[Diseases to differentiate from COPD, with emphasis on bronchial asthma].
Differential diagnosis of chronic obstructive pulmonary disease (COPD) from asthma is not a difficult task for many clinicians. Patients with COPD have a history of heavy smoking and show a slowly progressive dyspnea on exertion and there is little variability in symptoms, and they show a poor response to bronchodilators and corticosteroids. Asthma usually begins in early childhood with atopy, shows episodic dyspnea with wheezing, especially during night and early morning. Some patients, however, show adult onset, irreversible airflow limitation, and neutrophilic airway inflammation. The airway remodeling in asthma may be the cause of confusing pathophysiology. Other diseases showing airway hyperresponsiveness, such as allergic bronchopulmonary aspergillosis, Churg-Strauss syndrome, and left heart failure presenting cardiac asthma, may sometimes show similar clinical pictures to COPD. Chronic airway diseases are also possible candidates for differential diagnosis of COPD. Bronchiectasis, sinobronchial syndrome, diffuse panbronchiolitis, obliterative bronchiolitis, and other chronic airway diseases should be considered. Some interstitial lung diseases, such as smoking-related interstitial lung diseases and lymphangioleiomyomatosis, often show obstructive ventilatory impairment, and therefore should be considered in differential diagnosis of COPD.