[Differential diagnoses of dyspnoea]

Dyspnoea is a very subjective phenomenon based on the variation in severity for a given degree of functional impairment. It is difficult to grade dyspnoea. Dyspnoea is caused by a variety of physiological, pathophysiological, psychological and environmental factors. The mechanisms leading to dyspnoea are not completely understood. It is known that mechanical reasons like ventilation disturbances (obstruction, restriction), impairment of the ventilation muscles, skeletal deformation and many other reasons can cause dyspnoea. Every pulmonary or cardiac disease may induce dyspnoea depending on the progression of the underlying disease. The aim of this article is to give an overview of basic pathophysiological mechanisms, diagnostic procedures and considerations with regard to possible differential diagnoses.