Your Kidneys and How They Work
What Is "Renal Function"?
Your health care team may talk about the
work your kidneys do as renal function. If you have two healthy kidneys, you
have 100 percent of your renal function. This is more renal function than you
really need. Some people are born with only one kidney, and these people are
able to lead normal, healthy lives. Many people donate a kidney for
transplantation to a family member or friend. Small declines in renal function
do not cause a problem. In fact, you can be healthy with 50 percent of your
renal function if it remains stable.
But many people with 50 percent of their
renal function have a kidney disease that will get worse. You will have some
serious health problems if you have less than 20 percent of your renal
function. If your renal function drops below 10 to 15 percent, you cannot live
long without some form of renal replacement therapy -- either dialysis or
Why Do Kidneys Fail?
Most kidney diseases attack the nephrons,
causing them to lose their filtering capacity. Damage to the nephrons may
happen quickly, often as the result of injury or poisoning. But most kidney
diseases destroy the nephrons slowly and silently. It may take years or even
decades for the damage to become apparent.
The two most common causes of kidney
disease are diabetes and high blood pressure. If your family has a history of
any kind of kidney problems, you may be at risk for kidney disease.
Diabetes is a disease that keeps the body
from using sugar as it should. If sugar stays in your blood instead of breaking
down, it can act like a poison. Damage to the nephrons from unused sugar in the
blood is called diabetic nephropathy. If you keep your blood sugar levels down,
you can delay or prevent diabetic nephropathy.
High Blood Pressure
High blood pressure can damage the small
blood vessels in your kidneys. The damaged vessels cannot filter poisons from
your blood as they are supposed to.
Your doctor may prescribe blood pressure
medication. A group of blood pressure medicines called ACE inhibitors appears
to give extra protection to the kidneys in patients with diabetes.