Reference: Pediatrics. 2022 Oct 1;150(4):e2021055633
Practice Point: Febrile infants 29-60 days old with a positive UA and those ≤ 28 days old with low-risk PECARN criteria have an extremely low likelihood of bacterial meningitis and can be spared the lumbar puncture.
EBM Pearl: A philosophical bias towards action leads to overdiagnosis and overtreatment whereas a bias towards inaction risks unrecognized and untreated disease. Pick your poison (or rather, practice philosophy) until the data are in.
There are many milestones celebrated during the first year of a child’s life. For some parents, the two-month mark may be the biggest, offering the relief that a fever no longer buys your baby an automatic lumbar puncture (LP). But wouldn’t it be great if we could really predict sick vs not sick in infants without the LP? We might be getting closer.
Authors of the PECARN cohort trial published a secondary analysis that evaluated the prevalence of bacterial meningitis and bacteremia in healthy infants ≤ 60 days old presenting to emergency departments with fevers ≥ 38°C and a positive urinalysis (UA). More than 7,000 infants with a UA, blood culture, and cerebral spinal fluid available for review were included in this secondary analysis. Many also had a procalcitonin and absolute neutrophil count (ANC), all of which are part of PECARN prediction criteria for severe bacterial infections in infants 29-60 days old. About 15% of the infants analyzed had a positive UA (57% male, 32% ≤ 28 days old), defined as the presence of nitrates, any leukocyte esterase, or > 5 white blood cells per high-power field.
While about half of the infants with a positive UA had culture-positive UTIs, they were extremely unlikely to have bacterial meningitis or bacteremia. And by extremely unlikely, we mean 0% chance (in this study anyway), as there were no cases of meningitis or bacteremia in infants 29-60 days old with a positive UA or in those ≤ 60 days old with positive UA, procalcitonin < 0.5 ng/mL, and ANC < 4 × 103 cells/mm3. Only 0.2% of infants with a negative UA were found to have bacterial meningitis and 1.1% were bacteremic.
These data highlight the implications of practicing with a bias towards action (as opposed to inaction) when the evidence is lacking. In the past, we had research to say that clinical judgment alone was inadequate for predicting which febrile babies might have meningitis, but we didn’t have any other tools to help us reliably predict sick vs not sick without invasive diagnostic testing. So at the time, the path clearly chosen by experts and professional organizations was towards doing an LP even if that meant 100,000 babies got an LP to save one unrecognized case of meningitis. But now the prevalence of meningitis is lower and this ratio would be closer to a million babies getting LPs to find one case of meningitis. Today, thanks to this study and its parent PECARN cohort, the evidence is no longer lacking and we no longer have to enact so much philosophical bias in our decision making. We can use UAs and the validated lab-based PECARN criteria to predict which febrile infants have a serious bacterial infection without doing LPs on all of them. Oh, one last exciting outcome here we have to mention: we finally found a situation where procalcitonin is actually useful!
For more information, see the topic Urinary Tract Infection (UTI) in Children in DynaMed.
DynaMed EBM Focus Editorial Team
This EBM Focus was written by Katharine DeGeorge, MD, MS, Deputy Editor at DynaMed and Associate Professor of Family Medicine at the University of Virginia. Edited by Alan Ehrlich, MD, Executive Editor at DynaMed and Associate Professor in Family Medicine at the University of Massachusetts Medical School; Dan Randall, MD, Deputy Editor at DynaMed; Nicole Jensen, MD, Family Physician at WholeHealth Medical; Vincent Lemaitre, PhD, Senior Medical Writer at DynaMed; and Sarah Hill, MSc, Associate Editor at DynaMed.