Toxic-Megacolon

ToxicMegacolonYanjunWangFirstyearpostgraduatestudentTheFirstAffiliatedHospitalofNanjingMedicalUniversity2016.05.11Case1SymptomatologyA53-year-oldmancomplaintwithabdominalpain,bloodydiarrheaandfever(upto39.5℃)foraboutonemonthPhysicalexaminationT38.8℃,P100/min,R18/min,Bp100/60mmHgperiumbilicalpain,distentionandanasarcaLaboratoryinvestigationsBloodRT:WBC13.5×10^9/L(↑),N79.4%(↑)StoolRT:occultbloodtest(+),WBC（++++）Bloodbiochemicaltest:Albumin18.91g/L(↓),Kalium3.30mmol/L(↓),Calcium1.76mmol/L(↓),Sodium132.4mmol/L(↓)Fig1A.PlainabdominalfilmObviousdilationofascending,transverseanddescendingcolonwithair-fluidlevel(blackarrow)andthewidestpartwasupto8.8cm(redline).Fig1B-1D.Axialcontrast-enhancedCTFig1B.dilationofascendingandtransversecolonwithanodularluminalcontour(arrow)Fig1C.asitesandthickenedwallofdescendingcolonwithair-fluidlevelFig1D.muralstratification,atargetsign(whitearrow)andgasbubbles(arrowhead)adjacenttothewallaresuggestiveofpneumatosis1B1B1C1DFig1E-1G.Coronalcontrast-enhancedCTimages(venousphase)distensionofascending,transverseandsigmoidcolonabnormalhaustralpatternandnodularpseudopolypswallthickeningofdescendingcolonwithsightenhancementascites1E1G1FDiagnosisToxicmegacolonwithulcerativecolitisDefinitionToxicmegacolonisararebutsevereandpotentiallyfatalcomplicationofcolitispathologicallydefinedbyinflammationofallthelayersofthecolonicwallandcharacterizedbytotalorsegmentalnonobstructivecolonicdistensionofatleast6cm,associatedwithsystemictoxicitySimpleanatomyofcolonHaustrumTaeniaecoliCecumAscendingcolonHepaticflexureSpleenicflexureTransversecolonOmentalappendicesSigmoidcolonRectumAnalcanalAppendixIleumEpidemiologyToxicmegacolonmaybepresentatanyageandaffectsbothsexesNopreciseincidencerateisavailableforTM,anditvariesdependingonetiologyandpopulationInflammatoryboweldiseaseUlcerativecolitis--mostcommonCrohn’sdiseaseInfectiousClostridiumdifficile--PseudomembranouscolitisSalmonella,Shigella,Yersinia,Campylobacter,E.coliCytomegalovirusRotavirusEntamebaAspergillosisCryptosporidiumEtiologyIschemiccolitisMalignancyKaposi’ssarcoma;ColonicLymphomaPotentialtriggersandexacerbatingfactorsHypokalemia,hypomagnesemiaBariumenemaDiscontinuationofsteroidsNarcoticsAnticholinergicsChemotherapyColonoscopyEtiologyPathogenesisTheprecisepathophysiologyoftoxicmegacolonisnotfullyunderstood.However,anassociationbetweeninflammatoryconditionsofthecolonanddecreasedsmoothmusclecontractilityiswellestablishedItispostulatedthatmoresevereinflammationanddamagetothecolonicwallarenecessaryforthedevelopmentofTMandthedepthofinflammationseemstobecorrelatedwiththeextentofcolonicdilatationDiagnosticApproachHistoryPhysicalexaminationLaboratoryinvestigationsImagingstudiesHistorySignsofInflammatoryboweldiseaseandacutecolitisAbdominalpain;(Bloody)Diarrhea;Vomiting;Weightloss;Historyofpreviousexacerbations;ExtraintestinalmanifestationsPossibleexposuretoentericpathogensFamily,environment;RecenttravelsMedication,especiallyAntibiotics;Steroids;Antidiarrheals;Anticholinergics;OpiatesImmunestatusChemotherapy,malignancy;HIVPhysicalexaminationAbdominalpain,tenderness,distensionConstipation,obstipationReducedbowelsoundsFeverTachycardia,hypotensionMentalchangesLaboratoryinvestigationsInflammationElevatedwhitebloodcellcountElevatedC-reactiveproteinElevatederythrocytesedimentationrateAnemiaElectrolyteimbalancesBloodcultureFecalscreeningforpathogensStoolsamplesforC.diff.cultureandA/BtoxinassayClinicalCriteria(byJalanetal.)Maincriteria(atleastthreeofthefollowing)Fever(38.6℃)Tachycardia(120/min)Leukocytosis(10.5×109/L)AnemiaInadditionatleastoneofthefollowingDehydrationAlteredlevelofconsciousnessElectrolyteimbalancesHypotensionImagingstudiesImagingstudiesPlainabdominalradiographsarecrucialforthediagnosisaswellasfortheday-to-daymonitoringofpatientswithTMBecauseofthehighriskofperforation,contrastenemaiscontraindicatedinTMCTishelpfulinconfirmingthedevelopmentoftoxicmegacolonandisparticularlyusefulindetectinglife-threateningabdominalcomplicationsPlainabdominalradiographsThetransverseorrightcolonisusuallythemostdilatedcolonicsegment,frequentlymorethan6cmandnotrarelyupto15cmonsupinefilms;Distensionoftheleftcolonislessfrequent,anddistensionofthesigmoidcolonandrectumisquiterareColonicairfluidlevelsareoftenpresentonuprightfilmsandthenormalhaustralpatternsmaybeabsentDistensionofsmallbowelandstomachcouldbeapredictorofTMCTCircumferentialthickeningofthewallofthecolonwithadiffusedistributionEdematoussubmucosalchangeswiththemultilayerappearance(targetsign)Thickenedhaustralfoldswithparallelbandsofhighandlowattenuation(accordionsign)PericolicstrandingandascitesCTcanfindsomecomplications,suchaspeforation,abcessorascendingpyelophlebitisHirschsprung’sdiseaseIntestinalpseudo-obstructionDifferentialDiagnosisHirschsprung’sdiseaseHirschsprung’sdisease(HD)isacongenitalabsenceofganglioncellsofthesubmucosalandmyentericplexusofthebowel,whichbeginsattheinternalanalsphincterandcanextendtovaryingdistancesItisusuallydiagnosedinthenewbornperiod,with