3. What factors promote the development of edema?
Edema occurs because of either:
Excessive fluid filtration out of capillaries, which can be due to either:
- Elevated hydrostatic pressure usually due to heart failure (see Starlings Forces) or over-hydration
- Reduced plasma colloid osmotic pressure (hypoproteinemia) which itself can be due to:
- Excessive protein loss from the kidneys or bowel
- Reduced production from the liver
- Increased capillary membrane permeability