FeverZhouYunTheAffiliatedHospitalofMedicalCollegeofNingboUniversityEmergencyDepartmentObjectiveDefinitionPathophysiology

PathogenesisEtiologyandclassificationClinicalmanifestationDefinitionDefinitionoffever:AtemperatureabovethenormalrangeNormalbodytemperature36-37℃(setpoint)Circadianvariation：<1℃：36.3-37.2℃

RectalT0.5℃>OralT0.5℃>AxillaryTFeverPyrogensElevatedset-pointMaintaininganabnormallyelevatedTemperatureBMR(basalmetabolicrate)increasesT=Elevatedset-pointBMR10%=T0.6oCHyperthermia

FeverduetoadisturbanceofthermalregulatorycontrolExcessiveheatproduction(e.g.statusepilepticus,hyperthyroidism)Decreaseddissipationofheat(e.g.extensiveskindisease)

Lossofregulation(e.g.injuryofthehypothalamicregulatorycenter)HyperthermiaExcessiveheatproductionTDecreaseddissipationLossofregulationPathophysiology

Heatproduction

ShiveringBasalmetabolicrate

↑

Heatisproducted

bytissuesAbsorbedfromtheenvironment↑

Dermalvasoconstriction↑

HeatlossThevolumeofbloodflowingtoskin’ssurface↑Vaporization(sweating)

↑TransfertheheattothesurroundingmediumDermalvasodilation↑

PathophysiologyRegulatedbythecentralnervoussystemThebodytemperatureisundercontrolofthePreopticareaoftheanteriorhypothalamus370C390CHeatProductionHeatLossHeatProductionHeatLossShiveringMetabolicactivityvasoconstrictionSweatingVasodilationSet-pointcoolingelevatingPathophysiologyHypothalamicthermostatInherentSetPoint:37oCLowest:4a.m;Peak:8~10p.mFeverfollowthispatternFactorsaffectbodytemperatureExerciseMenstrualcycleEnvironmentaltemperaturePathogenesisoffeverWhatwillmakethehypothalamuschangethesetpoint?Pyrogens

SubstancesthatcancausefeverEitherexogenousorendogenous

ExogenousPyrogensFromoutsidethehostMostofthemarewithhighmoleculeweightCouldnotpenetrateblood-brainbarrierStimulatingmonocytesandmacrophagestoinducetheformationofendogenouspyrogenExogenousPyrogensMajorityaremicroorganism,theirproductsortoxinsGram-:

Endotoxin(lipopolysaccaride,LPS)Gram+:

Lipoteichoicacid Peptidoglycan ExotoxinsandenterotoxinsExogenousPyrogensOthersSteroidhormonemetabolitesAntigen-antibodycomplexEndogenousPyrogensInresponsetoinvasivestimuli:ExogenouspyrogenChemicalagents(amphotericinandotherdrug)Producedbycellsofimmunesystemofthehost(macrophages,lymphocytes)Proteinsdesignated‘monokines’and‘lymphokines’CytokinesEndogenousPyrogensCytokinesIL(interleukin)TNF(tumornecrosisfactors)IFN(interferon)Phagocytesandlymphocytes:majorsourceofpyrogeniccytokinesItmayalsoreleasedthroughautonomousproductionandsecretionPathogenesisoffeverBacteriaprovokereleaseofIL-1ViralproteinsstimulateIFNCombinedproductionofseveralcytokinescausefeverEtiologyandclassificationInfectivefeverNon-infectivefeverInfectivefeverMetabolitesfromorganismcausefeverMostcommoncausesoffever(50%~60%)Bacteriapyrogens:Commoncauseofinfectivefever(43%)Viralpyrogens:(6%)Non-infectivefeverAbsorptionofnecroticsubstancesInjuryIschemicnecrosisCellnecrosisAllergy

Antibiotics(penicillin-based)EndocrineandmetabolicdisturbancesHyperthyroidismDehydrationNon-infectivefeverDecreasedeliminationofheatfromskinHeartfailureExtensivedermatitisAntigenantibodyreactionRheumaticfeverSerumdiseaseConnectivetissuediseaseNon-infectivefeverDysfunctionofcentralheatregulationPhysical:heatstrokeChemical:barbituratepoisoningMechanical:cerebralhemorrhageDysfunctionofvegetativenervoussystemSympatheticoveractivityClinicalmanifestationThegradeoffeverLowgradefever:37.3~38℃Middlegradefever:38~39℃Highgradefever:39.1~41℃Hyperthermiafever:>41℃ClinicalmanifestationClinicalcourseoffeverOnsetSuddenonsetPneumoniaGradualonsetTyphoid

Persistence

VariespatternSubsidence

CrisisLysisCharacteroffeverContinuousFeverT:keptat39℃~40℃constantlyCircadianvariation:<1℃PneumoniaTyphoidfeverCharacteroffeverRemittentFeverT:>39℃

Circadianvariation>2℃RheumaticfeverTuberculosis

SepticaemiaAcuteinfectiousendocarditisCharacteroffeverIntermittentFeverT:suddenrising(fewhours)andsuddendecreasingMalaria

AcutepyelonephritisCharacteroffeverRecurrentFeverT:abruptlyrisingtothepeak,lastingforseveraldays,suddenlydecreasingtothenormalHodgkindiseaseCharacteroffeverUndulantFeverT:Risinggraduallytothepeak(>39℃)decreasinggraduallytothenormal,repeatingforseveraltimesBrucellosisCharacteroffeverIrregularFeverTuberculosisRheumaticfeverBronchopneumoniaFeverpatternasdiagnosticcluesFeverPatternCauseAlternate-dayfeverPlasmodiumvivax,P.Ovalefevereverythirdday

P.MalariaRelapsingfeverdailyfor3~6daysBorreliaspfever-freeintervalratbitefever

forabout1weekContinuous“undulating”Brucellosis,typhoidPeriodicpyrexiaHodgkin’sdisease(Pel-EbsteinPhenomenon)withvariablecyclesAssociatedsymptomsChillsorrigorSepticaemiaAcuteinfectionsCongestionofconjunctivaHemorrhagefeverHerpessimplexHerpesvirus(lobarpneumonia)BleedingtendencyInsevereinfection(hepatitis)Blooddyscrasia(leukemia)AssociatedsymptomsLymphadenopathyLymphomaCancermetastasisEnlargementofliverandspleenHepatitisRashDrugrashMeaslesAssociatedsymptomsArthralgiaGoutRheumaticdis