早產(chǎn)兒常見之問題早產(chǎn)兒常見之問題(2)BPD

(bronchopulmonarydysplasia):支氣管肺發(fā)育不全NEC

(necrotizingenterocolitis):壞死性腸炎PDA

(patentductusarteriosus):開放性動(dòng)脈導(dǎo)管Gestationalageestimationand

birthweightclassificationInfantareclassifiedbyGAasPreterm(<37weeks)Term(37-416/7weeks)Postterm(42weeksormore)BirthweightclassificationNormalbirthweight(NBW):2500gmormoreLowbirthweight(LBW):<2500gmVerylowbirthweight(VLBW):<1500gmExtremelowbirthweight(ELBW):<1000gmPrematurityIncidence:5-10%Etiology:mostforunknownreasonsLowsocioeconomicstatusMalnutritionWomenunderage16orover35IncreasedmaternalactivitySmokingAc.orchr.maternalillnessMultiple-gestationbirthsPriorpoorbirthoutcomeObstetricfactorsFetalconditionsInadvertentearlydeliveryProblemofprematurity(1)RespiratoryRespiratorydistresssyndrome(RDS)ApneaBronchopulmonarydysplasia(BPD)NeurologicIntraventricularhemorrhage(IVH)Periventricularleukomalacia(PVL)CardiovascularHypotensionPatentductusarteriosus(PDA)Problemofprematurity(2)HematologicAnemiaHyperbilirubinemiaNutritionalFeedingproblemsType,amount,androuteoffeedingGastrointestinalNecrotizingenterocolitis(NEC)MetabolicAcidosisHyper-orhypoglycemiahypocalcemiaProblemofprematurity(3)RenalLowGFRInabilitytohandlewater,solute,andacidloadsTemperatureregulationHypothermiaandhyperthermiaImmunologicGreaterriskforinfectionOphthalmologicRetinopathyofprematurity(ROP)Intraventricularhemorrhage(IVH)Inprematureinfant:

--occursinthegelatinoussubependymal

germinalmatrix--highlyvascularareawithimmatureblood

vesselsInterminfant:--germinalmatrixbecomeattenuatedand

tissue’svascularsupporthasstrengthened.Intraventricularhemorrhage(IVH)TheincidenceofIVH:

---60~70%of500-750ginfants

---10~20%of1000-1500ginfants80~90%ofcasesoccurbetweenbirthandthe3rddayoflife;50%occuronthe1stday.20~40%ofcasesprogressduringthe1stweekoflife;delayedhemorrhagemayoccurin10~15%ofpatientsafterthe1stweekoflife.New-onsetIVHisrareafterthe1stmonthofliferegardlessofbirthweight.--prematurity

--RDS

--Hypoxic-ischemicorhypotensiveinjury

--reperfusionofdamagedvessels

--increasedordecreasedcerebralbloodflow

--reducedvascularintegrity

--increasedvenouspressure

--pneumothorax

--hypervolemia

--hypertensionPredisposingfactorsforIVH:ClinicalmanifestationsDiminishedorabsentMonoreflexPoormuscletoneLethargyApneaSomnolencePeriodsofapnea,pallor,orcyanosisFailuretosuckwellAbnormaleyesignsDecreasedmuscletoneorparalysisMetabolicacidosisShockDecreasedhematocritoritsfailuretoincreaseaftertransfusionPeriventricularleukomalacia(PVL)AcommonassociatedcysticfindingMaybeduetoprenatalorneonatalischemicorreperfusioninjuryTheresultofnecrosisoftheperiventrucularwhitematterDamagetothecorticospinalfibersintheinternalcapsule.Periventricularleukomalacia(PVL)Usuallyasymptomaticuntiltheneurologicalsequelaeofwhitematternecrosisbecomeapparentinlaterinfancyasspasticdiplegia.Maybepresentatbirthbutusuallyoccurslaterasanearlyechodensephase(3-10daysoflife)followedbythetypicalecholucent(cystic)phase(14-20daysoflife).Intraventricularhemorrhage(IVH)GradeI-Germinalmatrixhemorrhage(subependymalregionorlessthan10%oftheventricle;~35%ofIVH)GradeII-IVHwith10-50%fillingoftheventricle(~40%ofIVH)GradeIII–morethan50%involvementwithdilatedventriclesGradeIV-IVHwithextensionintotheparenchymaPatentductusarteriosus(PDA)Connectthemainpulmonarytrunk(orproximalleftpulmonaryartery)withthedescendingaorta,5-10mmdistaltotheoriginoftheleftsubclavianarteryArisingfromthedistaldorsalsixthaorticarchIswelldevelopedbythesixthweekofgestationalageIsmoreprevalentinfemalethanmaleIsafrequentcomplicationofHMDinpreterminfant,ininfantbornathighaltitudesNormalpostnatalclosureFirststage:contractionandcellularmigrationofmedialsmoothmuscle

-->resultfunctionalclosurecommonlyoccurredwithin12hoursinfulltermbabySecondstage:connectivetissueformationandreplacementofmusclefiberswithfibrosis-->ligmentumarteriosumBothPGE2andPGI2relaxtheductusarteriosusIncidencePrematurity:inversewithGA,PDAisfoundinabout45%ofinfantunder1750gand80%ininfantsweighting<1000gRiskfactor:1.RDSandsurfactanttreatment2.Fluidoverload3.Asphyxia4.Congenitalsyndrome,congenitalheartdisease5.HighaltitudePathophysiologyDuctalconstrictioniscausedbymultiplefactors:

1.oxygen

2.thelevelofprostaglandin

3.availableductusmusclemassWithinthefirsthoursafterbirth->fallinpulmonaryvascularresistanceandariseinsystemicresistanceifPDAopenedlefttorightshunt(+)-->resultinincreasedpulmonarybloodflow,leftventricularvolumeoverload,increasedleftventricularend-diastolicvolumeandpressure->CHFPathophysiologyRenal,mesentericandcerebralbloodflowdecreasedduetoductalstealThesewithmoderateandlargeductsarepronetothedevelopmentofpulmonaryvascularobstructivediseaseby1yearofageorbeyondPreterminfantmaydevelopCHFearlierbecauseofincompletedevelopmentofthemedialmusculatureinthesmallpulmonaryarteriolesAmongthosewithRDS,theymaybeainitialperiodofimprovementasthepulmonarystatusimprovesClinicalfindings(Terminfants)Pulmonaryvascularresistancedeterminestheclinicalmanifestations:AcontinuousmurmurisheardinfrequentlyLargePDAhas1.boundingperipheralpulsepressure,2.widepulsepressure(differencebetween

systolicanddiastolicpressure)3.hyperactiveprecordium:duetoelevated

strokevolumeClinicalfindings(Terminfants)4.HypotensionparticularintheseofELBW5.HeartfailureinlargePDAdoesn’tdevelop

until3to6weeksofageAssociatedwithpulmonarydisease,leftheartobstructivelesionandcoarctationofaorta,pulmonaryresistancemaybehigh-->righttoleftshunt-->nomurmurClinicalfindings(preterminfants)1.Thesameclinicalsignastermbaby2.However,manypretermbabywith

largePDAhavenomurmur3.MostwillhaveanincreasedpressureDiagnosisChestxray:cardiacenlargement,pulmonaryplethora,aprominentmainpulmonaryarteryandleftatrialenlargementEKG:leftventricularhypertrophy,leftatrialhypertrophyEchocardiography:1.M-mode:normalLA:Aaratioininfantsis

between0.8-1.0,Aratio>1.2suggestsleft

atrialenlargement(intheabsenceofleft

ventricularfailureorvolumeoverload)2.2-D:PDATreatmentTerminfants:NoevidenceofcardiovascularembarrassmentshouldbefollowedandcatheterclosureorthoracoscopicorsurgicaldiversionDigoxinanddiureticsforPDAwithCHFPreterminfants1.Ventilatorsupportandfluidrestriction2.Indomethacintreatmentproducesclosurein

85%ofpatients3.Prophylacticadministrationofindomethacinearlyafterbirthinveryprematureinfants(<1250g)decreasedtheincidenceofPDA,CHF,IVHandpossiblymortality

----butnotroutineduetotheriskofleukomalacia,decreasedrenalfunction,plateletfunctionandNECPreterminfants4.Ibuprofen(10mg/kg)mayhavefewersideeffect.ArchivesofDiseaseinChildhood:Fetal&NeonatalEdition.76(3):F179-84,1997May.(ibuprofendidnotsignificantlyreducemesentericandrenalbloodflowvelocity.)

JournalofPediatrics.135(6):733-8,1999Dec.5.BloodtransfusioninanemicpretermbabydiminishestheleftventriclevolumeoverloadandhastenductusclosurebyincreasingarterialoxygencontentPreterminfantsEarlyindomethacintreatment(inprematureinfantswithrespiratorydistresssyndrome)improvesPDAclosurebutisassociatedwithincreasedrenalsideeffectsandmoreseverecomplicationsandhasnorespiratoryadvantageoverlateindomethacinadministrationinventilated,surfactant-treated,preterminfants<32weeks'gestationalage.

(JournalofPediatrics.138(2):205-11,2023Feb.)PDACoilocclusionisasafeandeffectivemethodofpercutaneousclosureofsmalltomoderate-size(minimumdiameter<or=4mm)

PDAs.ThelargestPDAthatcanbeclosedwiththistechniqueremainstobedetermined.JournalofPediatrics.130(3):447-54,1997Mar.AgeofonsetoftreatmentIVdosage(mg/dl)1st2nd3rd12-24hours,4thdoseor2ndcourse<3days0.20.10.13-7days0.20.20.2>7days0.20.250.25Contraindicationsforindomethacin1.serumcreatine>1.7mg/dl2.Frankrenalorgastrointestinal

bleedingorgeneralizedcoagulopathy3.NEC4.sepsisNecrotizingenterocolitis

(NEC)Necrotizingenterocolitis1.Definition

2.Incidence

3.Pathology&Pathogenesis

4.Clinicalmanifestations

5.Diagnosis

6.Management

7.ComplicationDefinitionThemostcommonlife-threateningemergencyofthegastrointestinaltractinthenewborn

stage.Anacquiredneonataldisordercharacterizedbyvariousdegreesofmucosalortransmuralnecrosisoftheintestine.IncidenceDecreasedbirthweight&gestationalage

incidence&fatilityRareinterminfants.Overallmortality20—40%.NeonatalICU

1—5%Noassociationwith

orrace.Occuressporadicallyorinepidemicclusters.Mostinvolvedthedistalpartoftheileumandtheproximalsegmentofcolon.

Pathology&Pathogenesis(1)Cause:remainsunclearbutismultifactorial.Noprovencausehasbeenestabilished.Thegreatestrisk

PrematureInteractionsbetweenmucosalinjury(ischemia,infection,inflammation)andthehost’sresponsetotheinjury(circulatory,immunologic,inflammatory)Pathology&Pathogenesis(2)Clusteringofthecasesinfectiousagent(E.Coli.,Klebisella,Enterobacter,Salmonella,Coronavirus,Rotavirus,Enterovirus)Nopathogenisidentified.Rarelyoccuresbeforeenteralfeeding.Muchlesscommonininfantsfedhumanmilk.Triad

intestinalischemia,oralfeeding,pathogenicorganismsInitialischemicortoxicmucosaldamage

Lossofmucosalintegrity

Enteralfeedings+Bacterialproliferation

Necrosisoftheintestine

Gasaccumulationinthesubmucosaofbowelwall

(penumatosisintestinalis)

Transmuralnecrosisorgangrane

Perforation,Sepsis,DeathClinicalmanifestationsAvarietyofsignsandsymptomsandmaybeonsetinsidiouslyorsuddenly.

Usuallyoccursinthefirst2weeks.Ageofonsetisinverselyrelatedetothegestationalage(VLBW

3month).Firstsigns:abdominaldistensionwithgastricretention.25%

bloodystoolProgressmaybeberapid,butunusuallytoprogressfrommildtosevereafter72hr.SignsandsymptomsassociatedwithnecrotizingenterocolitisGastrointestinalAbdominaldistentionAbdominaltendernessFeedingintolerance

DelayedgastricemptyingVomittingOccult/grossbloodstoolChangeinstoolpattern/diarrheaAbdominalmassErythemaofabdominalwallSystemic

LethargyApnea/respiratorydistressTemperatureinstabilityAcidosisGlucoseinstabilityPoorperfusion/shockDICPositiveresultsofbloodcultureDiagnosisAveryhighindexofsuspicionintreatinginfantsatriskisessential.Clinicaltriad:Feedingintolerance,abdominaldistention,grosslybloodystools.Labstudies:CBC,electrolytes,bloodculture,stoolscreening,stoolculture,…Radiologicstudies:1.X-rayofabdomen:

Pneumomatosisintestinalis(50-75%)Portalvenousgas2.HepaticultrasonographyKUBdemonstratingabdominaldistention,hepaticportalvenousgas

(arrow),andbubblyappearanceofpneumatosisintestinalis(arrowhead).

ThelattertwosignsarepathognomonicforNEC.

Intestinalperforation.Cross-tableabdominalroentgenograminapatientwithNECdemonstratingmarkeddistentionandmassivepneumoperitoneumasevidentbythefreeairbelowtheanteriorabdominalwall.ManagementBasicNECprotocol:1.Nothingbymouth(NPO)2.Useofanasogastrictube3.Antibiotics4.Monitoringofvitalsigns&abdominalcircumference5.Removaloftheumbilicalcatheter6.Monitoringoffluidintakeandoutput7.Monitoringforgastrointestinalbleeding8.Laboratorymonitoring9.Septicworkup10.Radiologic

studiesManagementby

StagesClassifiedbyclinicalsyndrome

(1986WalshandKliegman)StageI:SuspectedNECSystemic:Nonspecific,apnea,bradycardia,

andtemperatureinstabilityGastrointestinal:Increasedgastricresiduals

OccultbloodstoolRadiographic:NormalornonspecificTreatment:NPOwithantibioticsfor3daysStageIIA–MildNECSystemic:Nonspecific,similartostage1Gastrointestinal:AbsentbowelsoundsandGrossbloodstools.

Radiographic:Ileuswithdilatedloops,focalareasofpneumatosisintestinalisTreatment:NPOwithantibioticsfor10-14days

StageIIB–ModerateNECSystemic:MildmetabolicacidosisandmildthrombocytopeniaGastrointestinal:Tenderness,abdomianlwalledema,

palpablemass

Radiographic:Extensivepneumatosis,

portalvenousgas,earlyascites

Treatment:SimilartostageIIBStageIIIA–AdvancedNECSystemic:Hypotension,bradycardia,respiratoryfailure,coagulopathyseveremetabolicacidosisGastrointestinal:Spreadingedema,erythemaindurationoftheabdomen

Radiographic:Prominentascites

Treatment:paracentesis,fluidresuscitation,inotropicagentsupport,ventilatorsupport,.StageIIIB–AdvancedNECSystemic:Deterioratingvitalsigns,shock,electrolyteimbalanceGastrointestinal:Perforationofthebowel

Radiographic:Perforationofthebowel

Treatment:SurgicalmanagementSurgicalmanagementIndicationforoperation:1.Evidenceofintestinalperforation2.Aspersistent,fixedsenileloop3.Erythemaoftheabdominalwall4.Apalpablemass5.BrownparacentesisfluidwithorganismsonGramstain6.Failuretoresponsetomedicaltreatment.PrognosisPneumatosisintestinalis:20%