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PersistentLowPltPostSplenectomyforITP

Idiopathic(immune)thrombocytopenicpurpura(ITP)isthemostcommonindicationforelectivesplenectomy.

Itisanacquireddisorderinwhichautoantibodiesareproducedagainstaplateletglycoprotein.

Thespleenisthemajorsitefortheproductionofantiplateletantibodiesandalsoservesastheprincipalsiteofplateletdestruction.

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Children usuallypresentwithacuteITP,oftenassociatedwitharecent

viralsyndrome.

In90%ofcases,thediseasespontaneouslyremitswithin6to12months. Onlyrefractorycasesrequiresplenectomy.

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Adults TypicallypresentwithamorechronicformofITPthatismuchless

likelytospontaneouslyremit.

Asymptomaticpatientswithplateletcountsgreaterthan50,000/mm3maysimplybefollowed.

Symptomaticpatientsorthosewithcountslessthan30,000/mm3shouldbetreatedwithoralglucocorticoids.

Greaterthan50%ofpatientsrespondtoglucocorticoids. Inrefractorycases,orinpatientswithbleeding,intravenousimmunoglobulin(IVIG)isused,althoughtheeffectsaretransient. Indicationsforsplenectomyarefailuretorespondtomedicaltherapy

andintolerablesideeffectsfromsteroidadministration.

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Patientswhofailsplenectomyorrelapseafteraninitialresponseshouldbeinvestigatedfor

accessorysplenictissue.

Aperipheralsmearandmagneticresonanceimaging(MRI)ornuclearmedicinestudieswithtechnetium(Tc)-99mlabeledheat-damagedredcellsareindicated.

Ifaccessorysplenictissueisfound,re-explorationshouldbeconsidered(NEnglJMed2002;346:995)

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VentilatoryComplicationsinBurns.

Thermalinjurytotheairwaygenerallyislimitedtotheoropharynxorglottis. Theglottisgenerallyprotectsthesubglotticairwayfromheat,unlessthe

patienthasbeenexposedtosuperheatedsteam.

Edemaformationcancompromisethepatencyoftheupperairway,mandatingearlyassessmentandconstantre-evaluationoftheairway.

Gasescontainingsubstancesthathaveundergoneincompletecombustion(particularlyaldehydes),toxicfumes(hydrogencyanide),andcarbon

monoxidecancausetracheobronchitis,pneumonitis,andedema.

Mortalitymaybeincreasedbyasmuchas20%inthesepatients.

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Carbonmonoxideexposureissuggestedbyahistoryofexposureinaconfinedspacewithsymptomsof:

Nausea Vomiting Headache Mentalstatuschanges Cherry-redlips.

Carbonmonoxidebindstohemoglobinwithanaffinity249timesgreaterthanthatofoxygen.

Resultsinextremelyslowdissociation(t1/2250min)onR.A.NirHus

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W/100%O2thet1/2dropto40minviaN.R. Thearterialcarboxyhemoglobinlevelisobtainedasa

baseline,andifitiselevated(>5%innonsmokersor>10%

insmokers),oxygentherapyshouldcontinueuntilnormallevelsareachieved.

Theincreasedventilation-perfusiongradientandthereductioninpeakairwayflowindistalairwaysandalveoli

canbeevaluatedusingaxenon-133ventilation-perfusionlungscan.

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Majorinjuriesrequireendotrachealintubationwithalarge-boretube(7.5to8mm)tofacilitatepulmonarytoilet

ofviscoussecretionsandmechanicalventilationwithpositivepressure.

Decreasedpulmonarycomplianceisoftenseenafterinhalationinjuryandcanleadtoiatrogenicventilator-associatedlunginjury.

Aconstrictingtruncalescharcanlimitchestexcursion. Escharotomiescanbeusedtorelievetheconstrictionand

allowadequatetidalvolumes.

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CharacteristicsLithogenicBile Theprimarybilesaltsare:

Cholate Chenodeoxycholate

Synthesizedintheliverbycholesterol. Theyareconjugatedintheliverwithtaurineandglycine. 95%ofthebileacidpoolisreabsorbedandreturned

throughtheenterohepaticsystemtotheliver.

Theremaining5%isexcretedinthestool.NirHus

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CharacteristicsLithogenicBile Thekeytomaintainingcholesterolinsolutionisthe

formationofmicelles,abilesaltphospholipid-cholesterol

complex,andcholesterol-phospholipidvesicles.

Instatesofexcesscholesterolproduction,theselargevesiclesmayalsoexceedtheircapabilitytotransportcholesterol,andcrystalprecipitationmayoccur.

butthecholesterol-phospholipidvesiclescarrythemajorityofbiliarycholesterol.

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CharacteristicsLithogenicBile Pigmentstonescontainlessthan20%cholesterolandare

darkowingtothepresenceofcalciumbilirubinate.

Blackpigmentstones(duetounconjugatedbilirubin)aresmallandtarry,andarefrequentlyassociatedwithhemolyticconditionssuchashereditaryspherocytosisand

sicklecelldiseaseorcirrhosis.

Notassociatedwithinfectedbile. Locatedalmostexclusivelyinthegallbladder

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CharacteristicsLithogenicBile Brownpigmentstonesaresoftandearthyintextureand

aretypicallyfoundinbileducts,especiallyinAsian

populations.

ContainmorecholesterolandcalciumpalmitateandoccurasprimarycommonductstonesinWesternpatientswithdisordersofbiliarymotilityandassociatedbacterialinfection.

E.colisecrete-glucuronidasethatcausesenzymatichydrolysisofsolubleconjugatedbilirubinglucuronidetoproduceinsolublefreebilirubin,whichthenprecipitateswithcalcium.

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