Answer. The kidneys perform the vital functions of filtering out waste products, excess salt and fluids from the body, in addition to producing hormones that stimulate red blood cell production, control blood pressure and strengthen our skeleton. Disorders that injure the kidneys result in the development of chronic kidney disease (CKD), a condition in which the normal functions of the kidney are impaired which can, in turn, have a significant negative impact on the health and well-being of the affected person. Remarkably, more than 20 million Americans have CKD and an additional 20 million are at increased risk to develop CKD, especially those with diabetes mellitus, high blood pressure, a family history of kidney disease, old age and those who are African-American, Hispanic, Asian, American Indian or Pacific Islander.  Whereas prevention and early detection are keys to the treatment of CKD, its onset is often silent and many people are unaware that they have CKD until it is severe.  In contrast, knowledge of the warning signs of kidney disease can result in early treatment which may halt or slow down the disease progression.

What are the warning signs of kidney disease? When kidney function deteriorates, waste products, salt and fluids accumulate in the body and initially can result in subtle symptoms such as nausea, vomiting, weakness, fatigue, loss of appetite, dry and itchy skin, trouble sleeping, difficulty concentrating and poor school performance. As the kidney function worsens, one can experience weight gain from excess fluids, swollen feet and ankles, puffiness around the eyes and high blood pressure. Anemia (low red blood cell count) often occurs and contributes to the feeling of fatigue, and nausea/vomiting may result in poor food intake and the development of malnutrition. 

Finally, one of the early signs of CKD in children is poor growth. Since CKD can be diagnosed with blood and urine tests and blood pressure assessment, it is imperative that people with symptoms of CKD, and those previously noted to be in a high risk group for the development of CKD, be evaluated by their healthcare provider since early detection and treatment is so crucial.  Failure to slow or stop the progression of CKD can lead to kidney failure and the need to start dialysis or receive a kidney transplant to maintain life.

As part of the evaluation for CKD, a urine specimen is tested for the presence of protein and glucose. Patients with CKD will often have abnormal amounts of protein leak into the urine as a result of kidney damage, while the detection of glucose may be the first sign of diabetes mellitus, the most common cause of kidney failure in adults. Blood is tested for the creatinine level as creatinine is a waste product that comes from muscles and is normally removed from the body by the kidney. 

On the other hand, when the kidney function is poor, creatinine accumulates in the blood and a value greater than 1.5 mg/dl in adult females and 2.0 mg/dl in adult males is very abnormal. Unfortunately, this test alone is a poor indicator of kidney disease since nearly one-half of kidney function must be lost before a substantial rise of the creatinine level occurs. A better test is the glomerular filtration rate (GFR), which can be calculated from the blood creatinine test value, the patient’s age, gender and body size. A low level, less than 90, usually indicates that the kidneys are not functioning normally. Patients at risk for CKD should request that this test be determined by their physician.

In summary, the early physical findings associated with CKD can be non-specific and subtle. All people, but especially those determined to be at high risk for the disorder, should be aware of the warning signs of kidney disease and should seek a thorough medical evaluation if the signs arise and persist. Only in this manner will it be possible to decrease the frequency and severity of CKD in children and adults.

Answer provided by Bradley Warady, MD and Tarak Srivastava , MD. Dr. Warady is Professor of Pediatrics at the University of Missouri-Kansas City School of Medicine. He is the Chief, Section of Pediatric Nephrology and Director of Dialysis and Transplantation at The Childrens Mercy Hospital. Dr. Srivastava is a Fellow, Pediatric Nephrology at The Childrens Mercy Hospital.    

The American Association of Kidney Patients presents Ask the Doctor, an opportunity for readers to submit kidney related health questions to healthcare professionals who specialize in an area of concern. The answers are not to be construed as a diagnosis and therefore, alterations in current healthcare should not occur until the patient’s physician is consulted.

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