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Clinical features and inflammatory markers in pediatric pneumonia: a prospective study


In this prospective, observational study on previously healthy children <18 years, we aimed to study the diagnostic ability of clinical features and inflammatory markers to (i) predict pathologic chest radiography in suspected pneumonia and (ii) differentiate etiology in radiological proven pneumonia. In 394 cases of suspected pneumonia, 265 (67%) had radiographs consistent with pneumonia; 34/265 had proof of bacterial etiology. Of the cases, 86.5% had received pneumococcal conjugate vaccine. In suspected pneumonia, positive chest radiography was significantly associated with increasing C-reactive protein (CRP) values, higher age, and SpO2 ≤92% in multivariate logistic regression, OR 1.06 (95% CI 1.03 to 1.09), OR 1.09 (95% CI 1.00 to1.18), and OR 2.71 (95% CI 1.42 to 5.18), respectively. In proven pneumonia, bacterial pneumonia was significantly differentiated from viral/atypical pneumonia by increasing CRP values and SpO2 >92% in multivariate logistic regression, OR 1.09 (95% CI 1.05 to 1.14) and OR 0.23 (95% CI 0.06 to 0.82), respectively. Combining high CRP values (>80 mg/L) and elevated white blood cell (WBC) count provided specificity >85%, positive likelihood ratios >3, but sensitivity <46% for both radiographic proven and bacterial pneumonia.

Conclusion: With relatively high specificity and likelihood ratio CRP, WBC count and hypoxemia may be beneficial in ruling in a positive chest radiograph in suspected pneumonia and bacterial etiology in proven pneumonia, but with low sensitivity, the clinical utility is limited.

What is Known:
Pneumonia is recommended to be a clinical diagnosis, and neither clinical features nor inflammatory markers can reliably distinguish etiology.
The etiology of pneumonia has changed after routine pneumococcal conjugate vaccine.
What is New:
High CRP and WBC counts were associated with infiltrates in children with suspected pneumonia and with bacterial infection in proven pneumonia.
In the post-pneumococcal vaccination era, viral etiology is expected, and in cases of pneumonia with low CRP and WBC counts, a watch-and-wait strategy for antibiotic treatment may be applied.

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Fig. 1
Fig. 2



Acute lower respiratory tract infection


Area under the curve


Community-acquired pneumonia


C-reactive protein


Interquartile range


Polymerase chain reaction


Receiver operating characteristics


White blood cells


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We are grateful to all participating children and their parents and nurses and doctors on call for recruiting patients and collecting data. We thank Drs. R Bull and R Grotli at the Department for Radiology, Akershus University Hospital, for performing the radiological examinations; Dr. I Aaberge and A Aase for the pneumococcal serological analyses at the Department of Bacteriology and Immunology, the Norwegian Institute for Public Health; and Dr. Line Sletner at our department for the advise on statistical analyses and staff at the laboratories at Akershus University Hospital for performing the laboratory analyses.

Authors’ contributions

All authors provided substantial contributions to the study’s conception and design and acquisition, analysis, or interpretation of the data.

Drs. Berg, Inchley, Fjaerli, and Nakstad executed the clinical part of the work.

Dr. Leegaard was responsible for the microbiological laboratory analyses.

Dr. Lindbaek was responsible for the primary care part of the study.

Dr. Berg drafted the initial manuscript, and all other authors revised it critically for important intellectual content. All authors approved the final manuscript as submitted and agreed to be accountable for all aspects of the work.

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Correspondence to Are Stuwitz Berg.

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Conflict of interest

The authors declare that they have no conflicts of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and approved by both the Regional Ethics Committee and the local Data Protection Officer. Furthermore, the study was in accordance with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Source of funding

The study was supported by research grants from Akershus University Hospital and South-Eastern Norway Regional Health Authority and grants from the Grimsgaard Foundation and the Norwegian Organization for Surveillance of Antimicrobial Resistance.

Additional information

Communicated by David Nadal

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Berg, A.S., Inchley, C.S., Fjaerli, H.O. et al. Clinical features and inflammatory markers in pediatric pneumonia: a prospective study. Eur J Pediatr 176, 629–638 (2017).

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  • Pneumonia
  • Clinical features
  • Inflammatory markers
  • Pneumococcal vaccination