Acute paranephritis

Acute paranephritis (from the Greek para - near, past, outside and nephritis, from nephrоs - kidney) is an acute purulent inflammation of the perirenal fatty tissue. It is caused by the same microorganisms as a kidney abscess, but most often Escherichia coli is detected, spreading in an ascending manner, less often - Staphylococcus spp., spreading hematogenously.

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Risk factors

Risk factors for paranephritis include urinary stasis, urinary tract obstruction, urolithiasis, neurogenic bladder dysfunction, and diabetes mellitus. Currently, due to the widespread use of antibiotics, paranephritis occurs much less frequently.

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Symptoms acute paranephritis

Symptoms of acute paranephritis in the initial stage of the disease have no characteristic symptoms and begin like any acute inflammatory process with an increase in body temperature to 39-40 ° C, chills, malaise.

Local symptoms of acute paranephritis are initially absent. During this period, acute paranephritis is often mistaken for an infectious disease. After 3-4 days, and sometimes later, local symptoms appear in the form of pain in the lumbar region of varying intensity, tenderness upon palpation in the costovertebral angle on the corresponding side, protective contraction of the lumbar muscles, and tenderness upon tapping in this area.

Sometimes, hyperemia and swelling of the skin are present in the lumbar region on the affected side. Somewhat later, a curvature of the spine is detected in the direction of the affected side due to the protective contraction of the lumbar muscles, a characteristic position of the patient in bed with the leg brought to the stomach and sharp pain when it is extended (the so-called psoas symptom, or the symptom of a "stuck heel"). It is not easy to recognize acute paranephritis at the onset of the disease, since local symptoms are weakly expressed or the clinical picture is masked by the manifestation of the disease, the complication of which is paranephritis. Often, the course of the disease resembles an infectious or purulent disease with an unclear localization of the focus. And it is no coincidence that such patients are often hospitalized in infectious and therapeutic departments, much less often - in surgical and urological departments.

Symptoms of acute paranephritis largely depend on the localization of the purulent process. In anterior paranephritis, during abdominal palpation in the area of the corresponding hypochondrium, pain often occurs; in some observations, there is tension in the muscles of the abdominal wall. Sometimes, in the hypochondrium or slightly lower area, it is possible to palpate a dense, painful, immobile tumor-like inflammatory infiltrate.

In acute upper paranephritis, symptoms from the pleura and pain in the shoulder on the affected side, limited mobility of the diaphragm dome are often noted. In this case, the kidney may shift downwards, so it becomes accessible by palpation.

Lower acute paranephritis is characterized by a low location of the inflammatory infiltrate, palpated through the abdominal wall, as well as a pronounced psoas symptom.

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Forms

According to the mechanism of occurrence, primary and secondary paranephritis are distinguished. In primary paranephritis, there is no disease of the kidney itself. Microorganisms enter the perirenal tissue hematogenously from other foci of inflammation (furuncle, osteomyelitis, follicular tonsillitis). Most often, this occurs due to immunodeficiency, hypothermia or overheating of the body. Paranephritis can also occur after a lumbar injury or as a result of surgery on the kidney. In some cases, paranephritis is caused by inflammatory processes in neighboring organs - the uterus, ovaries, rectum, appendix.

Secondary paranephritis is usually a complication of a purulent-inflammatory process in the kidney itself (abscess, renal carbuncle, pyonephrosis). In this case, the inflammatory process of the renal parenchyma spreads to the perirenal fatty tissue.

Depending on the localization of the purulent-inflammatory process in the paranephric tissue, there are upper, lower, anterior, posterior and total paranephritis. In upper paranephritis, the purulent process is located in the area of the upper segment of the kidney, in lower - in the area of the lower segment, in anterior - along the anterior surface of the kidney, in posterior - along its posterior surface, in total paranephritis, all sections of the paranephric tissue are involved in the inflammatory process. Although extremely rare, there are cases of bilateral paranephritis. According to the clinical course, paranephritis can be acute and chronic.

Acute paranephritis initially goes through a stage of exudative inflammation, which may undergo regression or pass into a purulent stage. If the purulent process in the perirenal tissue tends to spread, then the interfascial septa usually melt, and, having reached large sizes, the pus can spread beyond the tissue, forming extensive purulent leaks (it can go down the ureter, along the iliac muscle into the small pelvis). Retroperitoneal phlegmon may form. Phlegmon can break through into the intestine, abdominal or pleural cavity, into the bladder or under the skin of the groin area, and spread through the obturator foramen to the inner surface of the thigh. Upper acute paranephritis is complicated by a subdiaphragmatic abscess with a breakthrough of pus into the pleura, and sometimes into the lung. In exceptional cases, the abscess breaks out into the lumbar region. Differential diagnosis should be carried out with acute appendicitis, subphrenic abscess, and pneumonia.

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Diagnostics acute paranephritis

Convincing confirmation of purulent acute paranephritis is obtaining pus during puncture of the perirenal tissue. However, a negative test result does not exclude purulent inflammation.

A general radiograph of the lumbar region often reveals a curvature in the lumbar spine toward the affected side, distinct smoothing or absence of the edge of the lumbar muscle contour on this side. The contours of the kidney, depending on the size and distribution of the infiltrate, are normal in some cases, while in others they are smoothed or even absent. A high position and immobility of the diaphragm, and effusion in the pleural sinus on the affected side are also possible.

Excretory urograms may reveal deformation of the renal pelvis and calyces due to compression of the latter by the inflammatory infiltrate. The upper section of the ureter is often displaced toward the healthy side. In the images taken during inhalation and exhalation, the contours of the renal pelvis and calyces are the same on the diseased side and blurred or doubled on the healthy side. This indicates immobility or severe limitation of mobility of the affected kidney. CT, ultrasound, and radioisotope examination methods may provide valuable information in purulent acute paranephritis. In some patients, diagnostic puncture of the perirenal infiltrate is used.

In severe septic conditions of the patient, true albuminuria is possible, as well as the presence of cylinders in the urine (as a result of toxic nephritis).

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Differential diagnosis

Differential diagnostics of acute paranephritis is carried out with many diseases, primarily with hydronephrosis, acute pyelonephritis, renal tuberculosis. The presence in the anamnesis of a chronic inflammatory process in the kidney, pyuria, bacteriuria, active leukocytes in the urine, deformation of the calyceal-pelvic system, characteristic of pyelonephritis, the detection of other kidney diseases with the corresponding clinical picture indicate in favor of paranephritis. It should be borne in mind the need to differentiate acute paranephritis from a renal neoplasm.

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Treatment acute paranephritis

Treatment of acute paranephritis consists of prescribing broad-spectrum antibiotics, combining them with sulfonamides and uroantiseptics. Detoxification and general strengthening treatment are mandatory - infusions of glucose, saline and colloidal solutions, vitamins, cardiac agents are prescribed, and blood transfusions are performed according to indications. The use of antibacterial therapy and active therapeutic measures in the early stage of acute paranephritis in a number of patients allows for the reverse development of the inflammatory process, which leads to recovery without surgical intervention.

If an abscess has formed or conservative treatment has failed for 4-5 days, when clinical symptoms increase, surgical treatment is indicated - revision of the retroperitoneal space, opening of the abscess and drainage of the perirenal space. The retroperitoneal space is exposed by an oblique lumbar incision and the purulent focus is opened. If the latter is located near the upper segment or along the anterior surface of the kidney, it is not always easy to find it. After opening the main purulent focus, the fascial septa are bluntly destroyed, among which small abscesses may be located. After opening the purulent focus, it must be well drained. The posterior corner of the wound should be left unsutured.

In acute paranephritis of renal origin (pyonephrosis, apostematous nephritis, renal carbuncle), if there is an indication for nephrectomy and the patient's condition is severe, it is advisable to perform the operation in two stages: the first is opening the abscess and draining the retroperitoneal space, the second is nephrectomy after 2-3 weeks, taking into account the patient's condition. Treatment of acute paranephritis with antibiotics, as well as general strengthening therapy, must be continued for a long time until the patient's condition stabilizes.

Forecast

Acute paranephritis usually has a favorable prognosis. In the secondary form of the disease, since it is a complication of one of the urological diseases, the prognosis depends on the nature of the latter.