T he University of Western Ontario
MEDICAL JOURNAL VOL. VII.
No. 2
Oedema and Its Management"=路 By EDWARD A. BARTRAM, M.D.,
London, Ontario problem of oedema is one that has aroused the interest of T HEphysiologists and clinicians for centuries. Although its mechanism is complex and many controversial points remain, recent investigation has shed much light on the subject, so that we are now able to formulate a rational basis for most types of oedema as they appear for clinical study. Oedema is a physical sign denoting excess fluid in the tissues of the body, chiefly in the intercellular spaces. It may be local or general in extent and when universally distributed loses its identity as oedema and becomes known as anasarca. Under normal conditions the outflow of fluid from the v ~ scular system into the tissue spaces and the inflow of fluid from the tissues into the vascular system and lymphatics is nicely adjusted. Oedema occurs when the balance is disturbed resulting in a greater passage of fluid into the tissue spaces than out of them. It is my intention to discuss generalized oedema and to mention the chief factors concerned in its mechanism. In order to understand the various types of oedema, we must be familiar with the forces which regulate the passage of fluid back and forth through the capillary wall. The influence of certain of these forces is now clearly understood, that of others is still veiled in mystery. In the mechanism of oedema, five important factors are involved. The first of these is the filtration or hydrostatic pressure within the capillary which tends to drive fluid into the tissue spaces. This is of primary importance in circulatory failure oedema, either cardiac or hepatic. The second factor concerns the colloid osmotic pressure exerted by the plasma proteins which tends to draw fluid from the tissues into the blood. Lowering of the colloid osmotic pressure is chiefly responsible for the widespread oedema of the "nephrotic syndrome" and the lesser grade of oedema associated with malnutrition. The third factor involves the permeability of the capillary wall, injury of the vessel allowing fluid *Read at the annual meeting of the Ontario Medical Association, London, Ontario, May, 1936.
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