NEW YORK (Reuters Health) – The benefits of a more selective approach to urinary tract imaging after an initial febrile urinary tract infection (UTI) in children outweigh the risks, a group of clinicians who instituted a more restrictive policy at their institution have found.

The benefits include a substantial reduction in rates of voiding cystourethrography (VCUG) and prophylactic antibiotic use, and less trauma and stress for the family. Importantly, these benefits are achieved without an increase in the rate of UTI recurrence within six months and without compromising detection of high-grade vesicoureteral reflux (VUR), the clinicians have found.

Dr. Alan R. Schroeder and colleagues from the department of pediatrics, Santa Clara Valley Medical Center in San Jose, California report their observations in the November issue of Archives of Pediatrics and Adolescent Medicine.

There is evidence of a strong association between febrile UTIs and urinary tract abnormalities in infants and young children. This led to the 1999 recommendation from the American Academy of Pediatrics that all infants and children up to 2 years of age undergo ultrasonography and voiding cystourethrogram following a first febrile UTI. For those with abnormal findings, VUR in particular, antibiotic prophylaxis is recommended.

In 2007, the United Kingdom National Institute for Health and Clinical Excellence (NICE) recommended a more selective approach to investigation, based on age and the presence of certain risk factors.

Having previously adhered to routine imaging according to the American Academy of Pediatrics guidelines, Dr. Schroeder’s team instituted a more selective approachadapted from the NICE guidelines.

Their algorithm calls for renal ultrasonography in most cases and restricts voiding cystourethrography based on the following risk factors: bacteremia with the UTI, inadequate clinical response of the UTI to antibiotic treatment within 48 hours, non-Escherichia coli pathogen, poor urine flow, elevated serum creatinine level, palpable abdominal or pelvic mass, or abnormal renal ultrasound findings. Routine prophylactic antibiotic use is discouraged under the selective approach.

Dr. Schroeder’s team compared outcomes in 98 children during a one-year period before selective use (September 1, 2006 to August 31, 2007) and 103 children during a one-year period after selective use (September 1, 2008 to August 31, 2009). All children were younger than 2 with a first febrile UTI.

After institution of the new algorithm, rates of VCUG decreased markedly, from 99% in period one to 13%. Forgoing unnecessary VCUG, the clinicians say, has many benefits, as it is “invasive, painful and expensive and carries irradiation risk.”

Rates of renal ultrasound fell from 99% in period one to 67% in period two. Rates of prophylactic antibiotic use also fell markedly; 95% of children in period two never used prophylactic antibiotics.

Importantly, the investigators say, similar numbers of cases of high-grade VUR were detected in period two (3 cases) as period one (2 cases). No cases of low-grade VUR were detected in period two, compared with 19 in period one. Detection of low-grade VUR often leads to unnecessary successive imaging, often with further VCUG, the authors note.

Based on their experience, Dr. Schroeder’s team says, “Clinicians can be more judicious in their use of urinary tract imaging.”

The writers of a linked commentary point out that febrile UTIs are among the most common serious bacterial illness in infants and young children and the influence that various imaging modalities and treatment strategies have on long-term outcomes remains unclear.

Dr. Ian K. Hewitt of Princess Margaret Hospital for Children, Perth, Australia and Dr. Giovanni Montini of Azienda Ospedaliero Universitaria Sant’Orsola-Malpighi, Bologna, Italy, say they agree with Dr. Schroeder’s team that the benefits of a selective approach to imaging outweigh the risks.

Drs. Hewitt and Montini caution, however, that the study was retrospective and focused on reflux rather than scarring. In addition, polymicrobial urine cultures were generally treated and accepted as true UTIs, while UTI recurrence within six months reflects only a short-term outcome.

They also note that compliance with the selective approach was reported as “only fair,” while that with the established American Academy of Pediatrics algorithm was almost 100%.

“There remains a lack of consensus as to the optimal investigative approach and subsequent management of febrile UTI,” Hewitt and Montini note. “Further prospective randomized controlled trials hopefully will lead to a further reduction in unnecessary imaging and improved outcomes,” they conclude. Reference:

Arch Pediatr Adolesc Med. 2011;165:1027-1032,1047-1048.