Urinary tract infections are divided into upper urinary tract infections and lower urinary tract infections according to the site of infection; they can be divided into isolated or sporadic infections and recurrent infections according to the relationship between two infections, the latter of which can be divided into reinfection and bacterial persistence, which is also called recurrence; they can be divided into simple urinary tract infections, complicated urinary tract infections and urinary sepsis according to the state of the urinary tract at the time of the infection episode. Urinary tract infections often occur in women, especially in sexually active and postmenopausal women.
1.Etiology
More than 95% of urinary tract infections are caused by a single bacterium. 90% of outpatients and about 50% of inpatients, the pathogenic bacteria is Escherichia coli, the bacteria serotype up to 140 kinds, to urinary tract infection Escherichia coli and patients isolated in the feces Escherichia coli is the same type of bacteria, mostly seen in asymptomatic bacteriuria or uncomplicated urinary tract infection; Aspergillus, Bacillus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus faecalis, etc. seen in Candida albicans and Cryptococcus spp. infections are seen in patients with diabetes mellitus, glucocorticoids and immunosuppressive drugs, and after renal transplantation; Staphylococcus aureus is seen in skin trauma and drug addicts causing bacteremia and sepsis; viruses and mycoplasma infections are rare but tend to increase in recent years. Multiple bacterial infections are seen in indwelling catheters, neurogenic bladder, stones, congenital malformations and vaginal, intestinal and urethral fistulas.
2.Clinical manifestations
1, acute simple cystitis
The onset of the disease is sudden, and the onset of female patients is mostly related to sexual activity. The main manifestations are bladder irritation signs, namely urinary frequency, urinary urgency, painful urination, discomfort in the bladder area or perineum and burning sensation in the urethra; urinary frequency varies in degree, and in severe cases, urge incontinence can occur; cloudy urine, white blood cells in the urine, common terminal hematuria, sometimes the whole hematuria, and even see blood clots discharge. There are usually no obvious symptoms of systemic infection, and the body temperature is normal or there is low fever.
2.Acute simple pyelonephritis
(1) Urinary symptoms include bladder irritation signs such as urinary frequency, urinary urgency, and painful urination; hematuria; affected or bilateral low back pain; and significant pressure pain or percussion pain at the affected spinal rib angle.
(2) Symptoms of systemic infection such as chills, high fever, headache, nausea, vomiting, loss of appetite, etc., often accompanied by elevated blood white blood cell count and increased blood sedimentation.
3. Asymptomatic bacteriuria
Asymptomatic bacteriuria is an insidious urinary tract infection, mostly seen in elderly women and pregnant women, patients do not have any symptoms of urinary tract infection, and the incidence increases with age.
4.Complex urinary tract infection
The clinical presentation of complicated urinary tract infection varies greatly and is often accompanied by other diseases that increase the risk of acquiring infection or treatment failure, which may or may not be accompanied by clinical symptoms (such as urinary frequency, urgency, painful urination, difficulty in urination, low back pain, spinal rib angle pressure, pain in the suprapubic area and fever, etc.). Complex urinary tract infections are often accompanied by other diseases, such as diabetes mellitus and renal failure; they also lead to more sequelae, and the most serious and fatal conditions include urinary sepsis and renal failure, which can be classified as acute and chronic, reversible and irreversible, etc.
3.Diagnosis
1, medical history taking
(1) The characteristics, duration and concomitant symptoms associated with clinical manifestations of urinary tract infection.
(2) Past history, drug history and history of related diseases to find the possible causes of the onset, concomitant diseases, history of previous drug treatment and factors that may affect the development and regression of the disease.
2.Physical examination
Including the examination of the extra-urinary genitalia; physical examination of the abdomen and kidney area. The pelvic and rectal examinations are meaningful to identify whether other diseases are combined.
3.Auxiliary examinations
(1) Laboratory tests include routine blood, routine urine, urine smear microscopy for bacteria, mid-stage urine bacterial culture + drug sensitivity, blood bacterial culture + drug sensitivity, and renal function tests.
(2) Imaging examinations include ultrasound, abdominal plain film, intravenous pyelogram, etc. CT or MRI examination can be selected if necessary.
4.Treatment
1.Female non-pregnancy urinary tract infection
(1) Treatment of acute simple cystitis is recommended by three-day therapy, i.e., oral compound sulfamethoxazole; or oxfloxacin; or levofloxacin. Since single-dose therapy is not as effective as three-day therapy, at present, it is no longer recommended. For areas where the pathogenic bacteria are resistant to sulfamethoxazole at a rate of 10% to 20%, furantoin may be used for treatment.
(2) Treatment of acute simple pyelonephritis recommends 14 days of antibiotic therapy, which can be shortened to 7 days for patients with mild acute pyelonephritis using highly effective antibiotics. For mildly symptomatic cases, oral quinolones can be used, or if the causative organism is sensitive to compound sulfamethoxazole, this drug can also be administered orally. If the causative organism is gram-positive, it can be treated with amoxicillin or amoxicillin/potassium clavulanate alone. For severe cases or those who cannot take oral drugs, they should be hospitalized and treated intravenously with quinolones or broad-spectrum cephalosporin antibiotics. For those who are resistant to β-lactam antibiotics and quinolones, amoxicillin can be used for treatment; if the causative organism is gram-positive cocci, ampicillin/sulbactam sodium can be used, and if necessary, combined drug therapy can be used. If the condition improves, a sensitive antibiotic can be selected for oral treatment with reference to the urine culture results. Adjustment of the regimen and follow-up during the medication period is important. Urine culture should be done every 1 to 2 weeks to observe whether the urinary bacteria are negative. Quantitative urine bacterial culture should be done at the end of the course of treatment and at the 2nd and 6th week after stopping the medication, and it is better to review it once a month afterwards.
(3) Complex urinary tract infection The treatment plan for complex urinary tract infection depends on the severity of the disease. In addition to antimicrobial therapy, treatment of anatomical abnormalities of the urinary tract and other underlying co-morbidities, as well as nutritional support if necessary, are also required. If the disease is severe, hospitalization is usually required. Firstly, the underlying diseases such as diabetes mellitus and urinary tract obstruction should be effectively controlled in a timely manner, and if necessary, joint treatment with endocrinologists and other related specialists is required; otherwise, it is difficult to cure the disease with antibiotic treatment alone. Secondly, treatment with broad-spectrum antibiotics should be used intravenously according to experience. During the medication period, the treatment plan should be adjusted in a timely manner according to changes in the condition and/or the results of bacterial drug sensitivity tests, and some patients still need a combination of drugs for at least 10 to 14 days.
2. Male cystitis
All men with cystitis should be excluded from prostatitis. For uncomplicated acute cystitis, oral compounded sulfamethoxazole or quinolones can be given at the same dose as in female patients, but a course of treatment is required for 7 days, while for patients with complicated acute cystitis oral ciprofloxacin, or levofloxacin, can be given for 7 to 14 days of continuous treatment.
3.Urinary tract infection during pregnancy
(1) Asymptomatic bacteriuria during pregnancy can be as high as 4% to 7%, often occurring in the first month of pregnancy, and up to 40% of these cases can progress to acute pyelonephritis. Anti-infective therapy is currently recommended for this group of patients. It is recommended that 3-5 days of antimicrobial therapy be given depending on the results of the drug sensitivity test.
One of the following regimens may be used.
①Furantoin.
② Amoxicillin.
③ Amoxicillin/clavulanic acid potassium.
Ask the patient to come to the hospital for a repeat urine culture at 1 week after stopping the drug and then monthly until the end of the pregnancy. For recurrent asymptomatic bacteriuria, antibiotic prophylaxis can be taken during pregnancy by taking furantoin or cefadroxil at bedtime each night.
(2) Acute cystitis is recommended to be treated with antibacterial drugs for 3-5 days based on urine culture and drug sensitivity test results, or furantoin, or amoxicillin, or second or third generation cephalosporins if it is too late to wait for the drug sensitivity test results. After treatment, a urine culture test should be performed to understand the effect of treatment. In case of recurrent acute cystitis, daily oral cefuroxime or furantoin at bedtime is recommended until the puerperium to prevent recurrence.
(3) Acute pyelonephritis has an incidence of 1% to 4% during pregnancy, mostly in the second trimester. It is recommended to first give intravenous infusion of antibacterial drugs according to the results of urine culture or blood culture and drug sensitivity test. After significant improvement of clinical symptoms, treatment can be changed to oral antibiotics. The total course of treatment should be at least 14 days.
4. Asymptomatic bacteriuria
Antimicrobial therapy is not recommended for premenopausal non-pregnant women, diabetic patients, the elderly, patients with spinal cord injury and asymptomatic bacteriuria with indwelling catheters. However, for patients with asymptomatic bacteriuria who undergo transurethral prostate surgery or other urological procedures or examinations that may result in bleeding from the urinary mucosa, treatment with sensitive antibiotics should be based on bacterial culture results.
5.Urinary tract infection associated with catheterization
(1) Asymptomatic bacteriuria Most asymptomatic bacteriuria is not recommended for antibiotic treatment. Some exceptions recommend appropriate treatment: nosocomial infections caused by more virulent microorganisms; patients who may be at risk for serious concurrent infections; patients undergoing urologic surgery; certain strains of infection that can cause high rates of bacteremia; and older female patients who may require short-term treatment after catheter removal.
(2) For symptomatic infections, it is recommended to replace catheters left in place for more than 7 days before taking a urine sample for culture and before applying antimicrobial therapy, or to use other means of drainage such as penile sleeve drainage or suprapubic cystostomy drainage. The choice of effective antibiotics is recommended based on urine culture and drug sensitivity test results. Initially, broad-spectrum antibiotics can be used empirically, and then the antibiotics can be adjusted according to the culture results. For milder symptoms, oral medication can be used, usually for 5-7 days. For severe symptoms, fever, positive blood cultures and difficulties in gastrointestinal administration, non-gastrointestinal drugs such as intramuscular or intravenous administration can be used. In severe cases, the medication is usually administered for 10-14 days. Occasional Candida infections may be treated with antifungal therapy. Long-term unfounded treatment with antibiotics is not recommended.