Renal insufficiency causes renal ischemia

Liver and renal insufficiency pathophysiological changes, mainly decreased renal blood flow and glomerular filtration rate.

Renal insufficiency renal ischemia causes the following two aspects:

1 Effective plasma volume decreased

Severe liver disease, due to massive ascites (a large number of plasma leakage), a large number of diuretic (lose a lot of body fluids), upper gastrointestinal bleeding and hypoalbuminemia, can hypovolemia, decreased cardiac output, causing the blood flow through the kidneys reduced, resulting in renal ischemia. This is the so-called low-power type hepatorenal syndrome (This type is less common). Most of hepatorenal syndrome in patients with cirrhosis and ascites is a high power type, the cardiac output and plasma volume does not decrease, or even increase, but because there are a lot of extrahepatic collateral circulation and telangiectasia, so a lot of collateral blood flow distribution in cycling and deposition in the capillaries, leaving decreased renal blood flow and glomerular filtration rate decreased, the occurrence of oliguria and azotemia. Since the late ascites increased, so that blood volume decreased, while the inferior vena cava and the darling pressure, reduction in cardiac output, renal ischemia further.

2 renal vasoconstriction and renal blood redistribution

Renal angiography, can be seen between the artery and the arcuate arteries leaf beaded or distorted shape, but the patient died, renal arteriography find these changes disappeared, indicating his lifetime there is a strong renal vasoconstriction. Renal vasoconstriction may be due to: ① effective plasma volume decreased by sympathetic - adrenergic system and the renin - angiotensin system, the role of the renal vasoconstriction; ② endotoxin absorption from the gut can not be cleared in the liver and into the bloodstream. Sympathomimetic endotoxin role and the renin - angiotensin system activity strengthened, causing renal vasoconstriction, renal ischemia; ③ produced in the gastrointestinal tract pseudo sympathetic neurotransmitter - amines, substituted in peripheral normal neurotransmitter sympathetic nerve endings and blood redistribution, which leads to decreased renal blood flow.

Measured using 133 Xe renal blood flow and its distribution in the kidney, blood flow to the outer renal cortex found lower than normal, while the inner cortical and medullary blood flow unchanged, indicating that the redistribution of blood in the kidney, resulting in blood flow The reduced cortical glomeruli, resulting in reduced glomerular filtration rate.

Renal insufficiency renal ischemia causes? Severe liver dysfunction, through various mechanisms, the renal blood flow, is caused by hepatic renal insufficiency main reason. Early changes in renal function is functional, but severe ischemia or duration too long, but also allows tubular epithelial cell degeneration or necrosis. Bile on glomerular cells have a certain toxicity, renal ischemia in rats given intravenous infusion of bile acids, can aggravate ischemia on renal tubular epithelial cell damage. Fulminant hepatitis, not only decreased renal blood flow, and bile reflux into the blood (cells jaundice), there are many in the renal tubules bile pigment cast formation, tubular epithelial cells often obvious degeneration or necrosis.