2022年醫(yī)學專題-缺血性腸病

IschemicColitisRi陳宏彰第一頁，共三十頁。ReferencebooksHarrison’sonline15thMarx:Rosen'sEmergencyMedicine:ConceptsandClinicalPractice,5thed.,Copyright?2002Mosby,Inc第二頁，共三十頁。IschemicColitisIschemiaofthecolonmostoftenaffectstheelderly

(90%ofpatients>60y/o).Ischemiccolitisisalmostalways

nonocclusive.

(emboliarethemostcommoncauseofacutemesentericischemia)Shuntingofbloodawayfromthemucosa

maycontributetothiscondition,butthe

mechanismisunknown.第三頁，共三十頁。IschemicColitisMostpatientsischemiaoccurssecondarytoarteriolarshunting,

spasm,orpoorperfusionofmucosalvessels.Mostcasesinvolvethesplenicflexure,whichissuppliedbyend-arteries.Therectumisusuallyspared,becauseitsbloodsupplyisdifferentfromtherestofthecolonandlessdependent

ontheinferiormesentericartery.Marx:Rosen'sEmergencyMedicine:ConceptsandClinicalPractice,5thed

第四頁，共三十頁。TypesofIschemicColitisAcutefulminantischemiccolitis

Subacuteischemiccolitis

HARRISON’SONLINE15TH

第五頁，共三十頁。TypesofIschemicColitisGangrenousischemiccolitis

acompletelossofarterialflowcausesbowelwallinfarctionandgangrene,whichcanprogresstoperforation,peritonitis,anddeath.Stricturingischemiccolitis

agrossimpairmentofthearterialsupply,leadingtohemorrhagicinfarctionofthemucosa,whichulcerates,healsbyfibrosis,andfinallyleadstostenosis.Transientischemiccolitis

atransient,reversibleimpairmentofthearterialsupply,whichcausesapartialmucosalsloughthathealsbymucosalregenerationinafewdays.themostcommon

Marx:Rosen'sEmergencyMedicine:ConceptsandClinicalPractice,5thed

第六頁，共三十頁。Acutefulminantischemiccolitismanifestations

Theonsetischaracteristicallyacute,withgeneralizedlowerabdominalpain,usuallyintheleftlowerquadrant,followedwithin24hoursbybloodydiarrheaorrectalbleeding.Dilationofthecolonandphysicalsignsofperitonitisareseeninseverecases.Withthegangrenoustype,bothsymptomsandsignsprogressrapidly.

第七頁，共三十頁。AcutefulminantischemiccolitisDiagnosticStrategyNospecificserummarkersproveninthediagnosisofintestinalischemia.

Abdominalfilmsmayreveal

thumbprintingfromsubmucosalhemorrhageandedema.*(bariumenemaiscontraindicatedincasesofgangrenousischemic

colitis

becauseoftheriskofperforation)第八頁，共三十頁。thumbprinting

第九頁，共三十頁。AcutefulminantischemiccolitisDiagnosticStrategySigmoidoscopyorcolonoscopymaydetectulcerations,friability,andbulgingfoldsfromsubmucosalhemorrhage.(Colonoscopyispreferredoversigmoidoscopy

)Thesegmentaldistributionandrectalsparingofthediseaseprocessaresuggestivebutarenotdiagnostic.第十頁，共三十頁。Colonoscopicviewshowingmarkederythemaandexudateinsigmoidcolon

第十一頁，共三十頁。Endoscopicviewofmucosaledema,exudates,andulcerationsinsigmoidcolon

第十二頁，共三十頁。Endoscopicimageofdescendingcolonshowingseverecolitiswithpneumatosisintestinalis.

第十三頁，共三十頁。AcutefulminantischemiccolitisDiagnosticStrategyAngiographyisnothelpfulinthemanagementofpatientswithpresumedischemiccolitisbecausearemediableocclusivelesionisveryrarelyfound.

CTscanisnormalinearlystagesofbowelinfarction,althoughitmayshownonspecificfindingssuchasbowelwallthickeningandpneumatosis.

第十四頁，共三十頁。CTshowingleftsidedcolonicthickening.第十五頁，共三十頁。PneumatosisIntestinalis第十六頁，共三十頁。PneumatosisIntestinalis第十七頁，共三十頁。AcutefulminantischemiccolitismanagementWhenischemiccolitisissuspected,asurgeonshouldbeconsulted.Gangrenousischemiccolitisorevidenceofperforationrequiresimmediatesurgeryassoonasthepatientisstabilized.

第十八頁，共三十頁。managementVasopressorsshouldbeavoided,ifpossible.Lowblood-flowstates(hypotension)shouldbeaggressivelyreversed.第十九頁，共三十頁。TypesofIschemicColitisAcutefulminantischemiccolitis

Subacuteischemiccolitis

第二十頁，共三十頁。Subacuteischemiccolitis

manifestations

Itproduceslesserdegreesofpainandbleeding,oftenoccurringoverseveraldaysorweeks.

Theleftcolonmaybeinvolved,buttherectumisusuallysparedbecauseofthecollateralbloodsupply.第二十一頁，共三十頁。Subacuteischemiccolitis

managementSubacute

Ischemic

colitiswithoutevidenceofperitonitisorperforationisgenerallyself-limitedandrequiresonlyconservativemanagement,includingbowelrest,parenteralfluids,andantibiotics.第二十二頁，共三十頁。Subacuteischemiccolitis

management

Mostcasesofnonocclusiveischemiccolitisresolvein2to4weeksanddonotrecur.Surgeryisnotrequiredexceptforobstructionsecondarytopostischemicstricture.

第二十三頁，共三十頁。DifferentialConsiderationsIschemic

colitisoftenmimicsinfectiouscolitis,inflammatoryboweldisease,orevencoloncarcinoma.ManycasesofcolitisintheelderlyonceconsideredtobeCrohn’sdiseaseorulcerativecolitisinretrospectwerereallycolonicischemia.

第二十四頁，共三十頁。DifferentialConsiderationsThefeaturesconsideredatypicalininflammatoryboweldiseases,suchas1.segmentaldistributionofthedisease,infrequentrectalinvolvement,2.highrateofspontaneousrecovery,lowrateofrecurrence,3.lackofadequateresponsetousualinflammatoryboweldiseasetherapy,4.frequentprogressiontofibroticstenosiswithdelayedobstructionThefeaturesabovearenowrecognizedascharacteristicofcolonicischemia.

第二十五頁，共三十頁。DifferentialConsiderationsAlwaysconsiderthediagnosisofischemic

colitiswhenevercontemplatingthediagnosisofinflammatoryboweldiseaseinanelderlypatient.

第二十六頁，共三十頁。DifferentialDiagnosisClinical

Radiologic

UlcerativecolitisBloodydiarrheaExtendsproximallyfromrectum;finemucosalulcerationCrohn’scolitisPerianallesionscommon;frankbleedinglessfrequentthaninulcerativecolitisSegmentaldisease;rectalsparing;strictures,fi