Acute renal failure: causes and pathogenesis

The causes of acute renal failure are not completely clear, however, four main mechanisms of its development are noted:

• Tubular obstruction;
• Interstitial edema and passive reverse current of the glomerular filtrate at the level of the tubules;
• Kidney hemodynamics disorder;
• Disseminized intravascular coagulation.

On a large statistical material, it is currently proved: the morphological basis of acute renal failure is the lesion of the mainly channel apparatus in the form of nephrothelial necrosis with damage to the basal membrane or without it; With an uncontrolled defeat of glomeruli. Some foreign authors as a synonym for the term “acute renal failure” use the Russian-speaking term “acute tubular necrosis”. Morphological changes, as a rule, are reversible, therefore, the clinical and biochemical symptom complex is also turned. Nevertheless, in a few cases, in severe endotoxic (less often exotoxic) effects, it is possible to develop bilateral total or subtotal cortical necrosis, which differ in morphological and functional irreversibility.

There are several stages of development of acute renal failure:

• Initial stage (exposure to the damaging factor);
• The stage of oliguria or anuria (an increase in clinical signs of the disease). The period of non-functioning of the kidneys is characterized by the instability of diuresis, the condition periodically shifts from anuria to oliguria and vice versa, therefore this period is called oligoanuric;
• Diuretic stage (the beginning of the resolution of the disease);
• Stage of recovery.

The action of damaging factors causes damage to the tubular apparatus and, above all, the epithelium of the tubules in the form of necrobiotic and dystrophic processes, which leads to the development of the oligoanuric stage. From the moment of damage to the canal apparatus, Anurius acquires a stable nature. Moreover, the detailed acute renal failure is characterized by another factor - the obstruction of the tubules that occurs as a result of the destruction of nephrothelia, its loading with pigmented slag. If the basal membrane is preserved and functions as a frame, then the regeneration process develops in parallel with nephrothelia necrosis. Channel regeneration is possible only while maintaining the integrity of the nephron. It was established that the newly formed epithelium at first is functionally inferior, and only by the 10th day from the onset of the disease, signs of restoration of its enzymatic activity appear, which clinically corresponds to the early diuretic stage.

In patients with surgical profile in stationary treatment, the causes of acute renal failure can be divided into two groups:

• Progression of the underlying disease or the development of complications;
• Complications of drug, infusion therapy or hemotransfusion complications.

In patients who underwent surgery, in the postoperative period, the determination of the etiological factors of acute renal failure represents a significant diagnostic difficulty. These are factors directly related to the trauma of the operation and complications of the postoperative period, among which peritonitis, destructive pancreatitis, intestinal obstruction, etc. are most likely. In this case, it is necessary to take into account the significant changes in some reactions of the body characterizing the purulent-inflammatory process. The fever in the purulent-septic process is often softened, the chills are not always accompanied by an appropriate increase in body temperature, especially in patients with hyperhydration. The development of acute renal failure in surgical patients underwent surgery. It makes it difficult to diagnose purulent complications from the abdominal organs. A significant improvement in the patient’s condition after hemodialysis indicates in favor of the lack of complication.

The conduct of anesthesiological manual can lead to toxic and toxic-allergic effects on the kidneys. For example, there is information about the nephrotoxicity of halotan. Often in these cases, anuria is preceded by arterial hypertension during the operation or on the first day of the postoperative period; long exit from drug sleep; extension of the Ivl.

Wrestling acute renal failure is most often due to acute obstruction of the urinary tract.

• Moestrifice obstruction:
  • Stone;
  • Blood clots;
  • Necrotic papillitis.
• Compression of the ureters:
  • Tumor;
  • Retroperitoneal fibrosis.
• Damage to the bladder:
  • Stones;
  • Tumor;
  • Shistosomosis
  • Inflammatory obstruction of the neck of the bladder;
  • Prostate adenoma;
  • Violations of the innervation of the bladder (damage to the spinal cord, diabetic neuropathy).
• Striterate of the urethra.

With acutely developed anuria, accompanied by pain, urolithiasis should be excluded. Even with unilateral obstruction of the ureter with severe pain (renal colic), it is possible to stop the urination with a healthy kidney (reflex anuria).

With necrotic papillitis (necrosis of the renal papillae), both triumphant and rennal acute renal failure develops. More often there is a trifle acute renal failure due to obstruction of the ureters with necrotic papillae and blood clots in diabetes, analgesic or alcohol nuclearpathy. The course of the alternal acute renal failure with necrotic papillitis reversibly. At the same time, rennal acute renal failure caused by acute total necrotic papillitis complicating purulent pyelonephritis often goes into irreversible renal failure.

It is possible to develop acute renal failure with a tour syndrome that complicated the prostate tour of the adenoma (occurs in about 1% of cases). The tour syndrome occurs after 30-40 minutes from the beginning of the prostate resection and is characterized by an increase in blood pressure, bradycardia, and an increase in bleeding from the wound; Many patients have excitement and cramps, coma is possible. In the early postoperative period, arterial hypertension is replaced by hypotension, which is poorly corrected; Oliguria, anuria develops. By the end of the day, jaundice appears. During the operation, it is necessary to constantly or fractionally rinse the operating wound and bladder with distilled water under a pressure of 50-60 cm water. Since the pressure in the venous vessels of the area of the operation does not exceed 40 cm of the water station, the irrigation fluid enters the venous vessels. The possibility of absorption of fluid through the paraverse space when opening the gland capsule is proved. The absorption rate of irrigation fluid from the field of surgery is 20-61 ml/min. Within an hour, from 300 to 8000 ml of liquid can be absorbed. When using distilled water, the hypoomolarity of blood plasma develops with the subsequent intravascular hemolysis of red blood cells, which was considered the main cause of the development of the tourist syndrome. However, subsequently, using non-grinding solutions, it was not possible to completely avoid the tourist syndrome and acute renal failure, despite the lack of hemolysis. At the same time, all researchers note hyponatremia, hypocalcemia and general hyperhydration. According to literary data, the following reasons for the development of acute renal failure are likely:

• Mechanical blockade of renal tubules by the deposition of blood pigment;
• The appearance of nephrotoxin under the action of electric current on the tissue;
• Disorders of blood circulation in the kidneys.

With a tour syndrome, acute renal failure occurs in 10% of patients, and in 20% of cases leads to death.

[1], [2], [3], [4], [5 -]. [7], [8], [9], [10]