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Urinary tract infection



A urinary tract infection, or UTI, is an inflammation of the bladder or the bladder and the kidneys. It's usually caused by bacteria from the skin outside the urethra (the tube that carries urine from the bladder outside the body) that move up the urethra and into the bladder. If the bacteria stay in the bladder, the infection is called cystitis. If the bacteria are in the kidneys, it's called pyelonephritis. These infections are not contagious.

UTIs are a common problem in children, but being common doesn't make them any less serious. Left untreated, they can lead to permanent kidney damage and even life-threatening conditions. Because children's kidneys are still developing, they're more vulnerable to damage and scarring from urinary tract infections.

UTIs are more common in newborn boys than girls, but among older children, UTIs are far more common in girls. They're a major cause of hospitalization in children.

Our staff has extensive experience in managing UTIs in children. As an academic medical center, we also have access to the most advanced technology for diagnosing your child's condition.

Signs & symptoms

The signs and symptoms of urinary tract infections in children depend on the child's age, and may include any or all of the following:

Signs of a UTI in Infants

  • Fever
  • Irritability
  • Unable to be consoled
  • Vomiting and diarrhea
  • Loss of appetite
  • Failure to gain weight

Since these are generalized symptoms in most infants, the possibility of a urinary tract infection may be overlooked.

As children reach toddler age, more classic signs appear, such as painful urination, urinary frequency and urgency. It becomes easier to recognize urinary tract infections as your child starts speaking and is toilet trained.

Signs of a UTI in Older Children

  • Burning or pain with urination
  • Frequent or urgent urination
  • Fever
  • Lower abdominal pain
  • New wetting episodes or more frequent occurrences
  • Side or back pain
  • Blood in urine

Sometimes the symptoms are caused or aggravated by other sources of urethral irritation, such as bubble baths, poor hygiene or constipation.

Infection of the bladder alone usually isn't associated with fever, and generally doesn't do any long-term damage to the bladder or kidneys. However, kidney infection is usually associated with a high fever and may cause permanent damage or scarring of the kidney, even after only one infection. This is particularly true in very young children.


Urinalysis and Culture

When you bring your child in for a urinary tract infection, we'll first discuss your child's general health and symptoms. Then we'll perform a urinalysis, which involves looking at your child's urine with a microscope. To be certain that there's an infection, we'll also do a urine culture to see if bacteria from the urine will grow in a culture medium. Your doctor will have the results of the urine culture after 24 hours. If there's an infection, an additional 24 hours is usually needed to find out which antibiotic will kill all of the bacteria.

The method of urine collection will affect the accuracy of the urine culture. It's important to:

  • Wash the skin around the urethra with a cleaning pad to remove bacteria on the skin surface.
  • If you collect the urine sample at home, place the sample in the refrigerator and then pack it in ice while traveling to the doctor's office.

To collect urine from infants and toddlers, a special bag is placed over the genital area. Because bacteria from the skin may contaminate these samples, it's sometimes necessary to insert a small plastic tube called a catheter through the urethra and into the bladder to get a clean specimen.

Other Tests

Children with confirmed urinary tract infections should be evaluated for abnormalities of the urinary tract. Twenty-five to 50 percent of children with a urinary tract infection have these abnormalities, and waiting until a child has two or more infections before doing the evaluation increases the risk of permanent kidney damage or scarring. This is especially important for infants and toddlers, since most of them will develop another urinary tract infection later.

We also test for vesicoureteral reflux, the abnormal backflow of urine from the bladder into the ureter and up to the kidney. Reflux is dangerous because it allows bacteria that might be in the bladder to reach the kidney. This can cause a kidney infection and lead to kidney damage.

Here are some of the basic tests we may suggest if your child has a confirmed urinary tract infection:

  • Voiding Cystourethrogram (VCUG) — This test gives us important information about the shape and size of the bladder, the bladder neck or opening and the tubes, called ureters, that drain the urine from the kidneys into the bladder.

    During the test, a small, plastic tube called a catheter is inserted into your child's urethra and passed into the bladder. Then the bladder is filled with a fluid that will show up on the X-ray, called contrast media. While your child's bladder is filling, he or she can watch a video; we encourage children to bring their favorite one, but we always have a few on hand.

    Pictures are taken while your child's bladder is filling. When your child's bladder is full, we remove the catheter and take a picture as he or she urinates. After the study is done, we'll review the films with you and your child and discuss a plan of care.

    This procedure isn't painful, but it can be uncomfortable when the catheter is inserted into the urethra, and the experience may seem scary — or at least unusual — to children. We ask that at least one parent stay with your child in the room at all times. We will explain everything as we go. The test usually takes 20 to 30 minutes.

  • Kidney and Bladder Ultrasound — This test is performed to get an outline of the kidneys, ureters and bladder. It looks for additional urinary tract defects that could be the cause of infection. Ultrasound doesn't involve radiation and is painless.
  • Kidney (Renal) Scan — We may recommend this test if the above tests are abnormal. It can better demonstrate the actual function and drainage of the kidneys. A kidney scan can also show if there's kidney damage and scarring.


All children with urinary tract infections are treated with a safe and well-tolerated antibiotic selected to treat the specific bacteria causing the infection. Children with a bladder infection are usually treated with a seven-day course of medication. Children with kidney infections should be treated for 10 to 14 days. A child who's very ill or who has a kidney infection will most likely need to be hospitalized for intravenous antibiotics until the fever subsides and we've received the results of the urine culture.

Another urine culture will be performed while your child's taking the antibiotic or when the medication is finished, to make sure the infection is gone.

If your child hasn't had an X-ray evaluation, the antibiotics should be continued until the X-rays are done and our office has told you that it's safe to stop the antibiotics.

Children with urinary infections may have unhealthy urination habits. Establishing a schedule and completely emptying the bladder every two to three hours often helps. This problem usually disappears as the child enters puberty. If your child shows no kidney damage at the time of initial evaluation, he or she has no increased risk for serious problems in the future.

Some children who have repeated urinary tract infections for no obvious reason may require continuous low-dose medication for a period of time.

Our clinic does not perform urethral dilation, a technique where the urethra is stretched. In the past, it was believed that many girls who got urinary tract infections had narrow or tight urethras. We now know that the size of the urethra is no different between girls who have infections and those who don't.

UCSF Benioff Children's Hospitals medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your child's doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your child's provider.

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Urology Clinic

Urology Clinic

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Our research initiatives

  • UCSF Baskin Lab

    The Baskin Laboratory investigates the causes of pediatric urological diseases present at birth or acquired later. The lab's research has a special focus on curing and preventing hypospadias, in which the urethra's opening is on the underside of the penis.

Awards & recognition

  • One of the nation's best in urology

  • Ranked among the nation's best in 10 specialties

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