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renal failure

2016-12-31 10:46

Do you know the cause of kidney failure? What are the causes of renal failure? The following are some of the specific causes of renal failure: the role of nephrotoxic substances, renal ischemia.
A substance that is toxic to the kidneys. Such as drug in sulfanilamide, carbon tetrachloride, mercury and bismuth agent; polymyxin antibiotics in lycopene, vancomycin, kanamycin, amphotericin B, and iodine contrast agent; biological toxins such as snake venom, cantharidin, can cause acute renal tubular necrosis in certain conditions.
Second, renal ischemia. Severe renal ischemia such as severe trauma, extensive burns, surgery, massive hemorrhage, postpartum hemorrhage, severe infection, septicemia, dehydration and electrolyte imbalance, especially with shock, are easily lead to acute tubular necrosis. In addition, intravascular hemolysis released from hemoglobin, and muscle mass trauma (such as muscle crush injury, inflammation) of myoglobin, excreted by kidney, renal tubular damage can be caused by acute renal tubular necrosis.
Among them, the specific pathogenesis of acute tubular necrosis is not yet fully understood. Its occurrence is related to:
The glomerular filtration rate is extremely reduced the mechanism may be due to the various causes of renal tubular ischemia or poisoning, occurrence of renal tubular epithelial cell injury, the proximal tubular sodium reabsorption is reduced, so that the urine sodium, increasing water consumption. When it flows through the distal tubule of the macula densa, stimulate the juxtaglomerular renin release, increased intrarenal angiotensin II activity, glomerular arterioles contraction, spasm, especially lead to glomerular blood flow decreased outer cortical glomerular filtration rate, extreme reduction. In addition, may also be due to renal ischemia, renal blood perfusion of the afferent arteriole reduced, directly stimulate the juxtaglomerular cell to release renin angiotensin II increased, resulting in contraction of afferent arterioles, decreased glomerular filtration rate and aldosterone secretion, promote sodium and water retention. Some scholars believe that glomerular filtration rate is due to capillary endothelial damage, swelling, caused by decreased permeability of the filtration membrane.
Some people think that the various reasons (shock, trauma, crush injury etc.) in acute renal failure induced by renal ischemia, the main reason is that the occurrence of reperfusion after ischemia, renal ischemia and filtration early to reduce or stop (oliguria or urine) is a kind of self protective mechanism of renal reabsorption, alleviating the burden of the renal tubular cells, reduce the oxygen consumption, increase the tolerance to hypoxia, once the renal ischemia were improved (reperfusion), can produce a large number of superoxide anion, the renal tissue injury, severe acute renal failure in a variety of physiological abnormalities is composed of characteristic syndrome, pathogenesis in the course of each different periods have different significance.
Rupture of the renal tubular wall, overflow of the original urine. After the injury of the renal tubules, the wall of the tube ruptured, and the original urine in the tube overflowed to the outside of the tube, resulting in less urine.
The tubular lumen obstruction, injury after necrosis of renal tubular epithelial cells and inflammatory exudate, blood red protein (muscle), into a mass and tube type, the occlusion of the lumen, urine nasty blocked, and oliguria; on the other hand, intraluminal urine swelling, and will increase the pressure in the kidney so, a further decline in glomerular filtration rate.
However, after the oliguria period, the renal tubular epithelial cells began to develop. At this time, because of the lack of the ability to concentrate urine, the urine specific gravity was still less than 1.015. The metabolites of azotemia and retention, osmotic diuresis, the urine volume increased, called the polyuria stage. The pathogenic factors have been removed, the ischemic and toxic substances have been eliminated, the blood circulation has been restored.
We understand the mechanism of renal failure, and hope that the patients in peacetime must be reasonable and standardized medication, so as not to cause serious damage to the kidneys, the body is not timely medical treatment.
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