RheumatologyMain31-40Q1A28~year-oldwomancomestothephysicianwithpaininherleftkneejoint.Shehadmilddiscomfortandpaininherrightwrist4daysagoandleftanklepain2daysago.Shehasnorecentrespiratoryillness,diarrhea,orurinarysymptoms.Shehasnovaginaldischarge.Thepatienthasnopreviousmedicalproblemsandtakesnomedications.Shedrinkshalfapintofvodkadailybutdoesnotuseintravenousdrugs.Sheissingleandsexuallyactive.Herlastmenstrualperiodwasaweekago.Temperatureis38.5℃(101.3℉),bloodpressureis120/80mmHg;pulseis93/min;andrespirationsare15/min.Examinationofthekneeshowswarmth,tenderness,decreasedrangeofmotion,andaneffusion.Moskinlesionsarepresentandherpelvicexaminationisunremarkable.Synovialfluidanalysisshowsawhitebloodcel!countof50,000/mm3.Whichofthefollowingisthemostlikelycauseofhersymptoms?A.AcuteHIVinfectionB.AcuterheumaticfeverC.Crystal-inducedarthritisD.GonococcalsepticarthritisE.InfectiveendocarditisF.Mon-gonococcalsepticarthritisG.ReactivearthritisA1

Correctanswer:DThefever,kneepain,andwhitebloodcell(WBC)countof50,000/mm3onsynovialfluidanalysisstronglysuggestsepticarthritis.Septicarthritisinayoung,sexuallyactiveindividualismostoftencausedbyNeisseriagonorrhoeae(75%ofcases).Gonococcalsepticarthritismaypresentwithasymmetricpolyarthralgias(mostoftenassociatedwithtenosynovitisandskinrash)oranisolatedpurulentmono-oroligoarthritis,insomepatients,asymmetricpolyarthralgiasmayprecedepurulentmonoarthritis.Roughly75%ofcasesare"silent,"meaningthattheprecedinggenitourinaryorpharyngealinfectiongoesunnoticed.Forthispatient,migratoryasymmetricpolyarthralgiasoftherightwristandleftankleprecededpurulentmonoarthritisoftheleftknee.Althoughskinrashandtenosynovitisarenotpresentinthispatient,purulentarthritisinasexuallyactiveindividualisgonococcalarthritisuntilprovenotherwise.Synovialfluidwhitebloodcel!countisabout50,000/mm3(slightlylowerthanothersepticarthritides).Gramstainofthesynovialfluid(positivein25%ofcases),bloodcultures(positivein20%-50%ofcases),andgenital/pharyngealmucosa!nucleicacidamplificationtests(positiveIn90%ofcases)areusedtoconfirmthediagnosis.Treatmentisceftriaxoneorcefotaxime.(ChoiceA)SymptomsofacuteHIVinfectiontendtopresent2-4weeksafterexposuretothevirus.Thesymptomsarenonspecificandincludefever,arthraSgias,sorethroat,lymphadenopathy,mucocutaneouslesions,diarrhea,andweightloss.(ChoiceB)Acuterheumaticfevergenerallyoccurs2-4weeksafterpharyngitiscausedbyGroupAStreptococcus.Symptomsofacuterheumaticfeverincludemigratoryarthritisofthelargejoints,erythemamarginatumrash,subcutaneousnodules,carditis,andSydenhamchorea.(ChoiceC)Crystal-inducedarthritisoftenpresentswithawarm,painful,swollenjointaccompaniedbylow-gradefever.Synovia!fluidanalysisshowsaWBCcountof5,000-80,000/mm3andcharacteristiccrystalsunderpolarizedlight.(ChoiceG)ReactivearthritismaybecausedbygenitourinaryinfectionwithChlamydiatrachomatisorbycertaingastrointestinalinfections.Itpresentswithatriadofarthritis,,conjunctivitis,andurethritis.Educationalobjective:Neisseriagonorrhoeaeisthemostcommoncauseofsepticarthritisinyoung,sexuallyactivepatients.Gonococcalsepticarthritismaypresentwithasymmetricpolyarthralgias(oftenassociatedwithtenosynovitisandskinrash)orasanisolatedpurulentmono-orpolyarthritis.DiagnosismaybeconfirmedbyGramstainofthesynovialfluid,bloodcultures,andgenital/pharyngealmucosalnucleicacidamplificationtests.Q2A24~year-oldwomancomestothephysiciancomplainingofaskinrashandpaininherwrists;anklesandelbowsoverthepast4days.Shehasalsohadafeverandsweats,butdeniesheadache,nauseaorvomiting.Shehasnosignificantpastmedicalhistoryanddoesnottakeanymedications.Sherecentlytookavacationwithhernewboyfriend.Shedeniesanyprevioussexuallytransmitteddiseasesbutacknowledgeshavingunprotectedsexwithhernewboyfriend.Shedoesnotusetobacco,alcoholorillicitdrugs.HertemperatureIs33.5°C(101.3°F)andherpulseis98/min.Heroropharynxisclearandthereisnothrushorlymphadenopathy.Herabdomenisbenignandthepelvicexaminationiswithinnormallimits.Shehaspainalongthetendonsheathswithactiveandpassivehandmovement.Aphotoofherskinrashisshownbelow.Whichofthefollowingisthemostlikelycauseofhersymptoms?A.LymediseaseB.SyphilisC.GonococcemiaD.MeningococcemiaE.AcuteHIVinfectionF.AcuterheumaticfeverA2Correctanswer:CThispatienthastheclassictriadofpolyarthralgia,tenosynovitis,andpainlessvesiculopustularskinlesionsfordisseminatedgonococcalinfection.Hercomplaintsofwrist,elbowandanklepainareconsistentwithgonococcalpolyarthralgias,andherpainelicitedalongthetendonsheathssuggeststenosynovitis.Thelesionsshowninthephotographaretypicalvesiculopustularlesionsofdisseminatedgonococcalinfection;theytendtonumberfromtwototenandmaybedismissedasfurunclesorpimples.Feversandchillsmaybepresent.Ahistoryofrecentunprotectedsexwithanewpartnerisfrequentlyassociatedwithdisseminatedgonococcalinfection,whilesymptomsofsymptomaticvenerealdiseasearemostoftenabsent.(ChoiceA)ArthritisandrashareassociatedwithLymedisease.Therash(erythemamigrans)ofLymediseaseoccursearlyoninillness,whilearthritis,typicallymonoarticularkneepain,doesnotoccuruntilmonthslater.Erythemamigransoccursatthesiteofatickbite,andhasa"bullseye"appearance.TenosynovitisisnottypicalofLymedisease.(ChoiceB)Theskinfindingsofsyphilisincludeapainlessulcerofthegenitaliathatoccursintheprimarystageofinfection,andamaculopapularrashofthepalmsandsolesinthesecondarystage.(ChoiceD)Meningococcemiapresentswithapetechialrash,highfever,headache,nausea/vomiting,stiffneck,andphotophobia.Thispatientspecificallydeniesmanyofthesesymptoms.Furthermore,arthritis,tenosynovitis,andtherashintheimagearenotconsistentwithmeningococcemia.(ChoiceE)ThesymptomsofacuteHIVinfectionincludefever,arthralgias,sorethroat,lymphadenopathy,mucocutaneouslesions,diarrhea,andweightloss.Hersymptomsaremoreconsistentwithdisseminatedgonococcalinfection.Allpatientswithdisseminatedgonococcalinfection,however,shouldundergoHIVscreening.(ChoiceF)Anepisodeofpharyngitistypicallyprecedestheonsetofacuterheumaticfeverby2-4weeks.Symptomsofacuterheumaticfeverincludemigratoryarthritisofthelargejoints,erythemamarginatum(raisedring-shapedlesionsoverthetrunkandextremities),subcutaneousnodules,carditis,andSydenhamchorea.Educationalobjective:Disseminatedgonococcalinfectionoftenpresentswithatriadofpolyarthralgias,tenosynovitis,andvesiculopustularskinlesions.Q3A64-year-oldmancomestotheemergencydepartmentwitha3-dayhistoryofprogressivelyincreasingpain;swelling,andrednessofhisrightknee.Thepainisseverewithweightbearing,andheisunabletoambulatewithoutassistance.Thepatientreportsnorecenttraumatothekneebuthashadsubjectivefever.Hewasdiagnosedwithgout10yearsagoandhadseveralrecurrencesofacutegoutinvolvingmultiplejoints,buthashadgoodcontrolsincehestartedtakingaliopurinoi.Sixweeksago,hewentonacampingtrip3nthemountainsofNewHampshire.Medicalhistoryisnotablefortype2diabetesmeilitusandhypertension.Currentmedicationsincludelisinoprilandmetformin.Thepatientdoesnotusetobacco,alcohol,orillicitdrugs.Histemperatureis33.3℃(100.9℉),bloodpressureis110/65mmHg,andpulseis110/min.Examinationshowsatender,swollen,erythematousrightkneewithmarkedlydecreasedrangeofmotion.TheremainderoftheexaminationIsunremarkable.Whichofthefollowingisthemostappropriatenextstepinmanagement?A.LymeserologyB.MRIofthekneeC.Naproxenandoutpatientfollow-upD.SerumuricacidlevelE.SynovialfluidanalysisF.X-rayofthekneeA3Correctanswer:EThispatient'spresentationwithfeverandacutemonoarticulararthritiswarrantsurgentsynovialfluidanalysis(cellcount,Gramstain,culture)toexcludesepticarthritis.Patientswithanestablisheddiagnosisofgoutwhohavetypicalsymptomsofaflarecanbemanagedwithoutjointaspiration.Althoughgoutcancauselow-gradefever,theprogressivenatureofthispatient'ssymptomsover3days(goutflarestypicallyhaveanabruptonsetwithmaximalsymptomswithin12-24hours)Increasesthelikelihoodofasepticjoint,particularlyinthesettingofdiabetes.Underlyingjointdisorders(eg,gout,pseudogout,osteoarthritis)increasetheriskforsecondaryjointinfection,inpatientswithcrystal-inducedarthritis(eg,gout),thepresenceofcrystalsalonedoesnotruleoutsepticarthritisasthesecanbepresentinsynovialfluidbetweenattacks.IftheGramstainispositiveandjointfluidwhitecellcountis>50,000/mm3;,thepatientshouldbestartedonempiricantibioticsuntilcultureresultsareknown,ifcrystalsarepresent,thefluidisnonpurulent,andGramstainisnegative,thepatientmaybemanagedasforastandardgoutflare(ChoiceC).(ChoiceA)Althoughthispatient'srecenttravelplaceshimatriskforLymedisease,Lymearthritisusuallydevelopsmonthsafterinitialinfection.Regardless,septicarthritisshouldbeexcludedfirst.(ChoiceB)MRIisusefultoevaluatesoft-tissuestructuresintheknee(eg.meniscus,ligaments)butisnotusuallyneededtoevaluateacutearthritis,especiallyinapatientwithnohistoryoftrauma.(ChoiceD)Theserumuricacidlevelisusefulinassessingtheeffectivenessofurate-loweringtherapyinchronicgout.Itislessusefulinevaluatingacutearthritisandisoftennormalduringanacutegoutattack.(ChoiceF)X-rayisusefulifafracture,pseudogout(chondrocalcinosis),orosteoarthritis(narrowjointspace,osteophytes)issuspected.However,rulingoutsepticarthritisisahigherpriority.Educationalobjective:Synovialfluidshouldbeobtainedurgentlyforcellcount,Gramstain,andculture3nanypatientwithpossiblesepticarthritis.Preexistingjointdisorderscanincreasetheriskforsecondaryinfectionofthejoint.Inpatientswithcrystal-inducedarthritis(eg,gout),thepresenceofcrystalsinthesynovialfluiddoesnotruleoutsepticarthritisasthesewillbepresentbetweenattacks.Q4A66-year-oldmartisadmittedtothehospitalforleftiowerquadrantabdominalpain;fever,andvomiting.CTscanoftheabdomenrevealsdiverticulitis.Thepatientisstartedonsupportivecareandantibiotics.Hissymptomsimproveover2days;however,onthethirddayofhospitalizationhereportsacutepainintherightankie,whichbecomes"unbearable"withinafewhours.Thepatienthadasimilarpain1yearagothatresolvedwithover-the-countermedication.Medicalhistoryisnotablefortype2diabetes,hyperlipidemia,andhypertension.Histemperatureis37.1℃(98.8℉),bloodpressureis140/90mmHg,andpulseis93/min.BMIIs36kg/㎡.Examinationshowsaswollen,erythematousrightanklewithmoderaterestrictionofmovementduetopain;theleftankleisnormal.Bothankleswerenormalatthetimeofadmissiontothehospital.Whichofthefollowingisthemostlikelydiagnosis?A.EnteropathicarthritisB.GoutC.NeuropathicjointD.OsteoarthritisE.PsoriaticarthritisF.RheumatoidarthritisG.SepticarthritisA4Correctanswer:BThispatientwithacute,rapidlyprogressinganklepainandapriorhistoryofsimilarpainhasacutegout.Althoughitismostcommoninthefirstmetatarsophalangealjoint,goutcanalsoinvolvethekneeandankle.Goutischaracterizedbyrecurrentattacksthattypicallydevelopovernightorearlyinthemorning,reachingmaximumintensitywithin12-24hours.Definitivediagnosisisobtainedviasynovialfluidanaiysisshowinginflammatorycellsandneedle-shaped,negativelybirefringenturatecrystals.Agoutattackcanbeprecipitatedbyconditionsthatcauseincreasedproductionordecreasedeliminationofuricacid,oranacutechangeinuricacidlevels.Commontriggersincludeheavyalcoholconsumption,intakeofurate-richfoods,trauma/surgery,dehydration,andmedicationsthatraise(eg,thiazidediuretics,cyclosporine)orlower(eg,allopurinol)uricacidlevels.(ChoicesAandE)Thespondyloarthropathies(eg,ankylosingspondylitis,psoriaticarthritis,reactivearthritis,enteropathicarthritis[associatedwithinflammatoryboweidisease])predominantlyaffecttheaxialskeleton.Thesedisorderscancauseacuteperipheraloligoarthritisbutitistypicallylessdramaticthangout.Mostpatientswillhaveadditionalsymptomsincludinglowbackpainandstiffness,andinflammationattendoninsertions(enthesitis).(ChoiceC)Neuropathic(Charcot)arthropathycausesdestructivearthritisinpatientswithlong-standingdiabeteswhohaveperipheralneuropathy.Althoughtheankleiscommonlyinvolved,obviousdeformitiesandchronicpainarecharacteristic.(ChoiceD)Osteoarthritismostoftencauseschronicpaininvolvingtheknees,hips,andhands.Acuteinflammatoryflare-upsareunusualintheabsenceofaprecipitatingfactor(eg.heavyoveruseofthejoint).(ChoiceF)Rheumatoidarthritiscauseschronicinflammatoryarthritis,mostcommonlyaffectingthemetacarpophalangealjoints.FindingsIncludestiffnessanddoughyswellingofthejoints,ratherthanacuteerythemaandeffusion.(ChoiceG)Septicarthritisischaracterizedbyacutemonoarticulararthritis,oftenwithfeverandchills.Onsetoccursoverdays(nothours,asinthispatient).Althoughoftencausedbyhematogenousseedingfromaconcurrentinfection,septicarthritisismorecommonlyduetogram-positiveorganismsratherthanthegram-negativesandanaerobesimplicatedindiverticulitis.Educationalobjective:GouttypicallypresentsasanacutemonoarticulararthritisthatquicklyprogressestomaximumIntensitywithin12-24hours.Triggersincludealcoholuse,surgery/trauma,dehydration,andcertainmedications(eg,diuretics).Q

5A68~year-oldwomanisbroughttotheclinicbyherdaughterduetoseverepaininherfingers.Herdaughtersays;"Momhashadhorribleproblemswithherjointsforalongtime,butshehasnevertriedtogethelp."Thepatientaddsthatherfingershavebecomemoreswollenandpainfuloverthelastfewweeks.Shehadsimilarsymptomsinherfootlastyear.Shewasgivenanunknownpainpill，butitwasineffective.Medicalhistoryisnotableforhypertension,hypothyroidism,andearlyAlzheimerdementia.Vitalsignsarenormal.ExaminationfindingsofthehandsareshownintheImagebelow.A.CalcinosiscutisB.ChondrosarcomaC.GoutD.OsteoarthritisE.PsoriaticarthritisF.RheumatoidnodulesA5Correctanswer:CThispatientwithmultiplewhitenodulesinthehandsandahistoryofpainfularthritisInthefingersandfeethastophaceousgout.Inmostcases,goutischaracterizedbyhyperuricemiaandprecipitationofuricacidcrystalsinthejoints,leadingtoepisodicmonoarticulararthritis(especiallyinthefirstmetatarsophalangealjointandknee).Thediagnosisisconfirmedwitharthrocentesisshowinganinflammatoryeffusionwithuricacidcrystals.Uratecrystalsmayalsodepositinthesofttissues,formingtumorsknownastophi.Tophicanulcerateanddrainachalkymaterial.Uricacidtophiarevirtuallypathognomonicforgout,andevenintheabsenceofmicroscopicconfirmationofcrystals,thediagnosiscanbemadeprovisionallyinpatientswithvisibletophiandahistoryofepisodicmonoarthritis.Anelevatedserumuricacidlevelisnonspecificbutcanalsocontributetothediagnosis.(ChoiceA)Calcinosiscutisischaracterizedbydepositionofcalciumandphosphorusintheskin.Itpresentswithscatteredwhitishpapules,plaques,ornodules.Thispatient'shistoryofpainfularthritisismoretypicalforgout.(ChoiceB)Chondrosarcomasarebonetumorsoccurringinthe5thor6thdecadeoflife.Theymostcommonlyaffectthepelvis,femur,orproximalhumerusandwouldlikelynotbeasmultifocalandbilateralasthediseasepictured.(ChoiceD)SevereosteoarthritiscanproduceHeberdenandBouchardnodes,whicharehard,bonynodulesoverthedistalandproximalinterphalangealjoints,respectively.Thispatient'stophiinvolvingseveraljointspacesandsofttissuestructuresaremoreconsistentwithgout.(ChoiceE)Psoriaticarthritiscanpresentwithdistalinterphalangealjointarthritis,asymmetricoligoarthritis,symmetricpolyarthritis,spondyloarthropathy,oraggressivelydestructivearthritismutilans.Mostpatientshaveestablishedpsoriasis,andnailchanges(eg,pitting)arecommon.(ChoiceF)Rheumatoidnodulesarefirm,flesh-colored,andnontender.Theytypicallyoccuroverpressurepointssuchastheelbowandextensorsurfaceoftheproximalulna.Educationalobjective:Inchronictophaceousgout,uratecrystalscanbedepositedintheskin,resultingintheformationoftumorswithachalkywhiteappearance.Q6A53-year-oldmancomestotheemergencydepartmentat6:00AMduetoseverepaininhisrightgreattoeforthepast3hours.Hispainbegansuddenlyasadullache:andrapidlyworsenedtoseverethrobbingthatisnotrelievedbyacetaminophen.Medicalhistoryisnotableforhypertension,type2diabetesmeilitus;andhypercholesterolemia.Thepatienthassmoked2packsofcigarettesdailyfor30years.Hedrinks2-3beersand3-4cupsofcoffeedaily,consumesfastfoodoften,anddoesnotexerciseregularly.Currentmedicationsincludemetformin,losartan,amlodipine,sitagliptin,andatorvastatin.Thepatient'stemperatureis36.8℃(98.2℉),bloodpressureis160/90mmHg,pulseis88/min,andrespirationsare16/min.Onexamination,therightgreattoeappearsmarkedlyswollen,red,andwarmtothetouch.Whichofthefollowinginterventionswouldbemostappropriatetopreventdevelopmentoffurthersimilarepisodesinthispatient?A.AlcoholcessationB.DiscontinueatorvastatinC.DiscontinuelosartanD.Low-doseprednisoneE.ModerationofcoffeeintakeF.SmokingcessationA6Correctanswer:AThispatienthassudden-onsetseverepaininthefirstmetatarsophalangealjoint(podagra)consistentwithacutegout.InitialtreatmentcanIncludenonsteroidalanti-inflammatorydrugs(eg,indomethacin),glucocorticoids,orcolchicine.Urate-loweringmedications(eg,allopurinol，febuxostat)areindicatedforpatientswithrecurrentattacksorcomplicateddisease(eg,tophi,uricacidkidneystones).Thispatientishavinghisfirstattackanddoesnotrequireurate-loweringmedication;however,hehasmultipleriskfactorsforrecurrentgout(ie,obesity,hypertension,insulinresistance)andshouldbecounseledonlifestylemodificationtoreducehisrisk.Weightlossandcaloricrestrictioncanreducetheriskofrecurrentgout.Inaddition,specificdietarychangesarealsorecommended.TheriskofattacksIsincreasedwithintakeofredmeatandseafoodbutisreducedindietsemphasizingproteinfromvegetarianandlow-fatdairysources.Riskisalsoincreasedbyheavyintakeofbeveragesandfoodscontainingfructoseandotherrefinedsugars.Heavyalcoholintake,especiallyfrombeeranddistilledspirits,isalsoassociatedwithanincreasedriskofgoutattack.Ethanolincreasesuricacidproductionandmayalsodecreaserenaleliminationofuricacid.(ChoicesBandC)Anumberofmedications,includingthiazideandloopdiuretics,aspirin,andbetablockers,canincreasetheriskofgoutyattacks.Losartanandcalciumchannelblockersloweruricacidlevelsandlikelyreducetheriskofanattack.Atorvastatinandrosuvastatinalsolowerserumuricacidslightly.(ChoiceD)Glucocorticoidsmaybeusedforacutetreatmentofgoutasweiiasshort-termpreventionofflare-upsinpatientsstartingurate-loweringtherapy.Otherwise,glucocorticoidsarenotrecommendedforroutinegoutprophylaxisandwouldberelativelycontraindicatedinpatientswithdiabetes.(ChoiceE)Higherconsumptionofcoffee(butnottea)isassociatedwithloweruricacidlevelsandadecreasedriskofgoutattack.(ChoiceF)Smokingisassociatedwithalowerriskofgoutduetodecreasedendogenousproductionofuricacid.Educationalobjective:Lifestylemodifications,includingalcoholcessationandweightloss,arerecommendedtopreventrecurrentgoutattacks.Medicationsforloweringserumurateareindicatedforpatientswithrepeatedattacksofgoutyarthritisorcomplicateddisease(eg,tophi,uricacidkidneystones).Q

7A60-year-oldmancomestotheurgentcarecenterafterbeingawakenedbyseverepaininhisrightgreattoe,whichissuddenlyswollenandverytendertothetouch.Hehasalsohadoccasionalheadachesand"unbearable"pruritusafterahotbathoverthepastseveralweeks.Thepatientdoesnotusealcohol,tobacco,orillicitdrugs.Histemperatureis36.8C(93.3F);bloodpressureis140/90mmHg;andpulseis90/min.Cardiopulmonaryexaminationisnormal.Theabdomenissoftandnontender,andthereisnoappreciableascites.Theliverspanis10cmatthemid-clavicularline,andthespleenispalpable2cmbelowthecostalmarginonfullinspiration.Hisrightgreattoeisswollenanderythematous,withseverepainonanymovement.Aspirationoftheaffectedmetatarsophalangealjointshowsnegativelybirefringentcrystalsandmanyleukocytesbutnoorganisms.Whichofthefollowingismostlikelyresponsibleforthispatient'ssymptoms?A.ChronickidneydiseaseB.HemochromatosisC.HyperparathyroidismD.InheritedenzymedeficiencyE.MyeloproliferativedisorderF.PerniciousanemiaG.PortalhypertensionA7Correctanswer:EThispatienthaspodagrafromanacuteattackofgout.Goutoccursasaresultofoverproductionorunderexcretionofuricacid.Overproductionofuricacidistypicallyrelatedtoconsumptionofahigh-uratediet,butanyconditionthatincreasescatabolismandturnoverofpurinescanraiseuricacidlevelsandtriggeragoutattack.Commoncausesincludehematologicmalignancies,tumorlysissyndrome,andpsoriasis.Myeloproliferativedisordersarecommonsecondarycausesofgout.Thispatienthasseveralclinicalfeaturessuggestingpolycythemiavera(PV),includingpruritustriggeredbyhotbaths(aquagenicpruritus),headaches,andhepatosplenomegaly.PVischaracterizedbyincreasedcellturnoverduetoclonalhyperproliferationinall3primarybonemarrowlineagesfie,redcells,whitecells,platelets).Upto40%ofpatientswithPVhavegout.AllopurinolinhibitsuricacidformationandisusedtopreventgoutattacksinpatientswithhyperuricemiaduetoPV.(ChoiceA)Chronickidneydisease(CKD)cancausegoutattacksduetodecreasedrenalexcretionofuricacid.CKDwithsignificanturemiacanalsocausepruritus,butsplenomegalyisnotseeninCKD.(ChoicesBandC)Hyperparathyroidismcauseselevatedserumcalciumconcentrations,leadingtochondrocalcinosisandcalciumpyrophosphatedihydratedepositiondisease(pseudogout).Hemochromatosisalsocausespseudogout,aswellaschronicarthritisresemblingosteoarthritis.However,pseudogoutusuallyaffectsthelargerjoints(eg.knee),andthecrystalsinpseudogoutarepositivelybirefringent(ChoiceD)Geneticdeficiencyofhypoxanthine-guaninephosphoribosyltransferase(Lesch-Nyhansyndrome)ischaracterizedbyseif-injuriousbehaviorsandneurologicdisability.ItisassociatedwithoverproductionofuricacidbutisusuallydiagnosedInchildhood.(ChoiceF)Perniciousanemiaisassociatedwithmacrocyticanemiaandneurologicabnormaiities,butnotwithinflammatoryarthritis.(ChoiceG)Portalhypertensioncancausesplenomegaly,aswellasseverepruritusduetoincreasedserumconcentrationsofbilirubin.However,portalhypertensionisnotassociatedwithgout.Educationalobjective:Goutisacommoncomplicationofmyeloproliferativedisordersduetoexcessiveturnoverofpurinesandtheresultingincreaseinuricacidproduction.Q8A52-year-oldmancomestotheemergencydepartmentwithpainandswellingofhisrightkneeforthelast24hours.Hehasnottraveledrecentlyandhasnorecenthistoryofinjuryorgastrointestinalorgenitourinaryinfection.Thepatientwasdiagnosedwithpulmonarysarcoidosis5yearsagowhenhedevelopedhilarlymphadenopathyandinterstitiallungdisease.Hissarcoidosisrespondedtotreatmentwithglucocorticoidsandwentintoremission.Hehasbeendisease-freeforthepast4years.Thepatientalsohasa10-yearhistoryoftype2diabetesmellltus,hypercholesterolemia;andhypertension..Bloodpressureis140/86mmHgandpulseis90/min,BMIis34kg/㎡.Physicalexaminationisnotableforamoderate-sizeeffusionoftherightkneewithsurroundingerythemaandwarmth.Thekneejointisaspirated.Microscopicexaminationofthefluidisshownintheimagebelow.Whichofthefollowingisthemostlikelyetiologyofthispatient'sjointeffusion?A.ImmunocomplexdepositionB.InfectionofthejointbyfungalorganismsC.infectionofthejointbyStaphylococcusaureusD.inflammatoryreactiontocalciumpyrophosphatecrystalsE.InflammatoryreactiontomonosodiumuratecrystalsA8Correctanswer:EThispatienthasacutegoutyarthritis.Goutusuallypresentswithisolatedattacksofintenselypainfulmonoarthritis,withnearly30%occurringinthemetatarsophalangealjointsorknees.Patientsalsodeveloplocalizederythemaandswelling,whichisoftenmistakenforcellulitis.Synovialfluidinacutegoutwillshowaninflammatorypattern,withacloudyappearance,elevatedleukocytecount(2,000-100,000cells/mm3),andneutrophilicpredominance.Underpolarizedmicroscopy,thesynovialfluidwillshowmonosodiumuratecrystals:NeedleshapedNegativelybirefringent(appearyellowwhenlyingparalleltothepolarizingaxis,andbluewhenlyingperpendicular)Patientsgenerallyrespondtononsteroidalanti-inflammatorydrugs(eg,indomethacin),colchicine,orcorticosteroids(systemicorintraarticular).Long-termprophylacticmedications(eg,allopurinol)areindicatedforpatientswithrecurrentattacks.(ChoiceA)Synovialimmunecomplexdepositionisseeninavarietyofautoimm