Kidney School™—a program of Medical Education Institute, Inc.

Module 1—Kidneys: How They Work, How They Fail, What You Can Do

When Kidneys Stop Working

Did you know that each kidney weighs about 5 ounces, and is about the size of your fist? These small organs play a big part in keeping you healthy.

In fact, the kidneys are so good at what they do that it's possible to live a healthy lifestyle with only one kidney. And many people do. Some people are born with only one kidney or choose to donate one of their kidneys to a family member or friend who has kidney disease. Others have kidney disease and reduced kidney function.

One kind of kidney disease is termed acute renal failure (ARF). This is a sudden loss of kidney function caused by an illness, injury, or toxin that stresses the kidneys. Many cases of ARF can be treated and reversed.

What Does "Renal" Mean?

Renal means "related to the kidneys."

Most people with kidney problems have chronic kidney disease (CKD). CKD is a long process where the kidneys slowly lose function. When the kidneys function at 15% or less, this is called kidney failure or end-stage renal disease (ESRD). But even if kidney function ends, it doesn't mean your life does!

More than 75% of the one million nephrons in each kidney must be damaged to cause illness. This means that small declines in renal function do not cause a problem right away. It can take many years to go from CKD to ESRD. Most people with CKD live out their lives without ever reaching ESRD.

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