1、UrinaryTractInfectionWuYitaiDepartmentofNephrology1.Definitions2.Epidemiology3.Etiology4.Pathogenesis 5.Pathology6.Clinical presentation 7.Diagnosis8.Treatments9.Complication10.PreventionUTI is defined as the presence of micro-organisms in the urinary tract.Most patients with UTI have significant ba
2、cteriuria,i.e.bacterial colony counts 105/ml,in a mid-stream“clean catch”urine.Conversely,colony counts 105/ml of midstream urine are occasionally due to specimen contamination.Acute urethral syndrome:dysuria,urgency,and frequency,but without bacteriuria.lLower UTI:1.urethritis2.cystitis(mucosal inf
3、ection)lUpper UTI:1.pyelonephritis2.prostatitis3.intrarenal and perinephric abscesses(tissue invasion)lUncomplicated UTI:1.Lack structural or functional abnormalities of the urinary tract2.Normal flow of urine3.NO interference with the normal defenseslComplicated UTI:1.Predisposing lesion of the uri
4、nary tract,structural or functional abnormalities,e.g.congenital abnormality of the urinary tract,stone,obstruction,catheter.2.Interference with the normal defenses,e.g.immunosuppression,renal disease,or diabetes.lCatheter-associated（nosocomial）infections:1.Symptomatic 2.Asymptomtic lNon Catheter-as
5、sociated（community-acquired）infections:1.Symptomatic 2.AsymptomticlAlmost half of all women will have at least one UTI in their lives.lUTI is uncommon in men under the age of 50,but very common among women.lAsymptomatic bacteriuria is more common among elderly men and women.Community-Acquired UTIgra
6、m-negative bacilli is the most common agentE.coliEnterobacterEnterococcusProteusStaphylococcus KlebsiellaE.coli Causative organisms:Escherichia coli Klebsiella,proteus and pseudomonas 1-Bacteria S.aureus,Staphylococcus epidermidis and S.saprophyticus Enterococci(Streptococcus faecalis粪链球菌粪链球菌)Mycoba
7、cterium tuberculosis Chlamydia trachomatis,Neisseria gonorrhoeae 2-Virus Herpes simplex virus ,HIV 3-Fungus Candida,Histoplasma capsulatum 4-Protozoon Trichomonas vaginalis,Schistoma haematobium CASE 1 32 year-old woman;Dysuria and frequency;P y u r i a i n t h e u r i n e sediment;Gram negative bac
8、illi.Escherichia coli (E.coli).CASE 2 65 year-old woman;Dysuria and frequency;Pyuria;Gram positive cocci.Enterococcus faecalisCASE 318 year-old woman Dysuria and frequency;Pyuria;Gram positive cocci;Staphylococcus.CASE 4 42 year-old diabetic woman with a catheter.Gram positive yeasts.Candida grew.As
9、cending route (the most common)Colonization of urethraThe urinary tract above the urethra is normally sterile.The urethral meatus and surrounding perineum are colonized with a mixture of skin and bowel flora.Vaginal flora or pathogens may contaminate the urethra.Host defense mechanisms:1.Urine:low p
10、H,high osmolality,high urea&organic acid concentration inhibit and kill microorganisms2.Regular urine flow:dilute and expel pathogens3.Bladder epithelial cells:coated with mucus (glycosaminoglycan)prevent bacteria from adhering to bladder walllGender and sexual activity.lPregnancy.lObstruction.（tumo
11、r,stricture,stone,BPH）lNeurogenic bladder dysfunction.lVesicoureteral refluxlBacterial virulence factorslGenetic factors（details in the following）Gender and sexual activity lThe female urethra appears to be prone to colonization with colonic gram-negative bacilli because of its proximity to the anus
12、,its short length,and its termination beneath the labia.lVoiding after intercourse reduces the risk of cystitis.lAn important factor predisposing to bacteriuria in men is urethral obstruction due to prostatic hypertrophy.PregnancylUTIs are detected in 2 to 8%of pregnant women.lPregnant women with as
13、ymptomatic bacteriuria.lBladder catheterization during or after delivery causes additional infections.Obstruction lTumorlStricturelStonelBenign prostatic hypertrophy(BPH)These conditions result in hydronephrosis and increase frequency of UTI.Neurogenic Bladder DysfunctionlInterference with bladder e
14、nervation,as in spinal cord injury,multiple sclerosis,diabetes.lThe infection may be initiated by the use of catheters for bladder drainage.lThe infection is favored by the prolonged stasis of urine in the bladder.Vesicoureteral RefluxlVesicoureteral reflux occurs during voiding or with elevation of
15、 pressure in the bladder.lCommon among children with anatomic abnormalities of the urinary tract.lRenal damage correlates with marked reflux,not with infection.Bacterial Virulence factorslSpecific O,K,and H serogroups.lAdherence of bacteria to uroepithelial cells is a critical first step in the init
16、iation of infection.lFimbriae mediate the attachment of bacteria to specific receptors on epithelial cells.lE.coli strains usually produce hemolysin and aerobactin.Genetic factorslHost genetic factors influence susceptibility to UTI.lThe number and type of receptors on uroepithelial cells are in par
17、t genetically determined.lGender and sexual activity.lPregnancy.lObstruction.（tumor,stricture,stone,BPH）lNeurogenic Bladder Dysfunction.lVesicoureteral RefluxlBacterial Virulence factorslGenetic factorsCystitisMucosal hyperemiaEdemaLeukocyte infiltrationEasy bleedingGranular surfaceSuperficial ulcer
18、Purulent exudateAcute PyelonephritisAcute inflammationHyperemia and edemaVolume increase Red colour Yellowish abscess Purulent exudateChronic PyelonephritisChronic inflammationPelvis deformed Cortex scarsVolume shrink Asymmetric Parenchyma atrophyInterstitial edema Neutrophil infiltration White bloo
19、d cell castIn microscopyCystitislBurning painlFrequency,urgencylSuprapubic painlDysuriaUrethritis lBurning painlFrequency,urgencylDysurialInfected with sexually transmitted pathogens Acute PyelonephritislAll cystitis symptoms（+）or（-）lFever,shaking chillslNausea,vomiting,diarrhealTachycardia,hypotent
20、ionlMuscle tendernesslCostovertebral angle（CVA）painlGram-negative sepsis,LeukocytosislLeukocyte casts in the urineCatheter-Associated UTIs lBacteriuria develops in at least 10 to 15%of hospitalized patients with indwelling urethral catheterslThe risk of infection is 3 to 5%per day of catheterization
21、.lMany infecting bacteria display markedly great antimicrobial resistance.How is it diagnosed?Diagnosis1.Patient history 2.Complete physical examination 3.Urine culture 4.Urine analysis 5.Other examinations Microscopic ExaminationDiagnosisDiagnosisLeukocyte esterase+Nitrite+Urine routine:pH,sg,prote
22、in,glucose,blood,ket,etc.Clean urine culture:bacterial counts 105/mlSuprapubic puncture,catheter collected urine 102/mlSignificant bacteriuria Microscopic bacteriuria(very important)Diagnosis（No definite standard method）Ultrasonography Intravenous pyelography（IVP）Abdominal CT/MRIStaphylococcus sapro
23、phyticus(5-15%)Enterobacteriaceae E.coli(86%)Klebsiella pneumoniaeProteus Enterococcus Single-dose therapy is less effectiveEspecially with -lactams3-day course recommendedTMP-SMX,fluoroquinolone,nitrofurantoinNOT appropriate for male patients and complicated UTIs7-day course:Diabetes,age 65 years,M
24、alesIf untreated:may lead to acute uncomplicated pyelonephritis treatmentEnterobacteriaceaeE.coli Klebsiella pneumoniaeProteus Staphylococcus saprophyticus Mild or moderate symptoms:lOutpatient treatment(714 days)lOral treatment:Fluoroquinolone,TMP/SMX,third generation cephalosporinSevere ill patien
25、t:lHospitalization requiredlParenteral therapy(14 days)lBroad-spectrum cephalosporins or FluoroquinolonesEnterobacteriaceaeE.Coli Klebsiella pneumoniaeProteusEnterococciPseudomonasStaphylococciMinimal or mild symptoms(10-14d).Oral therapy:fluoroquinolone(ciprofloxacin or ofloxacin)Severe ill patient
26、,parenteral therapy(10-21d).Hospitalization required,Imipenem alone Peni ci l l i n or cephal ospori n p l u s aminoglycoside Third generation cephalosporin:Ceftriaxone or ceftazidimeLow urinary tract infection(acute cystitis):l 7 days course antibioticsl Amoxicillin,cephalosporine,nitrofurantoinPye
27、lonephritis:2-4 weeks course antibiotics Cephalosporins,extended spectrum penicillins Parenteral treatment Follow-up urine culture tests,monthly Low-dose prophylaxis to recurrent infectionsAsymptimatic bacteriurial Antibiotics treatments are needed.For bacteriuria in asymptomatic catheterized patien
28、t:Catheter removed as soon as possible.The bacteriuria should be ignored.If becomes symptomatic:Remove catheterTreatment as described for complicated infectionsIf the catheter cannot be removed,antibiotic therapy usually proves to be unsuccessful.Renal Papillary necrosislPatients with diabetes,sickl
29、e cell disease,chronic alcoholism,and vascular diseaselHematuria,pain in the flank or abdomen,chills and feverlAcute renal failure with oliguria or anurialIVP:ring shadowlOften bilaterallDrink plenty of fluids and frequent urination.lKeeping the perineal area clean.lDo not take invasive method of ex
30、amination if possible.lProphylactic low-dose antibiotics,daily or thrice-weekly administration of a single dose of TMP-SMX,TMP,nitrofurantoin,fluoroquinolone.lPatient who suffer refluence of bladder-ureter should change the urination habit（twice urination，i.e.after urination for several minutes,to urinate again）
