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1、ColonicVolvulusTamimQaumHarvardMedicalSchool,YearIIIDefinition·Torsionofthecolonarounditsmesentericaxis,leadingto1)Compromisedbloodflow,and2)Aclosedloopobstruction·Dualmechanismofinfarction:1)Torsionofvesselsstopsflowofbloodtocolonicwall.2)Torsionofcoloncreatesclosedloopobstruction(withven
2、ousobstruction,luminalsecretion,andcolonicwalldistentionleadingtoarterialobstruction).·Anatomicrequirements:1)Redundantsegmentoffreelymovablebowel.2)Proximityofpointsoffixationofthebowel.EpidemiologyofVolvulus·Incidence:2per100,000·Accountsfor25%ofobstructioncasesinpregnancybecauseuterusdi
3、splacesallmobilesegmentsofcolon.·Sigmoidvolvulus=75-80%.·Cecalvolvulus=20-25%.·Tranversecolonvolvulus=3%(70cases);uncommonbecauseofshort,broadattachmentofcolonicmesentery.·Splenicflexurevolvulus=1-2%(30cases);riskfactors:absenceofgastrosplenic,splenocolic,&phrenicoloicligaments.·Stomach,ga
4、llbladder,andsmallbowelvolvulusarerare.EpidemiologyofSigmoidVolvulus·IntheUnitedStates,sigmoidvolvulusaccountsfor<10%ofintestinalobstructioncases.·InBolivianandPeruvianAndes,sigmoidvolvulusaccountsfor80%ofintestinalobstructioncases.·InUSandWesternEurope,sigmoidvolvulusisassociatedwithchron
5、icconstipationandlaxativeabuse(developmegacolonwithmaximaldilationofsigmoid);nogenderdifference.·Indevelopingcountries,sigmoidvolvulusisassociatedwithdietshighinvegetablefiber(90%ofptsaremen).EpidemiologyofSigmoidVolvulus·Elderlypatients(averageage:72).40%institutionalizedordebilitated.Unc
6、learwhyelderlymorepredisposed,butpossiblypoorfluid/fiberintake,andconstipation.·SeeninpatientswithneurologicorpsychiatricdisorderssuchasParkinson’sdisease,multiplesclerosis,Alzheimer’sdisease,pseudobulbarpalsy,&chronicschizophrenia.·Isalsoassociatedwithhypothroidism,scleroderma,amyloidosis
7、,Crohn’sdisease,pregnancy,Chagas’disease,andcolonichypertrophyassociatedwithhighfiberdiets.ClinicalPresentationofSigmoidVolvulus·Abruptonsetofsevere,continuouscrampyabdominalpainwithcolickycomponentduetoperistalsis·Constipationvsabsenceofstoolsvs.absenceofflat
