The Reason for Edema of Nephrotic Syndrome

Patients with Nephrotic Syndrome have one obvious characteristic: edema or swelling. Generally, the reasons are as follows:
Firstly, when patients are suffering from Nephrotic Syndrome, a large amount of protein will leak out, which leads to low protein in plasma, thus causing the decline of plasma oncotic pressure. When it declines from normal one(3.3～4kPa) to 0.8～1.1kPa, water in the blood vessels will move to the interstitial fluid, thus causing edema or swelling.
Secondly, effective blood volume decrease, which can also leads to edema or swelling. The moving out of water in plasma leads to the decrease of effective blood volume. In this case, ADH increases,and the reabsorption water of renal tubules increases, as well. The renin- angiotensin- aldosterone system starts, which leads to secondary hyperaldosteronism, thus causing increased absorption of sodium and inhibiting the coming into being of natriureticfactor. So the discharge of sodium decreases in the kidney, which leads to the retention of water and sodium in the body, thus causing serious edema or swelling.