White blood cells, C-reactive protein and erythrocyte sedimentation rate in pneumococcal pneumonia in children

Can C-reactive protein, procalcitonin and mid-regional pro-atrial natriuretic peptide measurements guide choice of in-patient or out-patient care in acute pyelonephritis? Biomarkers In Sepsis (BIS) multicentre study

Whereas C-reactive protein (CRP), procalcitonin (PCT) and mid-regional pro-atrial natriuretic peptide (ANP) may be of use at the bedside in the management of adult patients with infectious disorders, their usefulness has not been established in the setting of acute pyelonephritis. To assess the effectiveness of CRP, PCT and ANP measurements in guiding emergency physicians' decisions whether to admit to hospital patients with acute pyelonephritis, we conducted a multicentre, prospective, observational study in 12 emergency departments in France; 582 consecutive patients were included. The reference standard for admission was defined by experts' advice combined with necessity of admission or death during the 28-day follow-up. Baseline CRP, PCT and ANP were measured and their accuracy in identifying the necessity of admission was analysed using area under curves (AUC) of receiver-operating characteristic (ROC) plots. According to the reference standard, 126 (22%) patients required admission. ANP (AUC 0.75, 95% CI 0.69-0.80) and PCT (AUC 0.75, 95% CI 0.71-0.80) more accurately predicted this than did CRP (AUC 0.69, 95% CI 0.64-0.74). The positive and negative likelihood ratios for each biomarker remained clinically irrelevant whatever the threshold. Our results did not support the use of these markers to help physicians in deciding about admission of patients experiencing acute pyelonephritis in daily practice.

Inflammatory parameters predict etiologic patterns but do not allow for individual prediction of etiology in patients with CAP: results from the German competence network CAPNETZ

Background

Aim of this study was to evaluate the correlation of inflammatory markers procalcitonin (PCT), C-reactive protein (CRP) and leukocyte count (WBC) with microbiological etiology of CAP.

Methods

We enrolled 1337 patients (62 ± 18 y, 45% f) with proven CAP. Extensive microbiological workup was performed. In all patients PCT, CRP, WBC and CRB-65 score were determined. Patients were classified according to microbial diagnosis and CRB-65 score.

Results

In patients with typical bacterial CAP, levels of PCT, CRP and WBC were significantly higher compared to CAP of atypical or viral etiology. There were no significant differences in PCT, CRP and WBC in patients with atypical or viral etiology of CAP. In contrast to CRP and WBC, PCT markedly increased with severity of CAP as measured by CRB-65 score (p < 0.0001). In ROC analysis for discrimination of patients with CRB-65 scores > 1, AUC for PCT was 0.69 (95% CI 0.66 to 0.71), which was higher compared to CRP and WBC (p < 0.0001). CRB-65, PCT, CRP and WBC were higher (p < 0.0001) in hospitalised patients in comparison to outpatients.

Conclusion

PCT, CRP and WBC are highest in typical bacterial etiology in CAP but do not allow individual prediction of etiology. In contrast to CRP and WBC, PCT is useful in severity assessment of CAP.

Efficacy of serum procalcitonin in evaluating severity of community-acquired pneumonia in childhood

Microbe-specific diagnosis of community-acquired pneumonia (CAP) in childhood is difficult in clinical practice. Chest radiographs and non-specific inflammatory markers have been used to separate presumably bacterial from viral infection but the results have been inconsistent. The aim of the present study was to evaluate the usefulness of procalcitonin (PCT) in assessing the severity as well as the bacterial or viral aetiology of CAP. Serum PCT was measured by an immunoluminometric assay in 100 patients with CAP; 26 were treated as inpatients and 74 as outpatients. The pulmonary infiltrate was considered to be alveolar in 62 and interstitial in 38 cases, according to the radiological diagnosis. The bacterial and viral aetiology of pneumonia was studied by an extensive serological test panel. No differences were found in PCT concentrations between the 4 aetiological (pneumococcal, atypical bacterial, viral, unknown) and the 3 age (< 2, 2-4 and > or = 5 y) groups. Serum PCT was >0.5 ng/ml in 69%, >1.0 ng/ml in 54% and >2.0 ng/ml in 47% of all patients. PCT was higher in patients that were admitted than as outpatients (medians 17.81 vs 0.72 ng/ml, respectively, p<0.01) and higher in alveolar than in interstitial pneumonia (medians 9.43 vs 0.53 ng/ml, respectively, p<0.01). In conclusion, serum PCT values were found to be related to the severity of CAP in children even though they were not capable, at any level of serum concentration, to differentiate between bacterial and viral aetiology.

Serum and pleural fluid procalcitonin in predicting bacterial infection in patients with parapneumonic effusion

This study evaluated the value of procalcitonin (PCT) levels in pleural effusion to differentiate the etiology of parapneumonic effusion (PPE). Forty-one consecutive PPE patients were enrolled and were divided into bacterial and non-bacterial PPE. Blood and pleural effusion samples were collected for PCT measurement on admission and analyzed for diagnostic evaluation. PCT of pleural fluid was significantly increased in the bacterial PPE group (0.24 ng/mL) compared to the non-bacterial PPE group (0.09 ng/mL), but there was no significant difference for serum PCT. A PCT concentration of pleural fluid >0.174 ng/mL (best cut-off value) was considered positive for a diagnosis of bacterial PPE (sensitivity, 80%; specificity, 76%; AUC, 0.84). Pleural effusion PCT in the bacterial PPE is significantly different from those of the non-bacterial PPE and control groups, so the diagnostic use of PCT still warrants further investigation.

Persistent systemic inflammation and atypical enterocolitis in patients with NEMO syndrome

The NEMO syndrome is a primary immunodeficiency with immune and non-immune manifestations. The immune deficiency is heterogeneous showing defects in humoral, innate, and cell-mediated immunity. While the clinical aspects of the immunodeficiency are increasingly well understood, little is known about autoimmune manifestations in NEMO patients. We therefore sought to examine serologic markers of systemic inflammation and intestinal pathology in a kindred of patients with the NEMO syndrome. We observed persistent elevation of erythrocyte sedimentation rates in five patients, and two were symptomatic, with a chronic but atypical enterocolitis. Though pathologic lesions in these two patients were consistent with acute inflammation, sustained clinical improvement was only achieved with systemic and/or topical glucocorticoid therapy. Our data suggest that some patients with the NEMO syndrome exhibit persistent elevation of inflammatory markers similar to systemic autoimmune diseases and may subsequently develop an atypical enterocolitis.

Differentiation of bacterial and viral community-acquired pneumonia in children

BACKGROUND

Microbe-specific diagnosis of pediatric community-acquired pneumonia (CAP) and the distinction between typical-bacterial, atypical-bacterial and viral cases are difficult. The aim of the present study was to evaluate the role of four serum non-specific inflammatory markers and their combinations, supplemented by chest radiological findings, in the screening of bacterial etiology of pediatric CAP.

METHODS

Serum procalcitonin (PCT), serum C-reactive protein (CRP), blood erythrocyte sedimentation rate (ESR) and white blood cell (WBC) counts were determined in 101 children with CAP, all confirmed on chest radiograph. Evidence of etiology was achieved in 68 patients (67%) mainly using a serologic test panel including 15 pathogens.

RESULTS

For the combination of CRP > 100 mg/L, WBC count > 15 x 10(9)/L, PCT > 1.0 ng/mL and ESR > 65 mm/h, the likelihood ratio for a positive test result (LR+) was 2.7 in the distinction between pneumococcal and viral CAP and 3.9 between atypical and viral CAP. If there was a higher value in one of these four parameters (CRP > 200 mg/L, WBC count > 22 x 10(9)/L, PCT > 18 ng/mL or ESR > 90 mm/h) LR+ changed to >or=3.4, which means a significant increase from pre-test to post-test disease probability. An alveolar radiological infiltration was associated with higher values in non-specific inflammatory markers when compared with interstitial infiltrates, but there were no significant associations between radiological and etiological findings.

CONCLUSIONS

CRP, WBC count, PCT and ESR or their combinations have a limited role in screening between bacterial and viral pediatric CAP. If all or most of these markers are elevated, bacterial etiology is highly probable, but low values do not rule out bacterial etiology.

Validity of the quick-read C-reactive protein test in the prediction of bacterial pneumonia in the pediatric emergency department

BACKGROUND

C-reactive protein (CRP) values are clinically useful in differentiating viral from bacterial illnesses in children, but the regular test is impractical in the emergency department (ED) setting.

OBJECTIVE

To investigate the validity and feasibility of the 2-min bedside Quick Read (QR)-CRP test in the prediction of bacterial pneumonia in children in the ED.

METHODS

Fifty randomly selected children aged 4 days to 17 years, who presented to a pediatric ED with symptoms and signs of pneumonia over a 6-month period, were prospectively studied. The diagnosis of bacterial/viral pneumonia was based on clinical and radiological findings. CRP was measured in leftover blood (0.2 ml) using the QR-CRP kit. Clinical and laboratory data were statistically analyzed against CRP values for ability to predict bacterial pneumonia.

RESULTS

Thirty-six patients (72%) were diagnosed with bacterial pneumonia and 14 (28%) with viral pneumonia; mean CRP levels were 121.3+/-122 and 27.2+/-26 mg/l, respectively (P=0.007). Significantly higher CRP levels were associated with bacterial than with viral pneumonia in the patients who presented before 96 h of symptom onset (P=0.013-0.028), but not in those who presented later. On receiver operating characteristics analysis, CRP was a better indicator of a chest radiograph picture of bacterial pneumonia (area under the curve=0.79) than absolute neutrophil count (0.78) or white blood cell count (0.73). Combining all three parameters yielded an area of 0.865.

CONCLUSION

The QR-CRP test seems to be an useful predictor of bacterial pneumonia in children, especially those with a shorter illness duration, and is feasible for use in the ED.

Management of community-acquired pneumonia in children

Community-acquired pneumonia (CAP) is a significant cause of childhood morbidity and mortality worldwide. Viral etiology is most common in young children and decreases with age. Streptococcus pneumoniae is the single most common bacterial cause across all age groups. Atypical organisms present similarly across all age groups and may be more common than previously recognized.A bacterial pneumonia should be considered in children presenting with fever >38.5 degrees C, tachypnea, and chest recession. Oxygen therapy is life saving and should be given when oxygen saturation is <92%. For non-severe pneumonia, oral amoxicillin is the antibacterial of choice with low failure rates reported. Severely ill children are traditionally treated with parenteral antibacterials. Penicillin non-susceptible S. pneumoniae prevalence rates are increasing and have been linked to community antibacterial prescribing. Most pneumococci remain sensitive to high-dose penicillin-based antibacterials but macrolide resistance is also a problem in some communities. However, primary combination treatment with macrolides is indicated in areas where there is a high prevalence of atypical organisms. The most common complications in CAP are parapneumonic effusions and empyema. The use of ultrasonography combined with intercostal drainage augmented with the use of fibrinolytic therapy has significantly reduced the morbidity associated with these complications. There is increasing evidence that a preventative strategy with the 7-valent pneumococcal conjugate vaccine (PCV-7) results in a significant fall in CAP in early childhood.

The utility of serum C-reactive protein in differentiating bacterial from nonbacterial pneumonia in children: a meta-analysis of 1230 children

BACKGROUND

Differentiating bacterial from nonbacterial community-acquired pneumonia in children is difficult. Although several studies have evaluated serum concentrations of C-reactive protein (CRP) as a predictor of bacterial pneumonia in this patient population, the utility of this test remains unclear.

OBJECTIVE

The purpose of this meta-analysis was to quantitatively define the utility of serum CRP as a predictor of bacterial pneumonia in acutely ill children.

METHODS

Multiple databases were searched, bibliographies reviewed, and 2 authorities in the field were queried. Studies were included if: (1) the patient population was between 1 month and 18 years of age; (2) CRP was quantified in all subjects as part of the initial evaluation of a suspected, infectious, pulmonary process; (3) a cutoff serum CRP concentration between 30 and 60 mg/dL was used to distinguish nonbacterial from bacterial pneumonia; (4) some criteria were applied to differentiate bacterial from nonbacterial or viral pneumonia; (5) all patients were acutely ill; and (6) a chest radiograph was obtained as part of the initial evaluation. The quality of each included study was determined across 4 metrics: diagnostic criteria; study design; exclusion of chronically ill or human immunodeficiency virus infected subjects; and exclusion of patients who recently received antibiotics. Data was extracted from each article; the primary outcome measure was the odds ratio of patients with bacterial or mixed etiology pneumonia and serum CRP concentrations exceeding 30-60 mg/L. Heterogeneity among the studies was determined by Cochran's Q statistic; the methods of both Mantel and Haenszel, and DerSimonian and Laird were used to combine the study results.

RESULTS

Eight studies fulfilled inclusion criteria. Combining all of the studies demonstrated a pooled study population of 1230 patients with the incidence of bacterial infection of 41%. Children with bacterial pneumonia were significantly more likely to have serum CRP concentrations exceeding 35-60 mg/L than children with nonbacterial infections (odds ratio = 2.58, 95% confidence interval = 1.20-5.55). Sensitivity analysis demonstrated that this difference was robust. There was significant heterogeneity among the 8 studies (Q = 37.7, P < 0.001, I2 = 81.4) that remained throughout the sensitivity analysis.

CONCLUSIONS

In children with pneumonia, serum CRP concentrations exceeding 40-60 mg/L weakly predict a bacterial etiology.

Community-acquired pneumonia: a review and recent advances

In the beginning of this 21st century, community-acquired pneumonias (CAP) are still responsible for a significant number of deaths among young children in many developing countries. Public health initiatives such as those proposed by the World Health Organization (WHO) for the management of CAP by means of identifying highly predictable signs and symptoms have had great positive impact in some communities. Still, this approach induces an overdiagnosis and overtreatment of CAP in children below the age of 5 years due to the misclassification of pneumonia in children with fast breathing associated with viral bronchiolitis. Even among children of developed countries, CAP is an important public health problem and many aspects of current diagnostic and management measures are discussed here. In this article, we review the epidemiology and basic concepts of CAP and update current information on clinical evaluation and management of the disease.

Discrepancy between total white blood cell counts and serum C-reactive protein levels in febrile children

Total white blood cell (WBC) counts and serum C-reactive protein (CRP) are used as inflammatory markers in febrile children. We studied the occurrence and clinical significance of discrepancy in these markers. From a 2-y period, we retrospectively reviewed the medical records of febrile children (> or =1 month of age) with WBC > or =15 x 10(9)/l and/or CRP levels > or =80 mg/l, as well as of children with lower values in both these parameters. WBC and CRP were discordant in 556 children and concordantly high in 194 children. A severe bacterial disease was presumed in 57% of children with concordantly high WBC and CRP, in 20% of those with discordant values, and in 5% of those with low levels of these markers (p<0.001). Non-streptococcal tonsillitis was the most common viral infection associated with elevated WBC and CRP. In conclusion, WBC and CRP are commonly discrepant in febrile children. Measuring both markers increases substantially the detection rate of bacterial infections.

Rapid optimization of antimicrobial chemotherapy given to pediatric patients with community-acquired pneumonia using PCR techniques with serology and standard culture

Children (n = 117; mean age 2.4 ± 2.9 years) were diagnosed as having community-acquired pneumonia (CAP) using clinical symptoms, chest X-rays, and hematological data. The causative pathogen was determined using real-time polymerase chain reaction (PCR) (6 bacteria), multiple reverse transcription-PCR (MPCR; 11 viruses), bacterial culture, and serology. The initial chemotherapy was evaluated based on the pathogens identified using PCR. We found 27 viral cases (23.1%), 25 bacterial cases (21.4%), 45 mixed infections with virus and bacteria (38.5%), 10 Mycoplasma pneumoniae (8.5%), 7 mixed infections with M. pneumoniae and another pathogen (6.0%), 1 Chlamydophila pneumoniae (0.9%), and 2 unknown pathogens (1.7%). Streptococcus pneumoniae and Haemophilus influenzae accounted for 58 (49.5%) and 27 (23.0%) of the cases, respectively. The median values (50%) of the white blood cell count (WBC) and C-reactive protein (CRP) using the box-and-whisker and plot method, respectively, were 11.7 × 10³ mm⁻³ and 1.4 mg/dl in viral infections, 15.6 × 10³ mm⁻³ and 4.8 mg/dl in mixed infections with virus and bacteria, 17.8 × 10³ mm⁻³ and 6.3 mg/dl in bacterial infections, 6.7 × 10³ mm⁻³ and 1.4 mg/dl in M. pneumoniae infections, and 21.5 × 10³ mm⁻³ and 6.4 mg/dl in mixed infections with M. pneumoniae and other bacterial infections. Sulbactam/ampicillin (n = 61), carbapenems (n = 12), and ceftriaxone (n = 7) were selected for the patients suspected of having bacterial infections alone or mixed infections with bacterial and viruses in accordance with our criteria defined tentatively. For those with M. pneumoniae and C. pneumoniae infections, azithromycin or minocycline was initially used. Treatments averaged 3–5 days. The empirical chemotherapy was improper in 9.4% of cases in relation to the etiologic agents finally identified. We conclude that rapid and comprehensive identification using PCR can provide optimal antimicrobial chemotherapy for CAP patients.

The quick-read C-reactive protein test for the prediction of bacterial gastroenteritis in the pediatric emergency department

OBJECTIVE

To determine the clinical usefulness of the bedside Quick-Read (QR) C-reactive protein (CRP) test for predicting bacterial gastroenteritis in the pediatric emergency department.

STUDY DESIGN

We tested for CRP in 44 children who presented to the emergency department with gastroenteritis and underwent blood tests and stool culture. C-reactive protein was measured in leftover blood or serum (0.2 mL) using the immunoturbidimetric QR-CRP test kit. Background and outcome data were collected from the files. Pearson correlation, analysis of variance, and logistic regression were used to determine the diagnostic ability of CRP.

RESULTS

Stool culture was positive for bacteria in 8 patients. High CRP levels correlated with a greater likelihood of a positive culture; the area under the receiver operating characteristics curve was 0.9427. The CRP values of 95 mg/L or higher had a sensitivity of 87% and a specificity of 91.7% for predicting culture-confirmed bacterial gastroenteritis.

CONCLUSIONS

The QR-CRP test seems to be a useful predictor of bacterial gastroenteritis in children. It is amenable for use in the emergency department, making it a promising tool for infection control and for aiding physicians in decisions regarding antibiotic treatment. The CRP levels of 95 mg/L or higher during the first 48 hours are suggestive of bacterial disease.

Distinction between bacterial and viral infections

PURPOSE OF REVIEW

To commence proper treatment as rapidly as possible and to reduce unnecessary antibiotic treatments, timely knowledge of whether the infection is bacterial or viral in origin would be beneficial for the clinician. As a reliable prediction of the causative agent of bacterial infection is not possible based on clinical features, there is an ongoing need for sensitive and specific markers of bacterial infection.

RECENT FINDINGS

The most common differential diagnosis methods are reviewed here. It is also demonstrated that the measurement of the expression of complement receptors, particularly CR1 (CD35), on neutrophils can be a useful preliminary test to differentiate between bacterial and viral infections. In addition, a novel marker of local and systemic bacterial infections designated 'clinical infection score (CIS) point', which incorporates quantitative analysis of complement receptors on neutrophils and standard clinical laboratory data and displays 98% sensitivity and 97% specificity in distinguishing between bacterial and viral infections, is presented.

SUMMARY

We conclude that the diagnostic yield of measured individual variables in distinguishing between bacterial and viral infections increases upon combination.

Rapid quantitative determination of C-reactive protein at chair side in dental emergency patients

OBJECTIVES

The objective of this study was to quantitatively determine, at chair side, the serum C-reactive protein (CRP) levels in dental emergency patients.

STUDY DESIGN

Quantitative CRP test was performed at chair side in 40 patients with acute alveolar abscess (AAA), acute periodontal abscess (APA), and alveolar osteitis (AO) at the time of dental emergency treatment and 1 week after. CRP levels were compared between groups and before and after treatments using ANOVA and Fisher's Exact tests.

RESULTS

Serum CRP levels were greater than 5 mg/L in 30 (75%) of the 40 patients. At 1-week follow-up, the decline in CRP levels was evident in the AAA group (P < .05), but not statistically significant in the APA and AO groups (P > .05).

CONCLUSION

Serum CRP levels are often elevated in patients with odontogenic infections and postoperative complications. Rapid reduction in serum CRP levels was likely to occur following successful treatment of AAA, but less likely to occur in APA and AO.

Children with pneumonia: how do they present and how are they managed?

OBJECTIVE

To describe the spectrum of clinical features and management of community acquired pneumonia in the UK.

DESIGN

Prospectively recorded clinical details for all children with possible pneumonia and chest x ray (CXR) changes in 13 hospitals in the North of England between 2001 and 2002.

RESULTS

89% of 711 children presenting to hospital with pneumonia were admitted; 96% received antibiotics, 70% intravenously. 20% had lobar CXR changes, 3% empyema and 4% required intensive care. Respiratory rate (RR), hypoxia and dyspnoea all correlated with each other and prompted appropriate interventions. Admission in children, not infants, was independently associated with RR, oxygen saturation, lobar CXR changes and pyrexia. Neither C-reactive protein, lobar CXR changes or pyrexia were associated with severity. Children over 1 year old with perihilar CXR changes more often had severe disease (p = 0.001). Initial intravenous antibiotics were associated with lobar CXR changes in infants and children and with dyspnoea, pyrexia and pleural effusion in children. The presence of pleural effusion increased duration of antibiotic treatment (p<0.001). Cefuroxime was the most often used intravenous antibiotic in 61%. Oral antibiotics included a penicillin in 258 (46%), a macrolide in 192 (34%) and a cephalosporin in 117 (21%). Infants stayed significantly longer (p<0.001) as did children with severe disease (p<0.01), effusions (p = 0.005) or lobar CXR changes (p< or =0.001).

CONCLUSIONS

There is a high rate of intravenous antibiotic administration in hospital admissions for pneumonia. Despite lobar CXR changes not being independently associated with severe disease, initial lobar CXR changes and clinical assessment in children independently influenced management decisions, including admission and route of antibiotics.

Acute phase markers for the differentiation of infectious and malignant pleural effusions

Acute-phase markers, such as C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha), have been studied in inflammatory and malignant disorders. We examined the diagnostic value of these markers for the differentiation among parapneumonic, tuberculous and malignant effusions. We studied 124 patients with pleural effusions, classified as exudates [total (n=97), parapneumonic (n=15), tuberculous (n=25), malignant (n=57)] and transudates due to congestive heart failure (n=27). CRP, IL-6 and TNF-alpha were measured in pleural fluid and serum. Pleural fluid CRP was higher in parapneumonic compared to tuberculous and malignant effusions, providing 100% sensitivity for a cut-off point of 5.3mg/dL. IL-6 was higher in both parapneumonic and tuberculous compared to malignant effusions. TNF-alpha was higher in tuberculous compared to malignant effusions, providing 96.0% sensitivity, and 93.0% specificity for a cut-off point of 88.1 pg/mL. Pleural fluid CRP levels were lower than serum in all groups, probably reflecting systemic inflammation, whereas IL-6 and TNF-alpha were higher in pleural fluid indicating local production. Our data suggest that these markers may provide useful information for the differentiation of infectious and malignant effusions in clinical practice. However, further studies are needed for the validation of these findings in usual clinical circumstances.

MxA-based recognition of viral illness in febrile children by a whole blood assay

Febrile children are often given antibiotics empirically and unnecessarily. MxA is a protein induced in peripheral lymphoid cells by type 1 interferons during active viral infection. The ability of a whole blood ELISA assay for MxA to identify children with viral illness was studied in 122 children who presented with acute onset fever and 52 age-matched healthy controls. The febrile children were divided into three groups according to their final diagnoses: etiologically diagnosed viral infection, clinically diagnosed viral infection, and bacterial infection. MxA levels in the bacterial infection group and controls were similar and low (90.9 +/- 69.7 and 76.9 +/- 63.2 ng/mL, respectively). In contrast, mean MxA levels in the two viral infection groups were higher than in both the bacterial and control groups (719.2 +/- 386.4 and 827.0 +/- 651.1, respectively). A receiver operating characteristic analysis showed that the area under the curve of the MxA level was greater than under the curves of both the white blood cell count and the C-reactive protein concentration. Whole blood assay of MxA is a clinically useful tool for diagnosing viral illness in febrile children and should help reduce use of unnecessary antibiotics.

Comparison of total white blood cell count and serum C-reactive protein levels in confirmed bacterial and viral infections

We report the association of reaction in inflammatory markers with the microbiologic etiology of infection in children. Total white blood cell counts were increased in most pneumococcal and Escherichia coli infections, but in less than one-half of Staphylococcus aureus infections. Adenoviruses were the only viral agents that often increased total white blood cell counts or serum C-reactive protein levels.

Clinical characteristics and outcome of complicated pneumococcal pneumonia in a pediatric population

The incidence of complicated pneumonia caused by S. pneumoniae is reported to be increasing. This increase may be related to host susceptibility and/or pathogen virulence. The objective of this study was to evaluate clinical and laboratory characteristics associated with complicated pneumococcal pneumonia, and to identify risk factors associated with prolonged fever and hospitalization. The study involved reviewing the records of all children who were hospitalized in four major hospitals in Jerusalem with a confirmed diagnosis of pneumococcal pneumonia during a 12-year period (1986-1997). Demographic, clinical, laboratory, and outcome variables were compared between those with uncomplicated and complicated pneumonia. One hundred and eleven children (median age, 2.2 years) were hospitalized with pneumococcal pneumonia during the study period. Forty-four (39%) of them had complicated pneumonia, characterized by pleural effusion, empyema, pneumothorax, pneumatocele, and/or atelectasis. There was no correlation between the isolation of penicillin-resistant S. pneumonia (16% of cases) and complicated pneumonia. Factors that were significantly associated with complicated pneumonia included weight <or=10% for age, respiratory distress (e.g., tachypnea, dyspnea), anemia, and a white blood cell count (WBC) <15,000/mm(3) at time of admission. Complicated pneumonia and a WBC <15,000/mm(3) on admission increased the risk for prolonged fever and an extended length of hospitalization. Based on these results, it is concluded that host factors such as anemia, low weight, and a low WBC are associated with complicated pneumonia. Both the presence of pulmonary complications and a relatively low WBC in children hospitalized for pneumococcal pneumonia are independent risk factors for protracted fever and extended hospitalization.

Quantitative analysis of complement receptors, CR1 (CD35) and CR3 (CD11b), on neutrophils improves distinction between bacterial and viral infections in febrile patients: Comparison with standard clinical laboratory data

There is an ongoing need for sensitive and specific markers of bacterial infection. In this prospective study, standard clinical laboratory data (neutrophil count, serum C reactive protein level, erythrocyte sedimentation rate) and quantitative flow cytometric analysis of neutrophil complement receptors, CR1 and CR3, were obtained from 289 hospitalized febrile patients. After microbiological confirmation or clinical diagnosis, 135 patients were found to have either bacterial (n = 89) or viral (n = 46) infection. The patient data was compared to 60 healthy controls. In bacterial infections, all measured variables were significantly increased, particularly the average amounts of CR1 and CR3 on neutrophils were over three-fold and two-fold higher, respectively, compared to viral infections and controls. We described a novel marker of local and systemic bacterial infections designated 'clinical infection score (CIS) point', which incorporates quantitative analysis of complement receptors on neutrophils and standard clinical laboratory data. CIS point varied between 0 and 8, and displayed 98% sensitivity and 97% specificity in distinguishing between bacterial and viral infections [average (S.D.); CIS points: 6.2 (1.7) vs. 0.6 (1.0); p < 0.001]. These findings suggest that the proposed CIS-based diagnostic test could potentially assist physicians in deciding whether antibiotic treatment is necessary.

Antibiotics in childhood pneumonia

Pneumonia is one of the most common global childhood illnesses. The diagnosis relies on a combination of clinical judgement and radiological and laboratory investigations. Streptococcus pneumoniae remains the most important cause of childhood community-acquired pneumonia. In addition, viruses (including respiratory syncytial virus) and atypical bacteria (Mycoplasma and Chlamydia) are likely pathogens in younger and older children in developed countries. In the minority of cases only, the actual organism is isolated to guide treatment. Antibiotics effective against the expected bacterial pathogens should be instituted where necessary. The route and duration of antibiotic therapy, the role of emerging pathogens and the impact of pneumococcal resistance and conjugate pneumococcal vaccines are also discussed.

Development and validation of a clinical prediction rule to distinguish bacterial from viral pneumonia in children

BACKGROUND

Distinguishing bacterial from viral pneumonia on admission to the hospital could guide the decision of whether or not to use antibiotics. We developed and validated a clinical prediction rule to distinguish bacterial from viral pneumonia in hospitalized children.

METHODS

We enrolled consecutive children, aged 1 month to 5 years, admitted to two tertiary children's hospitals in whom a bacterial or viral etiology for pneumonia was identified. Data from 175 children at one hospital were used to develop a clinical prediction rule or Bacterial Pneumonia Score (BPS). Data from 136 children at the second hospital were used to validate it. Based on receiver operating characteristic (ROC) curve analyses and multivariable logistic regression, significant clinical and laboratory predictors, along with the radiographic score for each participant, were included as factors in the BPS. The main outcome measure was the sensitivity and specificity of the BPS for bacterial pneumonia.

RESULTS

The BPS (possible range: -3 to 15; auROCc = 0.996, 95%CI: 0.99-1.0) was developed by attributing 3 points for axillary temperature > or = 39.0 degrees C, 2 points for age > or equal to 9 months, 2 points for absolute neutrophil count > or = [corrected] 8,000 cells/mm3, 1 point for bands > or = 5%, and -3 to 7 points for the chest X-ray findings. A BPS > or = 4 predicted bacterial pneumonia with a sensitivity of 100%, specificity of 93.8%, positive predictive value of 75.8%, and negative predictive value of 100%.

CONCLUSIONS

The BPS accurately identifies hospitalized children's risk of bacterial pneumonia, helping clinicians determine those not likely to benefit from antibiotic therapy.

Influenza pneumonia

BACKGROUND

Influenza and pneumonia are common childhood illnesses, but few studies have been conducted on influenza-related pneumonia in children. The aim of this study was to describe the frequency and characteristics of laboratory-documented and radiologically detected influenza pneumonia in children.

METHODS

This study involved children treated at the Department of Pediatrics, Turku University Hospital, from 1980 through 2003. Influenza A or B infection was documented with the use of antigen detection from nasopharyngeal aspirates. Children with chest radiographs obtained during influenza episodes were identified. Chest radiographs were reevaluated by a pediatric radiologist for verification of pneumonic infiltrates. Clinical and laboratory data were collected from medical records.

RESULTS

Pneumonia was detected in 134 (14%) of 936 children with influenza infection. The most frequent signs of influenza pneumonia were fever and cough. Of these children, 47% had no specific clinical signs or symptoms suggesting pneumonia. White blood cell count was <15 x 10/L in 89% and serum C-reactive protein concentration <80 mg/L in 85% of the children. One-half of the children had solely interstitial infiltrates, one-fourth solely alveolar and one- fourth both alveolar and interstitial infiltrates on the chest radiograph. The hospitalization rate was 68%, and the median duration of hospitalization was 2 days. Complicated pneumonias were rare, and mortality was low (0.7%).

CONCLUSIONS

Pneumonia is detected in a minority of children treated for influenza at a tertiary center. Unlike in adults, influenza pneumonia in children is usually a benign illness, and the mortality is low.

[CRP in the management of bacterial infections in emergency]

OBJECTIVES

To assess the interest of measuring CRP in emergency for diagnosing bacterial infections and making decisions about antibiotics and to compare its practical usefulness with clinicians' conclusions.

METHODS

Systematic CRP measurements in 80 consecutive patients admitted to emergency ward with possible bacterial infection.

RESULTS

were not transmitted to the physician in charge. Patients' files were analyzed retrospectively in two phases. In phase 1, two senior physicians assessed the diagnosis and need for antibiotics on the basis of the admission (emergency unit) files. In phase 2, a panel of experts examined the complete files (including discharge notes) to determine the likelihood of infection (obvious or probable, unlikely or excluded) and appropriateness of emergency antibiotics. Their recommendations were used as the standard, against which the usefulness of the laboratory indicators (including CRP) and decisions of the emergency physicians were assessed. ROC curves were used to determine threshold values for CRP and body temperature. We then calculated the sensitivity, positive predictive value and negative predictive value of these cutoffs and compared them with those for the phase 1 clinician recommendations.

RESULTS

The study included 76 patients (mean age: 74 years): 28 presented obvious or possible infections and 21 required emergency antibiotic therapy. Mean leukocyte values did not differ between groups. For diagnosis, the threshold value of CRP was 85 mg/L and of body temperature 37.8 degrees C; for prescribing antibiotics, the values were 130 mg/L and 38 degrees C, respectively. The sensitivity, specificity, negative and positive predictive values of CRP were, respectively, 79, 81, 76, and 83% for diagnosis of bacterial infection and 71, 71, 48 and 87% for prescription of an emergency antibiotic. These values were lower than those of clinician's conclusions.

CONCLUSION

Because of the variability in the thresholds used in its interpretation, the lack of specificity, and its poor predictive value for treatment decisions, CRP is of little interest in the diagnosis and treatment of patients with bacterial infections in intensive care. The cost generated by this examination is therefore not justified.

Diagnostic value of C reactive protein in infections of the lower respiratory tract: systematic review

OBJECTIVES

To evaluate the diagnostic accuracy of C reactive protein in detecting radiologically proved pneumonia and to evaluate how well it can discriminate between bacterial and viral infections of the lower respiratory tract.

DATA SOURCES

Medline and Embase (January 1966 to April 2004), with reference checking.

STUDY SELECTION

We included articles comparing C reactive protein with a chest radiograph or with microbiological work-up as a reference test. Two authors independently assessed methodological items.

RESULTS

None of the studies met all validity criteria. Six studies used an infiltrate on chest radiograph as reference test. Sensitivities ranged from 10% to 98%, specificities from 44% to 99%. For adults, the relation of C reactive protein with an infiltrate (in a subgroup analysis of five studies) showed an area under the curve of 0.80 (95% confidence interval 0.75 to 0.85). In 12 studies, the relation of C reactive protein with a bacterial aetiology of infection of the lower respiratory tract was studied. Sensitivities ranged from 8% to 99%, specificities from 27% to 95%. These data were epidemiologically and statistically heterogeneous, so overall outcomes could not be calculated.

CONCLUSION

Testing for C reactive protein is neither sufficiently sensitive to rule out nor sufficiently specific to rule in an infiltrate on chest radiograph and bacterial aetiology of lower respiratory tract infection. The methodological quality of the diagnostic studies is generally poor. The evidence not consistently and sufficiently supports a wide introduction of C reactive protein as a rapid test to guide antibiotics prescription.

Evaluation of a rapid bedside test for the quantitative determination of C-reactive protein

Regardless of its origin, any condition associated with inflammation is accompanied by an increase in serum C-reactive protein levels. This study compared the results of a rapid test for the bedside assay of C-reactive protein (QuikRead CRP, Orion Corporation, Orion Diagnostica, Espoo, Finland) with those of a standard laboratory assay in samples taken from 231 children aged less than 14years (126 males; median age 4.7years) attending the Emergency Department of Milan University's Institute of Pediatrics because of acute respiratory infection. The two methods showed similar median C-reactive protein levels (standard laboratory assay: 34.7mg/L, range 4–199mg/L; QuikRead CRP: 33.3mg/L, range <8–196mg/L; p=0.779) and a similar distribution of children with C-reactive protein levels of <20mg/L, 20–70mg/L and >70mg/L. This study shows for the first time that the rapid QuikRead CRP test can be performed at the bedside or in an outpatient clinic and, in less than 5min, gives the same quantitative results as those obtained using a more complex routine laboratory method.

Non-specific host response markers in the differentiation between pneumococcal and viral pneumonia: what is the most accurate combination?

BACKGROUND

Serum C-reactive protein (CRP), blood white cell count (WBC), serum procalcitonin (PCT) and erythrocyte sedimentation rate (ESR) were measured in 132 children hospitalized for community-acquired pneumonia. Serological evidence for viral infection was found in 38 cases and for pneumococcal infection in 41 cases, and the infiltrate was alveolar in 46 cases and interstitial in 86 cases. The aim of the present paper was to determine if there is a combination of these four host response markers and chest radiograph findings suitable for differentiating pneumococcal from viral etiology of pneumonia.

METHODS

The 50th, 75th and 90th percentiles of CRP, WBC, ESR and PCT in the total group of 132 patients were calculated. By using these cut-off limits, the likelihood ratios of a positive test result were calculated for the possible combinations of CRP, WBC, ESR and PCT, and the likelihood ratio was 1.50 or more for six combinations.

RESULTS

The highest likelihood ratio (1.74) was achieved with the combination CRP > 90th (80 mg/L) or WBC > 75th (17.0 x 10(9)/L) or PCT > 75th (0.84 microg/L) or ESR > 90th (63 mm/h) percentile. For this combination, the sensitivity was 61% and the specificity 65%. When the 90th percentile cut-off limit was applied also for WBC (>22 x 10(9)/L) and PCT (>1.8 microg/L), the specificity increased to 76%, but the sensitivity decreased to 37%. When the presence of an alveolar infiltration was included in the combination, the likelihood ratio was 1.89; the specificity was as high as 82% and the sensitivity as low as 34%.

CONCLUSIONS

CRP, PCT, WBC and ESR have only limited value in differentiating pneumococcal or other bacterial pneumonia from viral pneumonia. If there was a high value in at least one of the markers (CRP > 80 mg/L, PCT > 1.8 microg/L, WBC > 22 x 10(9)/L or ESR > 60 mm/h), viral infections were rare. There was no combination of these markers which was sufficiently sensitive and specific to be used in clinical pediatric practice.

Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of determination of procalcitonin (PCT) and C-reactive protein (CRP) levels for the diagnosis of bacterial infection. The analysis included published studies that evaluated these markers for the diagnosis of bacterial infections in hospitalized patients. PCT level was more sensitive (88% [95% confidence interval [CI], 80%-93%] vs. 75% [95% CI, 62%-84%]) and more specific (81% [95% CI, 67%-90%] vs. 67% [95% CI, 56%-77%]) than CRP level for differentiating bacterial from noninfective causes of inflammation. The Q value for PCT markers was higher (0.82 vs. 0.73). The sensitivity for differentiating bacterial from viral infections was also higher for PCT markers (92% [95% CI, 86%-95%] vs. 86% [95% CI, 65%-95%]); the specificities were comparable (73% [95% CI, 42%-91%] vs. 70% [95% CI, 19%-96%]). The Q value was higher for PCT markers (0.89 vs. 0.83). PCT markers also had a higher positive likelihood ratio and lower negative likelihood ratio than did CRP markers in both groups. On the basis of this analysis, the diagnostic accuracy of PCT markers was higher than that of CRP markers among patients hospitalized for suspected bacterial infections.

Performance of a bedside C-reactive protein test in the diagnosis of community-acquired pneumonia in adults with acute cough

PURPOSE

To evaluate the performance of a rapid, bedside whole blood C-reactive protein test as a diagnostic test for pneumonia in adults.

METHODS

We enrolled consecutive adults who presented with acute cough (duration < or =3 weeks). A fingerstick blood specimen for C-reactive protein level was obtained. Patients also provided information about demographic characteristics and symptoms. Physical examination findings, diagnoses, and treatments were abstracted from the medical record; illness duration and subsequent office visits were determined with follow-up telephone calls. A clinical prediction rule for pneumonia was calculated for each patient and compared with C-reactive protein levels.

RESULTS

Twenty (12%) of the 168 patients in the study had radiographic evidence of pneumonia. Median C-reactive protein levels were significantly higher for patients with pneumonia than in the remaining patients (60 mg/L vs. 9 mg/L, P <0.0001). The area under the receiver operating characteristic (ROC) curve for C-reactive protein level as a predictor of pneumonia was 0.83. C-reactive protein level and the clinical prediction rule were independently associated with pneumonia, yielding a combined area under the ROC curve of 0.93. C-reactive protein level was not associated with hospitalization or resolution of symptoms.

CONCLUSION

C-reactive protein levels could be a valuable addition to clinical prediction rules for pneumonia. A C-reactive protein level > or =100 mg/L might be a useful indication for chest radiography or empiric antibiotic therapy when the diagnosis of pneumonia is in doubt.

Community-acquired pneumonia in children: issues in optimizing antibacterial treatment

The treatment of community-acquired pneumonia (CAP) in children is empirical, being based on the knowledge of the etiology of CAP at different ages. As a result of currently available methods in everyday clinical practice, a microbe-specific diagnosis is not realistic in the majority of patients. Even the differentiation between viral, 'atypical' bacterial (Mycoplasma pneumoniae or Chlamydia pneumoniae) and 'typical' bacterial (Streptococcus pneumoniae) CAP is often not possible. Moreover, up to one-third of CAP cases seem to be mixed viral-bacterial or dual bacterial infections. Recent serologic studies have confirmed that S. pneumoniae is an important causative agent of CAP at all ages. M. pneumoniae is common from the age of 5 years onwards, and C. pneumoniae is common from the age of 10 years onwards. In addition to age, the etiology and treatment of CAP are dependent on the severity of the disease. Pneumococcal infections are predominant in children treated in hospital, and mycoplasmal infections are predominant in children treated at home.In ambulatory patients with CAP, amoxicillin (or penicillin V [phenoxymethylpenicillin]) is the drug of choice from the age of 4 months to 4 years, and at all ages if S. pneumoniae is the presumptive causative organism. Macrolides, preferably clarithromycin or azithromycin, are the first-line drugs from the age of 5 years onwards. In hospitalized patients who need parenteral therapy for CAP, cefuroxime (or penicillin G [benzylpenicillin]) is the drug of choice. Macrolides should be administered concomitantly if M. pneumoniae or C. pneumoniae infection is suspected. Radiologic findings and C-reactive protein (CRP) levels offer limited help for the selection of antibacterials; alveolar infiltrations and high CRP levels indicate pneumococcal pneumonia, but the lack of these findings does not rule out bacterial CAP. Most guidelines recommend antibacterials for 7-10 days (except azithromycin, which has a recommended treatment duration of 5 days). If no improvement takes place within 2 days, therapy must be reviewed.

Procalcitonin, C-reactive protein and leukocyte count in children with lower respiratory tract infection

BACKGROUND

Lower respiratory tract infection is the most common infection leading to unnecessary antibiotic treatment in children. Etiologic diagnosis is not immediately achieved, and the pathogen remains unidentified in a large number of cases. Neither clinical nor laboratory factors allow for a rapid distinction between bacterial and viral etiology. The aim of our study was to evaluate the reliability of procalcitonin (PCT), C-reactive protein (CRP) and leukocyte count in distinguishing pneumococcal, atypical and viral lower respiratory tract infection.

METHODS

PCT, CRP and leukocyte count were measured in children with microbiologically documented diagnoses of lower respiratory tract infection. The results were compared of children with pneumococcal, atypical and viral etiologies.

RESULTS

PCT and CRP showed significant correlation with a bacterial etiology of lower respiratory tract infection. No significance was found for leukocyte count. Using a cutoff point of 2 ng/ml for PCT and 65 mg/l for CRP, the sensitivities and specificities for distinguishing bacterial from viral lower respiratory tract infections were 68.6 and 79.4% for PCT and 79.1 and 67.1% for CRP. The sensitivities and specificities for distinguishing pneumococcal from other etiologies were 90.3 and 74.1% for PCT and 90.3 and 60% for CRP, respectively.

CONCLUSIONS

High PCT and CRP values show a significant correlation with the bacterial etiology of lower respiratory tract infection. PCT and CRP show good sensitivity for distinguishing pneumococcal from other etiologies. PCT shows higher specificity than CRP. PCT and CRP can help make decisions about antibiotic therapy in children with lower respiratory tract infections.

Serum procalcitonin concentrations in bacterial pneumonia in children: a negative result in primary healthcare settings

A microbe-specific diagnosis in community-acquired pneumonia (CAP) is difficult in children, and studies on nonspecific chest radiographic and host response markers have been inconsistent. Serum procalcitonin (PCT) is a newly recognized, promising marker for differentiating between bacterial and viral infections. Serum PCT was measured by a luminometric assay in 190 children with CAP diagnosed in the primary healthcare setting during a population-based study in a geographically defined population. The pneumococcal, mycoplasma, chlamydia, and viral etiology of infections was studied by an extensive serologic test panel. The median PCT concentrations were 0.47, 0.46, and 0.35 ng/mL in children aged <5 years, 5-9 years, and >/=10 years (P = 0.004). An elevated PCT >1.0 ng/mL was seen in 12.1% and >2.0 ng/mL in only 2.1% of the children. No association was seen between severity (inpatient vs. outpatient care) and etiology of CAP (evidence for pneumococcal, mycoplasma, or chlamydia, vs. viral infection). We conclude that serum PCT measurements have no role in the diagnosis of bacterial CAP in children in primary healthcare settings.

Characteristics of Streptococcus pneumoniae and atypical bacterial infections in children 2-5 years of age with community-acquired pneumonia

The characteristics of community-acquired pneumonia associated with Streptococcus pneumoniae infection were compared with those associated with atypical bacterial infection and with mixed S. pneumoniae-atypical bacterial infection in 196 children aged 2-5 years. S. pneumoniae infections were diagnosed in 48 patients (24.5%); atypical bacterial infections, in 46 (23.5%); and mixed infections, in 16 (8.2%). Although white blood cell counts and C-reactive protein levels were higher in patients with pneumococcal infections, no other clinical, laboratory, or radiographic characteristic was significantly correlated with the different etiologic diagnoses. There was no significant difference in the efficacy of the different treatment regimens followed by children with S. pneumoniae infection, whereas clinical failure occurred significantly more frequently among children with atypical bacterial or mixed infection who were not treated with a macrolide. This study shows the major role of both S. pneumoniae and atypical bacteria in the development of community-acquired pneumonia in young children, the limited role of clinical, laboratory, and radiological features in predicting etiology, and the importance of the use of adequate antimicrobial agents for treatment.

The discriminative value of C-reactive protein levels in distinguishing between community-acquired bacteraemic and respiratory virus-associated lower respiratory tract infections in HIV-1-infected and -uninfected children

This study assessed the value of routine CRP measurements to discriminate between bacterial and viral lower respiratory tract infection (LRTI) in HIV-1-infected and -uninfected children. A total of 570 children, prospectively enrolled, were categorised into four aetiological groups, as follows: (i) bacteraemic pneumonia (n = 50), (ii) respiratory virus-associated LRTI (n = 146), (iii) bacteraemic and respiratory virus-associated (mixed) LRTI (n = 10), and (iv) LRTI of undetermined aetiology (n = 364). The discriminative ability of threshold CRP values was evaluated, and values predicting bacteraemic pneumonia were used to construct receiver-operating characteristic (ROC) plots. Median CRP values were significantly higher in bacteraemic pneumonia (195 mg/L, p < 0.0001), and threshold CRP values ranging from 10 to 100 mg/L differentiated bacteraemic from virus-associated LRTI (p < 0.0001). The discriminative ability of CRP values assessed by ROC plots in pneumonia is 80%, and CRP > or = 10 mg/L identified 90% of all bacteraemic pneumonia. In HIV-1 infection, median CRP values were significantly higher in bacteraemic pneumonia (200 mg/L) but correlated with levels in uninfected children, irrespective of LRTI aetiology. Although CRP responses are significantly different in bacteraemic and virus-associated LRTI, the considerable overlap between these aetiological groups hinders selection of threshold CRP values that are clinically useful in differentiating bacteraemic from virus-associated LRTI pneumonia.

Emerging resistance to antibiotics against respiratory bacteria: impact on therapy of community-acquired pneumonia in children

Perhaps because of its etiologic complexity, community-acquired pneumonia (CAP) in infants and children remains a significant problem worldwide. Over the last few years, difficulties related to CAP treatment in children have greatly increased because of the emergence of resistance to the most widely used antibiotics against some of the bacterial pathogens involved in the development of the disease. There are few data describing the impact of antibiotic resistance on clinical outcomes in CAP, but many experts believe that the clinical impact is limited. We here discuss the prevalence of different etiologic agents in CAP of children, the diagnostic criteria, problems related to antibiotic resistance, therapeutic strategies, and future implications.

Diagnosis of Streptococcus pneumoniae lower respiratory infection in hospitalized children by culture, polymerase chain reaction, serological testing, and urinary antigen detection

A prospective study of 154 consecutive high-risk hospitalized children with lower respiratory infections was conducted to determine the clinical utility of a pneumolysin-based polymerase chain reaction (PCR) assay compared with blood and pleural fluid cultures and serological and urinary antigen tests to determine the incidence of Streptococcus pneumoniae. Whole blood, buffy coat, or plasma samples from 67 children (44%) tested positive by PCR. Sensitivity was 100% among 11 promptly tested culture-confirmed children and specificity was 95% among control subjects. Age, prior oral antibiotic therapy, and pneumococcal nasopharyngeal colonization did not influence PCR results, whereas several surrogates of disease severity were associated with positive tests. Although serological and urinary antigen tests had comparable sensitivity, specificity varied among infected children, and statistical agreement among all assays was limited. These findings support the use of PCR tests to evaluate the protective efficacy of pneumococcal conjugate vaccines and to identify promptly children with pretreated or nonbacteremic pneumococcal lower respiratory infections.

Serum procalcitonin in pneumococcal pneumonia in children

Serum procalcitonin (PCT), a marker of bacterial infection, was measured in children with pneumonia to examine whether PCT can be used to screen pneumococcal (PNC) from viral pneumonia. The number of patients was 132; mean age 3.0 yrs, and 64% were males. In all cases, pneumonia was radiologically confirmed, being alveolar in 46 and interstitial in 86 cases. The aetiology of infection was studied by a panel of serological tests for PNC, for five other respiratory bacteria and for seven common respiratory viruses. PNC infection was found in 25, mixed viral-PNC infections in 13 and viral infection in 17 cases. In general, serum PCT was not associated with the type or aetiology of pneumonia. PCT values were >1.0 mg.L(-1) in 40% of PNC cases, as compared to 12-15% in viral or mixed cases, respectively (p<0.05). PCT values were significantly higher in >2 yrs old children than in younger ones. The cut-off limits of 0.5 ng.mL(-1), 1.0 ng.mL(-1) and 2.0 ng.mL(-1) were tested for screening between PNC and viral pneumonia. The highest sensitivity of 55% was found at the 0.5 ng.mL(-1) cut-off level, whereas the highest specificity of 88% was reached at the level of 1.0 ng.mL(-1). The likelihood ratios, however, were far from optimal for both the positive and negative results. Although marginally higher in pneumococcal pneumonia than in viral pneumonia, serum procalcitonin cannot be used to discriminate between these two types of pneumonia.

Serum C-reactive protein cannot differentiate bacterial and viral aetiology of community-acquired pneumonia in children in primary healthcare settings

Whether serum C-reactive protein (CRP) can be used to distinguish bacterial from viral pneumonia was studied in 193 paediatric patients who were identified in a prospective, population-based study. The proportion of patients < 5 y of age was 51%, 53% of these and 12% of the older patients were treated in hospital. Pneumococcal aetiology of infection was studied in paired sera by antibody and immune-complex assays, and chlamydial, mycoplasmal and viral aetiologies by routine antibody assays. CRP concentration was measured by immunoturbidometry. Pneumococcal infection (mixed infections with other agents included) was present in 57 cases, mycoplasmal and/or chlamydial infection (pneumococcal infections excluded) in 43, and viral infection (pneumococcal, mycoplasmal and chlamydial infections excluded) in 29 cases. The mean CRP concentrations (95% confidence interval) in these groups were 26.8 mg/l (20.1-33.5 mg/l), 31.8 mg/l (20.5-33.1 mg/l) and 26.1 mg/l (19.1-33.1 mg/l), respectively, and 24.9 mg/l (18.8-31.0 mg/l) in patients with no aetiological findings. When CRP values were compared between the 2 diagnostic groups of pneumococcal infections (antibody and immune-complex positive) no difference was found. In infants < 12 months of age the mean CRP concentration was 14.6 mg/l, and in 11 (65%) of them it was unmeasurable (< 10 mg/l). No significant differences were seen between hospitalized patients and outpatients. In conclusion, CRP concentration had no significant association with the microbial aetiology of pneumonia.

Mycoplasma pneumoniae and Chlamydia pneumoniae infections in children with pneumonia. Mowgli Study Group

The most common clinical signs, host responses and radiographic patterns were studied in 203 Italian children hospitalized for community-acquired pneumonia in order to clarify the role of clinical and radiological characteristics in the diagnosis of Mycoplasma pneumoniae and/or Chlamydia pneumoniae infections. Antibody measurements in paired sera and polymerase chain reaction on nasopharyngeal aspirates were used to establish the diagnoses of acute M. pneumoniae and C. pneumoniae infection, and the aetiologic data were correlated with the clinical, laboratory and radiographic data obtained on admission. No significant association was observed between evidence of M. pneumoniae and/or C. pneumoniae infection and periods of episode during the year, mean age of the study subjects, individual symptoms, physical findings or laboratory test results. Furthermore, no significant correlation was observed in relation to the radiological findings and M. pneumoniae and/or C. pneumoniae infection. This study shows that neither clinical findings nor laboratory parameters distinguished Mycoplasma pneumoniae and/or Chlamydia pneumoniae infection in children with pneumonia. Radiological findings also have a limited capacity to differentiate aetiologic agents. The priorities for future research include the development of rapid, easily accessible and cost-effective diagnostic tests useful for each episode of pneumonia in children.

Differential diagnosis between community-acquired pneumonia and non-pneumonia diseases of the chest in the emergency ward

Background: The differential diagnosis of community-acquired pneumonia and some non-pneumonia diseases involving the chest may sometimes be cumbersome. Adding some objective variables to the diagnostic strategy may be helpful.We evaluated the main objective variables that are usually available in the emergency ward and that may be valuable in this differential diagnosis. Methods: We recorded epidemiological, clinical, and analytical data, as well as that obtained from physical examination, from 284 consecutive patients diagnosed in the emergency ward as having community-acquired pneumonia. The diagnosis was reviewed by the investigators applying pre-set diagnostic criteria. Statistical analysis was then performed comparing data from patients with a definitive diagnosis of community-acquired pneumonia with those with a final diagnosis of non-pneumonia disease excluding acute exacerbations of chronic bronchitis. Results: In the univariate analysis, C-reactive protein (difference of means 93 mg/l; 95% C.I. 47, 140), erythrocyte sedimentation rate (d.m. 19 mm/h; 95% C.I. 3, 35), leukocyte count (d.m. 3.5x10(9)/l; 95% C.I. 0.5, 6.4), and temperature (d.m. 0.5 degrees C; 95% C.I. 0.1, 0.9) discriminated between community-acquired pneumonia and non-pneumonia diseases. In the multivariate analysis, only C-reactive protein remained in the equation. Conclusions: C-reactive protein, erythrocyte sedimentation rate, leukocyte count, and temperature were measurable variables that proved to be useful in the differential diagnosis between community-acquired pneumonia and non-pneumonia diseases. C-reactive protein appears to be the most suitable for this purpose.

[Investigations for etiologic causes in community-acquired pneumonia in children (besides imagery)]

The aim of laboratory investigations in acute lower respiratory tract infections in children is mainly to help to differentiate bacterial from viral infections. While blood cell counts and C reactive protein have good negative predictive value and specificity. Blood cultures are at the best positive in 10% of bacterial pneumonia. Immunofluorescence bacterial antigen detection in nasopharyngeal secretions are useful for the etiological diagnosis of viral pneumonia while polymerase chain reaction technique remains at the present time too expensive to be routinely used. Bronchoalveolar lavage is only indicated in respiratory infections that resist a first line well conducted treatment.

Use of pleural fluid C-reactive protein in diagnosis of pleural effusions

The aims of the study were to assess whether C-reactive protein (CRP) is a sensitive marker for discriminating between transudative and exudative and pleural effusions to evaluate whether it can be used to distinguish inflammatory pleural effusions from other types of effusion. Pleural fluid and serum CRP levels were obtained in 97 patients with pleural effusion, using an immunoturbidimetric method (Olympus AU-600 autoanalyser). We compared CRP levels between transudates and exudates, inflammatory effusions and other types of effusion. According to the criteria used, 16 patients were included in the transudate group and 81 patients in the exudate group. Pleural fluid CRP levels were significantly lower in the transudate group (P<0.04; 14.9 +/- 4.9 mg l(-1) and 35.5 +/- 4.9 mg l(-1) respectively). Also, the ratio of pleural fluid to serum was significantly lower in the transudate group (P<0.009; 0.8 +/- 0.5 mg l(-1) and 2.8 +/- 0.7 mg l(-1), respectively). In the exudate group, 35 patients had neoplastic effusions, 10 chronic non-specific pleurisy, 19 tuberculous pleurisy, 16 parapneumonic effusion and one Dressler Syndrome. When these sub-groups were compared, the parapneumonic effusion subgroup CRP levels (mean 89 +/- 16.3 mg l(-1)) were significantly higher than those in the other subgroups, other exudate of neoplastic effusion, tuberculous pleurisy and chronic non-specific effusion and the transudate group (P<0.0001; P<0.0001; P<0.0004 and P<0.0001, respectively). The ratio between pleural fluid and serum CRP was significantly higher in the parapneumonic effusion subgroup than in the neoplastic subgroup (P<0.0002; 6.6 +/- 2.7 mg l(-1) and 1 +/- 0.2 mg l(-1), respectively). Pleural fluid CRP levels > 30 mg l(-1) had a high sensitivity (93.7%) and specificity (76.5%) and a positive predictive value of 98.4%. In the differential diagnosis of pleural effusions, higher CRP levels may prove to be a rapid, practical and accurate method of differentiating parapneumonic effusions from other exudate types. Although the high level of CRP obtained in the exudate group may be due to the number of patients with parapneumonic effusion who were included, the pleural CRP level may also be helpful in discriminating between exudative and transudative pleural effusions.

The C-reactive protein

C-reactive protein (CRP) was identified in 1930 and was subsequently considered to be an "acute phase protein," an early indicator of infectious or inflammatory conditions. Since its discovery, CRP has been studied as a screening device for inflammation, a marker for disease activity, and as a diagnostic adjunct. Improved methods of quantifying CRP have led to increased application to clinical medicine. In the emergency department (ED), CRP must be interpreted in the clinical context; no single value can be used to rule in or rule out a specific diagnosis. We conclude that CRP has limited utility in the ED. It may be a useful adjunct to serial examinations in equivocal presentations of appendicitis in those centers without ready access to computed tomography (CT) scan. It may be elevated with complications or treatment failures in patients with pneumonia, pancreatitis, pelvic inflammatory disease (PID), and urinary tract infections. In patients with meningitis, neonatal sepsis, and occult bacteremia, CRP is usually elevated. However, CRP has no role in diagnosing these clinical entities, and a normal CRP level should never delay antibiotic coverage.

Etiology of acute lower respiratory tract infection in Central Australian Aboriginal children

BACKGROUND

Aboriginal children in central Australia have attack rates for acute lower respiratory tract infection (ALRI) that are similar to those in developing countries. Although mortality rates are much lower than in developing countries, morbidity is high and ALRI is still the leading cause of hospitalization. However, there are no data on the etiology of ALRI in this population.

METHODS

We prospectively studied 322 cases of ALRI in 280 Aboriginal children admitted to the hospital. Blood, urine and nasopharyngeal aspirate samples were examined for evidence of bacterial, viral and chlamydial infection.

RESULTS

The combination of blood culture, viral studies and chlamydial serology provided at least 1 etiologic agent in 170 of 322 (52.5%) cases. Assays for pneumolysin immune complex and pneumolysin antibody increased etiologic diagnosis to 219 (68.0%). Blood cultures were positive in 6% but pneumolysin immune complex and pneumolysin antibody studies were positive in one-third of cases. Evidence of viral infection was present in 155 (48%) of cases compared with 12% in controls (P < 001). There were only 7 possible cases and 2 definite cases of Chlamydia trachomatis and 3 cases of Chlamydia pneumoniae. Coinfection was common in these children.

CONCLUSION

These findings have implications for both standard treatment protocols and vaccine strategies. The high rate of coinfection may make it difficult to develop simple clinical predictors of bacterial infection. In the setting of a developed country with efficient patient evacuation services, management algorithms that focus on disease severity and need for hospital referral will be most useful to health staff in remote communities. Pneumococcal conjugate vaccines will be required to reduce the high attack rate of pneumococcal disease.