2022年医学专题-缺血性肠病

IschemicColitisRi陳宏彰第一页，共三十页。ReferencebooksHarrison’sonline15thMarx:Rosen'sEmergencyMedicine:ConceptsandClinicalPractice,5thed.,Copyright©2002Mosby,Inc第二页，共三十页。IschemicColitisIschemiaofthecolonmostoftenaffectstheelderly

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

nonocclusive.

(emboliarethemostcommoncauseofacutemesentericischemia)Shuntingofbloodawayfromthemucosa

maycontributetothiscondition,butthe

mechanismisunknown.第三页，共三十页。IschemicColitisMostpatientsischemiaoccurssecondarytoarteriolarshunting,

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

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

第四页，共三十页。TypesofIschemicColitisAcutefulminantischemiccolitis

Subacuteischemiccolitis

HARRISON’SONLINE15TH

第五页，共三十页。TypesofIschemicColitisGangrenousischemiccolitis

acompletelossofarterialflowcausesbowelwallinfarctionandgangrene,whichcanprogresstoperforation,peritonitis,anddeath.Stricturingischemiccolitis

agrossimpairmentofthearterialsupply,leadingtohemorrhagicinfarctionofthemucosa,whichulcerates,healsbyfibrosis,andfinallyleadstostenosis.Transientischemiccolitis

atransient,reversibleimpairmentofthearterialsupply,whichcausesapartialmucosalsloughthathealsbymucosalregenerationinafewdays.themostcommon

Marx:Rosen'sEmergencyMedicine:ConceptsandClinicalPractice,5thed

第六页，共三十页。Acutefulminantischemiccolitismanifestations

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

第七页，共三十页。AcutefulminantischemiccolitisDiagnosticStrategyNospecificserummarkersproveninthediagnosisofintestinalischemia.

Abdominalfilmsmayreveal

thumbprintingfromsubmucosalhemorrhageandedema.*(bariumenemaiscontraindicatedincasesofgangrenousischemic

colitis

becauseoftheriskofperforation)第八页，共三十页。thumbprinting

第九页，共三十页。AcutefulminantischemiccolitisDiagnosticStrategySigmoidoscopyorcolonoscopymaydetectulcerations,friability,andbulgingfoldsfromsubmucosalhemorrhage.(Colonoscopyispreferredoversigmoidoscopy

)Thesegmentaldistributionandrectalsparingofthediseaseprocessaresuggestivebutarenotdiagnostic.第十页，共三十页。Colonoscopicviewshowingmarkederythemaandexudateinsigmoidcolon

第十一页，共三十页。Endoscopicviewofmucosaledema,exudates,andulcerationsinsigmoidcolon

第十二页，共三十页。Endoscopicimageofdescendingcolonshowingseverecolitiswithpneumatosisintestinalis.

第十三页，共三十页。AcutefulminantischemiccolitisDiagnosticStrategyAngiographyisnothelpfulinthemanagementofpatientswithpresumedischemiccolitisbecausearemediableocclusivelesionisveryrarelyfound.

CTscanisnormalinearlystagesofbowelinfarction,althoughitmayshownonspecificfindingssuchasbowelwallthickeningandpneumatosis.

第十四页，共三十页。CTshowingleftsidedcolonicthickening.第十五页，共三十页。PneumatosisIntestinalis第十六页，共三十页。PneumatosisIntestinalis第十七页，共三十页。AcutefulminantischemiccolitismanagementWhenischemiccolitisissuspected,asurgeonshouldbeconsulted.Gangrenousischemiccolitisorevidenceofperforationrequiresimmediatesurgeryassoonasthepatientisstabilized.

第十八页，共三十页。managementVasopressorsshouldbeavoided,ifpossible.Lowblood-flowstates(hypotension)shouldbeaggressivelyreversed.第十九页，共三十页。TypesofIschemicColitisAcutefulminantischemiccolitis

Subacuteischemiccolitis

第二十页，共三十页。Subacuteischemiccolitis

manifestations

Itproduceslesserdegreesofpainandbleeding,oftenoccurringoverseveraldaysorweeks.

Theleftcolonmaybeinvolved,buttherectumisusuallysparedbecauseofthecollateralbloodsupply.第二十一页，共三十页。Subacuteischemiccolitis

managementSubacute

Ischemic

colitiswithoutevidenceofperitonitisorperforationisgenerallyself-limitedandrequiresonlyconservativemanagement,includingbowelrest,parenteralfluids,andantibiotics.第二十二页，共三十页。Subacuteischemiccolitis

management

Mostcasesofnonocclusiveischemiccolitisresolvein2to4weeksanddonotrecur.Surgeryisnotrequiredexceptforobstructionsecondarytopostischemicstricture.

第二十三页，共三十页。DifferentialConsiderationsIschemic

colitisoftenmimicsinfectiouscolitis,inflammatoryboweldisease,orevencoloncarcinoma.ManycasesofcolitisintheelderlyonceconsideredtobeCrohn’sdiseaseorulcerativecolitisinretrospectwerereallycolonicischemia.

第二十四页，共三十页。DifferentialConsiderationsThefeaturesconsideredatypicalininflammatoryboweldiseases,suchas1.segmentaldistributionofthedisease,infrequentrectalinvolvement,2.highrateofspontaneousrecovery,lowrateofrecurrence,3.lackofadequateresponsetousualinflammatoryboweldiseasetherapy,4.frequentprogressiontofibroticstenosiswithdelayedobstructionThefeaturesabovearenowrecognizedascharacteristicofcolonicischemia.

第二十五页，共三十页。DifferentialConsiderationsAlwaysconsiderthediagnosisofischemic

colitiswhenevercontemplatingthediagnosisofinflammatoryboweldiseaseinanelderlypatient.

第二十六页，共三十页。DifferentialDiagnosisClinical

Radiologic

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