Dyspnoea is an unpleasant sensation of difficulty in breathing. Patients may complain of breathlessness, difficulty in ‘catching their breath’, a feeling of suffocation, or tightness in the chest. Dyspnoea should be graded by the exertional capability of the patient and the impact on their lifestyle. It is useful to document when breath-lessness occurs, e.g. after 200 yards on the flat, up 1 flight of stairs.
In general dyspnoea arises from either the respiratory or cardiovascular system and it is often difficult to distinguish between them. Although the presence of orthopnoea and paroxysmal nocturnal dyspnoea suggests a cardiovascular cause, patients with lung disease may experience orthopnoea due to abdominal contents restricting the movement of the diaphragm.
For diagnosis, respiratory dyspnoea is best considered according to the speed of onset and further differentiated by a detailed history and clinical examination (see Table 3.2).