Neumonia viral vs bac

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ORIGINAL ARTICLE

Differentiation of bacterial and viral pneumonia in children
R Virkki, T Juven, H Rikalainen, E Svedström, J Mertsola, O Ruuskanen
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Thorax 2002;57:438–441

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Correspondence to: Dr O Ruuskanen, Department of Pediatrics, Turku University Hospital, Kiinamyllynkatu 4-8, 20520 Turku, Finland; olli.ruuskanen@tyks.fi Revised version received 2 October 2001 Accepted for publication 1 November 2001

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Background: A study was undertaken to investigate thedifferential diagnostic role of chest radiographic findings, total white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and serum C reactive protein (CRP) in children with community acquired pneumonia of varying aetiology. Methods: The study population consisted of 254 consecutive children admitted to hospital with community acquired pneumonia diagnosed between 1993 and 1995. WBC, ESR, and CRPlevels were determined on admission. Seventeen infective agents (10 viruses and seven bacteria) were searched for. Chest radiographs were retrospectively and separately reviewed by three paediatric radiologists. Results: A potential causative agent was found in 215 (85%) of the 254 cases. Bacterial infection was found in 71% of 137 children with alveolar infiltrates on the chest radiograph, while72% of the 134 cases with a bacterial pneumonia had alveolar infiltrates. Half of the 77 children with solely interstitial infiltrates on the chest radiograph had evidence of bacterial infection. The proportion of patients with increased WBC or ESR did not differ between bacterial and viral pneumonias, but differences in the CRP levels of >40 mg/l, >80 mg/l, and >120 mg/l were significantalthough the sensitivity for detecting bacterial pneumonia was too low for use in clinical practice. Conclusions: Most children with alveolar pneumonia, especially those with lobar infiltrates, have laboratory evidence of a bacterial infection. Interstitial infiltrates are seen in both viral and bacterial pneumonias.

hildhood community acquired pneumonia is a common illness. Several bacteria andviruses and their combinations can cause the infection, but there is a lack of rapid and commercially available laboratory tests for most pathogens which may explain why the aetiology is rarely established in clinical practice and why antibiotic treatment is empirical in most cases. Up to 60% of the cases are associated with respiratory virus infections, so unnecessary and ineffective antibiotictreatment may often be used.1 Many published studies have addressed the differentiation of bacterial from viral pneumonia using clinical,2–5 radiological,2–9 and routine haematological tests,2–5 9–11 but these methods have not been found to be sufficiently reliable in differential diagnosis. These studies have been hampered by incomplete aetiological approaches. Some studies have looked only for alimited number of microbes,2–5 7 12 some have used insensitive techniques,2 4 13 and some have used only serological tests14 or bacterial antigen tests.13 It is therefore not well established whether bacterial and viral pneumonia can be differentiated by routine radiological and laboratory tests. This 3 year study was undertaken to investigate the chest radiographic changes in childhood communityacquired pneumonia of many different aetiologies. In addition, the differential diagnostic roles of the total white blood cell count (WBC), erythrocyte sedimentation rate (ESR), and serum C reactive protein (CRP) levels were studied. To obtain the maximum yield of microbiological diagnoses we collaborated with several research laboratories and searched for 17 infective agents using many different...