A urinary tract infection is a bacterial infection of the urinary bladder (cystitis), the kidneys (pyelonephritis), or both.
Urinary tract infections are caused by bacteria.
Newborns and infants may have no symptoms other than a fever, whereas older children have pain or burning during urination, pain in the bladder region, and a need to urinate frequently.
The diagnosis is based on an examination and culture of the urine.
Proper hygiene may help prevent urinary tract infections.
Antibiotics are given to eliminate the infection.
Urinary tract infections (UTIs) are common in childhood. Nearly all UTIs are caused by bacteria that enter the opening of the urethra (the tube that drains urine from the bladder out of the body) and move upward to the urinary bladder and sometimes the kidneys. Rarely, in severe infections, bacteria may enter the bloodstream from the kidneys and cause infection of the bloodstream (sepsis) or of other organs.
During infancy, boys are more likely to develop urinary tract infections. After infancy, girls are much more likely to develop them. UTIs are more common among girls because their short urethras make it easier for bacteria to move up the urinary tract. Uncircumcised infant boys (because bacteria tend to accumulate under the foreskin) and young children with severe constipation (because severe constipation also interferes with normal passage of urine) also are more prone to UTIs.
UTIs in older school-aged children and adolescents differ little from UTIs in adults (see Overview of Urinary Tract Infections). Younger infants and children who have UTIs, however, more commonly have various structural abnormalities of their urinary system that make them more susceptible to urinary infection. These abnormalities include vesicoureteral reflux (VUR), which is an abnormality of the ureters (the tubes connecting the kidneys to the bladder) that allows urine to pass backward from the bladder up to the kidney, and a number of conditions that block the flow of urine. As many as 50% of newborns and infants with a UTI and 20 to 30% of school-aged children with a UTI have such abnormalities.
Up to 50% of infants and preschool children with a UTI—particularly those with fever—have both bladder and kidney infections. If the kidney is infected and reflux is severe, 5 to 20% of children go on to have some scarring of the kidneys. If there is little or no reflux, very few children have scarring of the kidneys. Scarring is a concern because it may lead to high blood pressure and impaired kidney function in adulthood.