2. EDEMA : presence of excess fluid in the body tissues
3. A. Intracellular Edema a . depression of the metabolic systems of the tissues b. lack of adequate nutrition to the cells
4. A. Extracellular Edema a. abnormal leakage of fluid from the plasma to the interstitial spaces across the capillaries failure of the lymphatics to return fluid from the interstitium back into the blood The most common clinical cause of interstitial fluid accumulation is excessive capillary fluid filtration
5. Factors That Can Increase Capillary Filtration 1. Filtration Coefficient – product of permeability and surface area of the capillaries ( Kf) 2. Capillary Hydrostatic Pressure ( Pc) 3. Interstitial Fluid hydrostatic Pressure ( Pif) 4. Capillary Plasma colloid Osmotic Pressure (iic) 5. Interstitial Fluid Colloid Osmotic Pressure (iiif) Filtration = Kf x ( Pc – Pif – iic + iiif )
6. Major Factors that cause Increased Capillary Filtration of Fluid and Protein into the Interstitium: 1. Increased capillary Hydrostatic Pressure 2. Decreased Plasma Colloid Osmotic Pressure 3. Increased Capillary Permeability
7. Summary of Causes of Extracellular Edema Increased capillary pressure A. Excessive kidney retention of salt and water 1. Acute and chronic kidney failure 2. Mineralocorticoid excess
8. B. High venous pressure 1. Heart failure 2. Venous obstruction 3. Failure of venous pump a) paralysis of muscles b) immobilized parts of body c) Failure of venous valves
9. C. Decreased arteriolar resistance 1. Excessive body heat 2. Insufficiency of sympathetic nervous system 3. Vasodilator drugs
10. II. Decreased plasma protein A. Loss of proteins in urine (nephrotic syndrome) B. Loss of protein from denuded skin areas 1. Burns 2. Wounds C.Failure to produce proteins 1. Liver disease 2. Serious protein or caloric malnutrition
11. III. Increased capillary permeability A. Immune reactions that cause release of histamine B. Toxins C. B acterial infections D. Vitamin deficiency, especially vitamin C E. P rolonged ischemia F. Burns
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13. Safety Factors That Prevent Edema 1. The safety factors caused by low tissue compliance ( -3mmHg ) 2. The safety factor caused by increased lymph flow ( 7 mmHg ) 3. The safety factor caused by washdown of proteins from the interstitial spaces ( 7 mmHg )