支气管哮喘BronchialAsthma Outline BurdenofAsthmaDefinitionofAsthmaEtiologyandMechanismDiagnosisandClassificationAsthmaMedicationsAsthmamanagementandPrevention BurdenofAsthma HealthcareexpendituresveryhighDevelopedeconomiesmightexpecttospend1 2percentoftotalhealthcareexpendituresonasthma DevelopingeconomieslikelytofaceincreaseddemandPoorlycontrolledasthmaisexpensive investmentinpreventionmedicationlikelytoyieldcostsavingsinemergencycare AsthmaPrevalenceandMortality Source MasoliMetal Allergy2004 EpidemiologyofAsthma DefinitionofAsthma AchronicinflammatorydisorderoftheairwaysManycellsandcellularelementsplayaroleChronicinflammationisassociatedwithairwayhyperresponsivenessthatleadstorecurrentepisodesofwheezing breathlessness chesttightness andcoughingWidespread variable andoftenreversibleairflowlimitation Source PeterJ Barnes MD Mechanisms Source PeterJ Barnes MD AsthmaInflammation Source PeterJ Barnes MD AsthmaInflammation RiskFactorsforAsthma Hostfactors predisposeindividualsto orprotectthemfrom developingasthmaEnvironmentalfactors influencesusceptibilitytodevelopmentofasthmainpredisposedindividuals precipitateasthmaexacerbations and orcausesymptomstopersist FactorsthatInfluenceAsthmaDevelopmentandExpression HostFactorsGenetic Atopy AirwayhyperresponsivenessGenderObesity EnvironmentalFactorsIndoorallergensOutdoorallergensOccupationalsensitizersTobaccosmokeAirpollutionRespiratoryInfectionsDiet MajorIndoorAsthmaTriggers IsitAsthma RecurrentepisodesofwheezingTroublesomecoughatnightCoughorwheezeafterexerciseCough wheezeorchesttightnessafterexposuretoairborneallergensorpollutantsColds gotothechest ortakemorethan10daystoclear AsthmaDiagnosis Historyandpatternsofsymptoms Episodicsymptomsafteranincidentalallergenexposure seasonalvariabilityofsymptoms Positivefamilyhistoryofasthmaandatopicdisease Symptomsimprovedbyappropriateasthmatreatment Physicalexamination Maybenormal Themostusualabnormalphysicalfindingiswheezingonauscultation AsthmaDiagnosis Measurementsoflungfunction Spirometry PeakexpiratoryflowMeasurementofairwayresponsivenessMeasurementsofallergicstatustoidentifyriskfactorsExtrameasuresmayberequiredtodiagnoseasthmainchildren5yearsandyoungerandtheelderly TypicalSpirometric FEV1 Tracings 1 Time sec 2 3 4 5 FEV1 Volume NormalSubject Asthmatic AfterBronchodilator Asthmatic BeforeBronchodilator Note EachFEV1curverepresentsthehighestofthreerepeatmeasurements MeasuringVariabilityofPeakExpiratoryFlow MeasuringAirwayResponsiveness EtiologicDiagnosisIdentifyenvironmentalfactors AllergenchallengetestSkinpricktestSpecificIgE DifferentialDiagnosis Otherformsofobstructivelungdisease particularlyCOPDNon respiratorycausesofsymptoms e g leftventricularfailure Non obstructiveformsoflungdisease e g diffuseparenchymallungdisease Upperairwayobstructionandinhaledforeignbodies ControllerMedications InhaledglucocorticosteroidsLeukotrienemodifiersLong actinginhaled 2 agonistsSystemicglucocorticosteroidsTheophyllineCromonesLong actingoral 2 agonistsAnti IgESystemicglucocorticosteroids EstimateComparativeDailyDosagesforInhaledGlucocorticosteroidsbyAge DrugLowDailyDose g MediumDailyDose g HighDailyDose g 5yAge5yAge5yAge 5y RelieverMedications Rapid actinginhaled 2 agonistsSystemicglucocorticosteroidsAnticholinergicsTheophyllineShort actingoral 2 agonists PharmacologicTherapy Long termcontrolmedicationscorticosteroidsinhaledformsystemicsteroidsusedtogainpromptcontrolofdiseasewheninitiatinginhaledtxLong actingbeta2 agonistsusedconcomitantlywithanti inflammatorymedsforlong termsymptomcontrolespeciallynocturnalsymptomspreventsexercise inducedbronchospasm Long termcontrolmedicationsLeukotrienemodifierszafirlukast leukotrienereceptorantagonistzileuton 5 lipoxygenaseinhibitorisalternativetherapytolowdosesofinhaledsteroids nedocromil cromolynalternativetxtolowdoseinhaledsteroids cromolyn nedocromilrecommendedfor 12yrswithmildpersistentasthma Furtherstudyneeded PharmacologicTherapy QuickreliefmedicationsShortactingbeta2 agonists reliefofacutesymptomsAnticholinergics mayprovideadditivebenefittobeta2drugsinsevereexacerbation Maybealternativetobeta2 agonistsSystemicsteroids moderate to severepersistentasthmainacuteexacerbationsortopreventrecurrenceofexacerbations PharmacologicTherapy Treatment LongTermControl CorticosteroidsMostpotentandeffectiveReductioninsymptoms improvementinPEFandspirometry diminishedairwayhyperresponsiveness preventionofexacerbations possiblepreventionofairwaywallremodelingSuppresses cytosineproduction airwayeosinophilicrecruitment chemicalmediators Long actingbeta 2agonistsRelaxairwaysmoothmuscleDurationofaction 12hrsNotusedinacuteexacerbationsAdjuncttoanti inflammatorytxforlong termsymptomcontrolespeciallynocturnalsymptoms Treatment LongTermControl LeukotrienemodifiersLeukotrienesarepotentbiochemicalmediatorsreleasedfrommastcells eosinophils andbasophilsthat contractbronchialsmoothmuscleincreasevascularpermeabilityincreasemucussecretionsattract activateinflammatorycellsinairways Treatment LongTermControl AsthmaTreatment QuickRel