An accumulation of pus within a cavity, the term being generally reserved for collections of pus within one of the pleural cavities (see LUNGS). Since the advent of antibiotics, the condition is relatively uncommon in developed countries. The condition is virtually an ABSCESS, and therefore gives rise to the general symptoms accompanying that condition. However, on account of the thick, unyielding wall of the chest, it is unlikely to burst through the surface, and it is therefore of particular importance that the condition should be recognised early and treated adequately.

The condition most commonly follows an attack of PNEUMONIA; it may also occur in the advanced stage of pulmonary TUBERCULOSIS. Empyema also occurs at times through infection from some serious disease in neighbouring organs, such as cancer of the OESOPHAGUS, or follows upon wounds penetrating the chest wall.

Treatment may be by surgery or by drainage through a tube inserted into the pleural cavity, combined with instillation of agents which break down the secretions.