Digital Urology Journal: urinary tract infection

Urinary Tract Infections in Children

Aside from unexpected wetting, the most common urinary problem among children is infections. An estimated 3 percent of girls and 1 percent of boys have had a urinary tract infection (UTI) by the age of 11. Some researchers believe these estimates are low because many cases of UTI go undetected. The symptoms are not always obvious to parents, and younger children are usually unable to describe how they feel. Recognizing and treating urinary tract infections is important. Untreated UTIs can lead to serious kidney problems that could threaten the life of your child.

Front view of urinary tract.

Figure 1.--Front view of urinary tract

How Does the Urinary Tract Normally Function?

The kidneys filter and remove waste and water from the blood to produce urine. They get rid of about 11/2 to 2 quarts of urine per day in an adult and less in a child, depending on the child's age. The urine travels from the kidneys down two narrow tubes called the ureters. The urine is then stored in a balloon-like container called the bladder (see figure 1). In a child, the bladder can hold about 1 to 11/2 ounces of urine for each year of the child's age. So, the bladder of a 4-year-old child may hold about 4 to 6 ounces (less than 1 cup); an 8-year-old can hold 8 to 12 ounces. When the bladder empties, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys (see figure 2) and in front of the vagina in girls (see figure 3).

How Does the Urinary Tract Become Infected?

Normal urine contains no bacteria (germs). Bacteria may, at times, get into the urinary tract (and the urine) from the skin around the rectum and genitals by traveling up the urethra into the bladder. When this happens, the bacteria can infect and inflame the bladder, resulting in swelling and pain in the lower abdomen and side. This is called "cystitis."

Figure 2.--Side view of male urinary tract

If the bacteria travel further up through the ureters to the kidneys, a kidney infection can develop. The infection is usually accompanied by pain and fever. Kidney infections are much more serious than bladder infections.

In some children a urinary tract infection may be a sign of an abnormal urinary tract that may be prone to repeated problems. (See What Abnormalities Lead to Urinary Problems?) For this reason, when a child is found to have a urinary infection, additional tests are often recommended. (See What Tests May Be Needed After the Infection Is Gone?) In other cases, children develop urinary tract infections because they are prone to such infections the way, for example, other children are prone to getting coughs, colds, or ear infections. Or a child may happen to get an infection with a type of bacteria that has a special ability to cause urinary tract infections.

What Are the Signs of Urinary Tract Infection?

The lining of the bladder, urethra, ureters, and kidneys become irritated with a urinary tract infection, just like the inside of the nose or throat with a cold. If your child is an infant or is only a few years old, the signs of a urinary tract infection may not be clear, since children that young cannot tell you just how they feel. Your child may have a high fever, be irritable, or not eat.

An older child with bladder irritation may complain of pain in the abdomen and pelvic area. Your child may urinate often. If the kidney is infected, your child may complain of pain under the side of the rib cage (the flank) or low back pain. Crying or complaining that it hurts to urinate and producing only a few drops of urine at a time are other signs of urinary tract infection. Your child may have difficulty controlling the urine and may leak urine into clothing or bedsheets. The urine may smell unusual or look cloudy.

Side view of female urinary tract.

Figure 3.--Side view of female urinary tract

How Do You Find Out Whether Your Child Has a Urinary Tract Infection?

Only by consulting a health care provider can you find out for certain whether your child has a urinary tract infection.

Some of your child's urine will be collected and examined. The way urine is collected may depend on how old your child is. The health care provider may place a plastic collection bag over your child's genital area (sealed to the skin with an adhesive strip) if the child is not yet toilet trained. An older child may be asked to urinate into a container. The sample needs to come as directly into the container as possible to avoid picking up bacteria from the skin or rectal area. A doctor or nurse may need to pass a small tube into the urethra. Urine will drain directly from the bladder into a clean container through this tube (called a catheter). Sometimes the best way to get the urine is by placing a needle directly into the bladder through the skin of the lower abdomen. Getting urine through the tube or needle will make sure that the urine collected is pure.

Some of the urine will be examined under a microscope. If an infection is present, bacteria and sometimes pus will be in the urine. If the bacteria from the sample are hard to see at first, the health care provider may place the sample in a tube or dish with a substance that encourages any bacteria present to grow. Once the germs have multiplied, they can be then identified and tested to see which medications will provide the most effective treatment. The process of growing bacteria in the laboratory is known as performing a culture and often takes a day or more to complete.

The reliability of the culture depends on how long the urine stands before the culture is started. If you collect your child's urine at home, it should be refrigerated as soon as collected and the container should be transported in a plastic bag filled with ice.

How Are Urinary Tract Infections Treated?

Urinary tract infections are treated with antibiotics (infection-fighting drugs). After a urine sample is obtained, the health care provider may begin treatment with a drug that treats the bacteria most likely to be causing the infection. Once culture results are known, the health care provider may switch your child to another antibiotic, if necessary.

The way the antibiotic is given and the number of days that it must be taken depends in part on the type of infection and how severe it is. When a child is sick or not able to drink fluids, the antibiotic may need to be put directly into the bloodstream through a vein in the arm or hand. Otherwise, the medicine (liquid or pills) may be given by mouth or by shots. The medicine is given for at least 3 to 5 days and possibly for as long as several weeks. The daily treatment schedule recommended depends on the specific drug prescribed: the schedule may call for a single dose each day or up to four doses each day. In some cases, your child will need to take the medicine until further tests are finished.

After a few doses of the antibiotic, your child may appear much better, but often several days may pass before all symptoms are gone. In any case, your child should take the medicine for as long as the doctor says. Do not stop medications because the symptoms have gone away. Infections may return, and germs can resist future treatment if the drug is stopped too soon.

Children should drink fluids when they wish. Make sure your child drinks what he or she needs, but do not force your child to drink large amounts of fluid. The health care provider needs to know if the child is not interested in drinking.

What Tests May Be Needed After the Infection Is Gone?

Once the infection has cleared, additional tests may be recommended to check for abnormalities in the urinary tract. Repeated infections in abnormal urinary tracts may cause kidney damage. The kinds of tests ordered will depend on your child and the type of urinary infection. Because no single test can tell everything about the urinary tract that might be important to know, more than one of the following tests may be needed:

Kidney and bladder ultrasound: A test that examines the kidney and bladder using sound waves. This test shows shadows of the kidney and bladder that may point out certain abnormalities; this test cannot reveal all important urinary abnormalities. It also cannot measure how well a kidney works.
Voiding cystourethrogram (VCUG): A test that examines the urethra and bladder while the bladder fills and empties. A liquid that can be seen on x-rays is placed into the bladder through a catheter. The bladder is filled until the child urinates. This test can reveal abnormalities of the inside of the urethra and bladder. The test can also determine whether the flow of urine is normal when the bladder empties.
Intravenous pyelogram: A test that examines the whole urinary tract. A liquid that can be seen on x-rays is injected into a vein. The substance travels into the kidneys and bladder, revealing possible obstructions.
Nuclear scans: A number of tests using radioactive materials that are usually injected into a vein to show how well the kidneys work, the shape of the kidneys, and whether urine empties from the kidneys in a normal way. The many kinds of nuclear scans each give different information about the kidneys and bladder. Nuclear scans expose a child to no more radiation than he or she would receive from a conventional x-ray. At times, it can even be less.

What Abnormalities Lead to Urinary Problems?

Many children who get urinary tract infections have normal kidneys and bladders, but children who have an abnormality need to have it detected as early as possible in life to try to protect their kidneys against damage. Abnormalities that could occur include the following:

Vesicoureteral reflux. Urine normally flows from the kidneys down the ureters to the bladder in one direction. With reflux, when the bladder fills, the urine may also flow backward from the bladder up the ureters to the kidneys. This abnormality is common in children with urinary infections.
Urinary obstruction. Blockages to urinary flow may occur at many sites in the urinary tract. Blockages usually occur if the ureter or urethra is too narrow or a kidney stone at some point stops the urinary flow from leaving the body. Occasionally, the ureter may join the kidney or bladder at the wrong place, preventing urine from leaving the kidney in a normal way.

Do Urinary Tract Infections Have Long-Term Effects?

Young children are at the greatest risk for kidney damage from urinary tract infections, especially if they have some unknown urinary tract abnormality. Such damage includes kidney scars, poor kidney growth, poor kidney function, high blood pressure, and other problems. For this reason it is important that children with urinary tract infections receive prompt treatment and careful evaluation.

Points To Remember

Urinary tract infections occur in about 3 percent of girls and 1 percent of boys by age 11.
A urinary tract infection in a young child may be a sign of an abnormality in the urinary tract that could lead to repeated problems.
Symptoms of a urinary infection range from slight burning with urination or unusual smelling urine to severe pain and high fever.
Untreated urinary infections can lead to serious kidney damage.
Talk to a doctor if you suspect your child has a urinary tract infection.

Additional Resources

American Foundation for Urologic Disease
1128 North Charles Street
Baltimore, MD 21201
(800) 242-2383 or (410) 468-1800

This fact sheet was prepared in cooperation with the Bladder Health Council and the Pediatric Urology Health Council of the American Foundation for Urologic Disease, in partnership with the National Association For Continence and The Simon Foundation for Continence, U.S.

The illustrations in this publication appear courtesy of Children's National Medical Center, Washington, D.C.

National Kidney and Urologic Diseases Information Clearinghouse

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E-mail: nkudic@aerie.com

The National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health under the U.S. Public Health Service. Established in 1987, the clearinghouse provides information about diseases of the kidneys and urologic system to people with kidney and urologic disorders and to their families, health care professionals, and the public. NKUDIC answers inquiries; develops, reviews, and distributes publications; and works closely with professional and patient organizations and Government agencies to coordinate resources about kidney and urologic diseases.

Publications produced by the clearinghouse are carefully reviewed for scientific accuracy, content, and readability.

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