Introduction
In health, the volume and biochemical composition of both extracellular and intracellular fluid compartments in the body remains remarkably constant. Many different disease states result in changes of control either of extracellular fluid volume, leading to clinical abnormalities such as oedema and hypotension or hypertension, or of the electrolyte composition of extracellular fluid. A sensible approach to these abnormalities is therefore essential in a wide range of clinical settings.
