The main clinical manifestations of acute glomerulonephritis are proteinuria, hematuria, edema and hypertension. The pathogenesis of edema mainly includes the following aspects: first, the glomerular filtration rate caused by nephritis decreases, the water metabolism in the body decreases, and the urine output decreases. Secondly, after nephritis, renin, angiotensin, aldosterone and other hormones secreted by the kidneys increase, and these endocrine hormones can cause the kidneys to reduce the excretion of sodium and water, resulting in sodium and water retention in the body, thus edema occurs. Thirdly, due to hypoproteinemia after a large amount of proteinuria in nephritis, plasma colloid osmolality decreases, intravascular water decreases, and enters into the subcutaneous tissue interstitial space, thus edema occurs.