AUA Summit - What is a Urinary Tract Infection (UTI) in Children?


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What is a Urinary Tract Infection (UTI) in Children?

A UTI is when bacteria gets into your urine and travels up to your bladder. As many as 8 in 100 of girls and 2 in 100 of boys will get UTIs. Young children have a greater risk of kidney damage linked to UTI than older children or adults.

How Does the Urinary Tract Work?

The “urinary tract” is the organs in your body that make, store, and get rid of urine, one of the waste products of your body. Urine is made in the kidneys and travels down to the bladder through the ureters (the tubes that join them). The kidneys make about 1½ to 2 quarts of urine a day in an adult, and less in children, depending on their age. In children, the bladder can hold 1 to 1½ ounces of urine for each year of age. For example, a 4-year-old child’s bladder can hold 4 to 6 ounces—a little less than a cup.

The bladder stores the urine until it is emptied through the urethra, a tube that links the bladder to the skin, when you urinate. The urethra opens at the end of the penis in boys and in front of the vagina in girls.

The kidneys also balance the levels of many chemicals in the body (sodium, potassium, calcium, phosphorous and others) and check the blood's acidity. Certain hormones are also made in the kidneys. These hormones help control blood pressure, boost red blood cell production and help make strong bones.

Normal urine has no bacteria in it, and the one-way flow helps prevent infections. Still, bacteria may get into the urine through the urethra and travel up into the bladder.


Most often when you have a UTI, the linings of your bladder, urethra, ureters, and kidneys become red and swollen. Older children may complain of pain in the low stomach area or back, as well needing to urinate often. Your child may cry when he or she urinates, or complain that it hurts to urinate and pass only a few drops. He or she may also have trouble controlling urine and may have accidents or wet the bed.

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 not linked to the urinary tract. Your child may just have a high fever, or be grouchy and not eat. Sometimes a child will have only a low-grade fever, loose stools, or just not seem healthy. You may notice that the diaper urine "smells bad."

If your child has a high fever and appears sick without a clear reason (such as a runny nose or ear ache), you should take him or her to see a health care provider. If the cause is a kidney infection and it is not treated at once, the bacteria may spread to the bloodstream and cause a life-threatening infection or lasting kidney damage.

Here are some signs of a UTI:

  • Pain, burning, or a stinging feeling when urinating
  • Urinating often or feeling an urgent need to urinate, even without passing urine
  • Foul-smelling urine that may look cloudy or have blood in it
  • Fever
  • Pain in the low back or around the bladder


Normal urine is sterile and has no bacteria in it. But bacteria cover the skin and are found in large numbers in the rectal area and in stools. Bacteria may, at times, travel up the urethra into the bladder. When this happens, the bacteria multiply and, unless the body gets rid of the bacteria, may cause infection.

There are 2 basic types of UTIs: bladder infection and kidney infection. When the infection is in the bladder, it can cause swelling and pain of the bladder. This is called cystitis.

If the bacteria travel up 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 harm the kidney, especially in young children.

Many children who get urinary tract infections have normal kidneys and bladders, but abnormalities should be found as early as possible in life to help protect the kidneys. Two common abnormalities are:

Vesicoureteral Reflux

Urine normally flows from the kidney down the ureters and into the bladder. This one-way flow is usually maintained because of a "flap-valve" where the ureter joins the bladder. With vesicoureteral reflux, the urine flows backwards from the bladder up the ureters to the kidneys. This urine may carry bacteria from the bladder up to the kidneys and cause a more serious kidney infection (pyelonephritis).

Urinary Obstruction

Urine flow may get blocked at many places in the urinary tract. These blockages are mostly caused by abnormal narrow areas in the urinary tract that prevent normal flow of urine out of the body.

Can UTIs be Prevented in Children?

If your child has a normal urinary tract, certain habits can help prevent UTIs. Draining the bladder often is one of the body’s best defenses against UTIs. Drinking more fluids will increase urine flow to flush infection out of the body. Some children are more prone to getting UTIs, and low dose antibiotics can help. Treatment of constipation also helps.

In babies and small children, changing diapers more often can help prevent UTIs. When children start toilet training, it is important to teach them good bathroom habits. After each bowel movement, girls should wipe from front to rear — not rear to front. This keeps germs from spreading from the anus to the urethra. Children should also avoid “holding it in” if they need to urinate and can reach a bathroom. Urine sitting in the bladder too long gives bacteria a good place to grow.


If you think your child has a UTI, call your health care provider. The only way to diagnose a UTI is with a urine test. Your health care provider will collect a urine sample. The method your health care provider uses will depend on your child's age and maturity. If your toddler is not toilet-trained, your health care provider may simply attach a plastic bag to your child’s skin to collect the sample. If your child is older, you may be asked to help catch the sample as your child urinates. It is important to keep bacteria from the skin from getting into the sample. Your health care provider may need to pass a small tube into the urethra or a needle into the lower belly to collect a good sample from inside the bladder.

The urine sample is examined under a microscope. If there is an infection, your health care provider may be able to see bacteria and pus (white blood cells). This test takes only a few minutes. The health care provider may also order a urine culture, where bacteria from the urine are grown in a lab incubator. The bacteria can then be identified and tested to see which drugs will work best. Many kinds of bacteria can infect the urine, and different types of bacteria may need different types of antibiotics. It takes many days to get the results from the urine culture.


UTIs are treated with antibiotics. If your health care provider thinks your child has a UTI, he or she will choose a drug that treats the bacteria most likely to be causing the problem. Sometimes a few days later, after your health care provider has the urine culture results, the antibiotic might be changed to one that works better against the type of bacteria that was found in your child's urine. You can also help your child fight the infection by encouraging him or her to drink plenty of fluids and urinate often.

The antibiotic drug, the way it is given, and the number of days it must be taken may depend on the type of infection. If your child is very sick and not able to drink, the antibiotic may need to be given as shots with your child in the hospital. Otherwise, the meds may be given by mouth. Depending on the type of antibiotic used, your child may take a single dose per day or up to 4 doses per day. You may be asked to give your child meds until further tests are finished.

After a few doses of the antibiotic, your child may appear much better. Most UTIs are cured within a week if treated the right way, but often it may take weeks until all the symptoms are gone. It is important that your child take the antibiotic meds as ordered by your health care provider even if the symptoms have gone away. Unless UTIs are fully treated, they may return, or your child may get another infection.

If symptoms get worse or do not get better within 3 days, your child may need to go to the hospital.

After Treatment

Once the infection has cleared, your child's health care provider may suggest more tests, particularly if your child has been treated for a kidney infection. The tests are to make sure there are no problems in the urinary tract that might keep your child's body from fighting off infection, and to see whether there has been any damage to the kidney from the UTI. No single test can tell everything about the urinary tract that might be important to know after a UTI, so many tests are often ordered. If these tests show something abnormal in the urinary tract, your health care provider may want your child to see a pediatric urologist (a health care provider who specializes in problems of the urinary system in children).

The tests may include:

Kidney and/or Bladder Ultrasonography (Ultrasound)

This test gets pictures of the kidney and bladder using sound waves. This test may show shadows that point to some kinds of abnormalities, like blockages, but can't show all important urinary tract abnormalities. It also can't tell how well the kidney is working.

Voiding Cystourethrogram (VCUG)

This test can show abnormalities of the inside of the urethra and bladder, and if urine flow is normal when the bladder empties. It also shows if urine from the bladder is backing up into the ureters (vesicoureteral reflux) and whether it reaches the kidneys. For this test a small, soft tube (catheter) is placed into the urethra. A liquid that can be seen on x-rays is then put into the bladder through the tube until your child urinates.

Nuclear Scans

There are different kinds of scans of the bladder and kidneys, and each can give different kinds of information. These scans use liquids that have tiny amounts of a radioactive tracer in them. From these tests, a health care provider 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. Though the liquids used have radioactive matter in them, the amount is very small and will not hurt your child.

CT Scan or MRI

These tests look at the bladder and kidneys in 3-D. They are sometimes used in cases where other studies are not clear and more details of these organs may be needed.

More Information

Frequently Asked Questions

I've heard of UTIs in adults, but how did my child get one?

The normal body can protect itself from urinary infections. In some children, a UTI may be a sign of an abnormality. For this reason, when a child is found to have a UTI, more tests and x-rays may be ordered. Many children get UTIs because they don't use the restroom regularly or don't drain their bladder all the way. Also, some children who often get UTIs have trouble with bladder control during the day (dysfunctional elimination syndrome). Constipation is also linked to urinary infections, and treating this problem can lower the chance of getting a UTI. Drinking more water and urinating more help the body fight off urinary infections.

Do UTIs have long-term effects?

Young children have the greatest risk for kidney damage from UTIs, especially if they have some unknown urinary tract abnormality. The damage can cause scarring, poor growth, and abnormal kidney function, as well as high blood pressure and other problems. It is important that your child be checked carefully and treated at once.

Questions to Ask Your Health Care Provider

During Diagnosis:
  • Do my child's symptoms sound like a UTI?
  • What did the urine sample show?
About Treatment
  • What treatment do you suggest?
  • Are there any side effects to this treatment I should watch for?
  • Is there anything else I can do to help my child feel better?
  • How will I know if my child is getting better or worse?
  • How soon should my child feel better? Should I call you if my child doesn't feel better then?
About Preventing Future UTIs
  • How much water or other fluids should my child usually drink?
  • Can my child still take bubble baths?
  • Is there anything else I can do to help prevent my child from getting another UTI?
  • Should my child see a pediatric urologist to see if there is anything in his/her urinary tract that is not normal?
  • Should my child take antibiotics to prevent future UTIs?

Updated June 2023. 

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