SURGICALINFECTION醫(yī)療專題知識專家講座

SURGICALINFECTIONByDr.ShiChengProfessorofSurgeryDepartmentofGeneralSurgeryBeijingTiantanHospitalCapitalMedicalUniversityContentsIntroductionClassificationInflammationandsystemicsurgicalinfectionSepsisFungalinfectionTetanusTheappropriateapplicationofantibioticsIntroductionClassificationSpecificandNonspecificinfection:invasivemicro-organismsSpecificinfection:includingtuberculosis,tentanus,gasgangrene,etal.Nonspecificinfection:pyogenicAcute,subacuteandchronic:duration.(<threeweeksor>twomonths)Externalinfectionandinternalinfection:invasivewayOpportunisticinfection,superinfection,nosocomialinfection:conditionsInflammationandsystemicsurgicalinfectionSYSTEMICINFLAMMATORY

RESPONSESYNDROME(SIRS)

Patientpresentswithtwoormoreofthefollowingcriteria.1.temperature>38°Cor<36°C2.heartrate>90beats/minute3.respiration>20/minorPaCO2<32mmHg4.leukocytecount>12,000/mm3,<4,000/mm3or>10%immature(band)cellsEtiologyInfectionfactor:thecommoncause,Sepsis.Noninfectionfactor:severetrauma,burn,pancreatitis,shock,ischemia-reperfusioninjury.PathophysiologyLocalinflammationSystemicinflammationTheroleofinflammationmediatorinSIRSRegulationandoutofcontroloftheinflammationresponseSIRSSepsisTheconceptsSepsisThesystemicinflammatoryresponsetoinfection.SepsissyndromeSepsis(SIRS)associatedwithorgandysfunction,hypoperfusion,orhypotension.Hypoperfusionandperfusionabnormalitiesmayinclude,butarenotlimitedto,lacticacidosis,oliguria,oranacutealterationinmentalstatus.Bacteremia.Thepresenceofviablebacteriaincirculatingblood.

Systemic

Factorscontributingtotheincreasingincidenceofsepsis1.Miscellaneousconditions:childbirth,septicabortion,traumaandwidespreadburns,intestinalulceration.

2.widespreaduseofcorticosteroidandimmunosuppressivetherapiesfororgantransplantsandinflammatorydiseases

3.longerlivesofpatientspredisposedtosepsis,cirrhosisofliver,diabetics,malnutrition,anemia,cancerpatients,neutropenia,leukemia,dysproteinemias,patientswithmajororganfailure,andwithgranulocytopenia.4.Neonatesandtheelderlyaremorelikelytodevelopsepsis(ex.groupBStreptococcalinfections).5.aggressiveoncologicalchemotherapyandradiationtherapy6.AIDS,localconditionsatincreasedrisksofdevelopingsepsis1.Openingtrauma,burning,perforationofgastrointestine,surgery,puncture2.increaseduseofinvasivedevicessuchassurgicalprotheses,inhalationequipment,andintravenousandurinarycatheters.3.Intraductalobstruction4.Foreignbodyornecrotictissue.5.BloodobstacleoflocaltissueEtiologyGram-negativebacteria.Escherichiacoli,Klebsiellapneumoniae,Pseudomonasaeruginosa,Proteusspp.,Serratiaspp.,Neisseriameningitidis.Gram-positivebacteria.

Staphylococcusaureus,coagulase-negativeStaphylococcus,Streptococcuspneumoniae,Streptococcuspyogenes,enterococci.Othercauses.Opportunisticfungi(2%to3%),viral,rickettsia,andprotozoaOutcomeofInfecionResolution

AbscessFormation

DiffusionChronicinflammation

ClinicalManifestationsPrimaryinfectionfocusSystemicinflammationresponseHypoperfusionabnormalitiesoforgans.SystemicinflammationresponseFever,chills.Theymaybeabsentinseriousinfections,especiallyinelderlyindividuals.WBC,leukocytosiswithleftshiftTachycardia,tachypneaTachypneaaccompaniedwithmildrespiratoryalkalosisandalterationinmentalstatusmaybetheonlysignoftheelder.Hypoperfusionabnormalitiesoforganslacticacidosis,oliguria,Tachypnea,hypoxia,Pao2Anacutealterationinmentalstatus.Hyperbilirubinemia,thrombocytopenia,Septicshock,organfailure

PhysicalExaminationMildenlargementofliverorspleenSkineruption(reddishpatches)Metastaticabscess

Diagnosis

DiseaseEvidence

BacteremiaPositivebloodcultureSepsisTheevidenceofinfectionthemanifestationofSIRS

Sepsissyndrome

PositivebloodculturetheevidenceofsepsisHypoperfusionoforganshypoxemia,oliguria,alterationinmentalstatusDiagnosisGram-positivebacteriasepsisGram-negativebacteriasepsisCandidaalbicanssepsisAnaerobicbacteriasepsisDifferentsepsisclinicalcharacters

SepsiscommonpathogenicfeverchillshockrashdiseasebacteriametastaticabscessG+Carbuncle

Staphylococcus

continued

(-)warm(+)

Cellulitis

aureus

remittent

late

pyogenicinfectionofboneandjoint

G-biliary,urinary

Escherichiaintermittent(+)cold

(-)

intestinalinfectioncoli

early

seriousburn

Candida

afterapplyingCandidas

(+)

(+)(+)(-)

albicans

broad-spectrumalbicanantibioticsAnaerobic

seriousinfection

Bacteroidesbacteria

abdominalandfragilis

(+)

(+)(+)metastaticabscess

pelvic

cavity

TherapyTheoriginalfocusofinfectionmustbetreated

surgicaldrainagemaybeneededinsomecases

TheapplicationofantibioticsPatientswithseveresepsisshouldbeinICU.SupporttherapyInhibitionorblockadeofinflammationmediator

Monoclonalantibodiesagainstgram-negativeendotoxin,steroids,andanti-TNFantibodieshavenotdemonstratedsignificantreduction.Recentstudysuggestslow-dosesteroidsmayhelpinsepticshock,butthisisnotyetstandardofcare.Introduction

Surgicalfungalinfectionisanopportunisticinfection.Thedeeperinfectionisthemajor.MostsurgicalfungalinfectionsareinfactduetoCandida,butAspergillusinfectionsarealsoseen.PathogenesisC.albicansisanasexual,diploid,dimorphicfungusthatiswidespreadonhumansandintheirenvironment.Westilldon'tunderstandwhythiscommoncommensalsometimesbecomespathogenic,althoughimpairedhostdefencemechanismsseemcrucial.Riskfactorsforopportunisticfungalinfections1.Neutropaenicpatientsfollowingchemotherapy,andotheroncologypatientswithimmunesuppression;2.PersonsimmunecompromisedduetoAcquiredImmuneDeficiencySyndromecausedbyHIVinfection;3.Patientsinintensivecare(ICU),whoarenotnecessarilyneutropaenic,butarecompromisedduetothepresenceoflong-termintravascularlinesorotherbreachesintheirintegument,severesystemicillnessorburns,andprolongedbroad-spectrumantibiotictherapy.

Other(quoted)predisposingfactorsAPACHEscore>10;renaldysfunction;haemodialysis;surgeryforacutepancreatitis,orevenpossiblysplenectomy;recurentGITperforation;Hickmanncatheters.ClinicalmanifestationsC.albicanscausedigestivetract,respiratorytractandurinarytractinfection.BlooddisseminatedcandidiasisAspergilluscausepneumonia.DiagnosisIfyoudon'tsuspectit,you'llmissit!

Conventionaldiagnosisoftheseinfections,basedonbloodculturesorcultureoftheoffendingorganismfrommultiplesites.

Newerteststhathavebeenadvocatedforearlydiagnosisofsystemicfungalinfectioninclude:SandwichELISAforcirculatinggalactomannanPCRshowspromiseinthediagnosisofCandidainfections,evenunusualspecies.TreatmentTherapytoetiology.Antifungaltherapy.

AmphotericinB0.5-1mg/kg.divFluconazoleandotherAzoles400mg/firstday,200-400mg/dPreventionAppropriateapplyingantibioticsProphylacticapplyingantifungaldrugsWhatistetanus?Tetanusisanacute,sometimesfatal,diseaseofthecentralnervoussystem,causedbythetoxinofthetetanusbacterium,whichusuallyentersthebodythroughanopenwound.PathogenesisTetanusresultsfrominfectionwithCtetani,amobile,spore-forming,anaerobic,

gram-positivebacillus.Thisbacillusisfoundinoronsoil,manure,dust,clothing,skin,and10-25%ofhumanGItracts.Thesporesneedtissuewiththeproperanaerobicconditionstogerminate;theidealmediumiswoundswithtissuenecrosis.

PathogenesisThesporesofCtetanigerminateandproduce2toxins:tetanolysinandtetanospasmin.Theactionofthelatterhelpsexplaintheclinicalmanifestationsofthedisease.PathogenesisTetanospasminissynthesizedasasingle151-kdchainandiscleavedtogeneratetoxinswith2chainsjoinedbyasingledisulfidebond.Theheavychain(100kd)isresponsibleforspecificbindingtoneuronalcellsandforproteintransport.Thelightchain(50kd)blocksthereleaseofneurotransmitters.

PathogenesisOncethetoxinissynthesized,itmovesfromthecontaminatedsitetothespinalcordin2-14days.Whenthetoxinreachesthespinalcord,localizedorcephalictetanusmayoccurinitially,followedbygeneralizedtetanus.ClinicalManifestationIncubation

Theincubationperiodfortetanusisusually2to14days,withmostsymptomsbeginningaroundthe7-8day,butonsetmayrangefrom24hoursto3weeks.ClinicalManifestationTetanusoftenbeginswithmusclespasmsinthejaw(calledtrismus),accompaniedbydifficultyswallowingandstiffnessorpaininthemusclesoftheneck,shoulders,orback.Thesespasmscanspreadtothemusclesoftheabdomen,upperarms,andthighs.Symptomsstiffnessofjaw(alsocalledlockjaw)difficultyswallowingcontractionoffacialmusclesstiffnessofabdominalandbackmusclesSweatingpainfulmusclespasmsnearthewoundarea(iftheseaffectthelarynxorchestwall,theymaycauseasphyxiation)

PhysicalCommonfirstsignsoftetanusareheadacheandmuscularstiffnessinthejaw(ie,lockjaw),followedbyneckstiffness,difficultyswallowing,rigidityofabdominalmuscles,spasms,andsweating.Severetetanusresultsinopisthotonos,flexionofthearms,extensionofthelegs,periodsofapnearesultingfromspasmoftheintercostalmusclesanddiaphragm,andrigidityoftheabdominalwall.Lateinthedisease,autonomicdysfunctiondevelops,withhypertensionandtachycardiaalternatingwithhypotensionandbradycardia.

Complications

Themostcommoncomplicationisspasmofthevocalcordsand/orspasmsoftherespiratorymusclesthatcauseinterferencewithbreathing.Asphyxiation,pneumoniaOthercomplicationsincludemuscleavulsion,fractures,dislocationstachycardia,andheartfailure.DIFFERENTIALS

RabiesEncephalitisStrychninepoisoning

OtherProblemstobeConsidered:

Dentalinfections

Localinfections

Hysteria

Prevention

Therearetwoimportantcomponentsoftetanusprevention:tetanusimmunization(receivingroutinetetanusvaccinations)andwhat'sknownaspost-exposuretetanusprophylaxis(receivingashotafteraninjuryoccurs).

Prevention

Forchildren,tetanusimmunizationispartoftheDTaP(diphtheria,tetanus,andacellularpertussis)vaccinations.

ActiveimmunizationPost-exposuretetanusprophylaxisalsoinvolvesgettingtetanusshots,butafteraninjuryoccurs.

PassiveimmunizationTreatmentThoroughcleaningofthewound

Neutronlizethefreetoxin

Passiveimmunizationwithhumantetanusimmuneglobulin(TIG)shortensthecourseoftetanusandmaylessenitsseverity.Adoseof500Uappearsaseffectiveaslargerdoses.OrTAT20230-50000UIV

TreatmentTocontrolspasms

Diazepamiv,10mgtid.Luminal0.1im.Physiciansalsousesedativehypnotics,narcotics,inhalationalanesthetics,neuromuscularblockingagents,andcentrallyactingmusclerelaxants(eg,intrathecalbaclofen).TreatmentSecuringanadequateairway.Atracheotomyinseverecases(withrespiratoryproblems)Antibiotics

Metronidazole(eg,0.5gq6h)hascomparableorbetterantimicrobialactivity,andpenicillinisaknownantagonistofGABA,asistetanustoxin.TreatmentSupportivetherapy

ParenteralnutritionIntensivenursingTheappropriateapplicationofantibioticsBackgroundTheglobalincreaseinresistancetoantimicrobialdrugs,includingtheemergenceofbacterialstrainsthatareresistanttoallavailableantibacterialagents,hascreatedapublichealthproblemofpotentiallycrisisproportions.TheroleofantibioticsInhibitscellwallsynthesisImpairmentofbacterialDNAsynthesisDisruptionofmembranebarrierfunctionDisruptionofribosomalproteinsynthesisThecommonusedAntibioticsA.AmphotericinBB.PenicillinC.CephalosporinsD.β-lactamase:ImipenemE.AminoglycosidesF.QuinolonesG.ClindamycinH.Antianaerobic-microbacterialdrugs*

ProphylacticuseofantibioticsperioperativeperiodIndication(1)Severetrauma,severeburn,Anywoundwithknowngrossbacterialcontamination(2)Operationsenteringthegastrointestinaltract,respiratorytract,femalegenitaltractandbowelpreparationbeforecolonsurgery(3)Implantationofanypermanentprostheticmaterial(4)Highriskfactorofinfection:Diabetesmellitus,elder,malnutrition,granulocytopenia,Steroids,Immunosuppression,oncologicalchemotherapyetal.(5)Cardiacvalvulardiseaseorvalvesurgery,organtransplantation,Craniotomy

*AdministrationofprophylacticantibioticsChoiceofantibioticsTimingofadministrationDosageselectionDurationofprophylaxisRouteofadministrationGuidelinesforUseChoiceofantibiotics

Theantibioticsselectedforprophylaxismustcovertheexpectedpathogensforthatoperativesite.Cephalosporin

Recommeded:

Cefuroxime(2ndgenerationcephalosporin)GuidelinesforUseTimingofadministration

Givesingledoseinjection0-2hourspreoperation

ideallywithin30minutesoftheinductionofanaesthesiaDosageselection

Asinglestandardtherapeuticdoseofantibioticissufficientfo