Urinary Tract Infections in Children
As many as 8 percent of girls and 2 percent of boys will develop a urinary tract infection. Furthermore, young children have a greater risk of kidney damage linked to urinary tract infection than older children or adults. The information below should help you recognize a urinary tract infection in children before it causes serious damage.
What happens under normal conditions?
The urinary tract controls the outflow of urine, one of the body's liquid waste products. The kidneys produce about 1and 1/2 to two quarts a day in an adult, and less in children, depending on their age. Urine travels from the kidneys down tubes, the ureters, into a balloon-like container called the bladder. In children, the bladder can hold 1 to 1 and 1/2 ounces of urine for every year of age (e.g., four to six ounces, or a little less than a cup, in a four-year-old). When the bladder empties, it pushes the urine out of the body through a tube at the bottom of the bladder called the urethra. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls. In normal children, there is flow of urine only in one direction, from the kidneys, down the ureters, into the bladder and then out the urethra. This constant one directional flow helps prevent infections.
What causes urinary tract infections in children?
Normal urine is sterile and contains no bacteria. However, even under normal circumstances bacteria cover the skin and are present in large numbers in the rectal area and within bowel movements. Bacteria may, at times, get into the urinary tract and travel up the urethra into the bladder. When this happens, the bacteria multiply and unless the body gets rid of the bacteria, they can cause infection (urinary tract infection or "UTI."
There are two general types of UTIs—bladder infection and kidney infection. When the infection involves the bladder it can cause inflammation, swelling and pain of the bladder. This is called cystitis. If the bacteria travel upward from the bladder through the ureters and reach and infect the kidneys, the kidney infection is called pyelonephritis. Kidney infections are more serious than bladder infections, and can cause kidney damage especially in young children.
What are the symptoms of urinary tract infections in children?
Most often when there is a urinary tract infection, the linings of the bladder, urethra, ureters, and kidneys become red and irritated. This usually causes painful, frequent urination and children may pass urine with a foul odor. Many children start having urinary accidents, and/or bloody urine. If the kidneys become infected, children often have abdominal or back pain and fever. If your child is an infant or too young to tell you how he or she feels, the signs are likely to be vague and unrelated to the urinary tract. For example, your child may just have a high fever, or be irritable and not eating, or sometimes have only a low-grade fever, loose bowel movements or just not seem healthy. You may notice that the diaper urine "smells bad." If your child has a high temperature and appears sick without another obvious source for his/her discomfort (such as runny nose or ear ache), they should see a doctor. If a kidney infection is not treated promptly, the bacteria may spread to the bloodstream and cause a life-threatening infection or permanent kidney damage.
Older children may complain of pain in the low stomach area or back as well as the need to urinate frequently. Your child may cry when he or she urinates or complain that it hurts to urinate and produce only a few drops of urine. It may be hard for them to control their urine so they may have urinary accidents or bed-wetting. They may also produce urine that smells bad or looks cloudy.
How are urinary tract infections diagnosed in children?
If you think your child has a urinary tract infection, call your doctor. The only way to diagnose a urinary infection is with a urine test. Your doctor will collect a urine sample for evaluation. The method your physician uses will depend on your child's age. For instance, if your toddler is not toilet-trained, your doctor may simply attach a plastic bag to their skin to collect the sample. If your child is older, you may be asked to help catch the specimen as your child empties his or her bladder. Since it is critical that the collected urine be free from bacteria on the surrounding skin, it is sometimes necessary to pass a small tube into the urethra or a needle into the low abdomen into the bladder directly to collect a good sample.
This sample of urine is then examined under a microscope. If an infection is present, your doctor may be able to see bacteria and pus (white blood cells). This test takes only a few minutes. The doctor may also perform a urine culture, a process in which bacteria from urine are grown in a laboratory incubator to determine whether there is significant bacterial growth. The bacteria can then be identified and tested to see which drugs will most effectively treat the infection. There are many different kinds of bacteria that can infect the urine and different types of bacteria may require different types of antibiotic treatment. It takes several days to complete urine culture testing.
How are urinary tract infections treated in children?
Urinary tract infections are treated with antibiotics. If your doctor thinks your child has a urine infection, they will choose a drug that treats the bacteria most likely to be causing the problem. Sometimes a few days later, after the culture results are finished, the antibiotic drug might be changed to one that is more effective against the particular bacteria found in your child's urine. In addition to antibiotics, you can help your child's body fight the infection by encouraging lots of fluids and very frequent urination.
The specific antibiotic drug, way it is given and number of days that it must be taken may depend, in part, on the type and severity of infection. If your child is very sick and unable to take fluids, the antibiotic may need to be given as shots (injected directly into the bloodstream or muscle) with your child in the hospital; otherwise, oral medicine may be given. The daily treatment schedule your child's doctor recommends will depend upon the specific drug prescribed: it may call for a single dose each day or up to four daily doses. In some cases you will be asked to give your child medicine until further tests are finished.
After a few doses of the antibiotic, your child may appear much improved or even have returned to their normal activities, but often it may take weeks before all symptoms are gone. Even if they are improved, it is important that your child take the antibiotic medicines as prescribed by your doctor and not stop them because just because the symptoms have gone away. Unless urinary tract infections are fully treated, they may return, or your child may get another infection.
What can be expected after treatment for urinary tract infections in children?
Once the infection has cleared, your child's doctor may recommend additional tests, particularly if they have been treated for a kidney infection. The tests are performed to assure that there are no abnormalities in the urinary tract that might prevent your child's body from fighting off the infection and to assess whether there has been any kidney damage from urinary tract infections. The specific tests ordered will depend on your child and the kind of urinary infection they had. Unfortunately no single test can tell everything about the urinary tract that might be important to know after having a urinary tract infection. For that reason several tests are usually recommended. If these studies show a urinary tract abnormality, your doctor may want you to see a urologist.
Additional tests may include:
Kidney and/or bladder ultrasonography: This test gets pictures of the kidney and bladder using sound waves. This test may show shadows that indicate some kinds of abnormalities, like blockages, but cannot show all important urinary tract abnormalities. It also cannot tell how well the kidney works.
Voiding cystourethrogram (VCUG): This important test can show abnormalities of the inside of the urethra and bladder, and if urinary flow is normal during bladder emptying. It also tells your doctor if urine from the bladder is backing up into the ureters (vesicoureteral reflux) and whether it reaches the kidneys. In this test a small soft tube (catheter) is placed into the urethra. A liquid that can be seen on X-rays is then placed into the bladder through the tube until your child empties their bladder.
Nuclear scans: There are different kinds of scans of the bladder and kidneys each can be used to give different kinds of information. These scans use liquids that have tiny amounts of various radioactive tracer in them. From these tests a doctor can sometimes tell how well the kidneys work, the shape of the kidneys, and if the urine empties from the kidneys or bladder in a normal way. Although the liquids that are used have radioactive materials in them, the total amount of radiation exposure for your child is tiny.
CT scan or MRI: These are imaging tests examine the bladder and kidneys in three dimensions. They are sometimes used for complicated infections when the other studies are unclear and more detail of these organs may be needed.
Frequently asked questions:
I have heard of urinary tract infections in adults but how did my child get one?
The normal body has natural resistance to urinary infections. In some children a urinary tract infection may be a sign of an abnormality that lowers this resistance. For this reason, when a child is found to have a urinary tract infection, it may be recommended that they get additional tests and X-rays. In some cases, the problem may not show up on x-rays. Many children develop urinary tract infections because they do not use the restroom regularly or do not empty their bladder completely. In addition, some children with repeated UTIs have trouble with bladder control during the day. Similarly, constipation is associated with urinary infections and treating this problem can reduce the change of developing a UTI. Urologist call this condition "dysfunctional elimination syndrome." Drinking more water and urinating frequently are ways the body can enhance its ability to fight off urinary infections.
Do urinary tract infections have long-term effects?
Young children have the greatest risk for kidney damage from urinary tract infections, especially if they have some unknown urinary tract abnormality. The damage can cause scarring, poor growth and abnormal function of the kidney as well as high blood pressure and other problems. For those reasons, it is imperative that your child be evaluated carefully and treated promptly.
What kinds of abnormalities of the urinary tract could a child have if he/she has a urinary infection?
Many children who get urinary infections have normal kidneys and bladders, but the children who have abnormalities should be detected as early as possible in life to try to protect their kidneys against damage. Some of the more common abnormalities that may be present are:
Vesicoureteral reflux: Normally urine flows from the kidney down the ureters and into the bladder. This one-way flow is usually maintained because of a "flap-valve" mechanism at the where the ureter joins the bladder. When vesicoureteral reflux is present, the urine flows backwards from the bladder up the ureters to the kidneys. This refluxing urine may carry with it bacteria that is present in the bladder, up to the kidneys and cause a more serious kidney infection (pyelonephritis).
Urinary Obstruction: Blockages to urinary flow may occur at many locations in the urinary tract, and in children commonly represent birth abnormalities. These blockages are usually caused by abnormal narrow areas in the urinary tract that prevent normal flow of urine out of the body.
Can urinary tract infections be prevented?
If your child, who had a urinary tract infection, has been found to have a normal urinary tract, certain habits may be useful to prevent future urinary infections. Frequent bladder emptying is one of the body’s best defense mechanisms against urinary infections. Increased fluids and hence increased urine flow will also flush the infection out of the body. Treatment of constipation also helps. In some children who are very prone to getting urinary infections, it may be difficult to prevent recurrent infections and low dose preventive antibiotics are useful.
Reviewed: January 2011
Last updated: March 2013