O02 TRAIL, IP-10, CRP host-protein signature score distinguishes between viral and bacterial infection in sepsis patients

Background

Sepsis is a life-threatening organ dysfunction syndrome caused by the body's response to infection. Timely and appropriate sepsis management, including appropriate treatment of bacterial infection, improves outcomes. MeMed BV (BV), a test for differentiating between bacterial and viral infection, is based on computational integration of the circulating levels of three proteins (TRAIL, IP-10, CRP). Here we evaluate its ability to differentiate bacterial from viral infection in sepsis patients.

Methods

This was a sub-analysis of sepsis patients recruited prospectively in the Apollo study (NCT04690569). Apollo eligibility required the attending physician's clinical suspicion of acute infection and reported fever. Sepsis was defined as two or more SIRS criteria and a suspected bacterial or viral infection classified by expert adjudication. A bacterial or viral classification required at least 2/3 experts to assign the same aetiology label with confidence ≥90% or all 3 assign with confidence ≥70%. BV was measured using a platform generating a bacterial likelihood score (0–100). Based on pre-defined thresholds, scores 0–34 indicated viral (or other non-bacterial) infection, scores 35 to 65 were equivocal and 66–100 indicated bacterial infection (or coinfection). BV performance was assessed against expert panel classifications.

Results

Seventy-nine out of 1016 eligible Apollo patients had missing heart rate and respiration rate data and a further 136 could not be classified by the experts. Out of the remaining 801 patients, 217 adults with median age of 41.8 years (IQR: 29.2–61) and 149 children with median age of 2.4 years (IQR: 1.4–5.4) had two or more SIRS criteria. A total of 119 patients had at least three SIRS criteria and 39.6% (145/366) of the patients were hospitalized with a median duration of 4 days (IQR: 3–6 days). In the sepsis cohort, 91 patients were classified as bacterial and 275 as viral. BV yielded sensitivity and specificity of 98.8% (95% CI: 93.6%–100%) and 89.7% (95% CI: 85.3%–93.2%) and NPV of 99.6% (95% CI: 97%–99.9%), outperforming PCT [cut-off 0.5 ng/mL; sensitivity 52.8% (95% CI: 42%–63.3%); specificity 86.2% (95% CI: 81.5%–90%); NPV 84.6% (95% CI: 81.5%–87.3%)].

Conclusions

BV accurately distinguished bacterial from viral infection in sepsis patients. This new triage tool has the potential to help with timely identification of bacterial infection, enabling prompt treatment.

112. A Rapid Host-Protein Signature Based on TNF-related Apoptosis-Induced Ligand (TRAIL), Interferon Gamma Induced Protein-10 (IP-10) and C-Reactive Protein (CRP) Accurately Differentiates Between Bacterial and Viral Infection in Febrile Children: Apollo Sub-Study

Background

Identifying infectious etiology is essential for appropriate patient management, including antibiotic use. A host-protein signature for differentiating bacterial from viral infection has exhibited robust performance (AUC of 0.9, 95% CI 0.86-0.95) in prior studies. Performance data was lacking for a broad pediatric population recruited in emergency departments (EDs) and urgent care centers (UCCs).

Methods

Non-immunocompromised children were recruited prospectively from 5 EDs and 3 UCCs in the U.S. and 1 ED in Israel between May 2019 and August 2020. Eligibility required physician’s clinical suspicion of acute infection and reported fever. Reference standard etiology was adjudicated by experts based on clinical, laboratory, radiological, microbiological and follow-up data. For the primary analysis, experts blinded to one another, to the host-signature results and also to procalcitonin and CRP, classified cases as bacterial or viral. For the secondary analysis, experts blinded to one another and the host signature results, were permitted to classify cases as bacterial, viral or indeterminate; indeterminates were removed from the secondary analysis. Host signature (comprising TRAIL, IP-10 and CRP; MeMed BV®) was measured using a rapid platform (MeMed Key®) generating a bacterial likelihood score (0-100) in 15 minutes.

Results

The study cohort comprised 162 children (median age, 5.5 yrs; interquartile range, 8.5), of whom 69 (43%) presented within 2 days of symptom onset and 37 (23%) were hospitalized for a median of 3 days. Respiratory tract infection was the predominant syndrome (11% lower and 44% upper). Host signature attained AUC 0.87 (0.74-1) and 0.92 (0.79-1) in the primary and secondary analysis, respectively. With higher the signature score, there was a significantly higher likelihood of bacterial infection (p< 0.001; Table 1). The 3 bacterial infections assigned score < 35 (false negative) would have been identifiable by physical examination (Table 2).

Increasing host signature score is associated with increasing likelihood of bacterial infection across both the primary and secondary cohort

The performance of the host signature score in differentiating between bacterial and viral infection was evaluated by allocating children to one of five score bins and within each bin according to their adjudication label and determining if there is a meaningful increase in the relative likelihood of bacterial infection across the bins based on the Cochrane-Armitage test of trend. PPV, positive predictive value. NPV, negative predictive value. *Includes patients adjudicated as non-infectious

Three children assigned a bacterial adjudication label and a score of 35 or less (false negatives) have bacterial infections identifiable in physical exam

Conclusion

The host-protein signature measured using a rapid platform attained robust performance in differentiating bacterial vs viral infection in children with acute febrile illness, supporting its potential to enhance rational use of antibiotics in the ED and UCC.

Disclosures

Sheldon L. Kaplan, MD, Pfizer (Research Grant or Support) Mark Kellogg, PhD, MeMed (Scientific Research Study Investigator) Andrea T. Cruz, MD, MPH, American Academy of Pediatrics (Individual(s) Involved: Self): editorial board member Kristina G. Hulten, PhD, Pfizer (Research Grant or Support) Cesar A. Arias, M.D., MSc, Ph.D., FIDSA, Entasis Therapeutics (Grant/Research Support)MeMed Diagnostics (Grant/Research Support)Merk (Grant/Research Support) Richard Gordon, MD, MeMed (Scientific Research Study Investigator) Sergey Motov, MD, MeMed (Scientific Research Study Investigator) Theresa Jacob, PHD MPH, MeMed (Scientific Research Study Investigator) Natasha Ballard, MD, MeMed (Scientific Research Study Investigator) George Suits, MD, MeMed (Scientific Research Study Investigator) Jeffrey Harris, MD, MeMed (Scientific Research Study Investigator) Maanit Shapira, Ph.D, MeMed (Scientific Research Study Investigator) Richard E. Rothman, PhD, MD, Chem bio (Grant/Research Support) Karen C. Carroll, MD, MeMed (Scientific Research Study Investigator)Meridian Diagnostics, Inc. (Grant/Research Support)Pattern Diagnostics (Advisor or Review Panel member)Scanogen, Inc. (Advisor or Review Panel member) Karen C. Carroll, MD, Pattern Diagnostics, Inc. (Individual(s) Involved: Self): Grant/Research Support; Scanogen, Inc. (Individual(s) Involved: Self): Consultant Leticia M. Ryan, MD MPH, MeMed (Scientific Research Study Investigator) Richard Bachur, MD, MeMed (Scientific Research Study Investigator)

Maintenance of Certification Pediatrics: Pediatric Emergency Medicine (PEM): The New Part 3 Maintenance of Certification Assessment Option

ABSTRACT

Starting in 2022, the American Board of Pediatrics will launch the Maintenance of Certification Assessment for Pediatrics: Pediatric Emergency Medicine (MOCA-Peds: PEM) longitudinal assessment, which will provide an at-home alternative to the point-in-time examination. This longitudinal assessment will help engage PEM physicians participating in continuing certification in a more flexible and continuous lifelong, self-directed learning process while still providing a summative assessment of their knowledge. This commentary provides background information on MOCA-Peds and an introduction to MOCA-Peds: PEM and how it gives the PEM physician another option to participate in continuing certification.

Diagnosis of Concussion in the Pediatric Emergency Department

Pediatric visits to the Emergency Department (ED) for concussion are common and increasing. ED clinicians evaluating children with concussion should first ensure the absence of more serious injuries requiring immediate intervention, such as intracranial hemorrhage or cervical spine injury. In the ED setting, signs and symptoms of concussion are sometime subtle and often overlooked. A thorough physical exam is warranted but may be normal. Imaging and laboratory studies have no role in concussion diagnosis and should be reserved for cases where an injury requiring immediate intervention is suspected. Symptom management may include avoiding symptom-triggers (such as bright lights triggering headaches) and/or specific treatments such as nonsteroidal anti-inflammatories or antiemetics. Discharge instructions should include a recommendation for a brief period of rest, followed by outpatient management for return-to-activity decisions in conjunction with a primary care provider.

Urinary NGAL deficiency in recurrent urinary tract infections

INTRODUCTION

Children with recurrent urinary tract infections (rUTI) often show no identifiable cause of their infections. Neutrophil gelatinase-associated lipocalin (NGAL) is known to be upregulated within the uroepithelium and kidney of patients with UTI and exhibits a localized bacteriostatic effect through iron chelation. We hypothesize that some patients with rUTI without an identifiable cause of their recurrent infections have locally deficient NGAL production. We therefore explored whether a lack of NGAL production may be a factor in the pathogenesis of rUTI.

MATERIALS AND METHODS

Patients seen in the urology clinic for rUTI who were <21 years of age were enrolled. Patients were excluded if they had UTI at the time of enrollment, evidence of renal disease, decreased renal function, known anatomic abnormality of the genitourinary tract, or other reasons that predispose to UTI, such as neurogenic bladder, the need for intermittent catheterization, or unrepaired posterior urethral valves. Control patients were healthy children enrolled from the emergency department with no history of UTI or renal dysfunction, normal urinalysis at the time of enrollment, and presenting no diagnosis associated with increased NGAL levels, such as acute kidney injury or infection. NGAL was measured by immunoblot.

RESULTS

Fifteen cases and controls were enrolled. Median urinary NGAL levels were significantly decreased in rUTI patients compared with controls [15 (14-29) ng/ml vs 30 (27-61) ng/ml; p = 0.002)] Although comparatively diminished, measurable NGAL levels were present in all patients with rUTI.

CONCLUSIONS

Urinary NGAL is significantly decreased in patients with compared with patients without rUTI. These data suggest that some patients with rUTI may be predisposed to UTI because of a relative local deficiency in urinary NGAL production.

Advancing Urinary Protein Biomarker Discovery by Data-Independent Acquisition on a Quadrupole-Orbitrap Mass Spectrometer

The promises of data-independent acquisition (DIA) strategies are a comprehensive and reproducible digital qualitative and quantitative record of the proteins present in a sample. We developed a fast and robust DIA method for comprehensive mapping of the urinary proteome that enables large scale urine proteomics studies. Compared to a data-dependent acquisition (DDA) experiments, our DIA assay doubled the number of identified peptides and proteins per sample at half the coefficients of variation observed for DDA data (DIA = ∼8%; DDA = ∼16%). We also tested different spectral libraries and their effects on overall protein and peptide identifications and their reproducibilities, which provided clear evidence that sample type-specific spectral libraries are preferred for reliable data analysis. To show applicability for biomarker discovery experiments, we analyzed a sample set of 87 urine samples from children seen in the emergency department with abdominal pain. The whole set was analyzed with high proteome coverage (∼1300 proteins/sample) in less than 4 days. The data set revealed excellent biomarker candidates for ovarian cyst and urinary tract infection. The improved throughput and quantitative performance of our optimized DIA workflow allow for the efficient simultaneous discovery and verification of biomarker candidates without the requirement for an early bias toward selected proteins.

MStern Blotting-High Throughput Polyvinylidene Fluoride (PVDF) Membrane-Based Proteomic Sample Preparation for 96-Well Plates

We describe a 96-well plate compatible membrane-based proteomic sample processing method, which enables the complete processing of 96 samples (or multiples thereof) within a single workday. This method uses a large-pore hydrophobic PVDF membrane that efficiently adsorbs proteins, resulting in fast liquid transfer through the membrane and significantly reduced sample processing times. Low liquid transfer speeds have prevented the useful 96-well plate implementation of FASP as a widely used membrane-based proteomic sample processing method. We validated our approach on whole-cell lysate and urine and cerebrospinal fluid as clinically relevant body fluids. Without compromising peptide and protein identification, our method uses a vacuum manifold and circumvents the need for digest desalting, making our processing method compatible with standard liquid handling robots. In summary, our new method maintains the strengths of FASP and simultaneously overcomes one of the major limitations of FASP without compromising protein identification and quantification.

Urine proteomics for discovery of improved diagnostic markers of Kawasaki disease

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology. Absence of definitive diagnostic markers limits the accuracy of clinical evaluations of suspected KD with significant increases in morbidity. In turn, incomplete understanding of its molecular pathogenesis hinders the identification of rational targets needed to improve therapy. We used high-accuracy mass spectrometry proteomics to analyse over 2000 unique proteins in clinical urine specimens of patients with KD. We discovered that urine proteomes of patients with KD, but not those with mimicking conditions, were enriched for markers of cellular injury such as filamin and talin, immune regulators such as complement regulator CSMD3, immune pattern recognition receptor muclin, and immune cytokine protease meprin A. Significant elevations of filamin C and meprin A were detected in both the serum and urine in two independent cohorts of patients with KD, comprised of a total of 236 patients. Meprin A and filamin C exhibited superior diagnostic performance as compared to currently used markers of disease in a blinded case-control study of 107 patients with suspected KD, with receiver operating characteristic areas under the curve of 0.98 (95% confidence intervals [CI] of 0.97-1 and 0.95-1, respectively). Notably, meprin A was enriched in the coronary artery lesions of a mouse model of KD. In all, urine proteome profiles revealed novel candidate molecular markers of KD, including filamin C and meprin A that exhibit excellent diagnostic performance. These disease markers may improve the diagnostic accuracy of clinical evaluations of children with suspected KD, lead to the identification of novel therapeutic targets, and allow the development of a biological classification of Kawasaki disease.

Physicians' assessment of pediatric returns to the Emergency Department

BACKGROUND

Return visits to the Emergency Department (ED) requiring admission are frequently reviewed for the purpose of quality improvement. Treating physicians typically perform this review, but it is unclear if they accurately identify the reasons for the returns.

OBJECTIVES

To assess the characteristics of pediatric return visits to the ED, and the ability of treating physicians to identify the root causes for these return visits.

METHODS

This retrospective cohort study reviewed all returns within 96 h of an initial visit over a 2-year period at a tertiary care pediatric ED. Baseline characteristics were determined from review of patients' charts. The treating physicians, the primary author, and independent reviewers identified the root cause for the returns.

RESULTS

There were 97,374 patients that presented to the ED during the study, and 1091 (1.1%) of these children returned to the ED and were admitted. Returns were most common among children aged<5 years, arriving between 3:00 p.m. and 11:00 p .m. via private transportation, with infectious diseases. The physician involved in the care of the patient attributed 3.1% of returns to potential deficiencies in medical management, whereas the independent reviewers attributed 13% to potential deficiencies.

CONCLUSIONS

Both returns and the subset of returns due to potential deficiencies in management are more common than previously estimated, rendering review of returns a valuable quality improvement tool. However, EDs should not rely exclusively on the treating physicians to identify the reason for returns, as they seem to underestimate the frequency of returns due to potential deficiencies in medical management.

Errors of medical interpretation and their potential clinical consequences: a comparison of professional versus ad hoc versus no interpreters

STUDY OBJECTIVE

To compare interpreter errors and their potential consequences in encounters with professional versus ad hoc versus no interpreters.

METHODS

This was a cross-sectional error analysis of audiotaped emergency department (ED) visits during 30 months in the 2 largest pediatric EDs in Massachusetts. Participants were Spanish-speaking limited-English-proficient patients, caregivers, and their interpreters. Outcome measures included interpreter error numbers, types, and potential consequences.

RESULTS

The 57 encounters included 20 with professional interpreters, 27 with ad hoc interpreters, and 10 with no interpreters; 1,884 interpreter errors were noted, and 18% had potential clinical consequences. The proportion of errors of potential consequence was significantly lower for professional (12%) versus ad hoc (22%) versus no interpreters (20%). Among professional interpreters, previous hours of interpreter training, but not years of experience, were significantly associated with error numbers, types, and potential consequences. The median errors by professional interpreters with greater than or equal to 100 hours of training was significantly lower, at 12, versus 33 for those with fewer than 100 hours of training. Those with greater than or equal to 100 hours of training committed significantly lower proportions of errors of potential consequence overall (2% versus 12%) and in every error category.

CONCLUSION

Professional interpreters result in a significantly lower likelihood of errors of potential consequence than ad hoc and no interpreters. Among professional interpreters, hours of previous training, but not years of experience, are associated with error numbers, types, and consequences. These findings suggest that requiring at least 100 hours of training for interpreters might have a major impact on reducing interpreter errors and their consequences in health care while improving quality and patient safety.

Detection and diagnostic value of urine leucine-rich α-2-glycoprotein in children with suspected acute appendicitis

STUDY OBJECTIVE

Previously, we used a proteomics approach for the discovery of new diagnostic markers of acute appendicitis and identified leucine-rich α-2-glycoprotein (LRG) that was elevated in the urine of children with acute appendicitis and enriched in diseased appendices. Here, we sought to evaluate the diagnostic utility of enzyme-linked immunosorbent assay (ELISA) of urine LRG in a blinded, prospective, cohort study of children being evaluated for acute abdominal pain.

METHODS

Urine LRG concentration was measured with a commercially available LRG ELISA and selected ion monitoring mass spectrometry. Urine LRG test performance was evaluated blindly against the pathologic diagnosis and histologic grade of appendicitis.

RESULTS

Urine LRG was measured in 49 patients. Mean urine LRG concentration measured with commercial LRG ELISA was significantly elevated in patients with acute appendicitis but exhibited an interference effect. Direct measurements using selected ion monitoring mass spectrometry demonstrated that LRG was elevated more than 100-fold in patients with acute appendicitis compared with those without, with the receiver operating characteristic area under the curve of 0.98 (95% confidence interval 0.96 to 1.0). Among patients with acute appendicitis, elevations of urine LRG measured with ELISA and selected ion monitoring mass spectrometry correlated with the histologic severity of appendicitis.

CONCLUSION

Urine LRG ELISA allows for discrimination between patients with and without acute appendicitis but exhibits limited accuracy because of immunoassay interference. Direct measurements of urine LRG with selected ion monitoring mass spectrometry demonstrate superior diagnostic performance. Development of a clinical-grade urine LRG assay is needed to advance the diagnostic accuracy of clinical evaluations of appendicitis.

Risk stratification of children being evaluated for intussusception

CONTEXT

Intussusception is the most common cause of intestinal obstruction in young children, and delayed diagnosis may lead to bowel perforation.

OBJECTIVE

To determine predictive clinical criteria and develop a decision tree to risk-stratify children with possible intussusception.

DESIGN/METHODS

This is a prospective observational cohort study of children aged 1 month to 6 years who presented with possible intussusception. A data-collection form was completed before knowledge of any advanced imaging. Univariate analysis was performed, and decision trees were developed using recursive partitioning.

RESULTS

In the study, 310 patients were enrolled, including 38 (12.3%) with intussusception. The median age was 21.1 months and 61% were male. Univariate predictors of intussusception included age older than 6 months (P = 0.04), male gender (P = .007), history of lethargy (P = .001), and abnormal plain x-ray (P = .0001). Multivariate analysis through recursive partitioning identified decision trees (with and without the result of a plain abdominal x-ray) and allowed identification of patients at low risk. The decision tree based on the results of an abdominal x-ray (negative or positive), age (≤ 5 or >5 months), diarrhea (present or absent), and bilious emesis (present or absent) had the best test performance (sensitivity: 97% [95% confidence interval (CI): 86-100]; negative predictive value: 99% [95% CI: 93-100]; negative likelihood ratio: 0.08 [95% CI: 0.01-0.6]).

CONCLUSIONS

Among children who were being evaluated for intussusception, we prospectively determined clinical criteria and developed a decision tree to risk-stratify children with possible intussusception.

Discovery and validation of urine markers of acute pediatric appendicitis using high-accuracy mass spectrometry

STUDY OBJECTIVE

Molecular definition of disease has been changing all aspects of medical practice, from diagnosis and screening to understanding and treatment. Acute appendicitis is among many human conditions that are complicated by the heterogeneity of clinical presentation and shortage of diagnostic markers. Here, we sought to profile the urine of patients with appendicitis, with the goal of identifying new diagnostic markers.

METHODS

Candidate markers were identified from the urine of children with histologically proven appendicitis by using high-accuracy mass spectrometry proteome profiling. These systemic and local markers were used to assess the probability of appendicitis in a blinded, prospective study of children being evaluated for acute abdominal pain in our emergency department. Tests of performance of the markers were evaluated against the pathologic diagnosis and histologic grade of appendicitis.

RESULTS

Test performance of 57 identified candidate markers was studied in 67 patients, with median age of 11 years, 37% of whom had appendicitis. Several exhibited favorable diagnostic performance, including calgranulin A (S100-A8), alpha-1-acid glycoprotein 1 (orosomucoid), and leucine-rich alpha-2-glycoprotein (LRG), with the receiver operating characteristic area under the curve and values of 0.84 (95% confidence interval [CI] 0.72 to 0.95), 0.84 (95% CI 0.72 to 0.95), and 0.97 (95% CI 0.93 to 1.0), respectively. LRG was enriched in diseased appendices, and its abundance correlated with severity of appendicitis.

CONCLUSION

High-accuracy mass spectrometry urine proteome profiling allowed identification of diagnostic markers of acute appendicitis. Usage of LRG and other identified biomarkers may improve the diagnostic accuracy of clinical evaluations of appendicitis.

Serious bacterial infection in recently immunized young febrile infants

OBJECTIVE

The objective of this study was to investigate the prevalence of serious bacterial infection (SBI) in febrile infants without a source aged 6-12 weeks who have received immunizations in the preceding 72 hours.

METHODS

The authors conducted a medical record review of infants aged 6-12 weeks with a fever of > or = 38.0 degrees C presenting to the pediatric emergency department (ED) over 88 months. Infants were classified either as having received immunizations within the 72 hours preceding the ED visit (recent immunization [RI]) or as not having received immunizations during this time period (no recent immunization [NRI]). Primary outcome of an SBI was based on culture results; only patients with a minimum of blood and urine cultures were studied.

RESULTS

A total of 1,978 febrile infants were studied, of whom 213 (10.8%) had received RIs. The overall prevalence of definite SBI was 6.6% (95% confidence interval [CI] = 5.5 to 7.7). The prevalence of definite SBI in NRI infants was 7.0% (95% CI = 5.9 to 8.3) compared to 2.8% (95% CI = 0.6 to 5.1) in the RI infants. The prevalence of definite SBI in febrile infants vaccinated in the preceding 24 hours decreased to 0.6% (95% CI = 0 to 1.9). The prevalence of definite SBI in febrile infants vaccinated greater than 24 hours prior to presentation was 8.9% (95 CI = 1.5 to 16.4). The relative risk of SBI with RI was 0.41 (95% CI = 0.19 to 0.90). All SBIs in the RI infants were urinary tract infections (UTI).

CONCLUSIONS

Among febrile infants, the prevalence of SBI is less in the initial 24 hours following immunizations. However, there is still a substantial risk of UTI. Therefore, urine testing should be considered in febrile infants who present within 24 hours of immunization. Infants who present greater than 24 hours after immunizations with fever should be managed similarly to infants without RIs.

Urine proteomics for profiling of human disease using high accuracy mass spectrometry

Knowledge of the biologically relevant components of human tissues has enabled the invention of numerous clinically useful diagnostic tests, as well as non-invasive ways of monitoring disease and its response to treatment. Recent use of advanced MS-based proteomics revealed that the composition of human urine is more complex than anticipated. Here, we extend the current characterization of the human urinary proteome by extensively fractionating urine using ultra-centrifugation, gel electrophoresis, ion exchange and reverse-phase chromatography, effectively reducing mixture complexity while minimizing loss of material. By using high-accuracy mass measurements of the linear ion trap-Orbitrap mass spectrometer and LC-MS/MS of peptides generated from such extensively fractionated specimens, we identified 2362 proteins in routinely collected individual urine specimens, including more than 1000 proteins not described in previous studies. Many of these are biomedically significant molecules, including glomerularly filtered cytokines and shed cell surface molecules, as well as renally and urogenitally produced transporters and structural proteins. Annotation of the identified proteome reveals distinct patterns of enrichment, consistent with previously described specific physiologic mechanisms, including 336 proteins that appear to be expressed by a variety of distal organs and glomerularly filtered from serum. Comparison of the proteomes identified from 12 individual specimens revealed a subset of generally invariant proteins, as well as individually variable ones, suggesting that our approach may be used to study individual differences in age, physiologic state and clinical condition. Consistent with this, annotation of the identified proteome by using machine learning and text mining exposed possible associations with 27 common and more than 500 rare human diseases, establishing a widely useful resource for the study of human pathophysiology and biomarker discovery.

Acute pediatric monoarticular arthritis: distinguishing lyme arthritis from other etiologies

OBJECTIVE

Identify clinical predictors of Lyme arthritis among patients with acute monoarticular arthritis.

METHODS

A medical chart review was conducted of children </=18 years of age with monoarticular arthritis who underwent arthrocentesis in a pediatric emergency department located in the northeast United States. Patients were classified into 3 categories of arthritis: septic, Lyme, or nonseptic non-Lyme arthritis. Historical, clinical, and laboratory data were compared to identify distinguishing features of Lyme arthritis.

RESULTS

One hundred seventy-nine patients were studied: 46 (26%) patients with septic arthritis, 55 (31%) patients with Lyme arthritis, and 78 (43%) patients with nonseptic non-Lyme arthritis. Compared with those with septic arthritis, patients with Lyme disease were more likely to have a tick-bite history, knee involvement, and less likely to have a history of fever or elevated temperature at triage. Erythrocyte sedimentation rate, C-reactive protein, joint white blood cell count, and joint neutrophil percentage were also statistically lower. In comparison to nonseptic non-Lyme arthritis, knee involvement and tick-bite history were predictors of Lyme. Erythrocyte sedimentation rate, joint white blood cell count, and joint neutrophil percentage were also statistically different. Multivariate analysis comparing Lyme to septic arthritis demonstrated fever history and elevated C-reactive protein level to be negative predictors of Lyme arthritis and knee involvement to be a positive predictor (model sensitivity: 88%; specificity: 82%).

CONCLUSIONS

Lyme arthritis shares features with both septic and nonseptic non-Lyme arthritis. This overlap prevents the creation of a clinically useful predictive model for Lyme arthritis. In endemic areas, Lyme testing should be performed on all patients presenting with acute monoarticular arthritis.

Procalcitonin levels in febrile infants after recent immunization

BACKGROUND

Procalcitonin has been identified as a useful blood marker of serious bacterial infection in febrile infants. Many infants present with a febrile reaction after receiving immunizations. The effects of immunization on procalcitonin have not been investigated.

METHODS

We performed a prospective observational cohort study at a large, urban pediatric emergency department. Infants <or=90 days of age with fever of >or=38 degrees C were enrolled. Subjects were divided into 3 groups: infants with serious bacterial infection; subjects without serious bacterial infection who received recent (<48 hours) immunizations; and subjects without serious bacterial infection who did not recently receive immunizations. Procalcitonin was measured by using a quantitative immunometric assay.

RESULTS

Over 13 months, procalcitonin was measured for 271 infants. There were 44 (16%) patients with serious bacterial infection, 35 in the recent-immunization group, and 192 in the no-recent-immunization group. The median procalcitonin level for serious bacterial infection was 0.53 ng/mL, for recent immunization was 0.29 ng/mL, and for no recent immunizations was 0.17 ng/mL. Procalcitonin values were elevated for patients with serious bacterial infection compared with patients both with and without recent immunizations. Compared with patients who had no recent immunizations, procalcitonin levels were elevated in patients with recent immunization. Using a cut point of 0.12 ng/mL, the sensitivity of procalcitonin for serious bacterial infection was 96%, specificity was 23%, and negative predictive value was 96%. Two patients with recent immunization who had serious bacterial infection were identified with this cut point.

CONCLUSIONS

Among febrile infants with recent immunization, procalcitonin levels are increased compared with patients with fever and no identified bacterial infection. Despite this increase, procalcitonin can still reliably discriminate infants with serious bacterial infection.

Procalcitonin in young febrile infants for the detection of serious bacterial infections

OBJECTIVES

The objectives of the study were (1) to study the test performance of procalcitonin for identifying serious bacterial infections in febrile infants <or=90 days of age without an identifiable bacterial source and (2) to determine an optimal cutoff value to identify infants at low risk for serious bacterial infections.

METHODS

A prospective observational study was performed with febrile infants <or=90 days of age presenting to an urban, pediatric, emergency department. Serum procalcitonin levels were measured by using an automated high-sensitivity assay. An optimal procalcitonin cutoff value was selected to maximize sensitivity and negative predictive value for the detection of serious bacterial infections. Infants were classified as having definite, possible, or no serious bacterial infections.

RESULTS

A total of 234 infants (median age: 51 days) were studied. Thirty infants (12.8%) had definite serious bacterial infections (bacteremia: n = 4; bacteremia with urinary tract infections: n = 2; urinary tract infections: n = 24), and 12 infants (5.1%) had possible serious bacterial infections (pneumonia: n = 5; urinary tract infections: n = 7). Mean procalcitonin levels for definite serious bacterial infections (2.21 +/- 3.9 ng/mL) and definite plus possible serious bacterial infections (2.48 +/- 4.6 ng/mL) were significantly higher than that for no serious bacterial infection (0.38 +/- 1.0 ng/mL). The area under the receiver operating characteristic curve was 0.82 for definite serious bacterial infections and 0.76 for definite and possible serious bacterial infections. For identifying definite and possible serious bacterial infections, a cutoff value of 0.12 ng/mL had sensitivity of 95.2%, specificity of 25.5%, negative predictive value of 96.1%, and negative likelihood ratio of 0.19; all cases of bacteremia were identified accurately with this cutoff value.

CONCLUSIONS

Procalcitonin has favorable test characteristics for detecting serious bacterial infections in young febrile infants. Procalcitonin measurements performed especially well in detecting the most serious occult infections.

Status asthmaticus in children

PURPOSE OF REVIEW

The prevalence of severe asthma in children has risen in the past few decades. The present review explores our current understanding of epidemiology, pathophysiology and treatment of status asthmaticus in children.

RECENT FINDINGS

The pathophysiology of inflammation and airway hyperactivity continues to be a source of research. Early initiation of inhaled beta-agonists and oral or parenteral steroids remain the standard of care in the treatment of status asthmaticus. Other treatment modalities such as magnesium and intravenous beta-agonists show some benefit. There is a resurgence of interest in the use of methylxanthines. Alternatives to endotracheal intubation show some promise in preventing respiratory failure.

SUMMARY

Asthma remains the third leading cause of hospitalization in children younger than 15 years old. Researchers continue to explore the efficacy of old and new treatment modalities. Future research efforts targeting at-risk populations could dramatically decrease asthma morbidity and mortality.

Lyme disease update

PURPOSE OF REVIEW

Lyme disease is endemic to areas in both Europe and the United States and the incidence is increasing. Despite published guidelines, controversy persists about its diagnosis and management in patients who do not meet strict diagnostic criteria. This review summarizes important recently published studies and recommendations for the diagnosis and management of Lyme disease.

RECENT FINDINGS

Recent comprehensive guidelines have been published for the diagnosis and management of pediatric Lyme disease. In addition, recent studies may help physicians differentiate between Lyme and aseptic meningitis, as well as show the poor sensitivity of cerebrospinal fluid polymerase chain reaction. Controversy continues about the diagnosis and management of "chronic Lyme disease", despite the current medical literature. Recently published studies in the US have also better described southern tick-associated rash illness, an entity that may present a similar clinical picture to Lyme disease. Guidelines have also been published on the management and diagnosis of other tick-borne illnesses often seen as co-infections with Lyme disease. Finally, case reports have been published describing new cardiac manifestations associated with Lyme disease.

SUMMARY

Controversies persist about the diagnosis and management of Lyme disease. Recently published guidelines and primary research can aid clinicians in diagnosing Lyme properly.

Evaluating appendicitis scoring systems using a prospective pediatric cohort

STUDY OBJECTIVE

This article evaluates the performance of the previously published Alvarado and Samuel appendicitis scoring systems in a prospectively identified pediatric cohort.

METHODS

A prospective cohort of patients, aged 3 to 21 years, being evaluated for appendicitis was enrolled during 20 consecutive months at a large, urban, pediatric hospital. Study forms were completed by pediatric emergency medicine attending physicians before imaging or surgery. Final diagnosis was determined by pathology or follow-up telephone call. Each score was tested as proposed by the original authors. Sensitivity, specificity, and predictive values were calculated for all patients and prepubertal patients younger than 10 years.

RESULTS

Five hundred eighty-eight patients were studied. The median age was 11.9 years (interquartile range [IQR] 8.5; 14.9 years). Thirty-four percent of patients had appendicitis. An Alvarado score greater than or equal to 7 yielded a sensitivity of 72% (95% confidence interval [CI] 66% to 78%), specificity 81% (76% to 84%), negative predictive value (NPV) 85% (81% to 89%), and positive predictive value (PPV) 65% (59% to 72%). A Samuel score greater than or equal to 6 yielded a sensitivity of 82% (77% to 87%), specificity 65% (60% to 70%), NPV 88% (84% to 91%), and PPV 54% (48% to 60%). When analysis was limited to patients younger than 10 years, n=206, an Alvarado score greater than or equal to 7 yielded a sensitivity of 73% (62% to 84%), specificity 80% (73% to 86%), NPV 89% (83% to 94%), and PPV 58% (45% to 69%). A Samuel score greater than or equal to 6, when patients younger than 10 years were considered, yielded a sensitivity of 77% (66% to 87%), specificity 65% (56% to 72%), NPV 88% (82% to 94%), and PPV 45% (35% to 55%). Receiver operator characteristic curves had an area under the curve of 0.83 (95% CI 0.79 to 0.86) (Alvarado) and 0.81 (95% CI 0.78 to 0.85) (Samuel).

CONCLUSION

Although the Alvarado and Samuel scores provide measurably useful diagnostic information in evaluating children with suspected appendicitis, neither method provides sufficient PPV to be used in clinical practice as the sole method for determination of the need for surgery.

Atypical clinical features of pediatric appendicitis

BACKGROUND

The diagnosis of appendicitis remains challenging in children. Delays in diagnosis, or misdiagnosis, have important medical and legal implications. The typical, or classic, presentation of pediatric appendicitis has been modeled after adult disease; however, many children present atypically with subtle findings or unusual signs.

OBJECTIVES

To determine the frequency of atypical clinical features among pediatric patients with appendicitis and to investigate which atypical features are the strongest negative predictors for appendicitis among patients being evaluated for appendicitis.

METHODS

Children and adolescents with suspected appendicitis were enrolled over 20 consecutive months. Pediatric emergency physicians completed standardized data collection forms on eligible patients. Final diagnosis was determined by pathology or follow-up telephone call. Typical and atypical findings were defined strictly a priori.

RESULTS

Seven hundred fifty-five patients were enrolled. The median age was 11.9 years (interquartile range [IQR]: 8.5, 14.9 yr); 36% of patients were diagnosed with appendicitis. Among patients with appendicitis, the most common atypical features included absence of pyrexia (83%), absence of Rovsing's sign (68%), normal or increased bowel sounds (64%), absence of rebound pain (52%), lack of migration of pain (50%), lack of guarding (47%), abrupt onset of pain (45%), lack of anorexia (40%), absence of maximal pain in the right lower quadrant (32%), and absence of percussive tenderness (31%). Forty-four percent of patients with proven appendicitis had six or more atypical characteristics. The median number of atypical features for patients with proven appendicitis was five (IQR: 4.0, 7.0). The greatest negative predictors, on the basis of likelihood ratios, were as follows: white blood cell count (WBC) of <10,000 per cubic millimeter (likelihood ratios [LR], 0.18), absolute neutrophil count (ANC) of <7,500 per cubic millimeter (LR, 0.35), lack of percussive tenderness (LR, 0.50), lack of guarding (LR, 0.63), and no nausea or emesis (LR, 0.65).

CONCLUSIONS

Appendicitis in pediatric patients is difficult to diagnose because children present with a wide variety of atypical clinical features. Forty-four percent of patients with appendicitis presented with six or more atypical features. Two atypical features are the strongest negative predictors of appendicitis in children: WBC of <10,000 per cubic millimeter and an ANC of <7,500 per cubic millimeter.

Success of short-course parenteral antibiotic therapy for acute osteomyelitis of childhood

The outcome of acute osteomyelitis treated with sequential therapy consisting of a short course of parenteral antibiotics, followed by oral antibiotics, was studied. To be considered acute osteomyelitis, related symptoms must have been present for less than 2 weeks before diagnosis. Short-course parenteral antibiotics (therapy for 7 days or less) and then oral antibiotics were used to treat 29 patients (median age, 6.3 years). Pathogens were identified from blood cultures and bone aspirates. Staphylococcus aureus was isolated in 59%. Median duration of parenteral antibiotics and oral antibiotics was 4 days (range, 0-7 days) and 28 days (range, 14-42 days), respectively. Median duration of combined (parenteral and oral) therapy was 32 days (range, 20-49 days). No failures or complications were noted at the 6-month follow-up, which was available for 27 patients. Short-course parenteral antibiotic therapy followed by oral therapy appears to be effective for treatment of acute, uncomplicated osteomyelitis.

Advances in the emergency management of pediatric sepsis

PURPOSE OF REVIEW

Sepsis requires prompt recognition and aggressive therapy; early goal-directed therapy decreases morbidity and mortality. Recommendations on the specific management of pediatric sepsis have historically been extrapolated from adult literature and from expert/consensus opinion. This review serves to appraise recent recommendations and determine the applicability of newly promoted adult guidelines for pediatric sepsis.

RECENT FINDINGS

The first and most recent recommendations on the management of pediatric sepsis were published in 2002 by expert consensus with the recognition that there were few data from randomized controlled trials or meta-analysis. Previous to this, adult guidelines were used in the management of pediatric sepsis. New definitions for pediatric sepsis provided by expert consensus take into account the specific physiologic changes. Prompt correction of hemodynamic derangements has been shown to improve outcome through aggressive volume resuscitation and early initiation of vasopressor therapy. Frequent reassessment has been emphasized to ensure appropriate management.

SUMMARY

Prompt recognition, institution of appropriate therapy, and continual assessment for children with sepsis and shock are essential for improved outcomes. The emerging new literature on early goal-directed therapy is most applicable to care in the emergency department.

Hyperpyrexia among infants younger than 3 months

OBJECTIVE

To determine the prevalence of serious bacterial infection in infants younger than 3 months with fever > or =40 degrees C.

METHODS

We retrospectively identified all infants younger than 3 months with fever who presented to a pediatric emergency department. The medical records were reviewed. The prevalence of serious bacterial infection (SBI) among those patients with hyperpyrexia was compared with febrile infants with lower fever.

RESULTS

5279 infants younger than 3 months with fever were reviewed. Ninety-eight patients (1.7%) had triage temperature > or =40 degrees C rectally. Median age, temperature, and white blood count for those with hyperpyrexia were 58 days (interquartile range [IQR] 36-78 days), 40.2 degrees C (IQR, 40.0-40.4 degrees C), and 10,800/mm3 (IQR, 7900-14,600/mm3), respectively. Diagnostic studies included blood culture (100%), urine culture (100%), lumbar puncture (100%), chest radiographs (34%), and stool cultures (11%). SBI was found in 38% infants with hyperpyrexia: urinary tract infection was the most common SBI (71%). Among patients with hyperpyrexia, patients with SBI had similar mean white blood cell counts (14,000 vs. 10,200 cells/mm3) and age (54 vs. 53 days) as those with hyperpyrexia but no SBI. The prevalence of SBI among febrile infants with temperatures > or =40.0 degrees C was 38% (95% CI 27-48%) compared with those with fever < or =40 degrees C: 8.8% (95% CI 8.1-9.5%).

CONCLUSION

Hyperpyrexia is rare among febrile infants younger than 3 months. One-third of infants with temperature > or =40.0 degrees C had SBI. Future management algorithms might include hyperpyrexia as a risk factor for serious infection.

Reliability of the urinalysis for predicting urinary tract infections in young febrile children

BACKGROUND

Urinary tract infections (UTIs) are a common source of bacterial infection among young febrile children. Clinical variables affecting the sensitivity of the urinalysis (UA) as a screen for UTI have not been previously investigated. The limited sensitivity of the UA for detecting a UTI requires that a urine culture be obtained in some children regardless of the UA result; however, a proper urine culture requires an invasive procedure, so the criteria for its use should be optimized.

OBJECTIVES

To determine how the sensitivity of the standard UA as a screening test for UTI varies with age, and to determine the clinical situation that necessitates the collection of a urine culture regardless of the UA result.

METHODS

Retrospective medical record review of patients younger than 2 years with fever (>/=38 degrees C) seen in the emergency department during a period of 65 months. All urine cultures were reviewed for the collection method, isolates, and colony counts. A UA result was considered positive if the presence of 1 of the following was detected: leukocyte esterase, nitrite, or pyuria (>/=5 white blood cells per high power field). Patients who had a paired UA and urine culture were used to calculate the sensitivity, specificity, and likelihood ratios of the UA. The prevalence of UTIs was also subcategorized by age, race, sex, and fever.

RESULTS

Medical records of 37 450 febrile children younger than 2 years were reviewed. Forty-four percent were girls. Median age and temperature were 10.6 months and 38.8 degrees C. A total of 11 089 patients (30%) had urine cultures obtained. The sensitivity of the UA was 82% (95% confidence interval [CI], 79%-84%) and did not vary by age subgroups. The specificity of UA was 92% (95% CI, 91%-92%). The likelihood ratios for a positive UA and negative UA were 10.6 (95% CI, 10.0-11.2) and 0.19 (95% CI, 0.18-0.20), respectively. Prevalence of UTI was 2.1% overall (2.9% for girls and 1.5% for boys, respectively). Among girls, the prevalence of UTI was 5.0% in white patients, 2.1% in Hispanic patients, and 1.0% in black patients. Among boys, the prevalence was 2.2% in Hispanic patients, 1.4% in white patients, and 0.8% in black patients. Higher prevalence was also seen among patients with a temperature at or above 39 degrees C compared with those whose temperature was between 38.0 degrees C and 38.9 degrees C. The greatest prevalence of UTI (13%) was found among white girls younger than 6 months with a temperature at or greater than 39 degrees C. The posttest probability of a UTI in the presence of a negative UA can be calculated using the negative likelihood ratio and the patient-specific prevalence of UTI. When the prevalence of UTI is 2%, 1 UA among 250 will produce a false-negative test result.

CONCLUSIONS

The sensitivity of the standard UA is 82% (95% CI, 79%-84%) and does not vary with age in febrile children younger than 2 years. The prevalence of UTI varies by age, race, sex, and temperature. A negative likelihood ratio and estimates of prevalence can be used to calculate the risk of missing a UTI due to a false-negative UA result.

Nonresponders: prolonged fever among infants with urinary tract infections

BACKGROUND

The majority of young children with fever and urinary tract infections (UTIs) have evidence of pyelonephritis based on renal scans. Resolution of fever during treatment is 1 clinical marker of adequate treatment. Theoretically, prolonged fever may be a clue to complications, such as urinary obstruction or renal abscess.

OBJECTIVE

Describe the pattern of fever in febrile children undergoing treatment of a UTI. Compare the clinical characteristics of those patients with prolonged fever to those who respond faster to therapy.

SETTING

An urban pediatric hospital.

DESIGN

Medical record review.

METHODS

All children </=2 years old admitted to the pediatric service with a primary discharge diagnosis of pyelonephritis or UTI were reviewed for 65 consecutive months. Patients with previous UTI, known urologic problems, or immunodeficiency were excluded. Only patients with an admitting temperature >/=38 degrees C and those who met standard culture criteria were studied. Temperatures are not recorded hourly on the inpatient unit; therefore, they were assigned to blocks of time. Nonresponders were defined as those above the 90th percentile for the time to defervesce. Nonresponders were then compared with the balance of the study patients, termed responders.

RESULTS

Of 288 patients studied, the median age was 5.6 months (interquartile range: 1.3-7.9 months old). Median admission temperature was 39.3 degrees C (interquartile range: 38.5 degrees C-40.1 degrees C). Median time to defervesce ranged in the time block 13 to 16 hours. Sixty-eight percent were afebrile by 24 hours and 89% by 48 hours. Thirty-one patients had fever >48 hours (nonresponders). Nonresponders were older than responders (9.4 vs 4.1 months old) but had similar initial temperatures (39.8 vs 39.2 degrees C), white blood cell counts (18.4 vs 17.1 x 1000/mm(3)), and band counts (1.4 vs 1.2 x 1000/mm(3)). Nonresponders had similar urinalyses with regard to leukocyte esterase positive (23/29 vs 211/246), nitrite-positive (8/28 vs 88/221], and the number of patients with "too numerous to count" white blood cell counts per high power field (12/28 vs 77/220). Nonresponders were as likely as responders to have bacteremia (3/31 vs 21/256), hydronephrosis by renal ultrasound (1/31 vs 12/232), and significant vesicoureteral reflux (more than or equal to grade 3; 5/26 vs 30/219). Eschericia coli was the pathogen in cultures of 28 of 31 (nonresponders) and 225 of 257 (responders) cultures. The number of cultures with >/=100 colony-forming units/mL was similar (25/31 nonresponders vs 206/257 responders). Repeat urine cultures were performed in 93% of patients during the admission; all culture results were negative. No renal abscesses or pyo-hydronephrosis was diagnosed.

CONCLUSIONS

Eighty-nine percent of young children with febrile UTIs were afebrile within 48 hours of initiating parenteral antibiotics. The patients who took longer than 48 hours to defervesce were clinically similar to those whose fevers responded faster to therapy. If antibiotic sensitivities are known, additional diagnostic studies or prolonged hospitalizations may not be justified solely based on persistent fever beyond 48 hours of therapy.

Reevaluation of outpatients with Streptococcus pneumoniae bacteremia

BACKGROUND

The reevaluation process for outpatients recalled for Streptococcus pneumoniae bacteremia has not been standardized. Children who return ill or with new serious focal infections require admission and parenteral antibiotic therapy. Limited data exist to guide the follow-up management of those patients identified as having occult pneumococcal bacteremia.

OBJECTIVES

Characterize the outcomes of outpatients with pneumococcal bacteremia based on their evaluation at follow-up. For patients who are well-appearing without serious focal infection, propose a management scheme for reevaluation.

METHODS

Retrospective review of outpatients with pneumococcal bacteremia. Patients with immunocompromise, those identified with focal bacterial infection at the initial visit, or those admitted at the initial visit were excluded. Data were collected from the initial visit (when blood culture drawn) and follow-up visit with regard to clinical parameters, laboratory data, diagnoses, and any antibiotic treatment. Decision tree analysis was used to generate a model to predict children at high risk for persistent bacteremia (PB).

RESULTS

A total of 548 episodes of pneumococcal bacteremia were studied. Seventy-three children received no antibiotic, 239 oral antibiotic, and 236 parenteral antibiotic at the initial visit. Median age, temperature, and white blood cell (WBC) count were 13.5 months, 40.0 degrees C, and 20 400/mm(3). Forty-one patients had PB or new focal infections (15 with PB alone, 4 had focal infection and PB). Eight patients had meningitis at follow-up. Ninety-two percent returned because of notification of the positive blood culture result. A repeat blood culture was obtained in 92%, 23% had a lumbar puncture, 33% had a chest radiograph, and 12% were admitted. PB was associated with the antibiotic treatment group, elevation of temperature, and WBC count at follow-up. A simple management scheme using 2 sequential decision nodes of antibiotic treatment (none vs any) and then temperature at follow-up (>38.8 degrees C) would have predicted 16/19 patients with PB (sensitivity =.84 and specificity =.86).

CONCLUSIONS

All patients with pneumococcal bacteremia need prompt reevaluation. For well-appearing patients without new focal infection, the utility of diagnostic testing (specifically repeat blood cultures) and the need for admission may be determined by the use of antibiotics at the initial evaluation and the presence of fever at follow-up. The majority of patients can be managed as outpatients entirely. Patients who did not receive antibiotics at the initial evaluation and those treated with oral antibiotics but remain febrile are at the highest risk for persistent bacteremia.

Non-typhi Salmonella bacteremia in children

BACKGROUND

Non-typhi Salmonella (NTS) infections are a frequent cause of self-limited diarrheal illness in healthy children. Bacteremia is a known complication of NTS infection, but the management of children with bacteremia has been based on limited data.

OBJECTIVE

To study the outcomes of pediatric patients with NTS bacteremia.

METHODS

Retrospective review of patients with NTS bacteremia covering a 16-year period at an urban pediatric hospital. Clinical data from the initial visits and any follow-up visits or hospitalizations were abstracted from the medical record.

RESULTS

We studied 144 patients. Median age was 10.5 months. Fifty-four patients were hospitalized at the initial visit including all the patients with immunodeficiency (n = 12). Of the 90 patients initially managed as outpatients, 79 were subsequently admitted; only 1 of these patients developed a focal complication. Persistent bacteremia was found in 51 (41%) patients. Among nonimmunocompromised patients, persistent bacteremia was noted in 34% [95% confidence interval (CI), 20 to 52%] of those initially treated with oral antibiotics, 52% (CI 30 to 74%) of those initially treated with a parenteral dose of antibiotics and in 31% (CI 22 to 43%) of those who were not initially given antibiotics. No laboratory or clinical factors predicted persistent bacteremia. Twelve patients developed focal infections: 3 of 119 previously healthy children (2.5%, CI 0.5 to 7%); and 9 of 25 children with underlying medical conditions (36%, CI 19 to 57%). Focal infections included meningitis (3), osteomyelitis (4), septic arthritis (2), pneumonia (2) and cholangitis (1).

CONCLUSIONS

NTS bacteremia occurs in otherwise healthy children, although the risk of focal infections is small. Patients with NTS bacteremia frequently have persistent bacteremia at follow-up regardless of initial antibiotic treatment.

Occult pneumonias: empiric chest radiographs in febrile children with leukocytosis

STUDY OBJECTIVE

We sought to determine the incidence of radiographic findings of pneumonia in highly febrile children with leukocytosis and no clinical evidence of pneumonia or other major infectious source.

METHODS

We conducted a prospective cohort study at a large urban pediatric hospital. Clinical practice guidelines for the use of chest radiography in febrile children were established by the emergency medicine attending staff. All records of emergency department patients with leukocytosis (WBC count >/= 20, 000/mm3), triage temperature 39.0 degreesC or higher, age 5 years or less were reviewed daily for 12 months. Physicians completed a questionnaire to note the diagnosis, the presence of respiratory symptoms and signs, and the reason for the chest radiograph (if one was obtained). Patients were excluded for immunodeficiency, chronic lung disease, or major bacterial sources of infection other than pneumonia. Pneumonia was defined by an attending radiologist's reading of the radiograph.

RESULTS

We studied 278 patients. Chest radiographs were obtained in 225 for the following reasons: 79 because of respiratory findings suggestive of pneumonia and 146 because of leukocytosis and no identifiable major source of infection. Fifty-three patients did not undergo radiography. Pneumonia was found in 32 of 79 (40%; 95% confidence interval, 20% to 52%) of those with findings suggestive of pneumonia and in 38 of 146 (26%; 95% confidence interval, 19% to 34%) of those without clinical evidence of pneumonia. If patients who did not have a radiograph are assumed to not have pneumonia, the minimum estimate of occult pneumonia was 38 of 199 patients (19%; 95% confidence interval, 14% to 25%).

CONCLUSION

Empiric chest radiographs in highly febrile children with leukocytosis and no findings of pneumonia frequently reveal occult pneumonias. Chest radiography should be considered a routine diagnostic test in children with a temperature of 39 degreesC or greater and WBC count of 20,000/mm3 or greater without an alternative major source of infection.

Clinical implications of penicillin and ceftriaxone resistance among children with pneumococcal bacteremia

OBJECTIVES

To determine whether reduced penicillin or ceftriaxone susceptibility affects clinical presentation and outcome in children with pneumococcal bacteremia.

DESIGN

Retrospective review of patients with Streptococcus pneumoniae bacteremia.

RESULTS

We reviewed 922 cases of pneumococcal bacteremia. Of 744 isolates with known penicillin (PCN) susceptibilities 56 were PCN-nonsusceptible. The majority displayed intermediate resistance; 14 of 730 isolates with known ceftriaxone (CTX) susceptibilities were CTX-nonsusceptible. Neither the PCN- nor the CTX-nonsusceptible cohort displayed a difference from its susceptible counterpart in temperature, respiratory rate or white blood cell count on initial patient evaluation, although trend suggested they were more often admitted at the initial visit. At follow-up only children treated initially with antibiotic were evaluated. Children with PCN-nonsusceptible isolates were no more likely to be febrile than those with PCN-susceptible isolates (28% vs. 25%, P = 0.61) and were no more likely to have a positive repeat blood culture (0% vs. 1%, P = 0.59) or a new focal infection (10% vs. 6%, P = 0.79). Data concerning CTX-nonsusceptible organisms were limited by the low number of such isolates. Although patients with CTX-nonsusceptible pneumococci were more likely to be febrile at follow-up than those with CTX-susceptible organisms (67% vs. 24%, P = 0.04), we were unable to demonstrate a significant difference for other endpoints.

CONCLUSIONS

Reduced antibiotic susceptibility does not alter the clinical presentation of pneumococcal bacteremia. With current practice intermediate resistance to PCN is of little clinical significance in nonmeningitic systemic pneumococcal infections.

Parenteral vs oral antibiotics in the prevention of serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia: a meta-analysis

OBJECTIVE

To determine whether parenteral antibiotics are superior to oral antibiotics in preventing serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia.

METHODS

Using the MEDLINE database, the English language literature was searched for all publications concerning bacteremia, fever, or Streptococcus pneumoniae from 1966 to January 1, 1997. All nonduplicative studies with a series of children with S. pneumoniae occult bacteremia having both orally treated and parenterally treated groups were reviewed. Children were excluded from individual studies if at the time of their initial evaluation they were immunocompromised, had a serious bacterial infection, underwent a lumbar puncture, or did not receive antibiotics.

RESULTS

Only 4 studies met study criteria. From these studies, 511 total cases of S. pneumoniae occult bacteremia were identified. Ten of 290 (3.4%) in the oral group and 5 of 221 (2.3%) in the parenteral antibiotic group developed serious bacterial infections (pooled p-value = 0.467, pooled OR = 1.48; 95% CI, 0.5-4.3). Two patients in the oral group (0.7%) and 2 patients in the parenteral group (0.9%) developed meningitis (pooled p-value = 0.699, pooled OR = 0.67; 95% CI, 0.1-5.1).

CONCLUSION

The rates of serious bacterial infections and meningitis did not differ between children who were treated with oral and parenteral antibiotics. The extremely low rate of complications observed in both groups suggests no clinically significant difference between therapies. A study with >7,500 bacteremic children (or >300,000 febrile children) would be needed to have 80% power to prove parenteral antibiotics are superior to oral antibiotics in preventing serious bacterial infections.

Do oral antibiotics prevent meningitis and serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia? A meta-analysis

OBJECTIVE

To determine whether oral antibiotics prevent meningitis and serious bacterial infections in children with Streptococcus pneumoniae occult bacteremia.

DATA SOURCES

Using the Medline database, the English-language literature was searched for all publications concerning bacteremia, fever, or S pneumoniae from 1966 to April 1996.

STUDY SELECTION

All studies that included a series of children with S pneumoniae occult bacteremia containing orally treated and untreated groups. Children were excluded from individual studies if they were immunocompromised, had a serious bacterial infection, underwent a lumbar puncture, or received parenteral antibiotics.

DATA EXTRACTION

Three authors independently reviewed each article to determine the number of eligible children and the outcome of children meeting entry criteria.

DATA SYNTHESIS

Eleven of 21 studies were excluded, leaving 10 evaluable studies with 656 total cases of S pneumoniae occult bacteremia identified. Patients who received oral antibiotics had fewer serious bacterial infections than untreated patients (3.3% vs 9.7%; pooled odds ratio, 0.35; 95% confidence interval, 0.17 to 0.73). Meningitis developed in 3 (0.8%) of 399 children in the oral antibiotic group and 7 (2.7%) of 257 untreated children (pooled odds ratio, 0.51; 95% confidence interval, 0.12 to 2.09).

CONCLUSION

Although oral antibiotics modestly decreased the risk of serious bacterial infections in children with S pneumoniae occult bacteremia, there was insufficient evidence to conclude that oral antibiotics prevent meningitis. Published recommendations that oral antibiotics be administered to prevent serious bacterial infections in children with possible S pneumoniae occult bacteremia should be reevaluated in light of the lower risk of sequelae from S pneumoniae occult bacteremia and newer data concerning side effects from treatment.

Invasive pneumococcal infections in human immunodeficiency virus-infected children

Invasive pneumococcal infection (IPI) is the most common serious bacterial infection in human immunodeficiency virus (HIV)-infected children. Data from a population-based pediatric HIV surveillance project were used to determine the incidence of IPI in HIV-infected children and to conduct a case-control study assessing potential risk factors for IPI in HIV-infected children. There were 50 episodes of IPI and a cumulative incidence of 6.1 cases/100 patient-years through age 7 years. Children with IPI were more likely to have a prior AIDS diagnosis (odds ratio, 4.2; 95% confidence interval, 1.2-15.1) and higher levels of IgG and IgM (P=.01) than were controls. In a separate case-control study, the manifestations of IPI in HIV-infected children were compared with those in HIV-negative controls. Focal complication rates in the 2 groups did not differ; however, HIV-infected children were less likely than controls to have leukocytosis (P<.001) and more likely to have isolates with penicillin resistance (P=.03).

Bacteremia and meningitis among infants with urinary tract infections

A retrospective analysis of 354 patients < or = 2 years of age with urinary tract infections (UTIs) was performed to characterize patients with bacteremia or meningitis and to identify any objective predictors of these complications. Thirty-three patients with bacteremia were identified. Blood culture isolates included Escherichia coli (25), Staphylococcus aureus (4), enterococcus (1), group B Streptococcus (2), and Enterobacter (1). Besides one patient with group B Streptococcus bacteremia at 1.5 months of age, all bacteremias after one month of age were with E. coli. Bacteremia was limited to those < 6 months old and inversely related to age (R = 0.24, P = 0.0008). Grouped by age, the incidence of bacteremia was 21% for 0 < or = 1 month, 13% for 1.1-2.0 months, 4% for 2.1-3.0 months, and 8% for 3.1-6.0 months. Mean white blood cell count, initial temperature, initial serum bicarbonate, and erythrocyte sedimentation rate were not statistically significant between bacteremic (B) and nonbacteremic (NB) patients. Statistically significant differences were noted for percentage of bands (6.2% [NB] vs. 12.3% [B] P < 0.001), total band count (1048 [NB] vs. 2252 [B] P < 0.001), and band-neutrophil ratio (0.16 [NB] vs. 0.36 [B] P = 0.01); however, no practical value for any of these measures would reliably discriminate between bacteremic and nonbacteremic patients. Four patients, all neonates, had meningitis; too few patients with meningitis were identified for analysis. In summary, bacteremia with UTIs was observed to be inversely related to age and limited to patients less than six months of age. No objective parameters were identified to distinguish patients with bacteremia at the time of presentation.

Effect of antibiotic therapy on the outcome of outpatients with unsuspected bacteremia

The records of 559 consecutive outpatient children with unsuspected bacteremia (467 Streptococcus pneumoniae) were reviewed. When compared with patients receiving oral or parenteral antibiotics, those patients who received no antibiotics at the initial visit were in follow-up: (1) less likely to be improved (32% vs. 86%, P < 0.01); (2) more likely to be febrile (75% vs. 28%, P < 0.01); (3) more likely to be hospitalized (67% vs. 22%, P < 0.01); (4) more likely to have persistent bacteremia (28% vs. 3%, P < 0.01); and (5) more likely to have new focal infections (13% vs. 5%, P < 0.01). Compared with patients receiving parenteral antibiotics at the initial visit, patients receiving oral antibiotics were in follow-up: (1) less likely to be improved (81% vs. 89%, P < 0.05); and (2) more likely to have persistent bacteremia (5% vs. 0%, P < 0.05). There was no statistical difference between patients receiving parenteral or oral therapy in the development of focal infections, although children with new focal infections receiving oral antibiotics more often had persistent or new positive cultures. No patients receiving parenteral antibiotics at the initial visit had positive blood or spinal fluid cultures at the follow-up visit. Analyses of the subgroups with (1) occult bacteremia with all organisms, (2) unsuspected bacteremia S. pneumoniae and (3) occult bacteremia with S. pneumoniae show results similar to those for the entire group.(ABSTRACT TRUNCATED AT 250 WORDS)