Respiratory Causes of Breathlessness
The development of shortness of breath (SOB) is an expected outcome of overexertion, as normally occurs after strenuous exercise. SOB occurring at rest or during marginal exertion is considered abnormal. Multiple organ systems are involved in the differential diagnosis of SOB but for the purpose of this article, we concentrate on the pulmonary system and include chronic obstructive pulmonary disease (COPD), asthma, pneumonia, pneumothorax, interstitial lung disease, lung cancer and dysfunctional breathlessness. This is the second in a series of three articles focusing on diagnosis of the breathless patient.