Urinary tract infections (UTIs) are common in children and have a higher risk of complications when compared to this generally benign condition in adult females.  UTIs occur in up to 5% of girls and 1% of boys.

In girls, UTIs are most common in infancy (the "diaper years") and around the time of potty training.  This helps explain the main cause of UTIs in young girls, which is bacteria translocation from stool into the urethra.  UTIs in males occur mostly in the first year of life and are more common in those infants who are uncircumcised.  Infants with unexplained fever must have the urine checked for a UTI.  UTI's in children may not present with the typical changes seen in adults such as cloudy, smelly urine or painful urination.  Children with UTIs are at risk for developing renal scarring that may cause kidney damage and hypertension.  UTIs are easily treated with antibiotics, but recurrence of the UTI is common.

What causes a urinary tract infection (UTI) in children?

Nearly all UTIs in children are the result of bacteria from the stool contaminating the urethra.  This helps explain why infants in diapers and children during potty training are the most commonly affected.  Uncircumcised males are at increased risk of UTI due to poor cleaning of the area under the foreskin.  After the first year of life, females are ten times as likely to develop a UTI when compared to males.  This is due to a difference in anatomy.  Females have a much shorter urethra when compared to males.  Therefore bacteria are much more likely to reach the bladder.  When the infection travels through the ureters to the kidney, a more serious infection develops.

What are the germs that cause UTIs?

UTIs are caused mainly by bacteria from the stool, with Escherichia coli as the most common culprit.  Other causes include Klebsiella, Proteus, and Staphylococcus saprophyticus.  Viruses, particularly adenovirus, may also cause a UTI.

What are the symptoms of UTI?

Young children and infants often do not have symptoms that are common in adults with UTI's.  The following may be present.

• Painful urination
• Cloudy or smelly urine
• Pain in the sides of the abdomen or back
• Frequent urination
• Urinary urgency
• Bedwetting or daytime urine leakage

Symptoms that indicate a kidney infection in children include:

• Fever
• Vomiting
• Irritability or sick-feeling
• Diarrhea (occasionaly)

When are the symptoms of UTI, not caused by a UTI?

In children, pain on urination and genital discomfort is often caused by bath soaps (especially bubble baths!).

How is a UTI diagnosed?

A simple urine sample, called urinalysis, may be checked for bacteria and the byproducts of a UTI (i.e., white blood cells, nitrites).  Older children may provide urine for testing as a mid-stream voiding sample. In younger children and infants, voiding urine samples are frequently contaminated by bacteria on the skin in the genital area.  The urine samples in these children is more accurate when obtained by a catheter, which is a small, flexible tube inserted into the urethra under sterile conditions.  In infants, urine is sometimes collected in a plastic bag attached to the genital area.  This procedure provides less accurate results, but avoids the discomfort of catheter placement.

The best urine test for urinary tract infection is a urine culture.  A urine sample is provided with material that promotes bacterial growth.  The bacteria then replicates and can be more easily indentified.

How are the complications of a UTI diagnosed?

In some cases, especially for boys or infants, special tests are done to evaluate the urinary tract.  An ultrasound of the bladder and kidneys can identify dilation of the ureters or scarring of the kidneys. 

Backward movement of the urine towards the kidneys (which should not be present), may be identified by a voiding cystourethrogram (VCUG).  In this test, dye is injected into the bladder while radiology images are taken of the urinary tract.

Other imaging studies of the kidneys are occassionaly needed to evaluate for kidney scarring.

The blood pressure should be checked in all children with UTIs since renal scarring may lead to hypertension.

How is a UTI treated?

Most urinary tract infections respond well to an antibiotics.  Older children are often treated with an oral medicine such as amoxicillin, ciprofloxicin, Bactrim, or Septra.  Young children and those with severe infection may require intramuscular shots or even intravenous antibiotics.  Infants are often admitted to the hospital to monitor for spread of the infection to the bloodstream (i.e., bacteremia, sepsis).

What should happen after a UTI?

All children with UTIs should have the urine rechecked after treatment for a UTI.  If bacteria is still present, more antibiotics or further testing may be necessary.  Young girls with a UTI have a 60-80% chance of recurrence within 18 months.  Blood pressure should be checked frequently in children who are suspected to have renal scarring.  Children with abnormal dilation of the ureters or backward flow of urine (i.e., vesicoureteral reflux) may need daily antibiotics long-term.

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