• Mayo Clinic Q and A: Understanding chronic kidney disease

a close-up of a smiling middle-aged mother and teenage son in their kitchenDEAR MAYO CLINIC: Are there typically early symptoms of chronic kidney disease? I was diagnosed with it last month but don’t have any symptoms. What causes this disease? Can it be genetic?

ANSWER: In its early stages, chronic kidney disease rarely causes noticeable symptoms. Although genetics may play a role in its development, chronic kidney disease is most commonly the result of either diabetes or high blood pressure. When diagnosed early, there are often steps that can minimize the damage and slow the progress of chronic kidney disease.

Your kidneys are two bean-shaped organs — each about the size of a fist. They are located in the back of your abdomen on either side of your spine. Your kidneys’ main job is filtering waste and excess fluid from blood to make urine. Kidneys also perform other tasks, such as adjusting the balance of minerals and acids in the blood and regulating blood pressure.

Kidney disease happens when the kidneys have been damaged and no longer work the way they should. As in your situation, it's common for kidney disease not to cause any obvious symptoms when it first develops. As the disease worsens, symptoms may appear. But they are often vague and can include fatigue; shortness of breath; poor appetite; nausea; and swollen ankles, legs or hands.

Persistently foamy urine is a telltale sign of chronic kidney disease that may be due to damage of the filtering apparatus in your kidneys. As your kidneys filter blood, they take out waste products, while keeping substances your body needs, such as proteins. When your kidneys are damaged, they may not be able to retain proteins properly, and high levels of protein pass into your urine. The extra protein causes urine to become foamy. This typically happens in kidney disease states, such as glomerulonephritis (inflammation of the tiny filters in your kidneys), vasculitis (inflammation of the blood vessels in the body), or advanced diabetic kidney disease.

Chronic kidney disease does have a tendency to run in families, so some people are genetically more likely to develop the disease. Genetic disorders such as autosomal dominant polycystic kidney disease also can lead to serious kidney problems. Chronic kidney disease is more common in certain groups, including African-Americans, Native Hawaiians, Pacific Islanders, Native Americans and Asian-Americans.

A more significant risk factor for chronic kidney disease than genetics alone, however, is having a medical condition that could harm your kidneys. The two most common are high blood pressure and diabetes. If left untreated, over time, these diseases can weaken the tiny blood vessels within the kidneys that filter waste from the blood, making them unable to work properly.

Other conditions that can lead to chronic kidney disease include polycystic kidney disease, recurrent kidney infections, obstruction of the urinary tract, and disorders that cause inflammation within the kidneys, such as glomerulonephritis and interstitial nephritis. Some medications can affect kidney function, too. Finally, chronic kidney disease becomes more common as people age.

If a medical condition that affects the kidneys goes untreated, chronic kidney disease generally will worsen over time. Once kidneys have been damaged, it may not be possible to restore the function that's been lost. But if an underlying medical condition is identified and successfully treated, that often will help slow the progression of kidney disease. With some conditions, such as glomerulonephritis, kidney disease can be cured with treatment. This is particularly true when kidney disease is identified in its early stages.

Medication and lifestyle changes, such as losing weight, quitting smoking, and eating less animal protein and salt, also may be necessary to keep kidney disease in check. A nephrologist — a health care provider who specializes in kidney care — can work with you to identify specific steps you can take to help control your chronic kidney disease. — Dr. LaTonya Hickson, Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota

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