Actor Nick Cannon has been hospitalized in Colorado for a mild kidney failure, his wife Mariah Carey said on Twitter Wednesday.

Please pray for Nick as he's fighting to recover from a mild kidney failure. #mybraveman, the singer tweeted, sharing a photo of her and Cannon in his hospital bed.

But what exactly is this illness that had placed Cannon in the hospital?

According to the Centers for Disease Control and Prevention, the kidneys are responsible for keeping the right amount of water in the body and for helping to get rid of harmful wastes. These wastes are called urea, which pass from the body in the urine. When the kidneys fail, then an individual will need to have his or her blood filtered through a machine. This treatment is called dialysis and may need to be done times a week or that person may have to get a kidney transplant, according to the CDC's Web site.

It is hard to find what exactly is mild kidney failure when one scope some of the medical Web sites.

However, Dr. Bryan Becker, the immediate past president of the National Kidney Foundation, spoke to the Los Angeles Times through a media representative noting that there really isn't a term known as mild kidney failure.

Becker speculated that Cannon's hospitalization may have resulted from a decrease in kidney function.

Acute kidney failure

There is however, a term called acute kidney failure, which according to PubMed Health, which happens when the kidney suddenly loses its ability to remove waste and concentrate urine from the body without losing electrolytes. Electrolytes are minerals in the blood and other body fluids that carry an electric charge. They affect the amount of water that is inside a person's body, the acidity of someone's blood, an individual's muscle function and other important processes, according to PubMed Health.

People lose elctrolytes whenever they sweat and they must be replaced by drinking fluids. Some common electrolytes include calcium, chloride, magnesium, phosphorous, potassium and sodium.

Waste material that aren't removed from the body can build up.

Becker told the Los Angeles Times that Cannon's condition could be caused by an illness, dehydration or taking an over-the-counter medication such as Motrin or Advil.

For someone to have it and to be hospitalized raises an extra level of concern, Becker said.

Whatever the cause of Cannon's condition, Carey took to her Web site and stated that it has caused a reversal in the roles, as last year she was hospitalized after having their twins.

Last year it was me attached to the machines (after having dembabies) and Nick was there with me through it, and now here we are, she wrote. We're trying to be as festive as possible under the circumstances but please keep Nick in your thoughts because this is very painful. They tried to kick me out of the hospital but here I am pon de bed with Mr. C.

Carey did say however, that the two are doing well.

(I know, we could be in a lot worse places) but the truth is as long as we're together, we're OK, she wrote to inform fans. I'm not trying to make light out of the situation because it's a serious moment that's very tough on all of us so please keep us and our family in your prayers.