Role of Induced Sputum to Assess Airway Inflammation in Asthma - Study from a Tertiary Care Centre

Asthma is a serious global health issue affecting all age groups. Asthmatics are usually assessed by spirometry, which means the physiologic impairment. But their hall mark is airway inflammation, which is rarely assessed. Airway inflammation has been studied widely in patients with chronic asthma, and it is seen that it correlates with the severity of the disease. The objective of this study was to assess the use of induced sputum cytology to classify asthmatics as neutrophil & eosinophil predominant , and to study the relationship of level of control, severity of obstruction and their response to inhaled steroids in asthmatics with the inflammatory subtypes in stable asthmatic patients. Methods: A total of 80 asthmatics who attend the outpatient clinic at the department of respiratory medicine, govt medical college Kannur, who met the inclusion & exclusion criteria were taken for the study. Initially history was taken and spirometry done and graded according to severity and then sputum induction done with 3% saline. Sputum processed and diffentiated into neutrophil, eosinophil or mixed/ paucigranulocyte type. A comparative study was done and patients were treated with inhaled corticosteroid for 2 weeks and their response were evaluated. Result: Out of total 80 patients 60% were females. 18.8% were uncontrolled & 40% were well controlled. 21 patients had a neutrophil predominant picture, 44 had eosinophil predominant&6 had mixed picture. There was significant association between sputum phenotype & level of control, showing predominant neutrophil in uncontrolled. The response to inhaled steroid showed a significant improvement with eosinophilic phenotype. Conclusion: Sputum induction can be used as an important noninvasive measurement of airway inflammation, in the diagnosis and management of asthma. It can also be used to assess the type of airway inflammation in asthmatic patients who were not controlled by asthma management.