The characteristic feature of nephrotic syndrome is that patients may experience edema, which is related to the nature of this disease. The essence of this disease is due to some reason that damages the glomerular capillary filtration barrier. As a result, when blood passes through the glomeruli, it leaks proteins from the blood. A 24-hour urinary protein quantification will exceed 3.5 grams, which constitutes a large amount of urinary protein. Consequently, a large amount of protein is leaked into the urine, causing the protein concentration in the plasma to decrease. This leads to a reduction in the colloidal osmotic pressure of the plasma, causing fluid to move from inside the blood vessels to outside, thus leading to edema. Therefore, the most significant clinical feature of nephrotic syndrome is the potential to cause edema, and severe cases of edema may elevate blood pressure, lead to pulmonary edema, manifesting as difficulty breathing, chest tightness, and shortness of breath.