The Dangers of Calcium Overload

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The Dangers of Calcium Overload

Written by:

Lee Rosen, MD - UCLA School of Medicine

Berenson, MD - Cedars Sinai Health System, CA

Figlin, MD - UCLA School of Medicine

Published on: September 19, 2002   

We often hear about the virtues of calcium and the importance of getting

enough calcium in our diets to maintain healthy bones. But what if the body

contains too much calcium? The condition is called hypercalcemia, and if

left untreated, can wreak havoc in multiple organ systems in the body.

There are many causes of elevated calcium levels, but people with certain

types of cancer are at particular risk. Below, oncologists Dr. Lee Rosen,

Dr. Berenson, and Dr. Figlin, discuss the dangers of

hypercalcemia, and methods of treating it.

Why does the body need calcium, and what happens when there is too much?

LEE ROSEN, MD: Calcium is one of the chemicals in the body that regulates a

lot of different functions, including bone formation and bone loss, as well

as general metabolism. Many organs of the body require calcium for their

function.

JAMES BERENSON, MD: Hypercalcemia, means that the calcium level in the blood

is too high. High levels of calcium that occur cannot be cleared from the

blood by the kidneys. And when calcium is too high in the blood, it can

affect every major organ in the body. It affects the kidneys, heart

function, the GI tract, cognitive function, nerves, and the rest of your

body.

What causes hypercalcemia?

ROBERT FIGLIN, MD: The vast majority of hypercalcemia occurs from either an

increased level of a certain hormone, parathyroid, or from certain types of

cancer. In some cases, cancer cells make a hormone-- very much like the

hormones that our own body makes to regulate the calcium levels. The effect

of that hormone on bone is to make the bone release calcium into the

bloodstream. In other cases, cancer can spread directly to bone causing the

leaching out of calcium from the bone.

What are the signs of hypercalcemia in people with cancer?

JAMES BERENSON, MD: One of the troubling things with hypercalcemia is that

it's commonly diagnosed very late, because of the symptoms are not too

specific. Some patients complain of fatigue, constipation, or nausea, which

could be related either to other things that are going on with their cancer,

or possibly the treatment they're already taking.

But it's very important to diagnose hypercalcemia early because it can lead

to very, very serious complications, including coma and possibly even death.

In addition, the kidneys can be affected, and irreversible kidney failure

can occur.

Is this common in people with cancer?

LEE ROSEN, MD: Hypercalcemia is common enough that we see it routinely in

the clinic. Cancers of the breast, the prostate, the lung, multiple myeloma,

disease of the bone marrow, can all be associated with high blood calcium

levels.

How is hypercalcemia treated?

LEE ROSEN, MD: Usually the best medical therapy for hypercalcemia is to use

bisphosphonate therapy. This is a class of drugs that's been around for

several years now.

JAMES BERENSON, MD: These drugs reduce bone loss. And of course, with the

reduction in bone loss there's less calcium leaching out of the bone, and

thus less calcium in the blood to cause hypercalcemia in these patients.

LEE ROSEN, MD: The bisphosphonates are very effective in the long-term

control of hypercalcemia. Usually they take a couple of days to start

working, so while they're taking effect, you can use very vigorous

intravenous hydration, fluid, to flush the calcium almost out of the body

and follow it with some diuretics to promote excreting the calcium through

kidneys and into the urine. As far as side effects are concerned, all of the

bisphosphonates can cause kidney problems if given at too high a dose, too

frequently, or too rapidly.

Has the use of bisphosphonates changed the way hypercalcemia is treated?

JAMES BERENSON, MD: Yes, bisphosphonates really have changed the way we deal

with high calcium in our cancer patients. It was pretty universal to put

these patients in the hospital and monitor them over several days. Now many

of these patients can be simply monitored with some IV fluids in the clinic

and then given their dose of bisphosphonate, and then have their calcium

levels checked every few days until one is assured that it is coming back to

normal.

© 2002 Healthology, Inc.