An<unk>  is a group of<unk> s characterized by various deformities that result in the collapse of airways. Patients suffering from<unk>  usually present with shortness of breath due to damage to the airways within the lungs. This results in an inability to exhale air completely and an abnormally high amount of air may still present in the lungs after the end of full expiration. One of the main etiology of the<unk>  is long-term exposure to substances that irritate and damage the lung epithelium and lung parenchyma. This includes cigarette smoke, air pollution, chemical fumes, or dust etc. Patients are usually asymptotic during the initial phase of the<unk> . However, symptoms usually become more evident as the<unk>  process gets worse. The symptoms usually include a productive cough, difficulty in breathing, wheezing, and tightness in the chest. These<unk> s include asthma, COPD, bronchiolitis, bronchiectasis, heart failure, tuberculosis, cystic fibrosis, and lymphangioleiomyomatosis.<unk> s present with an obstructive pattern that is an increase in total lung capacity (TLC), increase in respiratory volume (RV), a decrease in forced vital capacity (FVC), a decreased forced expiratory volume (FEV1), and a decreased FEV1/FVC, on pulmonary function tests.
Obstructive lung disease
Restrictive lung disease
Interstitial lung disease
Alveolar lung disease
Reactive airways dysfunction syndrome
Chronic obstructive pulmonary disease
Asthma
Emphysema