BacterialmeningitisIntroductionBacterialmeningitisisaninflammationoftheleptomenings,usuallycausingbybacterialinfection.Bacterialmeningitismaypresentacutely(symptomsevolvingrapidlyover1-24hours),subacutely(symptomsevolvingover1-7days),orchronically(symptomsevolvingovermorethan1week).IntroductionAnnualincidenceinthedevelopedcountriesisapproximately5-10per100000.30000infantsandchildrendevelopbacterialmeningitisinUnitedStateseachyear.Approximately90percentofcasesoccurinchildrenduringthefirst5yearsoflife.EtiologyCausativeorganismsvarywithpatientage,withthreebacteriaaccountingforoverthree-quartersofallcases:Neisseriameningitidis(meningococcus)Haemophilusinfluenzae(ifveryyoungandunvaccinated)Streptococcuspneumoniae(pneumococcus)EtiologyOtherorganismsNeonatesandinfantsatage2-3monthsEscherichiacoliB-haemolyticstreptococciStaphylococcusaureusStaphylococcusepidermidisListeriamonocytogenesEtiologyElderlyandimmunocompromisedListeriamonocytogenesGramnegativebacteriaHospital-acquiredinfectionsKlebsiellaEscherichiacoliPseudomonasStaphylococcusaureusEtiologyThemostcommonorganismsNeonatesandinfantsundertheageof2monthsEscherichiacoliPseudomonasGroupBStreptococcusStaphylococcusaureus

EtiologyMajorroutesofleptomeninginfectionBacteriaaremainlyfromblood.Uncommonly,meningitisoccursbydirectextensionfromnearlyfocus(mastoiditis,sinusitis)orbydirectinvasion(dermoidsinustract,headtrauma,meningo-myelocele).PathogenesisSusceptibilityofbacterialinfectiononCNSinthechildrenSpecificimmuneImmaturityofboththecellularandhumoralimmunesystemsInsufficientantibody-mediatedprotectionDiminishedimmunologicresponseBacterialvirulencePathogenesisBacterialtoxicsandinflammatorymediatorscausesuppurativeinflammation.InflammatoryinfiltrationVascularpermeabilityalterTissueedemaBlood-brainbarrier

detroyThrombosisPathologyDiffusebacterialinfectionsinvolvetheleptomeninges,arachnoidmembraneandsuperficialcorticalstructures,andbrainparenchymaisalsoinflamed.Meningealexudateofvaryingthicknessisfound.Thereispurulentmaterialaroundveinsandvenoussinuses,overtheconvexityofthebrain,inthedepthsofthesulci,withinthebasalcisterns,andaroundthecerebellum,andspinalcordmaybeencasedinpus.

Ventriculitis(purulentmaterialwithintheventricles)hasbeenobservedrepeatedlyinchildrenwhohavediedoftheirdisease.PathologyInvasionoftheventricularwallwithperivascularcollectionsofpurulentmaterial,lossofependymallining,andsubependymalgliosismay

benoted.Subduralempyemamayoccur.Hydrocephalusisancommoncomplicationofmeningitis.ObstructivehydrocephalusCommunicatinghydrocephalus

PathologyBloodvesselwallsmayinfiltratedbyinflammatorycells.EndothelialcellinjuryVesselstenosisSecondaryischemiaandinfarctionVentricledilatation

whichensuesmaybeassociatedwithnecrosisofcerebraltissueduetotheinflammatoryprocessitselfortoocclusionofcerebralveinsorarteries.PathologyInflammatoryprocessmayresultincerebraledemaanddamageofthecerebralcortex.ConsciousdisturbanceConvulsionMotordisturbanceSensorydisturbance

Meningealirritationsignisfound

becausethespinalnerverootisirritated.CranialnervemaybedamagedClinicalmanifestationToxicsymptomalloverthebody

HyperpyrexiaHeadachePhotophobiaPainfuleyemovementFatiguedandweakMalaise,myalgia,anorexia,Vomiting,diarrheaandabdominalpainCutaneousrashPetechiae,purpura

ClinicalmanifestationClinicalmanifestationofCNSIncreasedintracranialpressureHeadacheProjectilevomitingHypertensionBradycardiaBulgingfontanelCranialsuturesdiastasisComaDecerebraterigidityCerebralhernia

ClinicalmanifestationClinicalmanifestationofCNSConsciousdisturbanceDrowsiness

CloudingofconsciousnessComaPsychiatric

symptom

IrritationDysphoriadullness

ClinicalmanifestationClinicalmanifestationofCNSMeningealirritationsignNeckstiffnessPositiveKernig’ssignPositiveBrudzinski’ssignClinicalmanifestationSymptomandsignsoftheinfantundertheageof3monthsInsomechildren,particularlyyounginfantsundertheageof3months,symptomandsignsofmeningealinflammationmaybeminimal.Feverisgenerallypresent,butitsabsenceorhypothermia

inainfantwithmeningealinflammationiscommon.Onlyirritability,restlessness,dullness,vomiting,poorfeeding,cyanosis,dyspnea,jaundice,seizures,shockandcomamaybenoted.Bulgingfontanelmaybefound,butthereisnotmeningealirritationsign.Complication

SubduraleffusionSubduraleffusionsoccurinabout10%-30%ofchildrenwithbacterialmeningitis.Subduraleffusionsappeartobemorefrequentinthechildrenundertheageof1yearandin

haemophilusinfluenzaeandpneumococalinfection.Clinicalmanifestationsareenlargementinheadcircumference,bulgingfontanel,cranialsuturesdiastasisandabnormaltransilluminationoftheskull.SubduraleffusionsmaybediagnosedbytheexaminationofCTorMRIandsubduralpricking.

ComplicationEpendymitis

NeonateorinfantwithmeningitisGram-negativebacterialinfectionClinicalmanifestation

Persistenthyperpyrexia,FrequentconvulsionAcuterespiratoryfailureBulgingfontanelVentriculomegaly(CT)Cerebrospinalfluid

byventricularpunctureWBC>50×109/LGlucose<1.6mmol/LProtein>o.4g/LComplicationHydrocephalusIncreasedintracranialpressureBulgingfontanelAugmentationofheadcircumferenceBrainfunctiondisorderOthercomplicationDeafnessorblindnessEpilepsyParalysisMentalretardationBehaviordisorder

LaboratoryFindingsPeripheralhemogramTotalWBCcount

20×109/L～40×109/LWBCDecreasedWBCcountatsevereinfectionLeukocytedifferentialcount80%～90%NeutrophilsLaboratoryFindingsRoutexaminationofcerebrospinalfluid(CSF)IncreasedpressureofcerebrospinalfluidCloudiness

EvidentIncreasedtotalWBCcount(>1000×109/L)EvidentIncreasedneutrophilsinleukocytedifferentialcountEvidentDecreasedglucose(<1.1mmol/l)

EvidentIncreasedproteinlevel

DecreasedornormalchloridateCSFfilmpreparationorcultivation:positiveresultLaboratoryFindingsEspecialexaminationofCSFSpecificbacterialantigentestCountercurrentimmuno-electrophoresisLatexagglutinationImmunofluorescenttest

Neisseriameningitidis(meningococcus)HaemophilusinfluenzaeStreptococcuspneumoniae(pneumococcus)GroupBstreptococcusLaboratoryFindingsEspecialexaminationofCSFOthertestofCSFLDHLacticacidCRPTNFandIgNeuronspecificenolase(NSE)LaboratoryFindingsOtherbacterialtestBloodcultivationFilmpreparationofskinpetechiaeandpurpuraSecretioncultureoflocallesionImageologyexaminationDiagnosisDiagnosticmethodsAcarefulevaluationofhistoryAcarefulevaluationofinfant’ssignsandsymptomsAcarefulevaluationofinformationonlongitudinalchangesinvitalsignsandlaboratoryindicatorsRoutexaminationofcerebrospinalfluid(CSF)DifferentialdiagnosisClinicalmanifestationofbacterialmeningitisissimilartoclinicalmanifestationofviral,tuberculous,fungalandasepticmeningitis.Differentiationofthesedisordersdependsuponcarefulexaminationofcerebrospinalfluidobtainedbylumbarpunctureandadditionalimmunologic,roentgenographic,andisotopestudies.Characteristics

ofCSFoncommondiseaseinCNS

PMTMVWFMTEPressure↑↑－or↑↑↑↑Cloudiness＋＋or＋＋＋＋－±－PandyT＋＋or＋＋＋＋or＋＋＋±or＋＋＋or＋＋＋－WBC↑↑↑N↑L－or↑L↑M－Protein↑↑↑↑↑↑－or↑↑↑－or±Glucos↓↓↓↓↓－↓↓－Chloridate－or↓↓↓↓－↓↓－CultivationBacteriumTBViralFungus－Treatment

AntibioticTherapyTherapeuticprincipleGoodpermeabilityforBlood-brainbarrierDrugcombinationIntravenousdripFulldosageFullcourseoftreatment

AntibioticTherapySelectionofantibioticNoCertainlyBacteriumCommunity-acquiredbacterialinfectionNosocomialinfectionacquiredinahospitalBroad-spectrumantibioticcoverageasnotedbelowChildrenunderage3monthsCefotaximeandampicillinCeftriaxoneandampicillin(childrenoverage1months)Childrenover3monthsCefotaximeorCeftriaxoneorampicillinandchloramphenicolAntibioticTherapyCertainlyBacteriumOncethepathogenhasbeenidentifiedandtheantibioticsensitivitiesdetermined,themostappropriatedrugs

shouldselected.Nmeningitidis:penicillin,

tert-

cephalosporin

Spneumoniae:penicillin,

tert-

cephalosporin,vancomycin

Hinfluenzae:ampicillin,

tert-

cephalosporin

Saureus:penicillin,

nefcillin,vancomycin

Ecoli:ampicillin,

chloramphenicol,tert-

cephalosporin

AntibioticTherapyCourseoftreatment7daysformeningococcalinfection10～14daysforHinfluenzaeorSpneumoniaeinfectionMorethan21daysforSaureusorEcoliinfection14～21daysforotherorganisms

Treatment

GeneralandSupportiveMeasuresMonitorofvitalsign

CorrectingmetabolicimbalancesSupplying

sufficient

heatquantityCorrectinghypoglycemia

CorrectingmetabolicacidemiaCorrectingfluidsandelectrolytesdisorderApplicationofcorticalhormoneLesseninginflammatoryreactionLesseningtoxicsymptomlesseningcerebraledema

GeneralandSupportiveMeasuresTreatmentofhyperpyrexiaandseizures

Pyretolysisbyphysiotherapyand/ordrugConvulsivemanagementDiazepamPhenobarbitalSubhibernationtherapy

TreatmentofincreasedintracranialpressureDehydrationtherapy

20%Mannitol5ml/kgviq6hLasix1-2mg/kgviGeneralandSupportiveMeasuresTreatmentofsepticshockandDICVolumeexpansionDopamineCorticosteroidsHeparinF