ABSTRACT
The patient with acute on chronic breathlessness can be a difficult diagnostic dilemma, especially where there is a background history of Chronic obstructive pulmonary disease (COPD) and heart failure. An acute increase in breathlessness in COPD is usually due to a bacterial or viral chest infection, while in heart disease it is often due to pulmonary oedema, perhaps precipitated by either an MI or an arrhythmia. COPD is a mixture of emphysema and bronchitis that often overlap. The airway obstruction and alveolar destruction lead to air trapping and hyperinflation of the lungs. This leads to decreased inspiratory capacity and increased accessory muscle use. In left-sided cardiac failure, the sensation of dyspnoea is caused by back pressure in the pulmonary circulation. The nature of the sputum is a key differentiating feature; pink frothy sputum may indicate pulmonary oedema, whereas thick mucoid or purulent sputum probably indicates an infective exacerbation of COPD.
