Bronchial Hyper-responsiveness in Post-tubercular Patients: A Case-control Study

Abstract

Introduction: Bronchial hyper-responsiveness is the manifestation of excessive bronchoconstriction in response to diverse types of stimuli both physical and chemical. It is the most characteristic feature of bronchial asthma; it also occurs in a spectrum of other diseases like Chronic Obstructive Pulmonary Disorders (COPD) and reactive airway syndrome and may be provoked by a variety of stimuli like histamine and methacholine. Patients of healed pulmonary Tuberculosis (TB) show varying extent of lung impairment such as fibrosis, collapse, emphysema and broncho alveolar destruction. Aim: To assess the incidence and severity of obstructive airway diseases in previously treated TB patients. Materials and Methods: This was a prospective case control study, carried out in the Department of Tuberculosis and Respiratory Diseases, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India, from September 2017 to September 2019, this study included 120 patients of previously treated TB, who were divided into two groups. The case group (71) included patients who completed treatment for TB and had dyspnoea. The control group (49) consisted of patients who completed the treatment but did not have dyspnoea. The patients were subjected to spirometry, histamine bronchial challenge test and computed chest tomogram along with routine investigations including sputum for Acid Fast Bacilli (AFB). Results: The present study showed significant histamine hypersensitivity among post TB patients. In the case group, 34 (56%) patients showed positive response to bronchial challenge test with histamine; while in control group only 7 (14%) showed a positive response (p-value=0.004). Pulmonary function test (spirometry) showed an obstructive pattern in 35 (49%) case group patients, while normal pattern was the most common finding seen in 23 (47%) in the control group followed by obstruction in 10 (21%) patients. Among the cases, the mean Forced Expiratory Volume in the first second (FEV1) was 65.77±15.98, while among the controls, it was 80.02±8.81. The case group had a mean Forced Expiratory Volume in the first second/Forced Vital Capacity (FEV1/FVC) of 78.09±15.75, as against 81.33±16.79 in the control group. Conclusion: Airway bronchial hyper-reactivity is a prominent feature in previously treated tubercular patients. This underlines the need for proper attention towards post-tubercular lung function impairment and proper treatment of such patients so as to lessen the impact of bronchial hyper-reactivity on patient symptoms and their quality of life.

Keywords

• histamine challenge test
• pulmonary function tests
• reactive airway dysfunction syndrome