Renal pyonephrosis

　　1. Etiology

　　This disease is caused by upper urinary tract calculi causing obstruction, with secondary infection being the most common;其次是肾和输尿管畸形引起感染性肾积水;it can also be secondary to pyelonephritis. The pathogenic bacteria are mostly Escherichia coli. The renal tissue is severely damaged, and the whole or part of the kidney becomes a purulent cyst.

　　2. Pathogenesis

　　When an atonic kidney develops infection and suppuration, renal pyonephrosis can occur when pus accumulates in the collecting system due to urinary tract obstruction. When acute pyelonephritis is complicated with acute obstruction, it can present with sudden onset of fever, chills, and lumbar pain. It usually rapidly progresses to sepsis. If the infection of an atonic kidney develops into purulent pyelonephritis without timely diagnosis and proper treatment, it will lead to complete destruction of the kidney.

　　Occasionally, when a chronically obstructed kidney becomes infected, it may present with a latent onset without obvious clinical symptoms. When renal pyonephrosis occurs, the patient presents with fever, discomfort, and a mass in the renal area. If it is complete obstruction, the urine test will show no abnormalities.

　　Pain, a painful mass in the lumbar region, and skin redness and swelling can occur when the patient bends over, which are late signs of renal pyonephrosis. If renal pyonephrosis is not treated in time, it can penetrate the renal capsule to form a perinephric abscess. Perinephric abscess is mainly formed by the rupture of intrarenal abscess into the perirenal space, and it is caused by bacteria from other inflammatory foci in the body spreading to the renal cortex through the blood flow, forming small abscesses on the surface of the cortex. About 25% of cases, the abscess can be cultured with various pathogenic bacteria, and bacteria can enter the blood circulation to cause sepsis.

　　1. Medical History:There is often a history of long-term renal infection or a history of surgery for renal or ureteral calculi.

　　2. Symptoms:The prominent manifestation is purulent urine. When the ureter is in communication with the purulent kidney, it can present with persistent gross purulent urine or intermittent purulent urine, an acute attack type. In addition to systemic symptoms such as chills, high fever, general weakness, and vomiting, there are also obvious local symptoms, such as lumbar pain and lumbar muscle tension; if it is a chronic course type, it presents with chronic infection and intoxication symptoms, such as low fever, night sweats, anemia, emaciation, etc., with mild local symptoms.

　　3. Signs and Symptoms:There is marked tenderness upon percussion over the renal area, and an enlarged kidney can be palpated in the腰部.

　　When the accumulated kidney develops infection and suppuration, renal empyema can occur when pus accumulates in the urinary collection system due to urinary tract obstruction. Acute pyelonephritis complicated with acute obstruction may manifest as sudden fever, chills, and back pain, which usually rapidly develops into sepsis. Therefore, early detection, early diagnosis, and early and effective treatment are of great significance for preventing the progression of the disease.

　　White blood cells in the blood are significantly elevated, routine urine examination shows a large number of pus cells, urine culture is positive, but if the upper urinary tract is completely obstructed, the routine urine examination may not show significant abnormalities, and urine bacterial culture may also be negative.

　　1. Cystoscopy examination:Pus can be seen flowing out of the orifice of the affected ureter.

　　2. X-ray examination:Abdominal X-ray shows unclear renal shadow, and sometimes upper urinary tract stones can be found. Intravenous urography shows poor or no renal shadowing in the affected kidney.

　　3. Ultrasound examination:B-ultrasound examination can show a liquid shadow in the kidney.

　　4. CT examination:It can show mixed density masses with different shapes and blurred edges in the renal parenchyma, with central low density. Enhanced scanning shows a significant decrease in renal parenchyma enhancement, and the renal pelvis and calyces are not visible.

    The diet of patients with renal empyema should be light and easy to digest, with an emphasis on eating more vegetables and fruits, a reasonable diet, and ensuring adequate nutrition. In addition, patients should also pay attention to avoiding spicy, greasy, and cold foods.

　　1. General supportive treatment such as rest, strengthening nutrition, and blood transfusion for anemic patients.

　　2. Rational use of antibiotics can select sensitive antibiotics according to the results of urine culture.

　　3. Early renal puncture and stenting, sufficient drainage, and observation of renal function recovery. If renal function is restored, correct the obstruction; if renal function cannot be restored and the contralateral renal function is good, nephrectomy on the affected side should be performed.

　　4. If the abscessed kidney is too large and tightly adhered to the renal capsule, it is estimated that nephrectomy is difficult. It is advisable to perform a nephrostomy first and then perform nephrectomy. In patients with chronic lesions, the renal cortex becomes a thin and atrophic fibrous sheath surrounding the expanded urinary collection system filled with pus, so it is recommended to perform nephrectomy, starting from the obstructed segment of the ureter and removing the kidney and ureter together.