Comparing the inflammatory biomarkers and methacholin bronchial hyperreactivity in patients with chronic cough

Chronic cough is a common symptom and is one of the primary reasons for referral to the policlinics of respiratory diseases. Almost all of the pulmonary problems can cause chronic cough, and also some extrapulmonary events can take place in etiology. The most frequent three causes of chronic cough is postnasal drip syndrome, asthma and gastrooesophageal reflux. Bronchial Provocation Tests (BPT) are performed to assess the bronchial hyperreactivity and differantiate cough secondary to asthma from other reasons. Methacholin is a stimulant used frequently in bronchial provocation tests. In this study we planned to compare the bronchial hyperreactivity to methacholin and inflammatory biomarkers in patients suffering chronic cough. 55 patients over 18 years old referring to Bulent Ecevit University Medical Faculty Health Practice and Research Center Repiratory Diseases Policlinic with complaint chronic cough and also 20 healthy volunteers between May 2012-February 2013 were included. Chest x-ray and spirometric analysis of both groups were found normal. BPT was performed to all of the participants. Also venous blood sample was collected from all patients for analysis of total serum immunglobulin E (IgE), eosinophilic cationic protein (ECP), serum white blood cell count (WBC), eosinophil , C-reactive protein (CRP) and sedimentation. Patients were evaluated for etiologic causes and postnasal drip syndrome was found in %38,2 of patients, gastrooesophageal reflux was found in %34,5 of patients and asthma was found in %5,4 of patients. Bronchial hyperreactivity to methacholin was found positive in 3 of patients suffering chronic cough, there was no positive test result in control group, the positivity ratio was also lower and no statistically importance was found. Also 6 cases having negative BPT result in chronic cough group had used inhaled corticosteroid for the last month and 3 of them also had clinical asthma diagnosis. Low positivity of BPT in patients suspected about asthma may be explained with false negative BPT results with use of inhaled corticosteroids or other possible causes interfere with asthma in cases with chronic cough and clinical asthma symptoms. There was no statistically important difference was found for inflammatory biomarkers in both groups; but as it has more significance recently, we believe that comprehensive studies are needed for this.