The Differential Diagnosis of Dyspnea

Dyspnea is a common symptom affecting as many as 25% of patients seen in the ambulatory setting. It can arise from many different underlying conditions and is sometimes a manifestation of a life-threatening disease.

This review is based on pertinent articles retrieved by a selective search in PubMed, and on pertinent guidelines.

The term dyspnea refers to a wide variety of subjective perceptions, some of which can be influenced by the patient's emotional state. A distinction is drawn between dyspnea of acute onset and chronic dyspnea: the latter, by definition, has been present for more than four weeks. The history, physical examination, and observation of the patient's breathing pattern often lead to the correct diagnosis, yet, in 30-50% of cases, more diagnostic studies are needed, including biomarker measurements and other ancillary tests. The diagnosis can be more difficult to establish when more than one underlying disease is present simultaneously. The causes of dyspnea include cardiac and pulmonary disease (congestive heart failure, acute coronary syndrome; pneumonia, chronic obstructive pulmonary disease) and many other conditions (anemia, mental disorders).

The many causes of dyspnea make it a diagnostic challenge. Its rapid evaluation and diagnosis are crucial for reducing mortality and the burden of disease.