Perinephric abscess

　　What are the causes of perinephric abscess? Perinephric abscess is a focal infection of the renal cortex under the renal capsule that progresses. Patients with perinephric abscess may have coexisting factors such as diabetes, stones, or urinary tract obstruction. Perinephric abscess rarely occurs in patients without complications of pyelonephritis. Historically, in the era without antibiotics, perinephric abscess was often caused by Staphylococcus aureus sepsis from skin or other infections. In special cases, such as the misuse of intravenous antibiotics, Escherichia coli and奇异变形菌 have become the most common pathogenic bacteria, while Staphylococcus aureus is less common.

　　Currently, the causative pathogens of perinephric abscess are mainly Escherichia coli and other enterobacteria and Gram-positive bacteria, such as Paracoccus, Proteus, Streptococcus faecalis, Staphylococcus, Alcaligenes, Pseudomonas aeruginosa, etc. A very small number are fungi, viruses, protozoa, and other pathogenic bacteria. Most are caused by urinary tract infection, ascending infection through the ureter to the kidney, or hematogenous infection spreading to the kidney. The incidence rate in women is several times higher than that in men. Women are more prone to occur during childhood, marriage, pregnancy, and old age. Ureteral obstruction and urinary retention can cause secondary pyelonephritis.

　　Perinephric abscess has an insidious onset, and its clinical manifestations are non-specific, making early diagnosis very difficult. There are no specific complications. The patient may experience pain when bending over, and painful mass in the lumbar region and skin redness are late signs of perinephric abscess.

　　Perinephric abscess has an insidious onset, and its clinical manifestations are non-specific, making early diagnosis very difficult. Symptoms may appear 2-3 days before seeking medical attention. After that, the diagnosis may be delayed for several days. Fever is the most common symptom, but it is often considered to be fever of unknown origin. Important signs include pain or tenderness in the lumbar or costovertebral angle, accompanied by or without palpable abdominal or lumbar mass.

　　The ipsilateral diaphragm may be elevated or fixed, accompanied by or without pleural effusion, and the patient may have chest pain. Muscle spasm of the psoas major muscle often leads to scoliosis (curving towards the affected side), so the patient may experience pain when bending over. Painful mass in the lumbar region and skin redness are late signs of perinephric abscess.

　　Preventing the occurrence of perinephric abscess can start from daily life, and everyone cannot do without daily life. How to prevent perinephric abscess? Pay attention to the following matters in the prevention of perinephric abscess:

　　1. Daily life and rest

　　Life should be regular, participate in appropriate physical exercise regularly, and pay attention to the combination of work and rest.

　　2. Diet nourishment

　　It is advisable to avoid spicy and sweet foods, consume low-salt diet, quit smoking and drinking, and have a moderate diet. In daily life, consume light and vitamin-rich foods as the main diet, and choose the following therapeutic diet according to the condition.

　　3. Differentiated nursing care

　　Conduct psychological counseling for patients to build confidence in treatment. At the same time, teach patients some methods to control emotions and adjust their mindset. Arrange a comfortable environment for the patients, keep the ward quiet, avoid noise and bed frame摇晃, and avoid excessive brightness. For those with yin deficiency, eat less ginger, mutton, and other foods, and eat more yin-nourishing foods. For those with yang deficiency, pay attention to keeping warm and eat less cold and cool foods.

　　There are no special preventive measures for perinephric abscess. Just strengthen nutrition, improve immunity, and maintain an optimistic mood. If the diagnosis of perinephric abscess is timely and the treatment is effective, the prognosis of the patient is good. Mortality is related to delayed diagnosis and inappropriate treatment.

　　Renal abscess, also known as renal empyema, refers to widespread suppurative lesions caused by renal parenchymal infection or hydrops of the renal pelvis and calyces due to urinary tract obstruction, infection, and the formation of a cyst filled with pus. What examinations should patients with perinephric abscess undergo?

　　1. Laboratory Examination

　　Routine laboratory test results are repeated and diverse. Blood routine examination shows an increase in white blood cells with nuclear left shift, varying degrees of anemia, and an elevated erythrocyte sedimentation rate. Only if the patient has other kidney diseases or bilateral lesions may there be an increase in serum creatinine and blood urea nitrogen. Urinalysis shows pyuria and proteinuria, but no hematuria. Thirty percent of patients have normal urine analysis, 40% have negative urine culture, and only 40% show positive results in blood culture.

　　2. X-ray Examination

　　Chest and abdominal X-ray examinations cannot definitively diagnose perinephric abscess, but they are helpful for diagnosis. Chest X-ray examination may show elevation and fixation of the ipsilateral diaphragm, pleural effusion, empyema, lower lobe atelectasis and consolidation of the lung, and formation of pneumonia scars. Abdominal X-ray examination may show scoliosis (concave towards the affected side), mass, kidney stones, loss of normal contour of the kidney and psoas major muscle, gas or kidney fixation in or around the kidney.

　　3. Imaging Examination

　　Most patients with perinephric abscess can be confirmed to have an abnormal kidney on excretory urography. The main manifestations include poor or no visualization of the affected kidney, mass, kidney displacement, renal pelvis or ureteral calculus, dilatation or obstruction of the renal pelvis (with or without calculus). However, none of these imaging features are specific to perinephric abscess.

　　The scintigraphy of gallium (Ga67) citrate or indium (In111) labeled white blood cells has little significance in diagnostics because they are time-consuming and cannot differentiate perinephric abscess from other kidney diseases. Renal arteriography is not a specific diagnostic method for perinephric abscess either, as it is an invasive examination method and its results are not superior to kidney ultrasound and CT scan, so arteriography is rarely used for the diagnosis of perinephric abscess.

　　4. Kidney Ultrasound

　　Kidney ultrasonography is a diagnostic examination method for perinephric abscess, but CT scan can better reflect the overall appearance of the lesion. CT manifestations include soft tissue mass, with CT values decreasing to 0-20 H units. Without contrast enhancement, the CT values of the inflammatory abscess wall decrease slightly more; after injection of contrast agent, the density of the abscess wall increases, the tissue structure around it disappears, the ipsilateral kidney or psoas major muscle expands, the renal fascia thickens, and gas or gas-liquid planes appear within the lesion. Percutaneous puncture guided by CT can confirm the diagnosis and identify the causative pathogen.

　　Perinephric abscess patients with obvious edema and large amounts of proteinuria but normal renal function can supplement protein diet moderately. When there is no edema and hypoproteinemia, the daily protein intake should be limited to 0.6 grams per kilogram (about 6 grams of protein in a bottle of milk, about 6 grams of protein in an egg, about 4 grams of plant protein in 50 grams of rice).

　　1. The diet for perinephric abscess patients should be high in protein and low in fat, with an emphasis on drinking soup and water to promote nutrient absorption.

　　2. Avoid spicy,刺激性, alcohol, cold and greasy foods for perinephric abscess patients.

　　Antibiotic treatment alone is difficult to be effective for patients with perinephric abscess, and it should be combined with early and complete drainage. Traditional treatment advocates incision and drainage of the abscess. For some cases, placement of an appropriately sized drainage tube percutaneously under ultrasound or CT guidance can also be satisfactory. If percutaneous drainage is ineffective, timely incision and drainage or nephrectomy must be performed.

　　Before the results of bacterial culture and drug sensitivity test are available, treatment with antibiotics targeted at the most likely pathogenic bacteria (staphylococcus, Escherichia coli) should begin. The choice of medication and dosage should be consistent with the treatment of intrarenal abscess. Adjustments should be made appropriately based on clinical response and drug sensitivity test. Infection must be treated with intravenous or later-stage oral antibiotics until it is confirmed that the infection has not completely regressed, often requiring several weeks. Timely diagnosis and effective treatment result in good prognosis for patients, with mortality related to delayed diagnosis and inappropriate treatment.

　　1. Timely incision and drainage should be performed, with the incision selected at a place with obvious fluctuation and parallel to the skin texture. The incision should be long enough and placed at a low position for better drainage. For deep abscesses, puncture localization should be performed first, followed by layer-by-layer incision.

　　2. Change the dressing in a timely manner after surgery.

　　3. Antimicrobial and anti-inflammatory drugs should be used for systemic treatment. For those with long-term unhealed wounds, the cause should be investigated.