泌尿系统感染Urinarytractinfection

1、UTI UTI - common affliction for which patients seek medical attention UTI can occur from infancy through old age more common in females than males 20% of all females will experience a UTI during their lifetime UTI Definitions The term “UTI” represents a wide range of clinical syndromes Bacteriuria:

2、the presence of bacteria in urine - does not necessarily imply infection Asymptomatic bacteriuria: presence of bacteria in the urinary tract in the absence of symptoms - clinical significance controversial outside certain patient populations - pregnant women - patients undergoing invasive procedures

3、 of the urinary tract UTI Definitions Cystitis: UTI presumed to be confined to the bladder - painful/burning urination - urgency or frequency - absence of symptoms or physical signs suggesting inflammation at other sites within the urinary tract Note: clinical criteria are notoriously inaccurate in

4、identifying the actual anatomic site of infection UTI Definitions Pyelonephritis: clinical diagnosis which implies a more invasive infection - inflammation of the kidney and renal pelvis is assumed to be present when patients have pain or tenderness involving the flank, together with other clinical

5、or laboratory evidence of UTI -fever, nausea, chills, malaise, headache, etc UTI Definitions Prostatitis: inflammation / infection of the prostate gland - may present as acute or chronic Intrarenal abscess / perinephric abscess: collection of pus in the kidney or in the soft tissue surrounding the k

6、idney UTI Definitions Complicated infections - underlying abnormality that predisposes patient to UTI or makes UTI more difficult to treat effectively Recurrent Infections Relapse - recurrence of infection by same organism after discontinuation of treatment Reinfection - recurrence of infection by a

7、 different organism after discontinuation of treatment UTI Pathogenesis UTI usually due to patients own intestinal flora - ascending route of infection - organisms enter the urinary tract in a retrograde fashion via the urethra Complicating factors such as catheters, nephrostomy tubes, surgery, urin

8、ary stones, etc - allow organisms to enter and persist in urinary tract - alter the typical spectrum of organisms - may have multiple etiologies UTI Pathogenesis Elderly patients - incontinant - functionally impaired - postmenopausal changes - neurological alterations Pregnant women - altered anatom

9、y Hematogenous route - endocarditis, bacteremias, tuberculosis - disseminated infections UTI Etiology Majority of UTI are due to a single pathogen The Enterobacteriaceae responsible for 90% of all UTI - gram negative bacilli - facultatively anaerobic - common intestinal flora Escherichia coli most c

10、ommonly isolated pathogen 80% of all UTI Community-Acquired UTI E.coli K.pneumoniae Proteus S.saprophyticus S.epi & gm - enterics Enterococcus Uro-pathogens E.coli, Klebsiella spp. -intrinsic gut organisms -highly motile -produce fimbriae (pili) attachment Proteus, Morganella, Providencia -Urease pr

11、oducing organisms -increases urinary pH - leads to crystal formation biofilms colonization of catheter protects bacteria from host defenses & antibiotics Nosocomial UTI catheter associated Short TermLong Term E.coli E.coli Pseudomonas Pseudomonas Proteus Proteus Enterobacter Candida Providencia Morg

12、anella S.aureus Enterococcus Urinalysis usually have increased numbers of WBC leukocyte esterase test is often positive nitrate test is often positive Urinalysis Urine culture: significant bacteriuria usually defined as 105 bacteria / ml. (108 / litre) lower numbers may be significant in children an

13、d in catheter collected specimens Specimen collection Should all patients with a suspected UTI be cultured? Community acquired vs nosocomial? Should all isolates be identified? Susceptibility testing? Specimen collection Clean catch mid stream specimensClean catch mid stream specimens - most frequen

14、tly used method - urethra cleaned prior to collection - first void urine allowed to pass to clear urethra - mid-stream collected in sterile container Collection bags (children)Collection bags (children) - used in young children lacking bladder control - often contaminated - most meaningful result is

15、 a negative culture Specimen collection Suprapubic aspiration / straight cathetersSuprapubic aspiration / straight catheters - invasive - specimen obtained directly from bladder Indwelling cathetersIndwelling catheters - urine obtained by inserting needle into catheter or through diaphram - preferab

16、le to obtain specimen from new catheter, rather than old catheter Specimen transport Sent to and processed by lab as quickly as possible - Require: method of collection time of collection patients antibiotics Specimens not received by lab in 1-2 hours MUSTMUST be refridgerated Urines not received wi

17、thin 24 hours or not refridgerated will be rejected by laboratory Antimicrobial Therapy Empiric Therapy - based on most probable pathogens - local rates of resistance - acute infection vs chronic - reinfection or relapse - indwelling catheter etc Management of UTI Anatomical/Functional Predispositio

18、n to UTI Impaired bladder emptying Dysfunction Neuropathy VUR BOO Diverticulum Management of UTI Anatomical/Functional Predisposition to UTI Obstruction Any level VUR Calculi very difficult to eradicate if UTI and stones Management of UTI Anatomical/Functional Predisposition to UTI Intrarenal Renal

19、scars Interstitial nephritis Papillary necrosis Medullary sponge kidney APKD Congenital calyceal obstruction Management of UTI Anatomical/Functional Predisposition to UTI Associated conditions Diabetes mellitus Pregnancy Immunosuppression Elderly Management of Female UTI Bacterial Factors Adherence

20、Adhesins Fimbriae Non-fimbrial Adhesins Biofilms Important in catheter UTI Soluble Virulence Factor Production Disrupt bladder protective mucus layer Management of Female UTI Bacterial Factors Iron Acquisition Mechanisms Siderophores and Haemolysins Allow growth Serogroup and Serum R O ag LPS outer

21、G -ve Prevent complement destruction Capsules K ag covers bacteria capsule Protects v phagocytosis and complement attack Management of Female UTI Bacterial Factors Ig Proteases Cleave gut IgA Ureteric Paralysis P. Fimbriae and endotoxin Motility Ascent of LUT Urease Production Hydrolyse urea and inc

22、reases ammonia which increases bacterial adherence Management of Female UTI Host Factors Colonisation of vagina, introitus, urethra Biological predisposition Hormone deficiency vaginal atrophy Spermicidal jelly increases vaginal pH Antibiotics reduce vaginal lactobacilli and increase pH Ascent to bl

23、adder Sexual milkback Catheterisation Management of Female UTI Host Factors Establishment of bacteria in bladder Urine composition (extremes inhibit bacterial growth) Reduced IgA and IgG Reduced GAG layer in the bladder Low urine flow Incomplete emptying Management of Female UTI MSSU when symptomati

24、c USS renal tract with post void residual KUB Targeted flexible cystoscopy (8% yield) macroscopic haematuria microscopic haematuria between UTIs persistent UTI Management of Female UTI 3 days oral antibiotics or x1 high dose if compliance poor 14 days antibiotics if pyelonephritis Address any underl

25、ying cause (rare) General advice increase fluid intake cranberry juice void before and after si Management of Female UTI Hygiene wash without soap pat or air dry cotton pants 6 months low dose prophylactic antibiotics alter gut flora may affect COCP Self-start antibiotic therapy Management of Male U

26、TI MSSU when symptomatic USS renal tract with flow rate and post void residual KUB Flexible cystoscopy macroscopic haematuria microscopic haematuria persistent UTI Management of Male UTI UTI - 7 days oral antibiotics Address underlying cause Management of Childhood UTI History fevers and rigors irri

27、tative LUTS incontinence change in voiding pattern bowel dysfunction Examination including neurology Management of Childhood UTI TREAT IMMEDIATELY AFTER MSSU COLLECTED WITH THERAPEUTIC ANTIBIOTICS AND CONTINUE PROPHYLACTIC ANTIBIOTICS UNTIL INVESTIGATIONS COMPLETED ONLY DISCONTINUE IF ALL INVESTIGAT

28、IONS NEGATIVE Management of Childhood UTI MSSU/Suprapubic aspiration/Bladder catheterisation when symptomatic USS renal tract with post void residual DMSA/MAG3 (if hydronephrosis) VCUG (if DMSA or MAG3 +ve) at least 6 weeks post UTI KUB (if ? SB/sacral agenesis) MRI (if spinal anomalies) Management of Childhood UTI UTI 3-5 days antibiotics Pyelonephritis non-toxic/ 3 months : im ab x1 + 10-14 d