Ultrasound Helps in Evaluating Urinary Tract Infections in Children

For infants and young children with urinary tract infection (UTI) seen in the emergency room (ER), a simple ultrasound examination may eliminate the need for more complicated X-ray tests, according to a new report.

The report's findings were published in the May 2011 issue of the Pediatric Infectious Disease Journal. The study also finds that many children diagnosed with their first UTI are infected with antibiotic-resistant bacteria. The lead author was Dr. Khalid Ismaili, from the Hôpital Universitaire des Enfants-Reine Fabiola (Brussels, Belgium).

The researchers analyzed data on 209 children seen at their hospital's emergency department with fever and UTI. Sixty-three percent of the patients were girls; three-fourths were less than two years old when UTI was diagnosed. In more than 90% of children, the infection was caused by the intestinal bacteria Escherichia coli. Many of these children were infected with antibiotic-resistant strains of E coli bacteria. This included a 58% rate of bacteria resistant to ampicillin--a penicillin antibiotic widely used as initial treatment for UTI.

The study also found that ultrasound could play an important role in detecting (VUR; "backwards" flow of urine from the bladder upwards toward the kidney). It is critical to identify and treat VUR--a common cause of UTI that can put children at risk of long-term kidney damage. In the study, all patients first underwent a simple ultrasound examination, followed by an X-ray test called voiding cystourethrography (VCUG) in which dye is injected into the bladder.

The study's findings revealed VUR (mostly mild) in 25% of the children. All but a few of these cases were also detected on ultrasound. Therefore, the much-simpler ultrasound test provided useful information on the probability of VUR and related abnormalities--including possible birth defects of the urinary tract. "The presence or absence of abnormal ultrasound represents the key for deciding about VCUG studies," Dr. Ismaili and coauthors wrote.

Eleven percent of the children in the study had recurrent infections at up to two-and-a-half years' follow-up. All of the children with recurrent infections had normal ultrasound and VCUG results.

Urinary tract infection is one of the most common types of infection in children--8% of girls and 2% of boys have at least one UTI before age 7. The new study provides healthcare providers with important new information on the "characteristics and clinical evolution" of infants and young children with their first UTI.

The findings demonstrated that most children experiencing their first UTI are girls under two years old. Many of these infections are caused by antibiotic-resistant bacteria, which may require modifications to treatment.

The study's findings also suggested that about one-fourth of young children with UTIs have VUR, which can be effectively detected by a simple ultrasound examination. Dr. Ismaili and colleagues concluded, "Ultrasound is an excellent screening tool that allows avoidance of unjustified VCUG studies."

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Hôpital Universitaire des Enfants-Reine Fabiola