小兒腸胃道出血

小兒腸胃道出血學(xué)習(xí)目標(biāo)

PGY1PGY21.認(rèn)識小兒腸胃道出血2.小兒腸胃道出血處置1.小兒腸胃道出血的分類2.能診斷小兒腸胃道出血3.小兒腸胃道出血處理INTRODUCTIONUppergastrointestinal(UGI)bleeding(arisingproximaltotheligamentofTreitzinthedistalduodenum)commonlypresentswithhematemesis(vomitingofredbloodorcoffeeground-likematerial)

and/or

melena(black,tarrystools).Hematochezia(brightredormaroon-coloredbloodorfreshclotsperrectum)isusuallyasignofalowergastrointestinal(LGI)source(definedasdistaltotheligamentofTreitz).ETIOLOGYThemostcommoncausesofUGIbleedinginchildrenvarydependinguponageandthegeographicsetting.InWesterncountries,themostcommoncausesaregastricandduodenalulcers,esophagitis,gastritis,andvaricesThemostcommoncausesofrectalbleedingininfantsareanalfissureorcow'smilkorsoyprotein-inducedcolitis.Inchildren12monthsandolder,themostcommoncausesofrectalbleedingareinfectiousgastroenteritisandanalfissures.

UGI

bleedingNeonates

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UGIbleedingTrueUGIbleedinginaneonatemustbedistinguishedfromswallowedmaternalbloodVitaminKdeficientbleeding(hemorrhagicdiseaseofthenewborn)shouldbeconsideredinneonateswhowerenotgivenvitaminKprophylaxisatbirthStressgastritisorulcersareassociatedwithcriticalillnessbutalsomayoccurspontaneouslyeveninthefirstfewdaysoflifeCongenitalanomaliesincludingintestinalduplicationsorvascularanomaliesmaypresentwithgastrointestinal(GI)hemorrhageCoagulopathyinaneonatemayalsobecausedbyinfection,liverfailure,oracongenitalcoagulationfactordeficiency.SeveraltypesofcoagulopathiescanpresentduringthenewbornperiodMilkproteinintolerancemaypresentwithUGIbleeding,althoughlowergastrointestinal(LGI)bleedingismuchmorecommon.Infants,childrenandadolescents—

UGIbleedingMallory-Weisssyndrome–Mallory-Weisssyndromeischaracterizedbylongitudinalmucosallacerationsinthedistalesophagus,usuallydevelopingafterforcefulretching.Thebleedingisusuallysmallandself-limited,butoccasionallyissevereEsophagealorGIforeignbody–AforeignbodycancauseGIbleedingifitissharp,caustic,

and/or

lodgedintheesophagus.Clinicalcluestothispossibilityincludeahistoryofachokingepisode,evenifitwastransientoroccurreddaysorevenweeksbeforethebleedingepisode.Rarely,ingestionofabuttonbatteryhasledtosevereUGIhemorrhageduetoaortoesophagealfistula,whichcanbefatal.Esophagitis–Esophagitisinthisagegroupusuallyiscausedbygastroesophagealrefluxdiseaseoreosinophilicesophagitis,andoccasionallybycausticingestion.PepticesophagitisalsomaydevelopafterrecurrentvomitingfromothercausesPepticulcersandgastritis–Gastritisandulcersoccasionallyoccurinallagegroups,typicallyinthesettingofcriticalillnessoruseofnonsteroidalantiinflammatorydrugs(NSAIDs).YoungchildrenareparticularlysusceptibletodevelopingUGIbleedingafterNSAIDuse.Bingedrinkingofalcoholisanimportantcauseofgastritisinadolescents.Gastritisorpepticulcersalsomayberelatedto

Helicobacterpylori

infectionoroccasionallytoaviralinfectionincludingcytomegalovirusBleedingfromesophagealvarices–Varicealbleedingisthemostcommoncauseof

severe

acuteUGIbleedinginchildren.Esophagealvaricesarecausedbyportalveinhypertension.Cluestoportalhypertensionincludesplenomegaly

and/or

ahistoryofthrombocytopenia,eveninapatientwithoutahistoryofliverdisease.

CLINICALASSESSMENTTheinitialevaluationofthepatientwithUGIbleedingshouldalwaysstartwithanassessmentofhemodynamicstabilityandresuscitation,ifindicated.Endoscopyusuallyisindicatedifthebleedingisbriskorunexplainedafterathoroughhistoryandphysicalexamination,orifthereareassociatedsignsofshock.Briskbleedingissuggestedbyrepeatedepisodesofgrosslybloodyemesisorlargevolumesofbloodaspiratedthroughanasogastrictube,orapersistentdropinhemoglobin.Insomecases,thesourceofthebleedingcanbetreatedthroughtheendoscopicprocedure.Endoscopicevaluationandtreatmentshouldgenerallybeperformedafterthepatientisstabilized,andwithin24to48hoursofpresentationofthegastrointestinal(GI)bleed.LaboratoryevaluationInmostcases,itshouldincludeacompletebloodcount,coagulationstudies,testsevaluatingliverfunction,bloodureanitrogen(BUN),andserumcreatinine.Forpatientswithepigastricabdominalpain,pancreatitisalsoshouldberuledoutwithscreeningamylaseandlipase;pancreatitisoccasionallyisassociatedwithgastritis,duodenitis,andpepticulcerdisease.TheBUNresultcanbehelpfulforconfirmingthesourceofbleeding.AnincreaseinBUNintheabsenceofrenaldiseaseisconsistentwithanUGI(ratherthanalowergastrointestinal[LGI])sourceofbloodlossbecausebloodintheproximalGItracthasrelativelymoretimetobeabsorbed,leadingtoanincreaseintheBUN.OtherdiagnostictestsAngiographymaybeusefulinpatientswithrapidbleedinginwhomendoscopyisunsuccessfulinfindingasource.Fordiagnosticpurposes,magneticresonanceangiography(MRA)orcomputedtomographicangiography(CTA)maybeused.Fortherapeuticpurposes,standardangiographymaybeusefulintreatingsomepatientswithvascularanomalies,hemobilia,orsomeulcersthatarenotamenabletoothertypesoftreatment.Radionucleotideimaging(ataggedredbloodcellscan)alsocanbeusedtodetectanobscurebleedingsourceforpatientswithverybriskbleeding.However,thisisrarelyhelpfulinpatientswithUGIbleedingbecauseendoscopyisfarmoresensitivefordetectingbleedingabovetheligamentofTreitz.MANAGEMENTNasogastrictube

—

Inpatientspresentingwithunexplainedgastrointestinal(GI)bleedingthatisclinicallysignificant(eg,morethanateaspoonestimatedbloodloss),nasogastricororogastrictubelavageissometimesusedtoconfirmthediagnosisandtodetermineifthebleedingisongoing.

Pharmacologicoptions

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AcidsuppressionusuallyisappropriateforchildrenwithclinicallysignificantUGIbleeding,totreatorpreventanypepticcomponentoftheunderlyingdisorder.VasoactiveagentsmaybehelpfulforselectedcasesofvascularbleedingEndoscopy

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Guidelinesrecommendthatendoscopybeperformedwithin24to48hoursforinfantsandchildrenpresentingwithUGIbleedingthatisacuteandsevere,particularlyiftransfusionsarerequired.Earlierendoscopymaybeneededifbleedingcannotbecontrolled.Hemodynamicallyunstablepatientsshouldbestabilizedpriortoendoscopy,includingtransfusionandcorrectionofcoagulopathyifpresent.Endoscopyisalsoappropriateinchildrenwithlow-gradebleedingthatisunexplainedandpersistentorrecurrent.Upperendoscopypermitsidentificationofthebleedingsource,allowsforriskstratificationregardingthelikelihoodofcontinuedbleeding,andpermitstherapeuticinterventionSurgeryorangiographyisreservedfortheuncommonpatientsinwhomendoscopyfailstocontrolbleedingorinwhomananatomicabnormalityexiststhatrequiressurgery,andifthepatientcannotbefullystabilizeddespiteresuscitativemeasures.LGIbleedingNeonatalperiodSwallowedmaternalblood

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Inanewborninfantwithrectalbleeding,therectalbloodshouldbetestedtodeterminewhetheritcomesfromtheinfantorwhetheritrepresentsmaternalblood,whichmayhavebeenswallowedduringdeliveryoringestedduringbreastfeedingfromcrackednipples.ThisisaccomplishedusingtheApttest(hemoglobinalkalinedenaturationtest),whichdetectsfetalhemoglobin.Analfissures

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Analfissuresarethemostcommoncauseofrectalbleedinginpatientsyoungerthanoneyearandarealsocommoninolderchildrenandadults.Theyarediagnosedeasilybyspreadingtheperinealskintoeverttheanalcanal.Inaninfant,thehistoryoftensuggestspainfuldefecationwithstraining,grunting,andlegstiffeningorbackarchingconsistentwithwithholdingbehaviorandstreaksofbrightredbloodonthesurfaceofthestools.

Necrotizingenterocolitis

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Necrotizingenterocolitis(NEC)isanacuteillnessofunclearetiologyassociatedwithintestinalnecrosis.NECshouldbesuspectedinanewbornwithnonspecificsystemicsignssuchasapnea,respiratoryfailure,lethargy,poorfeeding,ortemperatureinstability,andabdominalsignsincludingdistention,gastricretention(residualmilkinthestomachbeforeafeeding),tenderness,vomiting,diarrhea,andgrossoroccultLGIB.AlthoughmostinfantswhodevelopNECwerebornprematurely,approximately13percentofcasesoccurinterm.Pneumatosisintestinalis,thehallmarkofNEC,appearsasbubblesofgasinthebowelwallorintheportalsystem.Malrotationwithmidgutvolvulus

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Newbornswhohavemalrotationwithmidgutvolvulustypicallypresentwithabdominaldistension,emesiswhichmayormaynotbebilious,andmelenaorhematochezia(in10to20percentofcases).Biliousemesisintheneonatalperiodshouldbeassumedtorepresentasurgicalemergencyduetoobstructionuntilprovenotherwise.Alimiteduppergastrointestinal(UGI)contrastseriesisthebestexaminationtovisualizethepositionoftheduodenum.UGIcontrastseriesshouldbeperformedwheneverpossible,underfluoroscopyandbyanexperiencedpediatricradiologist.Bariumcontraststudiesmayrevealacorkscrewappearanceofthetwistedsmallbowel,ora"bird'speak"ifcompleteobstructionispresent.Hirschsprungdisease

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NewbornswithHirschsprungdiseasefrequentlyhavedelayedpassageofmeconium(>48hoursafterbirth).Somepresentwithacuteobstructionmanifestedbyvomiting(whichmaybebiliousorfeculent)andabdominaldistension.Otherinfantsmaypresentatseveralweeksofagewithprogressiveconstipationordiarrheaassociatedwithabdominaldistension.Onlyone-quarterofthepatientshavebloodinthestool.SignificantbloodinthestoolwithabdominaldistensionininfantswithknownorsuspectedHirschsprungdiseasemaybeindicativeofHirschsprung-associatedenterocolitis(toxicmegacolon)andshouldbeconsideredamedicalemergency.ThegoldstandardfordiagnosisisthedemonstrationofcompleteabsenceofganglioncellsintheMeissnerandtheAuerbachplexusonabiopsyspecimenofintestinalmucosaandsubmucosa.Treatmentgenerallyissurgicalresectionoftheaganglionicsegment.Coagulopathy

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Severaltypesofcoagulopathiescanpresentduringthenewbornperiod.Mostpresentwithotherbleedingsymptoms,suchasalargecephalohematomaaftervaginaldelivery,oozingfromtheumbilicalstump,prolongedbleedingaftercircumcisionorbloodsampling,orintracranialhemorrhageinaterminfant.

Occasionally,thesecoagulopathiescometomedicalattentionbecauseofLGIB,althoughthisrarelyoccursduringtheneonatalperiod.InfantsandtoddlersAnalfissures

Milk-orsoy-inducedcolitis

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Milk-orsoyprotein-inducedcolitisisaninflammatoryreactioncausedbyingestionofcow'smilkorsoyproteins,andisacommoncauseofbloodystoolsininfants.Itoccursalmostexclusivelyininfantsandusuallyresolveswithin6to18monthsofage.Upto25percentofpatientswithcow'smilkproteinintolerancewillhaveacross-reactiontosoyprotein,andafewinfantsaresensitivetootherfoodproteins.Treatmentinvolvesmeticulouseliminationofthecausativeproteinfromthemother'sdietiftheinfantisbreastfed,ortheuseofacasein-hydrolysateformula.Intussusception

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Intussusceptionisthemostcommoncauseofintestinalobstructionininfantsbetween6and36monthsofage.Inyoungergroup,intussusceptionusuallyisidiopathicandoccursintheileocecalregion,incontrasttoolderchildreninwhomapolyporMeckel'sdiverticulumorotherlesionsoftenserveasaleadpoint.

Patientsmayawakenfromsleepwithsevereabdominalpain.Theyvomitandmaypassastoolandimprovetemporarilybeforethecyclerepeats.Asausage-shapedmassinthedistributionofthecolon,typicallyintheareaofthetransversecolon,mayoccasionallybepalpableonabdominalexamination.Thestoolcontainsgrossoroccultbloodinmostbutnotallcases,andsometimeshastheappearanceof"currantjelly.“Ultrasonographyisthemethodofchoicetodetectintussusceptioninmostinstitutions.Thediagnosiscanalsobeestablishedwithanairorwater-solublecontrastenema,whichalsocantreat("reduce")theintussusceptionin75to90percentofchildreninwhomaleadpointisnotpresent.Meckel'sdiverticulum

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Meckel'sdiverticulumresultsfromincompleteobliterationoftheomphalomesentericduct.Itisusuallyasymptomatic,butmaycausepainlessrectalbleeding,whichmaybechronicandinsidious,oracuteandmassive.Thebleedingisoftencausedbymucosalulcerationofadjacentsmallboweltissueduetoproductionofacidbyectopicgastrictissuewithinthediverticulum.OthercomplicationsassociatedwithaMeckel'sdiverticulumareobstruction,perforation,diverticulitis,andintussusception.ThediagnosisismadebyaMeckelscan.Thescanconsistsoftheintravenousadministrationof99mtechnetiumpertechnetate,whichhasanaffinityforgastricmucosa,followedbyscintigraphytoidentifyareasofectopicgastricmucosa.AnyMeckel'sdiverticulumthatissymptomaticshouldberesected.AnasymptomaticMeckel'sdiverticulumdiscoveredincidentallyatlaparotomyusuallyalsoisresectedinchildren.Lymphonodularhyperplasia

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Lymphonodularhyperplasiaisacommonfindingininfantsandyoungchildrenwhoundergoendoscopyorradiographicstudiesoftheintestinaltract.Theetiologyisunknown.Itoccursfrequentlyinchildrenwithfoodproteininducedcolitis,inwhomitmaybeanabnormalfindingatcolonoscopy.Becauselymphonodularhyperplasiadisruptsthenormalmucosa,itmaypotentiallyleadtomucosalthinningandpredisposestoulceration,whichmaycausehematochezia.Lymphonodularhyperplasiaresolvesspontaneouslyovertimeandisanunlikelysourceofbleedinginolderchildren.Gastrointestinalduplicationcyst

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GastrointestinalduplicationcystscanbefoundatanyleveloftheGItractandfrequentlydonotcommunicatewiththebowellumen.Gastricmucosa(presentinapproximately50percentofduplicationcysts)canulcerate,perforate,andformfistulas.Formationofagastricduplication-colonicfistulaisunusualbutcanresultinalowergastrointestinalbleed.Inaddition,aduplicationcystthatcommunicateswiththeintestinecanresultinbleedingintotheGItract.Gastrointestinalduplicationcyststendtopresentininfancyiftheyaresymptomatic,buttheymaypresentinanyagegroup,andoftenremainasymptomatic.Infantileandveryearlyonsetinflammatoryboweldisease

—

Rarely,inflammatoryboweldisease(IBD)presentsbeforesixyearsofage.

PreschoolperiodAnalfissures

IntussusceptionMeckel'sdiverticulumInfectiouscolitis

—

AnumberofpathogenscancauseLGIBinpreschoolchildren:

Salmonella,Shigella,Campylobacter,E.coli0157:H7,andClostridioides

(formerly

Clostridium)

difficile

arethemostcommon.Thediagnosisofaninfectiousetiologyismadebyisolatingtheorganismfromthestoolorblood.Otherancillarytestssuchasoccultblood,fecalleukocytes,fecalcalprotectin,orfecallactoferrinarenonspecific.Hemolytic-uremicsyndrome

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HUSischaracterizedbythesimultaneousoccurrenceofmicroangiopathichemolyticanemia,thrombocytopenia,andacuterenalinjury.Thehighestratesareinchildrenundertheageoffiveyears.Mostcasesareassociatedwithaprodromalinfectionwithanenteropathogenproducingashiga-liketoxin,suchas

E.coli

0157:H7,inwhichcasediarrheaisaprominentfeatureandisfrequentlybloody.IgAvasculitis(Henoch-Sch?nleinpurpura)

—

ImmunoglobulinAvasculitis(IgAV;Henoch-Sch?nleinpurpura[HSP])isasystemicvasculitisofunclearetiologycharacterizedbypalpablecutaneouspurpura,abdominalpain,andarthralgias.Itisprimarilyachildhooddiseasethatoccursbetweentheagesof3and15years.Upto50percentofpatientsdevelopgrossoroccultgastrointestinalbleeding,andupto50percentdeveloprenaldisease.Juvenilepolyps

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Juvenilepolypsarebenignhamartomas,whichtypicallyoccurbetweentheagesof2and10years,withapeakat3to4years.Patientsusuallypresentwithpainlessrectalbleeding,withorwithoutmucus;