Oedema

This is an abnormal accumulation of fluid in the intercellular spaces of the body. It results from disruption to the physiology of capillary or lymphatic exchange by, for example:

• increased capillary hydrostatic pressure secondary to:
  • an elevation of blood pressure at the arterial end of the capillary
  • an increase in venous pressure at the venous end of the capillary e.g. heart failure
• an increase in capillary permeability with exudate of intravascular proteins e.g. in acute inflammation
• decreased intercellular lymphatic drainage

Ultimately, exceedingly elevated intercellular pressures may result in spread of fluid into the next available compartment as in pulmonary oedema and ascites.

Reference

1. Cho S, Atwood JE. Peripheral edema. Am J Med. 2002 Nov;113(7):580-6.