<unk>  is characterized by the pathological limitation of airflow in the airway that is not fully reversible .<unk>  is the umbrella term for<unk>  bronchitis, emphysema which could be differentiated according to pathologic findings. Airflow limitation may lead to shortness of breath (dyspnea), cough, wheezing, and finally respiratory failure. In clinical practice,<unk>  is defined by its characteristically low airflow on lung function tests. In contrast to asthma, this limitation is poorly reversible and usually gets progressively worse over time. Hallmark pathologic features of<unk>  bronchitis include: hyperplasia (increased number) and hypertrophy (increased size) of the goblet cells (mucous gland) of the airway, resulting in an increase in secretion of mucus, which contributes to the airway obstruction. Emphysema is determined by destruction of<unk>  acinus. Acinus is the structures distal to the terminal bronchiole, consisting of the respiratory bronchiole, alveolar ducts, alveolar sacs, and alveoli.<unk>  is mostly due to tobacco smoking; but can be due to other airborne irritants such as coal dust, asbestos or solvents, congenital conditions such as alpha-1-antitrypsin deficiency and as well as preserved meats containing nitrites. Diagnosis of<unk>  is based on spirometry findings in appropriate clinical setting. Smoking cessation is the main stay in the treatment. Bronchodilators and anticholinergic inhalers are the main pharmacologic therapy in<unk>  patients.<unk>  rehabilitation and sometimes lung volume reduction surgery are required in specific circumstances.
Chronic obstructive pulmonary disease
Asthma
Chronic bronchitis
Exercise induced asthma
Alpha 1-antitrypsin deficiency
Obstructive lung disease
Occupational asthma
Pulmonary amyloidosis