1、Urinary Tract Infection( U T I ) Ling Pan,General remarks,In this chapter, UTI resulting from bacterial invasion is discussed. Anatomically. It is divided into upper tract urinary infection (pyelonephritis) and lower tract urinary infection (cystitis) incidence：UTI is a common disease (2% in populat

2、ion), particularly in female adults( 10%).,Etiology and pathogenesis,Pathogen： gram-negative bacteria （ Specifically coliform bacteria, proteus bacteria ） Pyocyanic infection is frequently seen in patients with instrumentation. Proteus bacteria is often seen in patients with calculus.,Bacterial viru

3、lence factors A high degree of bacterial adherence, which is mediated by the bacterial fimbriae. Some bacteria can produce hemolysin which can resist the bodys defense system . Drug resistance strains,Host defense mechanisms Efficient emptying of the bladder with voiding . A protective glycosaminogl

4、ycan layer. The high osmolality and extremes of pH . IgG, IgA and organic acid secreted by urinary tract mucosa.,Host susceptibility factors urinary tract Obstruction such as calculus, vesicoureteral reflux or intrarenal reflux. (the presence of UTI with structurally or functionally abnormal urinary

5、 tract is called complicated UTI) The deformity of urinary system Instrumentation of the urinary tract Host defense system get weak, for instance, diabetes mellitus Pregnancy,gender neurogenicbladder Geneticfactor,Infection route,The ascending route: periurethral tissues urethra bladder ureter renal

6、 pelvisrenal medulla The hematogenous route Lymphogenous spread Direct extension from other organs may occur,Clinical manifestation,cystitis Irritative voiding symptoms frequency, urgency, dysuria (burning or discomfort on urination) ,suprapubic discomfort Urinalysis pyuria,bacteriuria, hematuria Bl

7、ood test: generally normal,Acute pyelonephritis Irritative voiding symptoms, flank pain. Systemic toxicity fever, shaking chills , nausea, vomiting Sign tenderness of ureter spot on palpation, exquisite tenderness on percussion of the costovertebral angle. Laboratory findings Blood test: leukocytosi

8、s and a left shit. Urinalysis: pyuria ,bacteriuria, hematuria. Blood culture: may be positive.,Asymptomatic bacteriuria no symptom is present, yet bacteriuria exists.,Laboratory findings,Urinalysis a finding of 5 WBC/Hp or 8000 WBC/ml UTI white cell casts pyelonephritis. hematuria, proteinuria,Labor

9、atory findings,Detection of bacteriuria Collection of urine sample: The urine is collected in midstream before drug is used or at least 7 days after drug administration. Avoiding contamination, being sent to the laboratory within 1h.,Urine culture CFUs 105/ml significant bacteriuria. CFUs between 10

10、4105/ml suspected UTI reexamination CFUs104/ml maybe contamination (Qualitative urine culture: if the urine for culture is from cyst puncture , then when positive, it indicate a true UTI),Urine smear examined by microscopy when 1 bacteriuria / oil-immersed HP Chemical test for bacteriuria Nitrate re

11、duction test the test is dependent on the bacterial reduction of nitrate in the urine to nitrite. it is effective in identifying infection due to gram-negative bacteria.,Imaging,Indication All male patients Female patient recurrent UTI complicated UTI disappointing response to antimicrobial therapy

12、4. ever infected during pregnancy,Imaging studies include Ultrasonography Intravenous pyelogram (IVP) Computed tomography Notice IVP should not be done in the acute phase of UTI.,Diagnosis OF UTI,significant bacteriuria A positive result of urine culture in which urine specimen is from cyst puncture

13、. Quantitative urine culture: a patient being symptomatic , CFUs 105/ml for once. a patient being asymptomatic,CFUs 105/ml for twice( it should be the same species),Diagnosis OF UTI,when a female patient with irritative voiding symptom and CFUs 102/ml, UTI should be considered and treatment for UTI

14、should be given.,Infection-localizing diagnosis,urine culture after bladder washout the assay for antibody-coated bacteria （ACB) urinary concentrating ability, urine 2-MG，urine white cell cast.,bilateral ureteral catheterrization. it is too invasive for general use. clinical practice 1. acute pyelon

15、ephritis fever(T38), shaking chills, back pain ,WBC tenderness on percussion of the costovertebral angle 2. 3 days of antibiotics treatment, if being curedcystitis, if not pyelonephritis.,Chronic pyelonephritis： the cortical scarring a corresponding caliceal deformity tubule damage and interstitial

16、inflammation and scarring,Differential diagnosis,1. renal tuberculosis a prominent irritative voiding symptom nullity to common antibiotics mycobacterium in urine PPD（+） stricture, cavities, calcification in IVP,2.urethral syndrome: exhibit irritative voiding symptom no significant bacteriuria Infec

17、tive urethral syndrome: caused by other pathogens such as virus, mycoplasms, chlamydia. Urinalysis show pyuria. Non- Infective urethral syndrome: no WBC is seen with urinalysis. Probably it is because of psychological problems.,treatment,Antibiotics GBacillus （ sulfonamide, quinolones, -lactam drug

18、semisythetic penicillins , cephalosporins ） After the drug sensitivity test for offending organisms is available, then antibiotics are given according to the test.,Acute cystitis:,single dose therapy and a 3-day course of therapy followed up to see whether the infection is controlled or not it shoul

19、d not be used in patients with pregnancy, complicated infection, suspected pyelonephritis or male patients,Acute pyelonephritis,intensive antimicrobial therapy should be administrated. antibiotics for 14 days orally. no effect within 72h adjust the treatment . Moderate acute pyelonephritis : intrave

20、nous therapy of antibiotics defervesces for 72h oral agent at least 14 days,Acute pyelonephritis,Severe acute pyelonephritis : a combination of antibiotics are given intravenously, often an aminoglycoside combined with a -lactam drug or cephalosporins.,Therapy for recurrent UTI ：,Relapsing infection

21、： infection occur within 6w of the cessation of antimicrobial therapy and is caused by the same organism. Reinfection： caused by an organism which is different from the original one.,Therapy for recurrent UTI ：,receive short course therapy of 7 days followed up 7 days after cessation of therapy. If

22、no symptom，bacteriuria and pyuria cure reinfection； Still with symptoms, bacteriuria and pyuria treat according to drug sensitivity test. If succeeded Reinfection, if failed a big dose antimicrobials for 6 weeks. patients with more than 3 UTIs/yearslong term prophylaxis therapy.,treatment,urinary tr

23、act infection in pregnancy choose drugs that are safe to fetus( ampicillin cephalexin) asymptomatic bacteriuria Women in pregnancy, children before school-age , previous symptomatic UTI, with complicated factors-should receive treatment.,Complication,Acute renal papillary necrosis： accompanied by diabetes or urinary tract obstruction. lead to sepsis or ARF. present with high fever, severe back pain, hematuria, and ureter obstruction treatm