Diagnostic and predictor role of some paraclinical markers in the differential diagnosis of acute infectious-inflammatory processes of the lower respiratory tract in children

Abstract

Diagnosis of acute infectious-inflammatory processes of the lower respiratory tract with a respect to justify etiotropic therapy is often based on evaluation of the activity of blood inflammatory markers and data of lungs' X-ray examination, but scientific evidence of their informativity in the differential diagnosis of community-acquired pneumonia and acute bronchitis is conflicting.

Purpose — to study the predictor role of some paraclinical indices in the verification of infectious and inflammatory diseases of the lower respiratory tract (community-acquired pneumonia and acute obstructive bronchitis) in children of different ages in order to optimize the treatment.

Materials and methods. To achieve the goal of the study, a cohort of patients with acute infectious-inflammatory pathology of children with different ages (75 patients) who received inpatient treatment at the pulmonology department of the Regional Children's Clinical Hospital in Chernivtsi has been formed by the method of simple random sampling. The first (I) clinical group was formed by 51 patients with a verified diagnosis of community-acquired pneumonia (CAP), acute course, and the second (II) clinical group included 24 children, in which the infiltrative acute process in the lungs was excluded, but who had broncho-obstructive syndrome. 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 attributive (AR) and relative (RR) risks, and 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 CAP 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 CRP — С-reactive protein) 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 CRP level in blood >6 mg/ml), indicating that they are enough, but only for confirming inflammation of the lung parenchyma. From the standpoint of clinical epidemiology, it has been proved that the asymmetry of findings at lung radiographs (asymmetry of pulmonary enhancement, asymmetric changes of lung roots and, especially, the presence of infiltrative changes at lung parenchyma) are the most informative diagnostic tests in pneumonia verification (ST=90–95%) and have a statistically significant predictor role in the final diagnosis (OR=11.6–150). When assessing the hemogram in children of the II clinical group it has been found that only the relative number of band neutrophils <5%, as a diagnostic test, had an insignificant amount (16%) of false-positive results, which allows to use this marker in confirming the diagnosis of acute obstructive bronchitis, but not as its predictor (OR=2.21; 95% CI: 0.69–7.06) or screening test (Se=29%). At the same time, a significant diagnostic and predictor role of the chest X-ray examination in the differential diagnosis of acute BOS with pneumonia has been established. Namely, symmetrical alteration of the lung root architecture at chest radiographs in the absence of infiltrative changes in the pulmonary fields was characterized by few false-negative results (10%), which allow the use of this feature as a screening pattern in the diagnosis of acute obstructive bronchitis. The absence of changes of pulmonary at chest radiographs should be used to confirm the diagnosis of acute obstructive bronchitis (Sp=98%), but not as a screening sign due to the significant number of negative results in the presence of the disease (Se=48%).

Conclusions. In general, the low diagnostic and predicting role of the common blood inflammatory markers for the diagnosis of acute inflammation of the lung parenchyma in children of different ages, as well as in the differential diagnosis of pneumonia and acute obstructive bronchitis have been confirmed.

At the same time, it has been found that such radiological features as asymmetry of pulmonary pattern enhancement and the presence of asymmetric infiltrative changes of the lung parenchyma are the most informative diagnostic tests in the verification of pneumonia (Se=80–88% and Sp=90–95%), and have a statistically significant predictor role in the final diagnosis (OR=38.95–150).

It has been shown that symmetrical changes of lung roots (their deformation, widening or infiltration) at chest radiographs in the absence of infiltrations in the pulmonary fields, as well as the absence of changes in the pulmonary pattern, have a statistically significant predictor role in the diagnosis of acute obstructive bronchitis (OR=20,78–55,0).

The study was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the institution specified in the work. Informed consent was obtained from the parents of the children for the research.