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Types of acute renal failure
Last reviewed: 19.10.2021
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Depending on the level of impact of the damaging factor leading to the development of acute renal failure, distinguish:
- prerenal (with violations of renal perfusion due to a sharp decrease in arterial pressure, hypovolemia, shock of various genesis, blockage of renal tubules, for example, in hemolysis and rhabdomyolysis);
- Renal (causes direct damage to the parenchyma in various kidney diseases, including inflammatory, vascular, toxic effects);
- postrenal (occurs with obstructive uropathy due to diseases of the urinary tract).
According to the degree of preservation diuresis distinguish neoliguric (typical for newborns) and oliguric acute renal failure. Characteristic features of neoliguric acute renal failure:
- normal diuresis;
- decreased GFR;
- increased excretion of potassium;
- reabsorption of water and sodium;
- an increase in azotemia (serum creatinine> 130 μmol / l, urea> 17 mmol / l).
Prerenal and postrenal acute renal failure is a functional acute renal failure, and renal is an organic one. However, the long-term functional acute renal failure turns into organic, as during this time the renal parenchyma is damaged regardless of the initial factor that led to the development of renal failure.
It should be emphasized that one can not identify the concepts of "oliguria" and "acute renal failure". Thus, the development of oliguria (a decrease in the daily volume of urine by more than 2/3) may be a protective physiological response of the kidneys to a decrease in renal blood flow in response to dehydration, hypovolemia, arterial hypotension, hypothermia, etc. If the degree of reduction of renal blood flow is reflected in the state of the filtration function kidneys and leads to a moderate development of azotemia (increase serum creatinine by 20-50%), then it is qualified to talk about the development of functional (prerenal) renal failure. In cases where functional disorders lead to structural changes in the renal parenchyma, oliguria reflects the development of true, organic (renal) acute renal failure and is always accompanied by severe azotemia.