Edema is caused by all of the following mechanisms, EXCEPT: Minimum daily requirement for potassium in healthy adults is estimated to be 2g. The average intake of potassium among the adult population of industrialized world is approximately is 2-3 per day. Recommended daily intake of potassium to reduce risk of high blood pressure, stroke, and hea disease is 4-5g/d.
Edema is the accumulation of interstitial fluid in abnormally large amounts. The lymphatic circulation takes up a significant poion of fluid from the interstitial tissues, along with extravascular proteins, and returns it to the blood. If the lymphatic circulation is obstructed, the lymphatic drainage is interrupted. Affected areas have large accumulation of fluid and are edematous. The vascular system also aids in maintaining fluid volume. The endothelium is the lining of the vessels and serves as a semipermeable membrane for fluids and components, primarily by keeping proteins intraluminal colloidal pressure and causing fluid leakage and edema. Capillary blood pressure (BP), or hydrostatic pressure, is the force in capillaries that drives fluids from the capillaries into the tissues. By increasing the hydrostatic pressure, fluids tend to be forced out of the capillaries into tissues, causing edema. Sodium and water also aid in maintaining fluid balance. Sodium retention causes water retention, leading to an expansion of the extracellular fluid volume both intravascularly and in the tissues with edema. The protein concentration of plasma also functions in the maintenance of fluid balance. The major protein involved is albumin. By decreasing the plasma protein concentrations, there is a decreased colloid osmotic pressure in the blood, so there is a decreased counterforce to the hydrostatic BP. Thus, there is increased fluid escaping from the capillaries and decreased resorption of fluid from tissues. Fluid tends to accumulate extracellularly, with generalized edema. Ref: Ganong's review of Medical Physiology, 23rd Ed, page 551
Increased vascular permeability
Obstruction to lymphatic flow
Sodium retention
Increased plasma proteins