新生儿缺氧缺血脑病ppt课件.ppt

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1、HYPOXIC-ISCHEMICENCEPHALOPATHYDEFINITIONHIE:Hypoxic-ischemicdamageofthebrainresultingfromperinatalasphyxia;Braindysfunction：encephalopathyPrimarycauseofpermanentdamagetoCNS.ETIOLOGYFetalasphyxia(80%-90%)AnyprocessthatImpairsmaternaloxygenationDecreasesbloodflowfromthemothertotheplacentaorfrompa

2、ecentatothefetusImpairsgasexchangeacrosstheplacentaoratthefetaltissureIncreasesfetalO2requirementwillexacerbateperinatalasphyxiaETIOLOGYFetalasphyxia(80%-90%)MaternalHypertension;Vasculardisease;Diabetes;Druguse;Hypotension;Infection;Hypoxiafrompulmonary,cardiac,orneurologicdiseasePlacentalorco

3、rdalPlacentalinfarctionorfibrosis;abruption;prematureseparation;insuficiencyCordalprolapse;entanglement;trueknot;compression;abnormalvesselsFetalHydrops;Infection;IUGR;PosttermETIOLOGYDiseasesafterbirth(10%)SevereanemiaSevereCHDShockRespiratoryfailure(centralorperipheral)TheproblemSevereasphyxi

4、a:2-4per1000full-termbirths20–50%mortality25%ofthesurvivorswillexhibitpermanentneuropsychologicalhandicaps:MentalretardationCerebralpalsyEpilepsyLearningdisabilityPATHOPHYSIOLOGYCBFchangesduetocardiacdysfunction&impairsofcerebrovascularautoregulationAbnormalmetabolismofbraintissueFailureofenerg

5、ymetabolismNeurologictoxityoftheexcitoryaminoacidCa++influxReperfutionOxygenfreeradicalsAsphyxiaincreaseinlactate(pH↓)hypoxia↓decreasedATP&GSdepletion↓↓cardiacoutput↓cerebrovascularautoregulation↓↓CBF↓faliureofATPproduction↓impairsionpumps(Na+-K+ATPase)↓excitoxicaminoacid(glutamate,NMDA)Ca++inf

6、lux↓openionchannels↓Na+,Cl-andH2Oinfluxdelayedneuronaldeath↓immediateneuronaldeathNMDA↓activatephosphoinosotol2ndmessengersystem↓openvoltage-dependentCa++channel↓Ca++influx↓activationofundesirableenzyme(lipasesandproteases)pertubationofmitochondrialrespiratoryelectronchaintransportgenerationoff

7、reeradicalsandleukotrienesdepletionofenergystores↓delayedneuronaldeath(apoptosis)afterCPR,reperfutionSevereasphyxiaCellinjuryProteasesROSEndonucleasesGenesLipasesNOPrimaryInsultNecrosisApoptosisHourstodaysHypothermiaSOD/Allopurino