Posts Tagged renal causes

Renal and Postrenal Causes of Renal Failure

As distinct from prerenal causes, renal causes of renal failure include all pathological conditions which affect parenchyma of kidneys. The most often reasons of acute kidneys affection are acute glomerulonephrites, interstitial nephritises, renotrophic intoxications, clottage of renal vessels, kidney infarct, etc. It is necessary to note, that the pathological process can affect both renal glomuluses (glomerulonephritis), disturbing the process of filtration, and epithelium of tubules (nephritis, intoxications), what results in their congestion and their disturbed reabsorbtion.

One of common forms of renal failure is congestion of renal tubules by haemoglobin of decayed erythrocytes that usually occures during massive hemolysis. Renal failure develops also in case of nephrectomy of both kidneys or their serious traumas.

The most common postrenal causes of renal failure are acute obstruction of ureters of both kidneys which can occure in case of urolithiasis, prelum of ureters by a ligature (during surgical operations), hematoma (because of traumas), tumour, etc. As a rule, simultaneous functional disorder of both ureters happens quite seldom.

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Prerenal Causes of Renal Failure

There are prerenal, renal and postrenal causes of renal failure.

Disturbance of blood supply of kidneys is the main prerenal cause of renal failure (RF). It is assumed that the process of renal filtration (the first stage of uropoiesis) depends entirely on the amount of blood flowing to kidneys. This amount is determined by arterial pressure. Therefore, in most cases, acute renal failure (ARF) is caused by a sharp drop of arterial pressure, because it reduces significantly the amount of blood going to kidneys.

The cause of such a drop is a critical condition, a shock, which is characterized by a severe disorder of blood circulation. This shock condition is cause by a considerable loss of blood, traumas, burns (a hypovolemic shock), heart-work disorder (a cardiogenic shock in case of myocardial infarction), a septic shock (in case of sepsis), an anaphylactic shock (when getting specific allergens in the sensitized organism) and so forth.

Thus, during a critical drop of blood supply of kidneys the process of urine filtration becomes impossible and uropoiesis stops. This state is called anuria.

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