Chronic obstructive pulmonary disease differential diagnosis


 * Philip Marcus, M.D., M.P.H. [mailto:pmarcus192@aol.com];

Overview
Chronic obstructive pulmonary disease is characterized by the pathological limitation of airflow in the airway that is not fully reversible. COPD is the umbrella term for chronic bronchitis, emphysema and a range of other lung disorders. This leads to a limitation of the flow of air to and from the lungs, causing shortness of breath (dyspnea), cough, and wheezing. In clinical practice, COPD 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. It should be differentiated from certain conditions that have similar presentation for instance congestive heart failure, chronic asthma, bronchiectasis, and bronchiolitis obliterans.

Features specific for Congestive heart failure
Chronic obstructive pulmonary disease (COPD) may be confused with congestive heart failure due to similar presentations like wheezing and shortness of breath. Features specific to congestive heart failure are:
 * Orthopnea
 * Paroxysmal nocturnal dyspnea
 * Fine crackles on ausculatation
 * Chest X ray findings of cardiac enlargement, pulmonary congestion (Kerley B lines, and pleural effusion)
 * The peak expiratory flow is low in COPD whereas there is higher flow in heart failure
 * Comet-tail sign on ultrasonography is a good indicator of heart failure–related dyspnea

Features specific for Bronchiectasis

 * Copious purulent sputum
 * Coarse crackles
 * Clubbing
 * CT findings suggestive of Bronchiectasis.

Features specific for Bronchiolitis obliterans

 * History of collagen vascular disease.
 * Young patient usually without a history of smoking
 * CT scan shows finding of mosaic attenuation and no evidence of emphysema.

Features specific for chronic Asthma
(By organ system)
 * Chronic asthma responds well to bronchodilators.
 * Normal diffusion capacity of lung on pulmonary function test.