Your Kidneys and How They Work
How Do Kidneys Fail?
Many factors that influence the speed of
kidney failure are not completely understood. Researchers are still studying
how protein in the diet and cholesterol levels in the blood affect kidney
Acute Renal Failure
Some kidney problems happen quickly, like
an accident that injures the kidneys. Losing a lot of blood can cause sudden
kidney failure. Some drugs or poisons can make your kidneys stop working. These
sudden drops in kidney function are called acute renal failure
ARF may lead to permanent loss of kidney
function. But if your kidneys are not seriously damaged, acute renal failure
may be reversed.
Chronic Renal Failure
Most kidney problems, however, happen
slowly. You may have "silent" kidney disease for years. Gradual loss of
kidney function is called chronic renal failure or chronic renal
End-Stage Renal Disease
The condition of total or nearly total and
permanent kidney failure is called end-stage renal disease (ESRD). People with
ESRD must undergo dialysis or transplantation to stay alive.
What Are the Signs of Kidney Disease?
People in the early stages of kidney
disease may not feel sick at all. The first signs that you are sick may be
general: frequent headaches or feeling tired or itchy all over your
If your kidney disease gets worse, you may
need to urinate more often or less often. You may lose your appetite or
experience nausea and vomiting. Your hands or feet may swell or feel numb. You
may get drowsy or have trouble concentrating. Your skin may darken. You may
have muscle cramps.
How Will My Doctor Detect Kidney Disease?
First, your doctor will probably send blood
and urine samples to a lab to test for substances that should not be there. If
the blood contains too much creatinine or urea nitrogen and the urine contains
protein, your kidneys may not be functioning properly.
Creatinine is a waste product in the blood
created by the normal breakdown of muscle during activity. Healthy kidneys take
creatinine out of the blood and put it in the urine to leave the body. When
kidneys are not working well, creatinine builds up in the blood.
In the lab, your blood will be tested to
see how many milligrams of creatinine are in one deciliter of blood (mg/dl).
Creatinine levels in the blood can vary, and each laboratory has its own normal
range. In many labs, the normal creatinine range is 0.6 to 1.2 mg/dl. If your
creatinine level is only slightly above this normal range, you probably will
not feel sick, but the elevation is a sign that your kidneys are not working at
full strength. One formula for estimating kidney function equates a creatinine
level of 2.0 mg/dl to 50 percent of normal kidney function and 4.0 mg/dl to 25
percent. But, because creatinine values are so variable and can be affected by
diet, you may need to have your creatinine measured regularly to see whether
your kidney function is decreasing.