[Acute dyspnea--what should I not forget?].

Acute dyspnea represents a diagnostic challenge even for the experienced physician. There are no prospectively evaluated diagnostic algorithms dealing with this frequent clinical problem. First of all, the emergency has to be assessed and life supporting measures have to be considered. In addition to a thorough medical history and clinical examination, chest X-ray, spirometry, ECG, hemoglobin measurement, BNP and D-dimer testing represent valuable diagnostic tools and are available to GP's. Most commonly, acute dyspnoea is pulmonary or cardiac in origin. Up to one third of all cases will have several causes. Functional dyspnea is difficult to diagnose but should be taken into consideration after excluding any somatic cause. Hyperventilation is found in both, organic and non organic diseases, and is therefore an inappropriate criterion to differentiate between the two. The mainstay in the management of any symptom is to primarily treat the underlying disease. A significant hypoxemia (SO2 < 90%, pO2 < 60 mmHg) ought to be corrected by supplemental oxygen. It is inappropriate to withhold oxygen from patients with COPD and severe hypoxemia just to avoid hypercapnia. Besides oxygen, opiates efficiently relief dyspnoea but harbour the risk of respiratory depression, altered mental status or aspiration.