Serious Bacterial Infections in Young Febrile Infants With Positive Urinalysis Results

Scoping review of clinical decision aids in the assessment and management of febrile infants under 90 days of age

BACKGROUND

Clinical decision aids (CDA) play an important role in the management of young febrile infants (under 90 days of age) who are at risk of serious or invasive bacterial infections (SBI/IBI). Since 2010, a number of tailored CDAs have been developed that allow for lower-risk infants to be managed safely while undergoing fewer investigations and not receiving parenteral antibiotics. We aimed to map the CDAs developed since 2010, their derivation methodology, and their variable components.

METHODS

A scoping review based on the Joana Briggs Institute framework was conducted for studies published between 2010 and 2025. A database search was conducted using Medline, Embase, Scopus, Web of Science, Google Scholar, and the Cochrane library. Studies evaluating the derivation, validation, and application of CDAs for the assessment of febrile infants were eligible for inclusion. Two reviewers independently screened, analysed, and extracted data from the literature.

RESULTS

A total of 32 studies met the inclusion criteria. The majority of studies were conducted in North America and Canada (56%), followed by Europe (28%), and Asia (16%). Of the 32 studies, 14 were retrospective, 9 prospective and 9 secondary analysis of an available dataset. There were 32 CDAs that were either derived or validated across 32 studies. The derivation methodology was classified into four themes: (i) expert consensus and evidence synthesis; (ii) regression analysis; (iii) recursive partitioning; and (iv) machine learning. CDAs typically either identified a low-risk cohort through sequential assessment (n = 12) or predicted the risk of IBI/SBI using prediction models (n = 20). CDA sensitivity and specificity ranged from 46 - 100% and 9 - 95% respectively for SBI/IBI. The majority (n = 18) of the more complex CDA prediction models have been published in the last five years. The most common variables included within the CDAs were age, urinalysis, height of fever, C-reactive protein, and absolute neutrophil count.

CONCLUSION

This scoping review highlights a wide range of CDAs with a trend towards prediction modelling rather than sequential assessment in the last five years. There is still variability in CDA properties, applicability, and diagnostic performance, necessitating further validation of common CDA and prediction models.

Role of urine Gram stain in young febrile infants with a suspected urinary tract infection: a cohort study

OBJECTIVE

To analyse the performance of the urine Gram stain for predicting a positive urine culture (UC) in young infants with fever without source (FWS) and pyuria.

DESIGN

Observational study; secondary analysis of a prospective registry-based cohort study.

SETTING

Paediatric emergency department; tertiary teaching hospital.

PATIENTS

Infants ≤90 days old with FWS, pyuria and urine Gram stain requested seen between 2010 and 2022.

MAIN OUTCOME MEASURE

Performance of the Gram stain, defined as positive if any bacteria were seen, for predicting urinary tract infection (UTI: UC by urethral catheterisation growing >10 000 CFU/mL of a single bacterial pathogen).

RESULTS

Among 367 febrile infants with pyuria, 281 (76.6%) had a positive Gram stain and 306 (83.3%) had a positive UC (277; 90.5% Escherichia coli).Rates of positive UC in patients with positive and negative Gram stains were 97.2% and 38.4%, respectively (p<0.01), showing a sensitivity of 89.2% (95% CI: 85.2% to 92.2%) and a specificity of 86.9% (95% CI: 76.2% to 93.2%). Sensitivity was lower for diagnosing UTIs caused by bacteria other than E. coli (69.0% vs 91.3% for UTIs caused by E. coli; p<0.01).Two (2.1%) of the 86 infants with negative Gram stains were diagnosed with bacteraemia unrelated to a UTI (Streptococcus pneumoniae and Staphylococcus aureus).

CONCLUSIONS

Around a third of infants with pyuria and a negative Gram stain will eventually be diagnosed with a UTI. These patients have a higher rate of UTIs caused by bacteria other than E. coli. Bacterial infections other than UTIs should also be considered in such cases.

National Survey on the Emergency Department Management of Febrile Infants 29 to 60 Days Old With an Abnormal Urinalysis

OBJECTIVES

Recent clinical practice guidelines recommend that decisions regarding lumbar puncture (LP) for febrile infants older than 28 days should no longer be based on urinalysis results, but rather independently determined by inflammatory markers and sometimes guided by shared decision-making (SDM). This study sought to assess management decisions for febrile infants aged 29 to 60 days with an abnormal urinalysis.

METHODS

A scenario-based survey was sent to emergency department physicians at all 15 Canadian tertiary pediatric centers. Participants were asked questions regarding management decisions when presented with a well-appearing febrile infant in the second month of life with either an abnormal or normal urinalysis.

RESULTS

Response rate was 50.2% (n = 116/231). Overall, few respondents would perform an LP based on either an abnormal or normal urinalysis alone (10.3% and 6.0%, respectively). However, regression analysis demonstrated that decisions regarding LP were influenced by urinalysis results ( P < 0.001), with respondents more likely to defer to inflammatory marker results for infants with a normal urinalysis result (57.8%) compared with those with an abnormal urinalysis (28.4%). Hospitalization (62.1%) and empiric antibiotic treatment by intravenous route (87.9%) were both frequent for low-risk infants with an abnormal urinalysis. Nearly half of respondents reported rarely (<25% of encounters) engaging families in SDM regarding LP decisions.

CONCLUSIONS

Knowledge translation initiatives reflecting current evidence should target use of inflammatory markers rather than urinalysis results to guide decisions regarding LP. Efforts emphasizing outpatient management with oral antibiotics and SDM for low-risk infants with an abnormal urinalysis could also further align management with current evidence and guidelines.

La prise en charge des nourrissons de 90 jours ou moins, fiévreux mais dans un bon état général

On constate des pratiques très variées en matière d'évaluation et de prise en charge des jeunes nourrissons fiévreux. Bien que la plupart des jeunes nourrissons fiévreux mais dans un bon état général soient atteints d'une maladie virale, il est essentiel de détecter ceux qui sont à risque de présenter des infections bactériennes invasives, notamment une bactériémie et une méningite bactérienne. Le présent document de principes porte sur les nourrissons de 90 jours ou moins dont la température rectale est de 38,0 °C ou plus, mais qui semblent être dans un bon état général. Il est conseillé d'appliquer les récents critères de stratification du risque pour orienter la prise en charge, ainsi que d'intégrer la procalcitonine à l'évaluation diagnostique. Les décisions sur la prise en charge des nourrissons qui satisfont aux critères de faible risque devraient refléter la probabilité d'une maladie, tenir compte de l'équilibre entre les risques et les préjudices potentiels et faire participer les parents ou les proches aux décisions lorsque diverses options sont possibles. La prise en charge optimale peut également dépendre de considérations pragmatiques, telles que l'accès à des examens diagnostiques, à des unités d'observation, à des soins tertiaires et à un suivi. Des éléments particuliers, tels que la mesure de la température, le risque d'infection invasive à Herpes simplex et la fièvre postvaccinale, sont également abordés.

Management of well-appearing febrile young infants aged ≤90 days

The evaluation and management of young infants presenting with fever remains an area of significant practice variation. While most well-appearing febrile young infants have a viral illness, identifying those at risk for invasive bacterial infections, specifically bacteremia and bacterial meningitis, is critical. This statement considers infants aged ≤90 days who present with a rectal temperature ≥38.0°C but appear well otherwise. Applying recent risk-stratification criteria to guide management and incorporating diagnostic testing with procalcitonin are advised. Management decisions for infants meeting low-risk criteria should reflect the probability of disease, consider the balance of risks and potential harm, and include parents/caregivers in shared decision-making when options exist. Optimal management may also be influenced by pragmatic considerations, such as access to diagnostic investigations, observation units, tertiary care, and follow-up. Special considerations such as temperature measurement, risk for invasive herpes simplex infection, and post-immunization fever are also discussed.

Conundrums in the Management of Febrile Infants under Three Months of Age and Future Research

Febrile infants under three months of age pose a diagnostic challenge to clinicians. Unlike in older children, the rates of invasive bacterial infections (IBIs), such as bacteraemia or meningitis, are high. This greater risk of IBI combined with the practical challenges of assessing young infants results in a cautious approach with many febrile infants receiving parenteral antibiotics "just in case". However, there is a range of validated tailored care guidelines that support targeted investigation and management of febrile infants, with a cohort identified as lower risk suitable for fewer invasive procedures and observation without parenteral antibiotics. This manuscript outlines five common conundrums related to the safe application of tailored-care guidelines for the assessment and management of febrile infants under three months of age. It also explores future research which aims to further refine the management of febrile infants.

Outcomes of Infants Who Are Febrile Aged 29-90 Days Discharged from the Emergency Department

OBJECTIVE

To evaluate the characteristics and outcomes of infants aged 29-90 days who are febrile discharged from the pediatric emergency department (ED).

STUDY DESIGN

This was a multicenter, retrospective cohort study of infants aged 29-90 days who visited any of the 7 Clalit Health Services pediatric EDs in Israel between January 1, 2019, and March 31, 2022. Infants who were febrile discharged from the ED after having blood and urine cultures taken were included. The primary outcome measure was the incidence of return visit (RV) to an ED. Secondary outcome measures were the incidence of invasive bacterial infection, urinary tract infection, pediatric intensive care unit admissions, and deaths. We assessed variables associated with the primary outcomes.

RESULTS

A total of 1647 infants were included. Their median (IQR) age at ED visit was 58.5 (47.7, 72.7) days, 53.1% were male. A total of 329 patients (20%) returned to the ED within 120 hours. Overall, 7.8% of discharged infants had a positive urine culture, 4 (0.2%) had a positive blood culture, and none had meningitis. One patient was admitted to the pediatric intensive care unit, and there was no death. Abnormal C-reactive protein was associated with RV among 61- to 90-day-old infants.

CONCLUSIONS

Infants aged 29-90 days who were febrile and discharged following a protocol-driven pathway from the pediatric ED had a relatively high RV rate. However, the rate of urinary tract infection was relatively low, and rate of invasive bacterial infection was extremely low. There were no deaths or serious sequelae.

Clinical characteristics and outcomes in febrile infants aged 29-90 days with urinary tract infections and cerebrospinal fluid pleocytosis

Introduction

Fever without a focus is a common reason for medical evaluations, hospitalizations, and the antimicrobial treatment of infants younger than 90 days. The presence of cerebrospinal fluid (CSF) pleocytosis could be challenge for clinicians who treat febrile young infants with urinary tract infection (UTI). We evaluated the factors associated with sterile CSF pleocytosis and the clinical outcomes of the patients.

Methods

A retrospective review of patients aged 29-90 days with febrile UTIs who underwent a non-traumatic lumbar puncture (LP) at Pusan National University Hospital from January 2010 to December 2020 was conducted. CSF pleocytosis was defined as white blood cell (WBC) counts ≥9/mm³.

Results

A total of 156 patients with UTI were eligible for this study. Four (2.6%) had concomitant bacteremia. However, no patients had culture-proven bacterial meningitis. In correlation analysis, although weak strength, CSF WBC counts were positively correlated with C-reactive protein (CRP) level (Spearman r = 0.234; P = 0.003). Thirty-three patients had CSF pleocytosis [21.2%; 95% confidential interval (CI), 15.5-28.2]. The time from fever onset to the hospital visit, peripheral blood platelet counts, and CRP level at admission were statistically significant in patients with sterile CSF pleocytosis compared to those without CSF pleocytosis. In the multiple logistic regression, only CRP was independently associated with sterile CSF pleocytosis (cutoff, 3.425 mg/dl; adjusted odds ratio, 2.77; 95% CI, 1.19-6.88). The proportion of fever defervescence by hospital day 2 was 87.9% in patients with CSF pleocytosis and 89.4% in those without CSF pleocytosis (P = 0.759). There was no statistical difference in the fever defervescence curves between the two patient groups (P = 0.567). No patients had neurological manifestations or complications.

Conclusions

Coexisting sterile CSF pleocytosis among febrile infants with UTIs suggest a systemic inflammatory response. However, the clinical outcomes between the two groups were similar. A selective LP should be considered in young infants with evidence of UTI, and inappropriate antibiotic therapy for sterile CSF pleocytosis should be avoided.