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Types of acute renal failure
Last reviewed: 04.07.2025
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Depending on the level of exposure to the damaging factor leading to the development of acute renal failure, a distinction is made between:
- prerenal (in case of renal perfusion disorders due to a sharp decrease in arterial pressure, hypovolemia, shock of various origins, blockade of renal tubules, for example, during hemolysis and rhabdomyolysis);
- renal (causes direct damage to the parenchyma in various kidney diseases, including inflammatory, vascular, and toxic effects);
- postrenal (occurs with obstructive uropathy due to diseases of the urinary tract).
Depending on the degree of preservation of diuresis, non-oliguric (typical for newborns) and oliguric acute renal failure are distinguished. Characteristic features of non-oliguric acute renal failure:
- normal diuresis;
- decreased SCF;
- increased potassium excretion;
- decreased reabsorption of water and sodium;
- increased azotemia (serum creatinine >130 μmol/l, urea >17 mmol/l).
Prerenal and postrenal acute renal failure represent functional acute renal failure, and renal - organic. However, long-term functional acute renal failure turns into organic, since during this time there is damage to the renal parenchyma, regardless of the initial factor that led to the development of renal failure.
It should be emphasized that the concepts of "oliguria" and "acute renal failure" cannot be identified. Thus, the development of oliguria (a decrease in the daily urine volume by more than 2/3) can be a protective physiological reaction of the kidneys to a decrease in renal blood flow in response to dehydration, hypovolemia, arterial hypotension, hypothermia, etc. If the degree of decrease in renal blood flow affects the state of the filtration function of the kidneys and leads to moderate development of azotemia (an increase in serum creatinine by 20-50%), then it is legitimate 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.