How Does Kidney Failure Cause High Blood Pressure

Renal hypertension is a secondary high blood pressure that caused by chronic kidney disease (CKD). More than 80% of CKD patients in late renal failure have high blood pressure. Do you know why and how does kidney failure cause high blood pressure?
We all know that the increase of pressure are of two reasons: one is (that) the substance that flow through vessels increases when the vessels invariant, the other is the vessels become narrower and the amount of substance the same as before. So we know the reason why kidney failure cause high blood pressure.
1 The capacity factors for high blood pressure: The function of renal artery is to filter the blood which flow through it, and then return these blood into the body’s circulation. When the renal parenchyma damaged, the capacity of filtering water and sodium weaken. When sodium intake exceeds the discharge capacity of the body, there will be retention of water and sodium. In this condition, the vessels don’t change and the amount of blood increased (water sodium retention), the pressure of blood increases. At the same time, the retention of water and sodium cause the thickening of vessel wall, the decrease of elasticity and the enhancement of vascular resistance, hence lead to hypertension.
2 Renin dependent high blood pressure: Renal artery stenosis, reduce of renal perfusion pressure, renal parenchyma disease, as well as cell tumour of the renin secretion, can make the juxtaglomerular cells release a lot of rennin. The main function of renin is to shrink blood vessels. The amount of blood don’t change, the vessels become smaller, so the pressure boosting. Renin and angiotensin can prompt the increase of aldosterone secretion again, then cause water sodium retention. Water sodium retention make further increases of blood volume, thus aggravate hypertension.
We have known that kidney failure can cause high blood pressure, and high blood pressure aggravates kidney disease. So if we want to control kidney disease, we have to control the high blood pressure, hence to reverse the stage of CKD.