How Does Renal Parenchyma Disease Cause Hypertension

Renal diseases can be classified into parenchymal lesion and vascular lesion according which part of the kidneys are damaged. Renal parenchymal diseases refers to a clinical condition in which kidney tissues are scarred and damaged.

Since renal functional units are damaged, kidney functions will be affected and patients will have a series of symptoms and discomforts among which hypertension is one common sign.

The pathogenesis and treatment for hypertension is different for different causes. Here we will introduce why renal parenchymal damages will cause increased blood pressure so that we can seek more targeted and effective treatment and medicines accordingly.

High blood pressure caused by acute renal parenchymal damages is mainly due to water and sodium retention, therefore timely diuretic treatment often can lower the blood pressure. While the pathogenesis of hypertension caused by chronic renal parenchymal disease is more complex and it can be caused by many factors.

Activation of RAAS (rennin-angiotensin aldosterone system). Renal parenchymal diseases can cause ischemia and hypoxia in the kidneys which will activate the RAAS. Angiotensin II has direct stimulation to vasoconstriction and aldosterone can worsen water and sodium retention so as to further increase high blood pressure.

Other factors that can cause sodium retention and blood volume increase can all cause blood pressure to increase such as decreased GFR, activation of RAAS and sympathetic nervous system, insulin resistance and reduced nitric oxide, etc. What is more, the above mentioned factors can increase vascular resistance and worsen high blood pressure.

Renal parenchymal diseases can affect one or both kidneys. The common unilateral renal parenchymal diseases include reflux nephropathy, chronic pyelonephritis, hydronephrosis and renal gland carcinoma, etc. Early removal of the diseased kidney can cure or greatly improve hypertension.

Common bilateral renal parenchymal diseases include primary and secondary glomerulonephritis, chronic interstitial nephritis and adult polycystic kidney disease.

Whatever the underlying disease of renal parenchymal impairments, the incidence of hypertension will increase along with the severity of renal function damages. It has been reported that more than 90% end stage renal disease patients will have elevated blood pressure. Therefore patients should receive early treatments so as to protect kidney functions and slow down illness progression.