Pyelonephritis

　　The main causes of pyelonephritis include the following points:

　　1. Pathogenic bacteria:The causative bacteria of pyelonephritis are mainly Escherichia coli, followed by Enterobacter, Proteus, Streptococcus faecalis, and others.

　　2. Urethral infection:Urethral infection is the most common route. When the body's resistance decreases and the urethral mucosa has slight damage, bacteria are prone to invade the bladder and kidneys, causing infection. Due to the fact that the female urethra is shorter and wider than that of males, the female infant's urethral opening is often contaminated with feces, making it more susceptible to disease.

　　3. 淋巴道感染。

　　4. 血行感染：细菌从身体内的病灶侵入血流，到达肾脏引起炎症，引起炎症，血行感染时，细菌首先到达肾皮质，并在该处形成多数小脓肿，然后沿肾小管向下行扩散到肾乳头和肾盂。

　　5. 直接感染：外伤或邻近肾脏的器官发生感染时，细菌可直接侵入肾脉引起炎症。

　　急性肾盂肾炎最严重的并发症是中毒性休克。产气型肾盂肾炎是一种很少见但可致命的肾盂肾炎，通常见于糖尿病患者，由致病菌(常是大肠杆菌的某一菌株)释放气体进入感染组织所致。

　　在得到充分治疗后，又无其他肾脏疾病或尿路畸形，急性肾盂肾炎通常可痊愈，并不引起肾脏瘢痕或持续性肾脏损害，相反在肾脏未完全发育成熟的婴幼儿，尤其是并发于肾脏疾病或尿路畸形的急性肾盂肾炎，常引起持续肾脏损害和瘢痕。

　　（一）急性肾盂肾炎

　　可发生于各种年龄，但以育龄妇女最多见，起病急骤，主要有下列症状

　　1.一般症状

　　高热、寒战，体温多在38～39℃之间，也可高达40℃。热型不一，一般呈弛张型，也可呈间歇或稽留型。伴头痛、全身酸痛，热退时大汗等。

　　2．泌尿系症状

　　会有腰痛，多为钝痛或酸痛，少数有腹部绞痛，沿输输尿管向膀胱方向放射，体检时在上输尿管点（腹直肌外缘与脐平线交叉点）或肋腰点（腰大肌外缘与十二肋交叉点）有压痛，肾叩痛阳性。患者常有尿频、尿急、尿痛等膀胱刺激症状。儿童患者的泌尿系系症状常不明显，起病时除高热等全身症状外，常有惊厥、抽搐发作。

　　3．胃肠道症状

　　有食欲不振、恶心、呕吐，个别患者可有中上腹或全腹疼痛。

　　（二）慢性肾盂肾炎

　　慢性肾盂肾炎时临床表现复杂，容易反复发作，症状较急性期轻，有乏力、低热、厌食及腰酸腰痛等症状，还伴有尿频、尿急、尿痛等下尿路刺激症状。

　　1.注意外阴及尿道口的清洁卫生 要勤换内衣，如不注意外阴的清洁卫生，细菌可以通过尿道进入膀胱，并由膀胱、输尿管逆流的动力入肾盂，然后再侵及实质，形成泌尿系统的感染。

　　2.饮食上要高热量、高维生素、半流质或容易消化的普通饮食。多饮水，每日入量不得少于3000毫升，以增加尿量，有利于冲洗泌尿道，促进细菌、毒素和炎症分泌物的排出。

　　3. Physically, appropriate exercise should be done to strengthen the body and improve the body's resistance to diseases.

　　4. Patients with the disease should be prohibited from taking a bath in a basin to avoid the backflow of bathwater into the bladder, causing infection. Commonly used drugs: Furanthoin, which is effective for urinary tract infections. Piperaquine, vitamin C, can enhance the effect of Furanthoin. (Vitamin C can acidify urine, and Furanthoin has enhanced antibacterial activity in acidic urine).

　　During the acute stage, the presence of acute inflammation may be found, such as an increase in the number of blood leukocytes, an increase in the percentage of neutrophils, and the following examinations are of greater significance for diagnosis.

　　(One) Urinary routine examination

　　The most convenient and fast way is to leave the first morning urine for testing. Any white blood cells exceeding 5 (>5/Hp) per high-power field are called pyuria.

　　(Two) Urinary cytology examination

　　The colony count of clean midstream urine culture greater than 105/ml has clinical significance.

　　(Three) Non-invasive localization examination of infections

　　1. Urinary concentrating ability: This test is not sensitive enough to be used as a routine method of promotion.

　　2. Uric acid measurement: The level of N-acetyl-β-D-glucosaminidase in urine during pyelonephritis is higher than that in lower urinary tract infections, so the enzyme exists in the epithelial cells of the renal tubules. To date, the urinary enzymes that can be used as a localization diagnostic method for urinary tract infections are still under study.

　　3. Urinary C-reactive protein measurement: During the course of the disease, the level of C-reactive protein (CRP) every other day can help estimate the efficacy, that is, CRP is a clear indication of efficacy, and its increase indicates ineffectiveness. CRP does not increase during acute cystitis. However, CRP may also increase in other infectious diseases, and the presence of false positives affects the localization significance of this test.

　　4. Urinary antibody-coated bacteria analysis: Immunofluorescence analysis confirms that bacteria from the kidneys are coated with antibodies, which can bind to fluorescent-labeled antibody IgG and show a positive reaction.

　　5. Direct localization method: In direct methods, Stamey's ureteral catheter method has higher accuracy, but it must be performed through cystoscopy or percutaneous puncture of the pelvis with a Skinny needle to obtain urine, so it is a traumatic examination method and is not commonly used. Fairley's bladder irrigation and sterilization followed by urine culture has high accuracy and is simple and easy to perform, and is commonly used in clinical practice.

　　(Four) X-ray examination

　　Kidney CT scan or magnetic resonance imaging scan should be performed to exclude other kidney diseases. Due to the fact that acute urinary tract infection itself is prone to cause vesicoureteral reflux, intravenous or retrograde pyelography should be performed 4 to 8 weeks after the infection is eliminated. There is no need to perform routine pyelography for acute pyelonephritis and uncomplicated recurrent urinary tract infections. For patients with chronic or long-standing diseases, urinary tract plain film, intravenous pyelography, retrograde pyelography, voiding cystoureterography can be performed as needed to check for obstruction, calculi, ureteral stenosis or compression, nephropexy, congenital malformations of the urinary system, and vesicoureteral reflux phenomenon, etc. In addition, it can also understand the formation and function of the pelvis and calyces to differentiate from renal tuberculosis, renal tumors, and other diseases. Renal angiography can show varying degrees of distortion of the blood vessels in chronic pyelonephritis.

　　(v) Isotope renal scan

　　It can understand the function of the individual kidney, urinary tract obstruction, vesicoureteral reflux, and residual urine in the bladder. The renal scan characteristics of acute pyelonephritis are a peak shift, a secretion segment that appears to be delayed by 0.5 to 1.0 minute compared to normal, and a slow decline in the excretion segment. In chronic pyelonephritis, the slope of the secretion segment decreases, the peak becomes blunt or widened and shifted, the onset time of the excretion segment is delayed, and it presents as a parabolic shape. However, these changes are not significantly specific.

　　(vi) Ultrasound examination

　　It is the most widely used and simplest method, which can screen for renal size inequality, calculi, tumors, and prostatic diseases caused by incomplete urinary tract development, congenital malformations, polycystic kidney disease, and renal artery stenosis.

　　Patients with pyelonephritis should avoid the following in diet:

　　1. Avoid high-sodium and high-salt foods

　　Patients with edema and hypertension should adopt a low-sodium or salt-free diet. A low-sodium diet generally uses less than 3 grams of salt or 10-15 milliliters of soy sauce per day. Foods high in salt should be avoided, such as salted vegetables, pickled vegetables, salted eggs, preserved eggs, salted meat, seafood, instant noodles, etc. Salt-free diet refers to cooking without adding salt or soy sauce, and using sugar, vinegar, sesame paste, and ketchup for seasoning.

　　2. Avoid excessive protein intake

　　The onset of pyelonephritis leads to a decrease in glomerular filtration rate, causing transient azotemia. Therefore, protein intake should be limited. Within the limited range, high-quality protein foods such as milk, eggs, lean meat, and fish should be selected. When the condition improves and urine output increases, with daily urine output greater than 1000 milliliters, protein intake can be gradually increased. However, it should not exceed 0.8 grams per kilogram of body weight per day.

　　3. Avoid excessive intake of high-potassium foods

　　When oliguria, anuria, or increased serum potassium levels occur, it is necessary to limit vegetables and fruits rich in potassium, such as soybean sprouts, chive, green garlic, celery, cauliflower, toon, spinach, bamboo shoots, lily, dried red dates, fresh mushrooms, seaweed, sauerkraut, Sichuan preserved vegetables, mushrooms, apricot, lotus root, sorghum, corn, lentils, tomato, luffa, bitter melon, etc. The intake of fluid should be controlled according to the amount of urine excreted by the patient each day. The general method of supplementation is to consume an additional 500 to 1000 milliliters of fluid in addition to the amount of fluid excreted the previous day.

　　(i) General treatment

　　Patients should drink plenty of water and urinate frequently to reduce medullary osmolality, enhance the function of phagocytic cells in the body, and flush out the cells in the bladder.

　　Patients with systemic infection symptoms such as fever should rest in bed. Taking sodium bicarbonate can alkalinize urine, alleviate bladder irritation symptoms, and enhance the efficacy of aminoglycoside antibiotics, penicillin, erythromycin, and sulfonamides, etc. Prompt treatment is required for conditions such as renal calculi and ureteral malformations.

　　(ii) Antimicrobial therapy

　　1. Acute pyelonephritis

　　Early acute pyelonephritis can be treated with sulfamethoxazole-trimethoprim or pipemidic acid, norfloxacin. In cases with severe infection and sepsis, intravenous administration is recommended. The choice of sensitive drugs should be based on the results of urine culture. For example, cefoperazone and amikacin are highly sensitive to staphylococcus, klebsiella, proteus, pseudomonas aeruginosa, and escherichia coli, with sensitivity rates above 90%.

　　2. Chronic Pyelonephritis

　　Acute onset should be treated according to acute pyelonephritis, and recurrent onset should be determined through urine bacterial culture and strain identification to clarify whether this recurrence is recurrence or re-infection.

　　(1) Recurrence refers to the strain turning negative after treatment, but it recurs within 6 weeks after discontinuation of medication, and the pathogen is completely the same as the previous infection. Common causes of recurrence include: ① Anatomical or functional abnormalities of the urinary tract causing poor urine flow. This can be clarified by intravenous pyelography or retrograde pyelography. If there are obvious anatomical abnormalities, surgery may be required to correct them. If the obstruction factor is difficult to remove, appropriate antibacterial drugs should be selected based on drug sensitivity and treated for 6 weeks. ② Inappropriate selection of antibacterial drugs or insufficient dose and course of treatment often lead to recurrence, which can be treated with medication selected according to drug sensitivity for 4 weeks. ③ Due to scar formation in the lesion site, poor blood flow, and insufficient concentration of antibacterial drugs in the lesion, it can be tried with larger doses of bactericidal antibacterial drugs such as cefamycin, ampicillin, hydroxycillin, and aztreonam, for a course of 6 weeks. If urinary tract infections occur 3 times or more within a year, it is also called recurrent urinary tract infection, and long-term low-dose treatment can be considered. Generally, low-toxicity antibacterial drugs such as trimethoprim-sulfamethoxazole or nitrofurantoin are selected, and about 605 patients have urine culture turn negative. In men with recurrence caused by chronic prostatitis, it is advisable to treat chronic prostatitis at the same time, and liposoluble antibacterial drugs such as trimethoprim-sulfamethoxazole, ciprofloxacin, rifampicin, and rifapentine should be selected. The course of treatment should be as long as 3 months. If necessary, surgery may be required to remove the lesion (hypertrophy, tumor) and so on.

　　If the urine culture remains positive after two courses of adequate antibacterial treatment, long-term low-dose treatment can be considered. Generally, trimethoprim-sulfamethoxazole or nitrofurantoin can be taken for 1 year or longer.

　　(2) Reinfection refers to the infection caused by another pathogen different from the previous one that invades the urinary tract after the urine culture turns negative. Generally, it recurs 6 weeks after the urine culture turns negative. The recurrence of urinary tract infections in women is mostly re-infection, which can be treated according to the treatment method for the first attack, and patients should be advised to pay attention to the prevention of urinary tract infections. At the same time, a comprehensive examination should be conducted to determine if there are any susceptible factors, and they should be removed.