What Do the Kidneys Do?

The kidneys have many important jobs. They make important hormones and, as the body's filtering system, help control water levels and get rid of wastes through urine (pee). They also help control blood pressure; red blood cell production; and the levels of acids, salts, and minerals (like calcium) in the body.

What Is Kidney Disease?

Kidney (or renal) disease is when the kidneys don't work as they should. This can happen for many reasons, such as when:

• Blood doesn't flow to the kidneys as well as it should.
• Tissues of the kidneys are damaged.
• The flow of urine from the kidneys gets blocked and causes kidney damage.

What Kidney Problems Can Happen in Kids?

Sometimes the kidneys don't develop properly before a baby is born, so they don't work as they should. Many of these problems can be found before a baby is born through routine prenatal testing and treated with medicine or surgery while the child is still young.

A baby also could be born with one or both kidneys missing, or have kidneys that are very small, or differently formed (with cysts or blockages, for example).

Some kidney conditions can develop later in kids, including:

• urinary tract infections (UTIs)
• kidney stones
• renal tubular acidosis
• Wilms tumor
• glomerulonephritis
• nephrotic syndrome
• nephritis. This is any inflammation of the kidney. It can be cause by infection, an autoimmune disease (such as lupus), or an unknown reason.
• high blood pressure (hypertension). This can be a sign of kidney problems, but having high blood pressure from another cause can also cause kidney problems.

What Are the Signs & Symptoms of Kidney Problems?

Kids with urinary tract or kidney problems might:

• have a fever
• have swelling around the eyes, face, feet, and ankles (called edema)
• feel burning or pain when peeing, or need to pee often
• have trouble controlling their peeing, if potty trained
• have nighttime bedwetting (after being dry for several months)
• have pink or brown colored pee, a sign of blood in the urine (hematuria)
• have bubbly or foamy pee, a sign of extra protein in the urine (proteinuria)
• have high blood pressure
• have a poor appetite, weight loss, or poor growth
• feel extra tired

How Are Kidney Diseases Diagnosed?

If a kidney disease is suspected, the doctor will do an exam and order urine tests, blood tests, imaging studies, or a biopsy to help make a diagnosis. These studies are usually suggested by a nephrologist (a doctor who treats kidney problems).

A urinalysis can quickly find problems (such as too many red blood cells) that might be a sign of inflammation or irritation in the urinary tract. It also can show if there are too many white blood cells, a sign of a bladder and kidney infection.

Blood tests are done to see how well the kidneys are filtering waste products and balancing the salts, minerals, and acid in the blood.

The doctor may do a kidney biopsy. Testing a tissue sample can help them diagnose a kidney problem in most cases.

Besides standard X-rays, doctors also might order these imaging studies:

• an ultrasound
• computerized tomography (CAT) scan
• a nuclear scan: A small amount of special radioactive material (less than that of a simple X-ray) is injected into a vein. The scan shows how the kidneys compare with each other in size, shape, and function. It also can detect scarring or other signs of recurrent or chronic kidney infection.
• voiding cystourethrogram (VCUG)

What Is Chronic Kidney Disease?

Chronic kidney disease is when the kidneys are damaged over time and can't work as well as they should to filter blood.

Sometimes, people with chronic kidney disease can develop kidney failure (or end-stage kidney disease), which is when the kidneys can no longer do their jobs at all. Then, they will likely need a kidney transplant or dialysis.

How Can Parents Help?

If your child has a kidney condition, turn to the care team for support before, during, and after treatment.

It also can help to find a support group. The care team might be able to recommend one in your area. You also can find more information online at:

• National Kidney Foundation
• Renal Support Network