缺血性肠病.pptx

IschemicColitisRi陳宏彰ReferencebookslHarrisons online 15thlMarx:Rosens Emergency Medicine:Concepts and Clinical Practice,5th ed.,Copyright2002Mosby,IncIschemicColitislIschemiaofthecolonmostoftenaffectstheelderly(90%ofpatients60y/o).lIschemiccolitisisalmostalways nonocclusive.(emboli are the most common cause of acute mesenteric ischemia)lShunting of blood away from the mucosa maycontributetothiscondition,butthe mechanismisunknown.IschemicColitislMostpatientsischemiaoccurssecondarytoarteriolar shunting,spasm,orpoor perfusionofmucosalvessels.lMostcasesinvolvethesplenic flexure,whichissuppliedbyend-arteries.lTherectum is usually spared,becauseitsbloodsupplyisdifferentfromtherestofthecolonandlessdependentontheinferiormesentericartery.Marx:RosensEmergencyMedicine:ConceptsandClinicalPractice,5thedTypesofIschemicColitis1.Acute fulminant ischemic colitis2.Subacute ischemic colitisHARRISONSONLINE15THTypesofIschemicColitisGangrenous ischemic colitis a complete loss of arterial flow causes bowel wall infarction and gangrene,which can progress to perforation,peritonitis,and death.Stricturing ischemic colitis a gross impairment of the arterial supply,leading to hemorrhagic infarction of the mucosa,which ulcerates,heals by fibrosis,and finally leads to stenosis.Transient ischemic colitis a transient,reversible impairment of the arterial supply,which causes a partial mucosal slough that heals by mucosal regeneration in a few days.the most commonMarx:RosensEmergencyMedicine:ConceptsandClinicalPractice,5thedAcute fulminant ischemic colitis manifestations 1.Theonsetischaracteristicallyacute,withgeneralized lower abdominal pain,usuallyintheleft lower quadrant,followedwithin24hoursbybloody diarrhea or rectal bleeding.2.Dilationofthecolonandphysicalsignsofperitonitisareseeninseverecases.3.Withthegangrenoustype,bothsymptomsandsignsprogressrapidly.Acute fulminant ischemic colitis Diagnostic StrategylNospecificserummarkersproveninthediagnosisofintestinalischemia.lAbdominal filmsmayreveal thumbprintingfromsubmucosalhemorrhageandedema.*(bariumenemaiscontraindicatedincasesofgangrenousischemiccolitisbecauseoftheriskofperforation)thumbprinting Acute fulminant ischemic colitis Diagnostic StrategylSigmoidoscopyorcolonoscopymaydetectulcerations,friability,andbulgingfoldsfromsubmucosalhemorrhage.(Colonoscopyispreferredoversigmoidoscopy)lThesegmental distributionandrectal sparingofthediseaseprocessaresuggestivebutarenotdiagnostic.ColonoscopicviewshowingmarkederythemaandexudateinsigmoidcolonEndoscopicviewofmucosaledema,exudates,andulcerationsinsigmoidcolonEndoscopicimageofdescendingcolonshowingseverecolitiswithpneumatosisintestinalis.Acute fulminant ischemic colitis Diagnostic StrategylAngiographyisnothelpfulinthemanagementofpatientswithpresumedischemiccolitisbecausearemediableocclusivelesionisveryrarelyfound.lCT scanisnormalinearlystagesofbowelinfarction,althoughitmayshownonspecificfindingssuchasbowelwallthickeningandpneumatosis.CTshowingleftsidedcolonicthickening.PneumatosisIntestinalisPneumatosisIntestinalisAcute fulminant ischemic colitis managementlWhenischemiccolitisissuspected,asurgeonshouldbeconsulted.lGangrenousischemiccolitisorevidenceofperforationrequiresimmediatesurgeryassoonasthepatientisstabilized.managementlVasopressorsshouldbeavoided,ifpossible.lLow blood-flow states(hypotension)shouldbeaggressivelyreversed.TypesofIschemicColitis1.Acute fulminant ischemic colitis2.Subacute ischemic colitisSubacute ischemic colitismanifestationslItproduceslesserdegreesofpainandbleeding,oftenoccurringoverseveraldaysorweeks.lTheleftcolonmaybeinvolved,buttherectumisusuallysparedbecauseofthecollateralbloodsupply.Subacute ischemic colitismanagementlSubacute Ischemiccolitiswithoutevidenceofperitonitisorperforationisgenerallyself-limitedandrequiresonlyconservative management,includingbowelrest,parenteralfluids,andantibiotics.Subacute ischemic colitismanagement lMostcasesofnonocclusiveischemiccolitisresolvein2to4weeksanddonotrecur.lSurgeryisnotrequiredexceptforobstructionsecondarytopostischemicstricture.Differential ConsiderationslIschemiccolitisoftenmimicsinfectious colitis,inflammatory bowel disease,orevencoloncarcinoma.lManycasesofcolitisintheelderlyonceconsideredtobeCrohnsdiseaseorulcerativecolitisinretrospectwerereallycolonicischemia.Differential ConsiderationslThefeaturesconsideredatypicalininflammatoryboweldiseases,suchas1.segmentaldistributionofthedisease,infrequentrectalinvolvement,2.highrateofspontaneousrecovery,lowrateofrecurrence,3.lackofadequateresponsetousualinflammatoryboweldiseasetherapy,4.frequentprogressiontofibroticstenosiswithdelayedobstructionlThefeaturesabovearenowrecognizedascharacteristicofcolonicischemia.Differential ConsiderationslAlwaysconsiderthediagnosisofischemiccolitiswhenevercontemplatingthediagnosisofinflammatoryboweldiseaseinanelderlypatient.DifferentialDiagnosisClinicalRadiologicUlcerativecolitisBloody diarrhea Extends proximally from rectum;fine mucosal ulceration CrohnscolitisPerianal lesions common;frank bleeding less frequent than in ulcerative colitisSegmental disease;rectal sparing;strictures,fissures,ulcers,fistulas;small bowel involvement IschemiccolitisOlder age groups;vascular disease;sudden onset,often painful Splenic flexure;“thumb printing”;rectal involvement rare ConclusionslAlwaysconsiderthediagnosisofischemiccolitiswhenevercontemplatingthediagnosisofinflammatoryboweldiseaseintheelderly.lThumbprintingofthecolononplainabdominalradiographssuggestsischemiccolitis.lSurgicalconsultationiswarrantedinallcasesofsuspectedischemiccolitis.Thanxforyourattention