C-reactive protein or erythrocyte sedimentation rate results reliably exclude invasive bacterial infections.

BACKGROUND: Clinicians utilize inflammatory markers, including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), to identify febrile children who may have an occult serious illness or infection. OBJECTIVES: Our objective was to determine the relationship between invasive bacterial infections (IBIs) and CRP and ESR in febrile children. METHODS: We performed a retrospective cross-sectional study of 1460 febrile children <21 years of age, who presented to a single Emergency Department (ED) between 2012 and 2014 for evaluation of fever of <14 days' duration, who had both CRP and ESR obtained. Our primary outcome was IBI, defined as growth of pathogenic bacteria from a culture of cerebrospinal fluid or blood. We reviewed all ED encounters that occurred within three days of the index visits for development of IBI. We examined the negative predictive value (NPV) of CRP and ESR for IBI. RESULTS: Of the 1460 eligible ED encounters, the median patient age was 5.3 years [interquartile range (IQR) 2.4-10.0 years] and 762 (50.4%) were hospitalized. The median duration of fever was 4 days (IQR 1-7 days). Overall, 20 had an IBI (20/1460; 1.4%, 95% confidence interval (CI) 0.9-2.1%). None of those with a normal CRP (NPV 273/273; 100%, 95% CI 98.6-100%) or a normal ESR (NPV 486/486; 100%, 95% CI 99.2-100%) had an IBI. CONCLUSIONS: In our cross-sectional study of febrile children, IBI was unlikely with either a normal CRP or ESR. Inflammatory markers could be used to assist clinical decision-making while awaiting results of bacterial cultures.

Accuracy of Clinician Suspicion of Lyme Disease in the Emergency Department.

BACKGROUND: To make initial management decisions, clinicians must estimate the probability of Lyme disease before diagnostic test results are available. Our objective was to examine the accuracy of clinician suspicion for Lyme disease in children undergoing evaluation for Lyme disease. METHODS: We assembled a prospective cohort of children aged 1 to 21 years who were evaluated for Lyme disease at 1 of the 5 participating emergency departments. Treating physicians were asked to estimate the probability of Lyme disease (on a 10-point scale). We defined a Lyme disease case as a patient with an erythema migrans lesion or positive 2-tiered serology results in a patient with compatible symptoms. We calculated the area under the curve for the receiver operating curve as a measure of the ability of clinician suspicion to diagnose Lyme disease. RESULTS: We enrolled 1021 children with a median age of 9 years (interquartile range, 5-13 years). Of these, 238 (23%) had Lyme disease. Clinician suspicion had a minimal ability to discriminate between children with and without Lyme disease: area under the curve, 0.75 (95% confidence interval, 0.71-0.79). Of the 554 children who the treating clinicians thought were unlikely to have Lyme disease (score 1-3), 65 (12%) had Lyme disease, and of the 127 children who the treating clinicians thought were very likely to have Lyme disease (score 8-10), 39 (31%) did not have Lyme disease. CONCLUSIONS: Because clinician suspicion had only minimal accuracy for the diagnosis of Lyme disease, laboratory confirmation is required to avoid both under- and overdiagnosis.