The main symptoms of nephrotic syndrome are massive proteinuria, hypoproteinemia, marked edema and hyperlipidemia. First, massive proteinuria is the most important clinical manifestation of patients with nephrotic syndrome and the most basic pathophysiologic mechanism of nephrotic syndrome. Massive proteinuria is defined as adult urinary protein excretion greater than 3.5 grams per day. Second, hypoproteinemia, plasma albumin drops to less than 30 g/L. Large amounts of albumin are lost from the urine in nephrotic syndrome, prompting compensatory synthesis of albumin in the liver and increased renal tubular catabolism. Third, edema, in nephrotic syndrome, plasma colloid osmotic pressure decreases, so that water from the vascular lumen into the tissue interstitial space, is the basic cause of edema in patients with nephrotic syndrome. Fourth, hyperlipidemia. Hypercholesterolemia is mainly due to increased hepatic synthesis of lipoproteins, hypertriglyceridemia is mainly due to catabolic disorders.