C-reactive protein velocity to distinguish febrile bacterial infections from non-bacterial febrile illnesses in the emergency department

Improved diagnostic markers for invasive pulmonary aspergillosis in COPD patients

Background

The prevalence of invasive pulmonary aspergillosis (IPA) among patients with chronic obstructive pulmonary disease (COPD) is steadily increasing, leading to high mortality. Although early diagnosis can significantly reduce mortality, the efficacy of current diagnostic methods is limited. Consequently, there is a need for novel approaches for early IPA detection.

Methods

This retrospective study involved 383 hospitalized COPD patients with GOLD stages III and IV. The IPA group (67 patients) and non-IPA group (316 patients) were identified at the First Affiliated Hospital of Guangzhou Medical University between January 2016 and February 2022. We analyzed common serological indicators in our hospital to identify predictive indicators for the early diagnosis of IPA in COPD patients.

Results

The sensitivity and specificity of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), lactate dehydrogenase (LDH), and ceruloplasmin (CER) for diagnosing IPA in COPD patients were as follows: CRP (91.2%, 57.7%), ESR (77.5%, 73.0%), PCT (60.5%, 71.4%), LDH (50.0%, 88.8%), and CER (60.7%, 74.3%). Combinations of biomarkers, such as CRP-ESR, CRP-LDH, ESR-LDH, ESR-CER, and LDH-CER, showed promising diagnostic potential, with larger area under the curve (AUC) values for IPA diagnosis in COPD patients. However, no statistically significant difference was observed between the diagnostic efficacy of single biomarkers and combined biomarkers. Notably, compared to those in the unassisted ventilation group, the patients in the assisted ventilation group (including noninvasive ventilation and tracheal intubation/incision-assisted ventilation group) exhibited significantly greater PCT and LDH levels, while the CER significantly decreased (p=0.021). There were no significant differences in biomarker levels between the ICU group and the non-ICU group. CRP (p<0.01), ESR (p=0.028), PCT (p<0.01), and CER (p<0.01) were positively correlated with hospitalization duration, whereas LDH was not correlated with hospitalization duration.

Conclusion

Our study highlights the diagnostic potential of CRP, ESR, PCT, LDH, and CER for IPA in COPD patients. CRP and LDH can also initially predict the need for assisted ventilation, while CRP can initially estimate the length of hospitalization. This study represents the first report of the potential of CER for diagnosing IPA, suggesting its significance for further research.

Estimated C-reactive protein (CRP) velocity for rapidly distinguishing bacterial from other etiologies in children presenting to emergency department with remarkably elevated CRP levels

The use of a single C-reactive protein (CRP) value to differentiate between bacterial and non-bacterial causes is limited. Estimated CRP velocity (eCRPv) has shown promise in enhancing such discrimination in adults. This study aims to investigate the association between eCRPv and bacterial etiologies among pediatric patients with very elevated CRP levels. We conducted a retrospective analysis of patients under 18 years of age who had been admitted to our Pediatric Emergency Department from 2018 to 2020 with a fever and CRP levels ≥ 150 mg/L. Bacterial and non-bacterial etiologies were determined from hospital discharge diagnoses, which were monitored independently by three physicians from the research team. The records of 495 suitable patients (51.2% males, median age 3.2 years) were retrieved of whom 444 (89.7%) were eventually diagnosed with bacterial infections. The mean CRP levels were significantly higher for bacterial etiologies compared with other causes (209.2 ± 59.8 mg/L vs. 185.6 ± 35.8 mg/L, respectively, p < .001), while the mean eCRPv values did not differ significantly (p = .15). In a time course analysis, we found that specifically in patients presenting ≥ 72 h after symptom onset, only a eCRPv1 level > 1.08 mg/L/h was an independent predictor of bacterial infection (aOR = 5.5 [95% CI 1.7-17.8], p = .004).   Conclusion: Pediatric patients with very high CRP levels and fever mostly have bacterial infections. eCRPv levels, unlike CRP values alone, can serve as the sole independent predictor of bacterial infection > 72 h from symptom onset, warranting further prospective investigations into CRP kinetics in pediatric patients. What is Known: • The use of a single C-reactive protein (CRP) value to differentiate between bacterial and non-bacterial causes is limited. • Estimated CRP velocity (eCRPv) has shown promise in enhancing such discrimination in adults, but data on CRP kinetics in pediatric patients is sparse. What is New: • eCRPv levels, unlike CRP values alone, can serve as the sole independent predictor of bacterial infection > 72 h from symptom onset in pediatric patients with remarkably elevated CRP levels.

Protocol for the diagnostic performance of C reactive protein, procalcitonin and interleukin-6 for serious bacterial infections among children ≤36 months old presenting with fever without source: a systematic review and meta-analysis

INTRODUCTION

The management of fever without source in children ≤36 months old remains a diagnostic challenge as the underlying aetiologies can vary from self-limiting viral infections to serious bacterial infections (SBIs). Biomarkers such as C reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6) have varying thresholds in the prediction of SBIs due to differences in SBI definitions, SBI prevalence, patient characteristics and timing of presentation. This protocol describes a systematic review and meta-analysis that aims to determine the thresholds at which CRP, PCT and IL-6 can perform optimally in distinguishing the presence of SBIs in children ≤36 months old, as well as to determine their performances in early detection of bacterial infections within 48 hours of fever onset.

METHODS AND ANALYSIS

We will systematically search electronic databases including MEDLINE, Cochrane Central Register of Controlled Trials, Cochrane CENTRAL, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature) and Science Citation Index from 1 July 2023 to 31 July 2023. We will include studies that report the diagnostic accuracy of CRP, PCT and IL-6 in detecting SBIs in children aged ≤36 months presenting with fever without apparent source. Randomised controlled trials (RCTs) and non-randomised studies including non-RCTs and controlled before-and-after studies will be included. A meta-analysis will be performed and diagnostic performances of these biomarkers will be reported.

ETHICS AND DISSEMINATION

The results of this study will provide guidance on clinical decision-making in young children presenting with fever without source. Ethics approval will not be required for this study. The authors aim to publish the findings in a peer-reviewed journal as well as present at international conferences.

PROSPERO REGISTRATION NUMBER

CRD42023439093.

Association of mTOR Pathway and Conformational Alterations in C-Reactive Protein in Neurodegenerative Diseases and Infections

Inflammatory biomarkers have been very useful in detecting and monitoring inflammatory processes along with providing helpful information to select appropriate therapeutic strategies. C-reactive protein (CRP) is a nonspecific, but quite useful medical acute inflammatory biomarker and is associated with persistent chronic inflammatory processes. Several studies suggest that different levels of CRP are correlated with neurological disorders such as Alzheimer's disease (AD). However, dynamics of CRP levels have also been observed in virus/bacterial-related infections leading to inflammatory responses and this triggers mTOR-mediated pathways for neurodegeneration diseases. The biophysical structural transition from CRP to monomeric CRP (mCRP) and the significance of the ratio of CRP levels on the onset of symptoms associated with inflammatory response have been discussed. In addition, mTOR inhibitors act as immunomodulators by downregulating the expression of viral infection and can be explored as a potential therapy for neurological diseases.

Early signaling of bacteremia in patients who present to the Department of Emergency Medicine with relatively low C-Reactive Protein (CRP) concentrations

OBJECTIVES

Examiningthe usefulness of C-reactive protein velocity (CRPv) as an early biomarker for the presence of bacteraemia in patients presenting to the Department of Emergency Medicine with acute infection/inflammation and suspected bacteraemia.

METHODS

A retrospective study examining a cohort of patients who presented to the E.R and in whom blood cultures were taken. CRPv was calculated as the difference in mg/hour/litter between two consecutive CRP tests performed within 12 hours.

RESULTS

256 patients were included in the cohort. Using CRPv in patients who at first presented with a relatively low (17.9≤mg/L 1^stquartile) CRP concentration, we found an AUC of 0.808±0.038 (p<0.001) for the presence of positive versus negative blood cultures (what is AUC?). This was better than the AUC that was obtained when the WBC for the same purpose.

CONCLUSIONS

CRPv may be a useful biomarker in the identification of patients with suspected bacteremiaand a low CRP-a challenging situation for clinicians who may underestimate the severity of illness in this patient group.

Differentiating between bacterial and viral infections by estimated CRP velocity

PURPOSE

Differentiating between acute viral and bacterial infection is challenging due to the similarity in symptom presentation. Blood tests can assist in the diagnosis, but they reflect the immediate status and fail to consider the dynamics of an inflammatory response with time since symptom onset. We applied estimated C-reactive protein (CRP) velocity (eCRPv), as derived from the admission CRP level divided by time from symptom onset, in order to better distinguish between viral and bacterial infections.

METHODS

This cross-sectional study included patients admitted to the emergency department with a confirmed viral (n = 83) or bacterial (n = 181) infection. eCRPv was defined as the ratio between the absolute CRP level upon admission to time from symptom onset (in hours). Absolute CRP and eCRPv values were compared between the 3 groups.

RESULTS

Bacterial patients presented with higher CRP levels (133 mg/L) upon admission compared to viral patients (23.31 mg/L) (P < 0.001). Their median value of eCRPv velocity was 4 times higher compared to the viral patients (1.1 mg/L/h compared 0.25 mg/L/h, P < 0.001). Moreover, in intermediate values of CRP (100-150 mg/L) upon admission, in which the differential diagnosis is controversial, high eCRPv is indicative of bacterial infection, eCRPv >4 mg/L/h represents only bacterial patients.

CONCLUSIONS

During an acute febrile illness, the eCRPv value can be used for rapid differentiation between bacterial and viral infection, especially in patients with high CRP values. This capability can potentially expedite the provision of appropriate therapeutic management. Further research and validation may open new applications of the kinetics of inflammation for rapid diagnosis of an infectious vs. a viral source of fever.

C-Reactive Protein Velocity (CRPv) as a New Biomarker for the Early Detection of Acute Infection/Inflammation

C-reactive protein (CRP) is considered a biomarker of infection/inflammation. It is a commonly used tool for early detection of infection in the emergency room or as a point-of-care test and especially for differentiating between bacterial and viral infections, affecting decisions of admission and initiation of antibiotic treatments. As C-reactive protein is part of a dynamic and continuous inflammatory process, a single CRP measurement, especially at low concentrations, may erroneously lead to a wrong classification of an infection as viral over bacterial and delay appropriate antibiotic treatment. In the present review, we introduce the concept of C-reactive protein dynamics, measuring the velocity of C-reactive protein elevation, as a tool to increase this biomarker’s diagnostic ability. We review the studies that helped define new metrics such as estimated C-reactive protein velocity (velocity of C-reactive protein elevation from symptoms’ onset to first C-reactive protein measurement) and the measured C-reactive protein velocity (velocity between sequential C-reactive protein measurements) and the use of these metrics in different clinical scenarios. We also discuss future research directions for this novel metric.

Association between C-Reactive Protein Velocity and Left Ventricular Function in Patients with ST-Elevated Myocardial Infarction

C-reactive protein velocity (CRPv), defined as the change in wide-range CRP concentration divided by time, is an inflammatory biomarker associated with increased morbidity and mortality in patients with ST elevation myocardial infarction (STEMI) treated with primary percutaneous intervention (PCI). However, data regarding CRPv association with echocardiographic parameters assessing left ventricular systolic and diastolic function is lacking. Echocardiographic parameters and CRPv values were analyzed using a cohort of 1059 patients admitted with STEMI and treated with primary PCI. Patients were stratified into tertiles according to their CRPv. A receiver operating characteristic (ROC) curve was used to evaluate CRPv optimal cut-off values for the prediction of severe systolic and diastolic dysfunction. Patients with high CRPv tertiles had lower left ventricular ejection fraction (LVEF) (49% vs. 46% vs. 41%, respectively; p < 0.001). CRPv was found to independently predict LVEF ≤ 35% (HR 1.3 CI 95% 1.21–1.4; p < 0.001) and grade III diastolic dysfunction (HR 1.16 CI 95% 11.02–1.31; p = 0.02). CRPv exhibited a better diagnostic profile for severe systolic dysfunction as compared to CRP (area under the curve 0.734 ± 0.02 vs. 0.608 ± 0.02). In conclusion, For STEMI patients treated with primary PCI, CRPv is a marker of both systolic and diastolic dysfunction. Further larger studies are needed to support this finding.

C-reactive protein velocity discriminates between acute viral and bacterial infections in patients who present with relatively low CRP concentrations

Background

To assess the utility of C-reactive protein (CRP) velocity to discriminate between patients with acute viral and bacterial infections who presented with relatively low CRP concentrations and were suspected of having a bacterial infection.

Methods

We analyzed a retrospective cohort of patients with acute infections who presented to the emergency department (ED) with a relatively low first CRP measurement (CRP1) ≤ 31.9 mg/L and received antibiotics shortly after. We then calculated C-reactive protein velocity (CRPv), milligram per liter per hour, for each patient based on CRP1 and the second CRP value (CRP2) measured within the first 24 h since admission. Finally, we compared CRPv between patients with bacterial and viral infections.

Results

We have presently analyzed 74 patients with acute bacterial infections and 62 patients with acute viral infections at the mean age of 80 and 66 years respectively, 68 male and 68 female. CRP1 did not differ between both groups of patients (16.2 ± 8.6 and 14.8 ± 8.5 for patients with viral and bacterial infections respectively, p value = 0.336). However, the CRP2 was significantly different between the groups (30.2 ± 21.9 and 75.6 ± 51.3 for patients with viral and bacterial infections respectively, p-value < 0.001) and especially the CRPv was much higher in patients with acute bacterial infections compared to patients with acute viral infections (0.9 ± 1.2 and 4.4 ± 2.7 respectively, p-value < 0.001).

Conclusion

CRPv and CRP2 are useful biomarkers that can discriminate significantly between patients who present with acute bacterial and viral infections, and relatively low CRP concentration upon admission who were suspected of having a bacterial infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06878-y.

Patients who are admitted to the Department of Internal Medicine with a very low C-reactive protein concentration

Introduction

C-reactive protein (CRP) is a marker commonly used in clinical practice as a reference for the inflammatory activity in vivo. Low levels are often associated with good health and lower risk for adverse outcomes.

Patients and methods

We examined medical records of the last 6 years, of all patients admitted for hospitalization in internal medicine wards who had the first CRP measurement below ≤ 0.03 mg/L (detection limit). Diagnosis criteria and 7 days’ survival were reviewed.

Results

Out of 61,590 total admissions to internal medicine wards, three hundred and thirteen patients had CRP equal to or lower than 0.03 mg/L (0.5%). Second CRP measurement revealed gradual increment up to 10.8 ± 35.4 mg/L. Four patients died within 7 days from admission.

Discussion

Presentation to the internal medicine department with a very low concentration of CRP is highly unusual, but it does not exclude the existence of significant acute morbidities. Clinicians should take additional CRP tests before any conclusion is considered regarding the presence or absence of an inflammatory response.

The superiority of 72 h leukocyte descent over CRP for mortality prediction in patients with sepsis

BACKGROUND

Detection of an eventful course in the early days of sepsis treatment is clinically relevant. The white blood cell count (WBCC) and C-reactive protein (CRP) are used in daily practice to monitor the intensity of the inflammatory response associated with sepsis. It is not entirely clear which of the two might better discriminate the outcomes of patients with sepsis.

METHODS

30-day mortality was assessed in a cohort of patients who were hospitalized with sepsis in the departments of Internal Medicine in a tertiary medical center. Admission and 72-hour time points were analyzed to discriminate between patients with increased versus decreased 30 days mortality risk.

RESULTS

The study included 195 patients. Higher 72 h CRP, WBCC, neutrophil counts and neutrophils to lymphocyte ratio were associated with increased mortality (p < 0.02). Baseline WBCC and CRP failed to discriminate between patients who died and those who survived (AUC = 0.551, 0.479). In multivariate analysis of the 72 h tests, higher WBCC count (OR = 1.12, 95%CI 1.05-1.20, p = 0.001), was associated with increased mortality whereas CRP was not (OR = 1.004, 95%CI 0.998-1.01, p = 0.146).

CONCLUSION

Patients who presented a 72-hour leukocyte descent had a better outcome and in this regard, WBCC was superior to 72-hour CRP in predicting 30 days mortality.

A second C-reactive protein (CRP) test to detect inflammatory burst in patients with acute bacterial infections presenting with a first relatively low CRP

A first C-reactive protein (CRP) test, as often performed by clinicians during the presentation of patients with an acute bacterial infection, might be misleading. The aim of our study was to explore the dynamic between a second CRP test taken within 12 hours from admission CRP test in a cohort of patients diagnosed with acute bacterial infection in comparison to CRP in a control group of apparently healthy individuals.This was a historical cohort study comprised of all patients admitted to the Sourasky Tel-Aviv Medical Center, Israel, between July 2007 and March 2016. The study cohort included adult patients who were diagnosed as having an infection, assumed to be of bacterial etiology (cellulitis and erysipelas, pneumonia, cholecystitis, pyelonephritis, or septicemia), who had a CRP test during the first 6 hours of hospital admission (baseline CRP), and a successive CRP test up to 12 hours from the first one (recurrent CRP). The control group was of healthy subjects who attended our medical center for a routine annual check-up.The study included 950 patients. Baseline CRP ranged from 0.04 to 454 mg/L. The median CRP velocity was 0.53 mg/L/h. Patients were grouped by baseline CRP into 4 groups (CRP < 10, 10-74.9, 75-199.9, ≥200). There was an increase in median CRP velocity between the first (0.48 mg/L/h) and the second (0.93 mg/L/h) groups, which then was decreased in the next 2 groups (0.46 and -2.58 mg/L/h, respectively). In 45 of 103 (44%) patients of the group of baseline CRP concentration less than 10 mg/dL with bacterial diagnosis, there was a complete overlap with CRP values of apparently healthy individuals during their routine annual checkup.A first single low CRP result cannot exclude the presence of a significant bacterial infection. Patients with acute bacterial infection might present with a relatively low CRP value that at times correspond to normal limit CRP concentrations. A second test, obtained within 12 hours of admission, might serve as an important tool to identify patient with an evolving inflammatory burst commonly seen during acute bacterial infection.

The potential benefit of a second C-reactive protein measurement in patients with gram-negative bacteraemia presenting to the emergency medicine department

BACKGROUND

Low C-reactive protein in acute bacterial infections could convey the erroneous impression of a mild infection. We focussed on gram-negative bacteraemia, a phenomenon frequently seen at the emergency room.

METHODS

Of 2200 patients with gram-negative bacteraemia, 460 patients with first C-reactive protein <30 mg/L and 460 patients with C-reactive protein >187 mg/L were reviewed. Following exclusions, we finally investigated 229 and 289 patients with low and high C-reactive protein concentrations, respectively.

RESULTS

The cohort was divided into low and high C-reactive protein groups. Median first C-reactive protein was 13.6 and 219.9 mg/L, respectively (interquartile range 6.4-21.6 and 195-270.1). Compared to patients with first high C-reactive protein, patients with first low C-reactive protein concentrations had a significant five-fold higher C-reactive protein level with their second test.

CONCLUSIONS

Patients with gram-negative bacteraemia can present with C-reactive protein within the range of apparently healthy individuals. A second C-reactive protein might help to avoid an erroneous decision regarding the severity of the infection.

Using the kinetics of C-reactive protein response to improve the differential diagnosis between acute bacterial and viral infections

PURPOSE

Differential diagnosis between acute viral and bacterial infection is an emerging common challenge for a physician in the emergency department. Serum C-reactive protein (CRP) is used to support diagnosis of bacterial infection, but in patients admitted with low CRP, its ability to discriminate between viral and bacterial infections is limited. We aimed to use two consecutive CRP measurements in order to improve differential diagnosis between bacterial and viral infection.

METHODS

A single-center retrospective cohort (n = 1629) study of adult patients admitted to the emergency department with a subsequent microbiological confirmation of either viral or bacterial infection. Trend of CRP was defined as the absolute difference between the first two measurements of CRP divided by the time between them, and we investigated the ability of this parameter to differentiate between viral and bacterial infection.

RESULTS

In patients with relatively low initial CRP concentration (< 60 mg/L, n = 634 patients), where the uncertainty regarding the type of infection is the highest, the trend improved diagnosis accuracy (AUC 0.83 compared to 0.57 for the first CRP measurement). Trend values above 3.47 mg/L/h discriminated bacterial from viral infection with 93.8% specificity and 50% sensitivity.

CONCLUSIONS

The proposed approach for using the kinetics of CRP in patients whose first CRP measurement is low can assist in differential diagnosis between acute bacterial and viral infection.

Septic patients presenting with apparently normal C-reactive protein: A point of caution for the ER physician

The presentation of septic patients with low C-reactive protein (CRP) concentrations to the emergency room (ER) might convey an erroneous impression regarding the severity of the disease.We analyzed a retrospective study of septic patients admitted to the internal medicine departments of a relatively large tertiary medical center, following admission to the ER. These patients had CRP concentrations of <31.9 mg/L, the determined cut-off for CRP concentrations in a large cohort of apparently healthy individuals in the community (n = 17,214, upper limit of mean + 3 standard deviations).By processing the electronic medical records, we found 2724 patients with a diagnosis of sepsis, 476 of whom had an admission CRP concentration of <31.9 mg/L. Following further analysis of these records, we found that 34 of the 175 patients (19.4%) who fulfilled the definition of sepsis, died within 1 week of hospitalization. Of special interest was the finding that within <24 h, a significant increment from a median CRP of 16.1 mg/L (IQR 7.9-22.5) to 58.6 mg/L (IQR 24.2-134.4), (P < .001) was noted, accompanied by a velocity change from 0.4 ± 0.29 to 8.3 ± 24.2 mg/L/h following antibiotic administration (P < .001).ER physicians should take into consideration that septic patients with a high in-hospital mortality rate can present with CRP concentrations that are within the range observed in apparently healthy individuals in the community. A second CRP test obtained within 24 h following antibiotic administration might influence attitudes regarding the severity of the disease.

Pentraxin 3: an immune modulator of infection and useful marker for disease severity assessment in sepsis

The acute phase protein pentraxin 3 (PTX3) is a pattern recognition receptor involved in regulation of the host immune response. This relatively newly discovered member of the pentraxin superfamily elicits both immunostimulatory and immunoregulatory functions preventing autoimmune pathology and orchestrated clearance of pathogens through opsonization of damage- and pathogen-associated molecular patterns (DAMP/PAMP). Thus, PTX3 has been described as a possible evolutionary precursor to immunoglobulins. While shown to provide protection against specific bacterial and fungal pathogens, persistent elevation of PTX3 levels following initial onset of infection appear to predict poor patient outcome and may contribute to disease sequelae such as tissue damage and coagulopathy. Measurement of PTX3 following onset of sepsis may improve patient risk assessment and thus be useful in guiding subsequent therapeutic interventions including steroidal anti-inflammatory and altered antibiotic therapies. In this review, we summarize the role of PTX3 in inflammatory syndromes and its utility as a marker of sepsis disease severity.

Use of time from fever onset improves the diagnostic accuracy of C-reactive protein in identifying bacterial infections

OBJECTIVE

To determine whether the input of time from fever onset will change the accuracy of C-reactive protein (CRP) in diagnosing bacterial infections in febrile children.

STUDY DESIGN

We performed a prospective observational study on febrile children presenting to the emergency department. The diagnostic performance of CRP at different time points from fever onset was compared using a receiver operating characteristic (ROC) curve.

RESULTS

Among 373 patients included, 103 (28%) had bacterial infection. The optimal cut-off for CRP suggesting bacterial infection changed with time from fever onset: 6 mg/dL for >12-24 h of fever; 10.7 and 12.6 mg/dL at >24-48 and >48 h of fever, respectively. The input of time from fever onset improved the area under the ROC curve from 0.83 (95% CI 0.78 to 0.88) for CRP overall to 0.87 (95% CI 0.77 to 0.96) and 0.90 (95% CI 0.84 to 0.97) at >24-48 and >48 h of fever, respectively. Duration of fever mostly affected the ability of CRP to correctly rule out bacterial infections. CRP level of 2 mg/dL obtained at ≤24 h of fever corresponds with a post-test probability for bacterial infection of 10%, whereas the same value obtained >24 h of fever reduces the risk to 2%.

CONCLUSIONS

Clinicians should apply different CRP cut-off values depending on whether they are trying to rule in or rule out bacterial infection, but also depending on fever duration at the time of CRP testing.

Laboratory features of common causes of fever in returned travelers

BACKGROUND

There can be considerable overlap in the clinical presentation and laboratory features of dengue, malaria, and enteric fever, three important causes of fever in returned travelers. Routine laboratory tests including full blood examination (FBE), liver function tests (LFTs), and C-reactive protein (CRP) are frequently ordered on febrile patients, and may help differentiate between these possible diagnoses.

METHODS

Adult travelers returning to Australia who presented to the Royal Melbourne Hospital with confirmed diagnosis of dengue, malaria, or enteric fever between January 1, 2000 and March 1, 2013 were included in this retrospective study. Laboratory results for routine initial investigations performed within the first 2 days were extracted and analyzed.

RESULTS

There were 304 presentations including 58 with dengue fever, 187 with malaria, and 59 with enteric fever, comprising 56% of all returned travelers with a febrile systemic illness during the study period. Significant findings included 9-fold and 21-fold odds of a normal CRP in dengue compared with malaria and enteric fever, respectively. The odds of an abnormally low white cell count (WCC) were also significantly greater in dengue versus malaria or enteric fever. Approximately one third of dengue presentations and almost half of the malaria presentations had platelet counts <100 × 10(9) /L. A normal CRP with leukopenia and/or thrombocytopenia occurred in 21% to 30% of dengue presentations, but not in malaria or enteric fever presentations.

CONCLUSIONS

There is a wide differential diagnosis for imported fever, but the non-specific findings of a normal CRP with a low WCC and/or low platelet count may provide useful information in addition to clinical clues to suggest dengue over malaria or enteric fever. Further systematic prospective studies among travelers could help define the potential clinical utility of these results in assisting the clinician when deciding for or against commencement of empiric antimicrobial therapy while awaiting confirmatory tests.

Predicting bloodstream infection via systemic inflammatory response syndrome or biochemistry

BACKGROUND

The yield of blood cultures is approximately 10%. This could be caused by inaccurate prediction of patients with bloodstream infection (BSI).

OBJECTIVES

To evaluate the usability of systemic inflammatory response syndrome (SIRS) or biochemical analyses as predictors for positive blood culture.

METHODS

We conducted a prospective cohort study at a Danish regional hospital from February 1 to April 30, 2010. All adult patients were included on the first time blood cultures were sampled during admission. Data were obtained from medical records, databases on microbiology, biochemistry, and antibiotic treatment. Data included time of admission, date and result of blood culture, results of biochemical analyses, and clinical measurements on the day of blood culture. Prediction of BSI was analyzed according to both individual parameters and parameters combined in different sepsis score groups. Associations were calculated using multiple logistic regression.

RESULTS

Patients with BSI (68 patients) were compared to patients without BSI (828 patients). Respiratory rate, body temperature, and C-reactive protein were strongest associated with BSI, with adjusted odds ratio (OR) 5.42, 95% confidence interval (CI) 1.13-25.9; OR 2.55, 95% CI 1.34-4.87; and OR 6.06, 95% CI 0.82-44.6, respectively. SIRS was associated with BSI, with crude OR 7.25, 95% CI 1.75-30.1. Neutrophil count and p-carbamide were not associated with BSI: adjusted OR 0.88, 95% CI 0.36-2.13 and OR 1.44, 95% CI 0.82-2.52, respectively. Only one of the sepsis score groups was associated with BSI: crude OR 2.13, 95% CI 1.08-4.19.

CONCLUSIONS

SIRS is an adequate predictor of BSI. By contrast, biochemical parameters were not useful as predictors of BSI.

Role of C-reactive protein velocity in the diagnosis of early bacterial infections in children after cardiac surgery

Fever after cardiac surgery in children may be due to bacterial infection or noninfectious origin like systemic inflammatory response syndrome (SIRS) secondary to bypass procedure. A marker to distinguish bacterial from nonbacterial fever in these conditions is clinically important. The purpose of our study was to evaluate, in the early postcardiac surgery period, whether serial measurement of C-reactive protein (CRP) and its change over time (CRP velocity) can assist in detecting bacterial infection. A series of consecutive children who underwent cardiac surgery with bypass were tested for serum levels of CRP at several points up to 5 days postoperatively and during febrile episodes (>38.0°C). Findings were compared among febrile patients with proven bacterial infection (FWI group; sepsis, pneumonia, urinary tract infection, deep wound infection), febrile patients without bacterial infection (FNI group), and patients without fever (NF group). In all, 121 children were enrolled in the study, 31 in the FWI group, 42 in the FNI group, and 48 patients in the NF group. Ages ranged from 4 days to 17.8 years (median 19.0, mean 46 ± 56 months). There was no significant difference among the groups in mean CRP level before surgery, 1 hour, and 18 hours after. A highly significant interaction was found in the change in CRP over time by FWI group compared with FNI group (P < .001). Mean CRP velocity ([fCRP - 18hCRP]/[fever time (days) - 0.75 day]) was significantly higher in the infectious group (4.0 ± 4.2 mg/dL per d) than in the fever-only group (0.60 ± 1.6 mg/dL per d; P < .001). A CRP velocity of 4 mg/dL per d had a positive predictive value (PPV) of 85.7% for bacterial infection with 95.2% specificity. Serial measurements of CRP/CRP velocity after cardiac surgery in children may assist clinicians in differentiating postoperative fever due to bacterial infection from fever due to noninfectious origin.

Year in review 2009: Critical Care--infection

In 2009 Critical Care provided important and clinically relevant research data for management and prevention of infections in critically ill patients. The present review summarises the results of these observational studies and clinical trials and discusses them in the context of the current relevant scientific and clinical background. In particular, we discuss recent epidemiologic data on nosocomial infections in intensive care units, present new approaches to prevention of ventilator-associated pneumonia, describe recent advances in biomarker-guided antibiotic stewardship and attempt to briefly summarise specific challenges related to the management of infections caused by multidrug-resistant microorganisms and influenza A (H1N1).