Is the Step-by-Step approach useful for ruling out systemic infection in young low-risk infants?
The Step-by-Step approach, using a basic physical examination and readily available urine and blood tests (without lumbar puncture; see the Synopsis section), can successfully identify low-risk infants younger than 90 days who will not need empiric antibiotic treatment and lumbar puncture. However, this approach has not been studied (nor has any other approach, I believe) in a randomized controlled trial to see whether it is effective at decreasing lumbar punctures or hospital admissions. (Level of Evidence = 1a)
This study was conducted at 11 European pediatric emergency departments. The researchers enrolled 2,185 previously healthy term infants younger than 90 days with fever without source. The relatively new Step-by-Step approach was evaluated in comparison with the Rochester criteria or the Lab-score (Arch Dis Child. 2010;95(12):968–973), both methods of ruling out invasive bacterial infection. All infants were evaluated via urine dipstick, a urine culture, white blood cell count, C-reactive protein level, procalcitonin, and blood culture. Eventually, 4% (n = 87) of the infants were given a diagnosis of systemic infection and approximately 45% (n = 991) were classified as low-risk using the Step-by-Step approach. Sensitivity and negative predictive value for ruling out infection were 92.0% and 99.3% for the Step-by-Step approach, 81.6% and 98.3% for the Rochester criteria, and 59.8% and 98.1% for the Lab-score. Seven of the 991 infants (0.7%) who were classified as low risk by the score were found to have a systemic infection using the Step-by-Step approach.
The Step-by-Step approach: Children at low risk of systemic infection have the following characteristics: not ill-appearing, younger than 21 days, no leukocyturia, procalcitonin level less than 0.5 ng per mL, C-reactive protein level less than 20 mg per L (190.5 nmol per L), and absolute neutrophil count less than 10,000 per mm3 (10.0 × 109 per L).
Study design: Decision rule (validation)
Funding source: Self-funded or unfunded
Setting: Emergency department
Reference: GomezBMintegiSBressanSDa DaltLGervaixALacroixLEuropean Group for Validation of the Step-by-Step ApproachValidation of the “Step-by-Step” approach in the management of young febrile infants. Pediatrics2016;138(2):e20154381.