by Dr. Mackenzie Walser
Are you one of the millions of people who have unrecognized kidney disease? It's worth finding out, because if the disease progresses, you may wind up on dialysis, which can be extremely disabling and a lifelong process -- unless you can get a transplant.
Initially, the main symptoms of kidney disease are fatigue, loss of appetite, itching, and muscle cramps. Later, the symptoms progress to include nausea and vomiting. By this time, you're in the later stages of the disease, when about three-quarters of kidney function has been lost. So you can't recognize kidney disease by the symptoms alone.
There are two simple tests to check for kidney disease. A routine blood test can detect impaired kidney function. Your doctor probably performs a routine blood chemistry test once a year or so. You can also test yourself. In either case, that test includes a measurement of creatinine, a substance produced continuously by the body, especially in muscle, and is excreted by the kidneys. When kidney function decreases, there is a higher level of creatinine in the blood that can be readily detected. The upper limit of normal creatinine concentration in the blood serum is about 1.5 milligrams per 100 milliliters. When creatinine concentration is higher than 1.5 milligrams per 100 milliliters of serum, kidney function must be reduced. The more kidney function is impaired, the higher serum creatinine concentration becomes. The average serum creatinine concentration at which dialysis becomes necessary for survival is about 7 milligrams per 100 milliliters, corresponding to about 1/10 of kidney function remaining. Some people start dialysis much earlier for example, they might start dialysis at a creatinine level as low as 3 mg per deciliter, though this is probably not necessary.
Along with routinely having your blood tested, you can easily test for urine protein. Paper strips for this purpose can be purchased at any pharmacy. Simply hold one of the strips in your urinary stream and see if it changes color (the label will give further details, including how to determine if there is glucose in your urine which is a sign of diabetes). But if this test does show urinary protein, you need not conclude that you have kidney failure. The first thing to do if you get a positive reading is to repeat the test. If a positive result still appears, you may have kidney disease, but you may instead have one of the other conditions that can make protein appear in the urine even though kidney function is normal.
The most common cause of such a result is fever, but there are other causes, too. If protein continues to appear in your urine, see your doctor. He or she will find out whether you have chronic kidney disease. If you don't have protein in your urine, you almost certainly don't have kidney disease.
If your kidney function is reduced, it's critical to know if the disease is progressing. This requires repeated creatinine measurements over a period of at least several months. If your creatinine concentration, though elevated, does not rise further, you may never develop kidney failure and may never require dialysis. If the disease is progressing, controlling your blood pressure and reducing your dietary protein can help slow the progression. Occasionally, people who have elevated creatinine concentrations go on for decades without progression, and may have no symptoms at all, providing their kidney function is not too severely impaired.
Don't take a chance with your kidneys; the stakes are too high! Get tested today.
For additional information, see COPING WITH KIDNEY DISEASE, by Mackenzie Walser, with Betsy Thorpe, published by John Wiley & Sons.