Renal cortex medulla abscess

　　Acute focal bacterial nephritis is a severe acute infection of the renal parenchyma, but the focus of infection has not liquefied (suppurated). It can affect one or more renal lobes. The infection is believed to be confined to renal lobes with intrarenal reflux. If such an inflammatory mass is not treated promptly and effectively, the inflammatory mass will liquefy into a renal cortex medulla abscess. Yellow granulomatous pyelonephritis is often associated with renal cortex medulla abscesses that occur concurrently with chronic urinary tract infections, renal calculi, and urinary tract obstruction.

　　Most adult cases of renal cortical medullary abscess are related to kidney stones, urinary tract obstruction, or damaged kidneys. In children, it is only related to vesicoureteral reflux. Diabetes is also an important triggering factor, especially for adult patients. The common pathogens in all age groups are aerobic Gram-negative bacteria. Its pathogenesis is that bacteria first invade the medulla to cause medullary infection, and then liquefy and invade the renal cortex. Possible complications include the rupture of abscesses through the renal capsule to form perinephric abscesses.

　　Pain may occur when the patient bends over. Painful mass, skin redness, and swelling are late signs of renal cortical medullary abscess. If renal pyelonephritis 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 renal abscess into the perirenal space. 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. Bacteria can enter the blood circulation to cause sepsis.

　　Both men and women can suffer from this disease, with an equal ratio of male to female. However, with the increase of age, the incidence rate increases. The clinical features include chills, fever, back pain or abdominal pain, as well as urinary system symptoms, common nausea and vomiting, and gastrointestinal symptoms. Chronic cases may have general malaise, fatigue, and weight loss. Physical examination often does not show specific findings, with tenderness at the costovertebral angle,腰部 or abdominal pain, and rarely can palpate a mass.

　　This disease is related to bacterial infection and usually secondary to urinary tract infection, ascending infection of the renal medulla. Therefore, clinical prevention should be aimed at the cause. It is recommended to drink plenty of water to maintain the patency of the urinary system, and to urinate once after sexual activity to reduce the possibility of obtaining urinary tract infection. For patients who have been infected, active treatment should be carried out to reduce the occurrence of complications.

　　1. Laboratory examination:In addition to urine analysis and positive urine culture, other examination results are similar to those of renal cortical abscess. This is due to the communication between the renal calyces and pelvis in renal cortical medullary abscess. Compared with renal cortical abscess, the positive rate of blood culture in this disease is higher.

　　2. Imaging examination:Ultrasound and CT are the most basic and effective diagnostic methods for renal cortical medullary abscess. For acute focal bacterial nephritis, renal ultrasound examination often cannot detect any abnormalities, but may show a solid hypoechoic mass shadow, with no clear boundary with the surrounding normal renal parenchyma, renal contour deformation, unclear differentiation between cortex and medulla, and CT without contrast enhancement often cannot confirm the symptoms of acute focal bacterial nephritis. However, after contrast enhancement, CT can show unclear boundaries, wedge-shaped, and non-liquefied low-density areas that can involve one or more renal lobes.

　　For renal abscesses, whether it is a kidney cortex abscess or a kidney cortex medullary abscess, the ultrasound findings are often variable, the lesions may not have internal ultrasound reflection and may resemble renal cysts or renal calyceal diverticula, or may appear as strong echo spots resembling tumors. The ideal imaging examination is CT, with characteristic findings being a decrease in the CT value of renal parenchymal lesions to 0-20H units, which cannot be enhanced after intravenous injection of contrast agent.

　　It is advisable to have a diet that is light and rich in nutrition, eat more vegetables and fruits such as bananas, strawberries, apples, etc. Because they are rich in nutrients, eating more foods that enhance immunity such as propolis and ejiao can improve personal resistance to diseases. In daily life, it is also necessary to reasonably match the diet and pay attention to sufficient nutrition. Avoid greasy, smoking, and drinking. Avoid eating cold and raw foods to prevent recurrent diseases.

　　As with kidney cortex abscesses caused by Staphylococcus, kidney cortex medullary abscesses caused by Escherichia coli infection sometimes also require only antibiotic treatment and do not need drainage. Acute focal bacterial nephritis with mild liquefaction and localized to the renal parenchyma generally does not require drainage. However, for severe cases, nephrectomy treatment is necessary.

　　When initiating antibiotic treatment, one may initially choose ampicillin (1g, intravenous injection, once every 4-6 hours) or ceftriaxone V (1g, intravenous injection, once every 8 hours). During treatment, it can be used in combination with aminoglycosides, such as gentamicin or tobramycin (1mg/kg) for intravenous injection, once every 8 hours. If renal function deteriorates, the dosage should be adjusted appropriately. During the medication process, adjustments should be made based on clinical efficacy or the results of drug sensitivity tests. After symptoms improve and fever subsides for 48 hours or after imaging confirms improvement in the condition, oral or intramuscular administration can be changed.