ABSTRACT
Edema is an increase in the volume of interstitial fluid. The latter is the extravascular portion of the extracellular compartment, formed as an ultrafiltrate of plasma. Plasma volume may or may not be increased in patients with edema. Whatever the etiology of edema, it is ultimately manifested by alterations in the Starling forces at the capillary level such that there is increased formation of interstitial fluid, or its removal is diminished, or both. "Generalized" edema is a symptom or sign of a primary clinical disorder which has set in motion a chain of events resulting in decreased renal excretion of sodium. Perhaps the major complexity was perceived when it was recognized that all conditions characterized by generalized edema have in common decreased renal excretion of sodium and water. Because the initiating event in the development of generalized edema is usually heart failure, cirrhosis, or renal disease, optimal treatment of the underlying condition whenever possible is important.
