ABSTRACT
The natural philosophers of ancient Greece believed that ‘pneuma’ (roughly equivalent to spirit or air) was endowed with the properties of life and intelligence. Oedema describes the abnormal collection of fluid within the extracellular compartment. Such collections will occur within the body cavities (as effusions in the pleural and pericardial cavities or ascites in the peritoneal cavity), within loose and relatively acellular connective tissue (dermis of skin, subcutaneous tissue or submucosa of gut), within the brain or within the alveolar spaces of the lungs. When swollen oedematous tissue is viewed microscopically, one sees only a widening of the clear space between cells. Pulmonary congestion and oedema is caused by left heart failure, but is most marked when there is stenosis (narrowing) of the mitral valve resulting in compensatory work hypertrophy of the muscular wall of the left atrium.
