes. It’s also possible for renal failure to lead to hypercalcemia. This can be due to the effects of something called mineral and bone disorder in CKD.

People with CKD make less of a hormone that helps the body absorb calcium. This leads to low levels of calcium in the blood.

When your body senses that blood calcium levels are low, it releases PTH. The actions of PTH cause calcium to be moved from your bones into your bloodstream. This can lead to an increase in blood calcium levels.

Additionally, because calcium and vitamin D levels can be low in people with CKD, some individuals may take supplements. In some situations, oversupplementation with calcium or vitamin D may lead to hypercalcemia

When to see a doctor

Hypercalcemia and renal failure can both cause serious health problems and potentially death if left untreated. Because of this, if you have symptoms consistent with hypercalcemia or renal failure, talk with a doctor.

A doctor can order blood, urine, and imaging tests to help see what may be causing your symptoms. Once they make a diagnosis, they can develop an appropriate treatment plan.

Dialysis can treat people with both hypercalcemia and renal failure. Either hemodialysis or peritoneal dialysis may be used.

Dialysis is a procedure that helps your kidneys filter blood and excess fluids from your body. It can also help restore the balance of minerals like calcium.

A doctor may use other potential treatments. These can depend on factors like the cause of hypercalcemia, the type of renal failure, and your age and overall health. They include:

  • saline infusion to increase urination and flush out excess calcium
  • calcitonin, a medication that reduces blood calcium levels
  • removal of the parathyroid gland in people with hyperparathyroidism
  • bisphosphonates for hypercalcemia caused by cancer
  • steroids for hypercalcemia caused by too much vitamin D
  • withdrawal of medications or supplements that are contributing to hypercalcemia

Treatment can often reverse acute renal failure due to hypercalcemia. However, people who have experienced acute renal failure have an increased risk of developing CKD in the future.

While hypercalcemia can be managed, the damage to the kidneys cannot be reversed once it has happened.

The two treatments for renal failure in people with late stage CKD include dialysis and kidney transplant. Which treatment option a doctor recommends depends on many factors, including your age, overall health, and preference.

Does renal failure cause hypocalcemia or hypercalcemia?

Renal failure can lead to both hypocalcemia and hypercalcemia. Generally speaking, calcium balance in people with renal failure is dysregulated.

Reduced kidney function can lead to a drop in blood calcium levels, causing hypocalcemia. The body’s response to hypocalcemia or using too much calcium or vitamin D supplements can in turn lead to hypercalcemia.

How much calcium is too much?

According to the National Institutes of Health, the daily upper limits of calcium intake for adults are 2,500 mg for adults 19–50 years old and 2,000 mg for adults 51 years and older.

What other complications can hypercalcemia cause?

In addition to kidney problems and renal failure, hypercalcemia may also lead to complications like:

Hypercalcemia is when there’s too much calcium in your blood. It typically happens due to the effects of hyperparathyroidism or cancer. Hypercalcemia can damage the kidneys and potentially lead to renal failure.

You can also develop hypercalcemia if you have chronic kidney disease. This is typically due to the body’s response to low blood calcium levels. Too much calcium or vitamin D supplements may also cause hypercalcemia.

If you have hypercalcemia and renal failure, your treatment will likely include dialysis and sometimes other treatments. While treatment can manage the symptoms of hypercalcemia, once kidney damage has happened, it cannot be reversed.