The pathogenesis of hydronephrosis

The normal function of the urinary system is the formation, storage and discharge of urine. The formation of urine is composed of glomerular filtration, renal tubular secretion and reabsorption. Under normal circumstances, the renal pelvis contraction, diastolic coordination action, resulting in renal pelvis hydrostatic pressure of about 10cm H2O or so, to ensure the smooth passage of urine.

 When the urinary tract obstruction, the renal pelvic pressure can be increased to 50 ~ 70cm H2O, on the one hand to increase the capsule pressure, on the other hand to reduce the glomerular capillary pressure, the glomerular filtration pressure reduced until the stop. The back pressure of the urine of the renal tubular distal expansion, proximal degeneration, loss of the original secretion and reabsorption function. Due to increased intracranial pressure to the blood vessels pressure, especially the output of the glomerular artery after compression, renal tissue nutrition disorders, renal papillary degeneration atrophy, by the convex concave, renal tubular degeneration and renal thinning, And finally atrophy into fibrous tissue cysts.

Observation of the ureteropelvic junction with optical and electron microscopy, mainly in the wall muscle changes, such as collagen tissue proliferation, deposition and fibrous tissue infiltration, which may be caused by local stenosis and then the main reason for the formation of obstruction. Ureteral contraction of the rhythm, urine retention can also form an obstruction.

This is part of the hydronephrosis in patients with renal pelvis and ureteral connection lumen although smooth but can still lead to obstruction reasons. Renal effusion is not static, but often cycle. In the water after 2 weeks, the renal ureter urine urea was significantly reduced, while the glucose and chloride has increased significantly.

Renal pelvis and re-absorption of the way may be:
① calyx bulb venous reflux; ② renal tubular reflux; ③ interstitial reflux; ④ lymphatic reflux. So acute obstruction if within 5 to 6 weeks to lift the obstruction, renal function can still be restored, which also prompted us to hydronephrosis, especially acute obstruction, can not easily decide the line of renal resection. After the formation of obstruction after the formation of hydronephrosis, depending on the severity of obstruction (obstruction is to continue to develop), renal pelvis adaptability (buffer) and the rate of urine flow, if the relative balance, you can stop the development, Thus stabilizing in the mild hydronephrosis stage.