Informativity of common inflammatory blood markers in the verification of acute inflammatory processes of the lower respiratory tract

Abstract

Verification of acute infectious inflammatory processes of the lower respiratory tract and indication for antibiotic therapy are often based on the evaluation of the activity of inflammatory blood markers, but the data on their informative value in the diagnosis of acute pneumonia and bronchitis in children are controversial and conflicting.

Purpose - to study the diagnostic value of some inflammatory blood markers in the verification of uncomplicated community-acquired pneumonia and acute obstructive bronchitis with the purpose of management’s optimization of infectious inflammatory diseases of the lower respiratory tract in children.

Materials and methods. At the pulmonological department of the Regional children’s clinical hospital in Chernivtsi city 75 children have been examined. In the I clinical group 51 patients with diagnosis of «community-acquired pneumonia» were enrolled, and the second (II) group consisted of 24 children with acute obstructive bronchitis. According to the main clinical characteristics, the comparison groups have been comparable. The results of the study have been analyzed by parametric («P», Student’s criterion) and non-parametric («Рφ», Fisher’s angular transform method) calculation methods, and methods of clinical epidemiology with an evaluation of the diagnostic value of the tests has been performed taking into account their sensitivity (Se) and specificity (Sp), as well as the odd ratio (OR) of the event, taking into account their 95% confidence intervals (95% CI).

Results. The analysis of the obtained dada has showed that in the patients with community-acquired pneumonia such common inflammatory blood markers (leukocytosis, relative neutrophilosis, shift of leukocyte formula to the left, elevation of erythrocyte sedimentation rate (ESR) or high level of С-reactive protein - CRP) are characterized by low sensitivity (Se in range between 11% and 63%) indicating that they are inadvisable for use as the screening tests for the verification of pneumonia. At the same time, it has been shown that these inflammatory blood markers are characterized by sufficient specificity (in the range from 75% to 93%) in the verification of pneumonia only under their significant increase (total leukocyte count >15.0x10⁹, ESR >10 mm/h and СRP level in blood >6 mg/ml), indicating that they are relevant enough, but only for confirming inflammation of the lung parenchyma.

It has been found that the normal level of leukocytes (<10.0x10⁹) in the hemogram did not have sufficient diagnostic (the number of false-negative and false-positive results was 46% and 45%, respectively) or probable predictor role (OR=1.44; 95%CI: 0.54-3.81) in the diagnosis of acute obstructive bronchitis, and therefore could not influence the composition of etiotropic treatment, namely to cancellation of antibiotic therapy. However, the number of rod neutrophils ≤5% in the common blood count has been characterized by a small number (16%) of false-positive results, which allows the use of this marker as confirming the diagnosis of acute obstructive bronchitis, and as well, as indication for antibiotic therapy discontinuation, but not as a predictor (OR=2.21; 95% CI: 0.69-7.06) or screening index (Se=29%).

Conclusions. Analysis of the data has showed that in children with community-acquired pneumonia such common indicators of inflammatory response (leukocytosis, relative neutrophilia, shift of leukocyte formula to the left, acceleration of ESR or high CRP level in the blood) are characterized by a large proportion of false-negative results, and thus indicates the inexpediency of their use as screening methods to verify pneumonia. At the same time, it has been shown that these inflammatory blood markers are characterized by sufficient specificity in the verification of pneumonia under their significant increase (number of blood leukocytes >15.0 x10⁹, ESR ≥10 mm/h and CRP level >6mg/ml), which indicates the possibility of their use to confirm inflammation of the lung parenchyma. Herewith the number of rod neutrophils in the hemogram ≤5% is characterized by a high specificity (Sp=84%), which allows to use this marker in confirming the diagnosis of acute obstructive bronchitis and, as well as, an indication for antibiotic therapy cancellation.

The research was carried out in accordance with the principles of the Helsinki declaration. The study protocol was approved by the Local ethics committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies.

No conflict of interest was declared by the authors.