内科学教学课件：Urinary Tract Infection( UTI )

UrinaryTractInfection

(UTI)Generalremarks

Inthischapter,UTIresultingfrombacterialinvasionisdiscussed.Anatomically.

Itisdividedintouppertracturinaryinfection(pyelonephritis)andlowertracturinaryinfection(cystitis)incidence：UTIisacommondisease(2%inpopulation),particularlyinfemaleadults(10%).Etiologyandpathogenesis

Pathogen：

gram-negativebacteria（Specificallycoliformbacteria,proteusbacteria）Pyocyanicinfectionisfrequentlyseeninpatientswithinstrumentation.Proteusbacteriaisoftenseeninpatientswithcalculus.BacterialvirulencefactorsAhighdegreeofbacterialadherence,whichismediatedbythebacterialfimbriae.Somebacteriacanproducehemolysinwhichcanresistthebody’sdefensesystem.DrugresistancestrainsHostdefensemechanismsEfficientemptyingofthebladderwithvoiding.Aprotectiveglycosaminoglycanlayer.ThehighosmolalityandextremesofpH.IgG,IgAandorganicacidsecretedbyurinarytractmucosa.HostsusceptibilityfactorsurinarytractObstructionsuchascalculus,vesicoureteralrefluxorintrarenalreflux.

(thepresenceofUTIwithstructurallyorfunctionallyabnormalurinarytractiscalledcomplicatedUTI)ThedeformityofurinarysystemInstrumentationoftheurinarytractHostdefensesystemgetweak,forinstance,diabetesmellitusPregnancy,genderneurogenic

bladderGenetic

factorInfectionrouteTheascendingroute:periurethraltissues→urethra→bladder→ureter→renalpelvis→renalmedullaThehematogenousrouteLymphogenousspreadDirectextensionfromotherorgansmayoccurClinicalmanifestationcystitisIrritativevoidingsymptomsfrequency,urgency,dysuria(burningordiscomfortonurination),suprapubicdiscomfortUrinalysispyuria,bacteriuria,hematuriaBloodtest:generallynormal

Acutepyelonephritis

Irritativevoidingsymptoms,flankpain.Systemictoxicityfever,shakingchills,nausea,vomitingSigntendernessofureterspotonpalpation,exquisitetendernessonpercussionofthecostovertebralangle.LaboratoryfindingsBloodtest:leukocytosisandaleftshit.Urinalysis:pyuria,bacteriuria,hematuria.Bloodculture:maybepositive.

Asymptomaticbacteriuria

nosymptomispresent,yetbacteriuriaexists.Laboratoryfindings

Urinalysisafindingof≥5WBC/Hpor≥8000WBC/ml↓UTIwhitecellcasts→pyelonephritis.hematuria,proteinuriaLaboratoryfindingsDetectionofbacteriuriaCollectionofurinesample:Theurineiscollectedinmidstreambeforedrugisusedoratleast7daysafterdrugadministration.Avoidingcontamination,beingsenttothelaboratorywithin1h.

UrinecultureCFUs≥105/ml→significantbacteriuria.CFUsbetween104~105/ml→suspectedUTI→reexaminationCFUs＜104/ml→maybecontamination

(Qualitative

urineculture:iftheurineforcultureisfromcystpuncture,thenwhenpositive,itindicateatrueUTI)

Urinesmearexaminedbymicroscopy

when≥1bacteriuria/oil-immersedHP

Chemicaltestforbacteriuria

Nitratereductiontest

thetestisdependentonthebacterialreductionofnitrateintheurinetonitrite.itiseffectiveinidentifyinginfectionduetogram-negativebacteria.Imaging

IndicationAllmalepatientsFemalepatientrecurrentUTIcomplicatedUTIdisappointingresponsetoantimicrobialtherapy4.everinfectedduringpregnancyImagingstudiesincludeUltrasonographyIntravenouspyelogram(IVP)Computedtomography

Notice

IVPshouldnotbedoneintheacutephaseofUTI.DiagnosisOFUTIsignificantbacteriuriaApositiveresultofurinecultureinwhichurinespecimenisfromcystpuncture.Quantitativeurineculture:apatientbeingsymptomatic,CFUs≥105/mlforonce.apatientbeingasymptomatic,CFUs≥105/mlfortwice(itshouldbethesamespecies)

DiagnosisOFUTIwhenafemalepatientwithirritativevoidingsymptomandCFUs≥102/ml,UTIshouldbeconsideredandtreatmentforUTIshouldbegiven.

Infection-localizingdiagnosisurinecultureafterbladderwashouttheassayforantibody-coatedbacteria（ACB)urinaryconcentratingability,urineβ2-MG，urinewhitecellcast.

bilateralureteralcatheterrization.

itistooinvasiveforgeneraluse.clinicalpractice1.acutepyelonephritisfever(T＞38℃),shakingchills,backpain,WBC↑tendernessonpercussionofthecostovertebralangle2.3daysofantibioticstreatment,ifbeingcured→cystitis,ifnot→pyelonephritis.Chronicpyelonephritis：

thecorticalscarringacorrespondingcalicealdeformitytubuledamageandinterstitial

inflammationandscarring

Differentialdiagnosis

1.renaltuberculosis

aprominentirritativevoidingsymptomnullitytocommonantibioticsmycobacteriuminurinePPD（+）stricture,cavities,calcificationinIVP2.urethralsyndrome:

exhibitirritativevoidingsymptomnosignificantbacteriuriaInfectiveurethralsyndrome:

causedbyotherpathogenssuchasvirus,mycoplasms,chlamydia.Urinalysisshowpyuria.

Non-Infectiveurethralsyndrome:noWBCisseenwithurinalysis.Probablyitisbecauseofpsychologicalproblems.treatmentAntibiotics

G—Bacillus（sulfonamide,quinolones,β-lactamdrugsemisytheticpenicillins,cephalosporins）Afterthedrugsensitivitytestforoffendingorganismsisavailable,thenantibioticsaregivenaccordingtothetest.

Acutecystitis:singledosetherapyanda3-daycourseoftherapy

↓followeduptoseewhethertheinfectioniscontrolledornotitshouldnotbeusedinpatientswithpregnancy,complicatedinfection,suspectedpyelonephritisormalepatients

Acutepyelonephritis

intensiveantimicrobialtherapyshouldbeadministrated.antibioticsfor14daysorally.noeffectwithin72h→adjustthetreatment.

Moderateacutepyelonephritis:intravenoustherapyofantibiotics↓defervescesfor72horalagentatleast14days

Acutepyelonephritis

Severeacutepyelonephritis:

acombinationofantibioticsaregivenintravenously,oftenanaminoglycosidecombinedwithaβ-lactamdrugorcephalosporins.

TherapyforrecurrentUTI：Relapsinginfection：

infectionoccurwithin6wofthecessationofantimicrobialtherapyandiscausedbythesameorganism.Reinfection：

causedbyanorganismwhichisdifferentfromtheoriginalone.

TherapyforrecurrentUTI：

receiveshortcoursetherapyof7days→followedup7daysaftercessationoftherapy.Ifnosymptom，bacteriuriaandpyuria→curereinfection；Stillwithsymptoms,bacteriuriaandpyuria→treataccordingtodrugsensitivitytest.IfsucceededReinfection,iffailed→abigdoseantimicrobialsfor6weeks.patientswithmorethan3UTIs/years→longtermprophylaxistherapy.treatmenturinarytractinfectioninpregnancychoosedrugsthataresafetofetus(ampicillincephalexin)asymptomaticbacteriuriaWomeninpregnancy,childrenbeforeschool-age,previoussymptomaticUTI,withcomplicatedfactors---shouldreceivetreatment.Complication

Acuterenalpapillarynecrosis：accompaniedbydiabetesorurinarytractobstruction.leadtosepsisorARF.presentwithhighfever,severebackpain,hematuria,an