Download BOARD REVIEW SESSION 2|SUNDAY,AUGUST 26,2012

BOARDREVIEWSESSION2|SUNDAY,AUGUST26,2012
Question#13
A55‐year‐oldmalepresentedwithfeverandmalaiseoftwoweeksdurationandwasdiagnosedas
subacutebacterialendocarditisbasedonafever,anewaorticmurmurandavegetationon
echocardiographyofhisaorticvalve.Hehadnoallergies.Threebloodcultureswereallpositiveon
theautomatedbloodculturedeviceat24hoursandhadGrampositivecocciinchainsonGram
stain.SubcultureontobloodagarhadnogrowthbutchocolateagarshowedrapidgrowthofGram
positivecocciinchains.Susceptibilitytestshadnogrowth.
Whichoneoftheregimensbelowwouldyourecommend?
A. Ceftriaxonefor2weeks
B. Ceftriaxoneandgentamicinfortwoweeks
C. Penicillinfor4weeks
D. Vancomycinfor4weekswithgentamicinfortwoweeks
E. Ampicillinandgentamicinfor4‐6weeks
Correctanswer:E
Rationale:
Endocarditisonanativevalveduetonutritionallydeficientstreptococcirespondslesswellto
therapythanthemorecommonviridansstreptococci.
MostoftheGranulicatellaadiacens(formerlyAbiotrophiaadiacens)andAbiotrophiadefectiva
isolates,theusualnutritionallydeficientstreptococcalspecies,havepenicillinMIC’sbetween.0.12
and0.5mcg/ml,theintermediaterange,butsomeareashighas4‐8mcg/ml.Thoseinthe
intermediaterangemightbetreatedwith4weeksofpenicillinorceftriaxoneplus2weeksof
gentamicin.
StreptococcalendocarditiswithapenicillinMIC’sabove0.5mcg/mlhavebeenrecommendedtobe
treatedwith4‐6weeksofeitherampicillinorpenicillinwithgentamicinfortheentireperiod.
However,oneretrospectivereviewfoundfavorableresultswithabout4‐6weeksofceftriaxone2
gm/dorpenicillin20mu/dplusgentamicinfortwoweeks(CID44:1585,2007).
Vancomycinplusgentamicinisanalternativeforpatientsallergictopenicillinbutnot
recommendedforotherpatients.IntheabsenceofanMIC,theseverityofendocarditiswith
nutritionallydeficientstreptococciwouldindicatethattheregimenin“e”aboveisthemost
conservative.
Susceptibilitytestingonamediumthatwillsupportgrowthofnutritionallydeficientstreptococci
wouldassistmanagementofthiscase.Forexample,an“Etest”susceptibilitytestonchocolateagar
mightbedone.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#14
A36‐year‐oldmanwithlymphomawasadmittedandhis3rdcycleofchemotherapybegun.Within
4daysofadmission,hedevelopedpneumoniaandwastreatedwithvancomycin,ceftazidimeand
tobramycin.
SputumrevealedaheavygrowthofStaphylococcusaureus,methicillinresistant(MRSA)witha
vancomycinMICof4mcg/ml.
Theisolatewassusceptibletolinezolid,daptomycin,tigecyclineandrifampin.
GramstainofatrachealaspiratecontinuestoshowmanyGrampositivecocciinclusters.
Hisserumlevelofvancomycinis12mcg/mltrough.
Whichofthefollowingwouldyourecommend?
A. Linezolid
B. Daptomycin
C. Tigecycline
D. IncreasedoseofVancomycintoachievetroughlevelsof25‐30mcg/ml
E. AddRifampintoVancomycinatcurrentdosingregimen
Correctanswer:A
Rationale:
Continuingvancomycininthispatientisnotanoption.TheCSLIhasloweredthebreakpointsof
vancomycinforStaphylococcusaureussothatsusceptibleisdefinedasanMICof2mcg/mlorless;
intermediate(VISA)is4‐8mcg/mlandresistantis16ormore.Rationaleforthischangehasbeen
published(ClinInfectDis2007;44:1208‐1215).
Thispatient’sisolateisaVISAstrain(MIC4mcg/ml)andisunlikelytorespondwelltovancomycin
atanydose.




LinezolidhasbeenshowntobeeffectiveinMRSAinfections,includingpneumonia.The
principleconcernaboutusingthisdrugistheoccasionalsideeffectofneutropeniaor
thrombocytopenia,whichwouldcomplicatehiscytotoxicregimen.Ceftaroline,arecently
marketedcephalosporinewithactivityinMRSApneumoniamaybeanalternativebutwas
notofferedasapossibilityinthisquestion.
ClinicaltrialofdaptomycininStaphylococcalpneumoniaindicatedpoorefficacyandthe
drugisnotindicatedforstaphylococcalpneumonia.Possiblyrelatedtothisfailurearethe
poorpulmonaryparenchymallevelsofdaptomycinduetobindingbysurfactant.
TigecyclinehasactivityagainstMRSAinvitrobutthereislittledatatosupportitsusefor
MRSApneumonia.
Increasingthedoseofvancomycinsothattroughbloodlevelsexceed20mcg/mlmay
increasethepossibilityofnephrotoxicity(evidencereviewedinAntimicrobAgents
Chemother2008;52:1330‐6)butasnotedaboveisnotlikelytobehighlyeffective.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Theadditionofrifampintoantimicrobialtherapyofsusceptiblestaphylococcalinfectionsremains
controversialandmayresultinrifampinresistance,particularlywithahighorganismburden,asin
thispatient.RifampinwasnotrecommendedintherecentIDSAguidelinesforMRSAinfections
exceptforthoseinvolvingimplantedprostheses(ClinInfectDis2011;52:1‐38).
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#15
AccordingtothelatestrecommendationsfromtheAmericanHeartAssociationonthepreventionof
endocarditis,whichoneofthefollowingpersonsshouldreceiveantibioticprophylaxisatthetime
ofadentalextraction?
A. A46‐year‐oldwithahistoryofrheumaticfeveratagefive
B. A27‐year‐oldwithmitralvalveprolapseandamitralregurgitantmurmur
C. A31‐year‐oldwhohadsuccessfulrepairofaVSDatagesix
D. A56‐year‐oldwhoisdoingwellthreemonthsaftercardiactransplantation
E. 37‐year‐oldinjectiondruguserwithahistoryofpreviousendocarditis
Correctanswer:E
Rationale:
In 2007, the American Heart Association revised their published guidelines for prevention of endocarditis
(previous iteration 1997). IE is felt to be more likely from frequent, random bacteremias associated with
daily activities than from bacteremias caused by dental, GI or GU procedures. There is a growing body of
evidence that prophylaxis for such procedures may prevent an exceedingly small number of cases, and the
risk of antibiotic-associated adverse events may exceed any benefit.
Recommendations in the most recent guidelines were based on evidence-based published data rather than
expert opinion as in the past.
Antimicrobial prophylaxis was recommended only for those with cardiac conditions associated with the
highest risk of adverse outcome from IE namely:




Prosthetic cardiac valve
Previous infectious endocarditis
Congenital heart disease (only those listed here)- a) unrepaired cyanotic CHD, including
palliative shunts and conduits. b) completely repaired CHD with prosthetic material or device,
whether placed by surgery or by catheter, during the first 6 months after the procedure. c)
repaired CHD with residual defects at or adjacent to prosthetic patch or device.
Cardiac transplantation recipients who develop valvulopathy.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#16
Thecountyhealthdepartmenthassoughtyouradviceaboutwhethertopurchasethenew
meningococcalprotein‐polysaccharidevaccine,Menactra,consideringthatthecostperdoseisso
high($80)thatthemoneywillhavetocomefromcutsinotherservices.
Youradviceiswhichofthefollowing:
A. TherearesafetyconcernsaboutthisvaccineincreasingtheincidenceofGuillain‐Barre
Syndromeand,untilresolved,makepurchaseofthisvaccinenotadvisable.
B. Thevaccineisrecommendedonlyfortravelerstoareasofhighdiseaseprevalence,suchas
sub‐SaharanAfricaandthusthecountryhasnopressingneedforthispurchasesince
travelerscangototravelclinics.
C. Thevaccine’smajorroleistoreducetypeBinfectionsthatoccurincrowdedconditions
suchascollegedormsandmilitarycampsandthusisnotneededforindividualslivingin
normalhouseholdsettings.
D. Asmallstockcouldbepurchasedforuseaspostexposureprophylaxisifanoutbreakoccurs
inalocalschoolbutthereisnootherreasontoadministerthisvaccine.
E. Previouslyunimmunizedadolescentsshouldbegiventhisvaccineandthusthecountry
shouldpurchasethisvaccine.
Correctanswer:E
Rationale:
EisthecorrectanswerforthisquadrivalentvaccinethatiseffectiveagainststrainsAandCand
YandW135:CandYareresponsibleformuchofthemeningococcaldiseaseeintheUS.Itistrue
thatthevaccinedoesnotprovideprotectionagainstserogroupB,whichaccountsforasubstantial
fractionofdiseaseintheUSincrowdedsituationssuchasdormsandbarracks,butthatisnota
reasontoavoidthevaccine.
Therearenomajorsafetyconcernswiththisvaccine,althoughit’sprudenttoavoidinpatientswith
ahistoryofGuillainBarresyndromes.
TheACIPhasrecommendedthisvaccineforallpreviouslyunimmunizedadolescentsage11or
older,forcollegefreshmenwhobelivinginadormitoryandforchildren2to11yearsofagewho
maybeatincreasedriskofmeningococcaldisease,forexample,becauseoftravelorasplenia.
Adolescentsvaccinatedatage11to12shouldreceiveaboosterdoseatage16,priortotheageof
greatestrisk,whichis16to21yearsofage.TheFDAhasalsoapprovedMenactraforchildrenas
youngas9monthsofage.AcombinationvaccinewithmeningococcalpolysaccharidesserotypesC
andYaswellasHaemophilusinfluenzaeb,allconjugatedtotetanustoxoid,wasapprovedbythe
FDAinJune,2012forchildrenages6weeksto18months.TheACIPhasnotyetactedonthese
vaccinesforinfantsasofthiswriting
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#17
A42‐year‐oldfirstgradeteacherhashadacoughforamonth.Herillnessstartedasfeverand
rhinorrhea.Afteraweekhercoughbecameworse.Sheisnowafebrileandfeelswellbetween
episodesofcoughing,whichoccureveryhourortwo.
Ifthisteacherhaspertussis,whichofthefollowingistrue?
A. Thiscouldnotbepertussisifthisteacherreceivedhernormalchildhoodimmunizations
andaboosterwithacellularpertussisvaccineatage19.
B. Iftherewereconfirmedtobepertussis,theteachershouldreceiveantibiotictherapyto
reducethedurationofhercoughing.
C. AtthisstageofillnessathroatculturewouldlikelybenegativeforB.pertussisevenifthe
labhadthespecializedmediaforthisorganism.
D. Thepatient’shusbandneedsprophylaxisifthisweredocumentedtobepertussis.
E. Thechildreninthepatient’sclassneedchemoprophylaxis.
Correctanswer:C
Rationale:
PertussisisincreasinglycommoninadultsandadolescentsintheUnitedStates.Immunization
amongchildrenisnotuniversallyeffective:70‐85%isthequotedefficacyrate.Moreover,immunity
wanesandthusthisteacher,ifexposedtopertussis,coulddevelopdisease.ThusAisincorrect.
Antimicrobialtherapyisusefulinreducingsymptomsprimarilyduringthecatarrhalphasebut
wouldbeunlikelytoreducethedurationofparoxysmalcoughing.ThusBiswrong.
DiagnosisishardtoestablishbutisbestdonebyPCRonnasopharyngealswabsinchildrenornasal
washesinadults.Falsepositivescanoccurifmethodologyisnotcarefullyselected.
MosthospitalsandclinicsdonotstocktheculturemediumnecessarytogrowBordetellapertussis
(Bordet‐GengouorRegan‐Lowemedium).Evenifyoualertedthelabtothepossibilityofpertussis,
acultureisunlikelytobepositiveintheparoxysmalphase(it’smorelikelyduringtheinitial1‐2
weeksofthecatarrhalphase).
Patientscantransmittheorganismforseveralweeksandthusthisteachermayhavebeen
transmittingorganismsforthepastmonth.Prophylaxisshouldbegiventoclosecontactswithin21
daysofexposure.Thereislittlebenefitforprophylaxisofthisteacher’scontactsbecauseshehas
beenillformorethan21days,alreadyhavingexposedhersusceptiblecontactsandhercontacts
arenotstatedtobehighriskpersons,suchasinfantsorpregnantwomen.
Additionally,inmostschooldistrictsallfirstgraderswouldhavebeenrequiredtobefully
immunizedwithacellularpertussisvaccine.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Reportingthisexposuretothelocalhealthdepartmentwouldprovideagoodreasonforreviewing
theimmunizationstatusofherstudentsandlookingforsecondarycases.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#18
A71‐year‐oldman,witha30‐pack/yearhistoryofcigarettesmokingandachroniccough,comesto
seeyouaspartofhisannualphysicalexam.Yourecommendaninfluenzavaccination,whichhe
refuses,statingthathehasaneggallergyandthathiswifeisonhighdosesteroids.Hehastwo
boiledeggsforbreakfasteachday.
Whichofthefollowingwouldyouadvisewithregardtoinfluenzaimmunization?
A. Offertheinactivatedvaccinedespitehisconcerns
B. Offertheinactivatedvaccineonlyifeggallergyskintestingisnegative
C. Offertheinactivatedvaccinewithcarefuldesensitizationprotocol
D. Offernasalmistinfluenzavaccinebecausethishasnoeggcontent
E. Offerzanamivirprophylaxisduringinfluenzaseason
Correctanswer:A
Rationale:
Fluvaccineisimportantforthispatientbecauseofhisageandhistoryofrespiratorydisease.
Systemicreactionsoflow‐gradefeverarewellworththebenefittothispatient.Thevaccineissafe
foranyonewhocaneateggsandthusthispatientdoesnotneedskintesting,ieanswerAiscorrect.
Boththeinactivatedandtheliveviruspreparationaremadefromeggs.
Forpatientswithahistoryofeggallergywhocannoteateggs,orforthosethathaveahistoryofa
positiveskintest,variousrecommendationshavebeenmadeforusingloweggcontent
preparationsinescalatingdosesforadesensitizationprocess,butthisisnottestable.Zanamivircan
exacerbaterespiratoryobstructivesymptomsinpatientswithchronicbronchitisorasthmaandbe
poorlytolerated.Thusthisisapoorchoice.
FluMistisnotindicatedforhealthypatients2‐49yearsold.Itisnotindicatedforthoseolderthan
49years.InarandomizedtrialcomparingFluMisttoTIVinadults,theefficacyofTIVwas75%
againstcultureorPCRconfirmedinfectioncomparedto48%forFluMIstalthoughthisdifference
wasnotstatisticallysignificant.Thefactthatthepatient'swifeisonsteroidsisnota
contraindication.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#19
Anursecomestoyoubecausehewouldprefertogettheseasonalinfluenzalivevirusvaccine
ratherthanthekilledvaccine.Heworksinacancerhospitalonthestemcelltransplantunit.
Whichofthefollowingwouldyouadviceregardingtheliveseasonalinfluenzavaccine:
A. Thereisnoriskoftransmissionofthisattenuatedvirus,andthushecanbevaccinatedand
continueworking.
B. Thereisariskoftransmission,butattenuatedviruscannotcausehumandiseasein
immunocompetentorimmunosuppressedpatientsandthushecancontinueworking.
C. Thereisasmallriskoftransmissioncausingdiseaseinimmunosuppressedpatientsthatis
verytransient:hecanbevaccinatedandresumeworkingaftera48‐hourperiodifheis
asymptomatic.
D. Thereisasmallriskoftransmissionandcausingdiseaseinimmunosuppressedpatients
thatisverytransient:hecanbevaccinatedbutshouldavoidpatientcontactfor7days.
Correctanswer:D
Rationale:
StudiesofLAIVrecipientshavedemonstratedthattheymayshedvaccinevirusforseveraldays.In
rareinstances,transmissionofvaccinevirustounvaccinatedpersonshasbeendemonstrated.Mild
symptomshavebeenobserved,however,seriousillnesshasnotbeenreportedamongunvaccinated
personswhohavebeeninadvertentlyinfected.LAIVvirusesarealsocold‐adapted(andcannot
effectivelyreplicateatnormalbodytemperature)andattenuated,andthereforewouldnotbe
expectedtobemoreinvasiveinpersonswithcompromisedimmunesystems.Thustheriskof
severediseaseinanimmunocompromisedpersonappearstobeextremelylow.
Dataarelimitedhowever.ThecurrentACIP/HICPACguidelinesrecommendthatHCWwhocarefor
severelyimmunocompromisedpatientsrequiringaprotectiveenvironment(generallypatients
withbonemarrowofHSCtransplants)shouldnotcareforthesepatientsfor7daysafterreceiving
LAIV.Heshouldbereassigned.
ACIPmakesitclearthatheneednotberestrictedfromcaringforotherpatientswithlesserdegrees
ofimmunosuppressionsuchasHIV,cancerchemotherapy,steroiduseorfromworkingina
neonatalintensivecareunit.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#20
A22‐year‐oldhikerpresentswitha3‐dayhistoryofincreasingshortnessofbreath.
Thepatientwasinexcellenthealthuntil3dayspriortoadmission,whenhenotedtheonsetofa
dry,hackingcough,malaise,severedyspneaandmyalgias.
Attheemergencyroom,histemperaturewas39.2°,heartratewas110,andregular;respirations
were28andshallow;bloodpressurewas110/70.Hisphysicalexamshoweddiffuseralesatthe
posteriorchest,butwasotherwiseunremarkable.Hematocritwas52;WBCwas9,800;urinalysis
wasunremarkable.HisX‐rayshowedadiffuseinterstitialandalveolarpattern,consistentwithan
acuterespiratorydistresssyndrome.
ThepatienthadjustreturnedfromahikingtripontheAppalachianTrailandhadbeencampingout
inawoodcabinwherehesawnumerousmice.Hehadconsiderableexposuretomousefeces.
Becauseofincreasingrespiratorydistress,thepatientwasintubated.Overthenext24‐48hours,
thepatientproducedscantyrespiratorysecretions,andmultipleculturesofsecretionsobtained
throughtheendotrachealtubewerenegativeinbacterial,viral,andfungalcultures.Thepatient
thenbegantoproducecopiouswateryrespiratorysecretions,consistentwithpulmonaryedema
fluid.
Despiteaggressivesupportivemeasures,thepatientexpired.
Whichofthefollowingisthemostlikelyetiologicagentofthisillness?
A.
B.
C.
D.
E.
Legionella
SinNombrevirus
Influenza
RSV
Bacilusanthracis
Correctanswer:B
Rationale:
Thispatienthasacompatiblehistorywiththehantaviruspulmonarysyndrome,duetoSinNombre
andrelatedviruses,involvingexposureinaclosedspace(cabin)thatwaspotentiallycontaminated
byrodentsandtheirurine.
MorecaseshavebeenreportedintheSouthwestthantheEast,butit’susefultoknowthishasbeen
reportedinVirginia.Rodentexposureisimportanttothetransmissiontohumanforallhantavirus
pulmonarysyndromes(inNorthAmericaSinNombreisthemostcommon,butnottheonlysuch
virus)Fortheboards,considerahantaviruspulmonarysyndromeifthereispneumoniaandrodent
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
exposure.DonotconfusethiswithvirusesfoundoutsidetheUnitedStatesthatcausehemorrhagic
feverratherthanpneumonia,i.e.Hantaanvirus.
Pneumoniaduetoplagueortularemiadoesnotpresentwitharespiratorydistresssyndrome,such
asthispatient,butasaseveresystemicfebrileillness.
Viralinfluenzawouldneedtobeexcludedbycultureofrespiratorysecretionsbutpresenceof
copiousrespiratorysecretionsisunusual.RSVpneumoniainanimmunologicallynormaladulthost
wouldbeextremelyunlikely.
Thereisnohistoryofexposuretodustfrominfectedcarcassesorhidesfromanimalswithanthrax.
Ofnote,thereisnoevidencethatanyspecifictherapyiseffectiveforSinNombre:ribavirinhas
demonstratednoefficacy.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#21
A22‐year‐oldmedicalstudentisseenforfeverofonedayduration.Hejustreturnedfromahiking
vacationinNevadaandNewMexico.Whiletherehedrankwaterfromlocalstreamsandwasbitten
bynumerousmosquitoes,deerfliesandticks.Hecuthisvacationshortbecausehebecameill.
Sixdaysbeforereturninghomehehadtheacuteonsetoffever,chills,headache,photophobia,and
myalgias.
Thedayheflewhome,afterthreedaysoffever,hefeltquitewell.
Hewasalsowellandafebrilethefollowingday,butafterthosetwodayswithoutfever,heagain
developedfeverandtheothersymptoms.
Onexamhewasfebrilewithamildtachycardia;thespleentipwaspalpable.Therewasnorash,and
therestoftheexamwasnormal.HisWBCcountwas1200with55%lymphocytes;plateletcount
was90,000.
Whichoneofthefollowingisthemostlikelydiagnosis?
A. ColoradoTickFever
B. RockyMountainSpottedFever
C. DengueFever
D. WestNileVirus
E. Leptospirosis
Correctanswer:A
Rationale:
Thispatienthasasaddlebackfeverillnesswithleukopeniaandthrombocytopenia,allcharacteristic
ofColoradoTickfever,aticktransmittedviralillness.Fevertypicallylasts2‐3days,then,after1‐3
dayswithoutfever,itrecursin50%.Splenomegalymaybeseen.
ThepatientcouldhaveRockyMountainSpottedFeverbutthepatientdoesnothaveasevereillness
andRMSFisnotbiphasic.
Dengueisnotendemicintheareasthispatienttraveled.
WestNileVirusdoesnotcausearelapsingfeverillness.
Leptospirosismaybeassociatedwithexposuretoriverwaterandmaycauseabiphasicillness,but
leukopeniaandthrombocytopeniaarequiterare.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#22
A46‐year‐oldmalewhowasworkinginEuropewenthikingandfishinginAustriaandSweden.
Severaldaysafterhishikingtrip,hehadfeverandnauseafortwodays,butthatresolvedwithout
therapyandhethenreturnedtotheUnitedStates.Now,twoweeksafterthatfebrileepisode,he
wasadmittedtoahospitalinConnecticutwithfeverandsevereheadachebutnoothercomplaints.
Hisphysicalexaminationwasnormalexceptfordiminisheddeeptendonreflexes.
Laboratorystudies:
CBC,Chemistryprofile:normalexceptforawbc=15000/mm3
LumbarPuncture:wbc20cells(100%lymphocytes),protein50mg/dl;glucose70mg.
MRI:normal
Hewastreatedwithceftriaxoneanddoxycyclinefor14daysandrecoveredcompletely.
Whatinterventionbeforehishikingtripwouldhavebeenmosteffectiveinpreventingthisillness
thatheexperienced,assumingthatheacquiredthisbiphasicillnessinEurope?
A.
B.
C.
D.
E.
Doxycyclineprophylaxis
Rabiesimmunization
Influenzaimmunization
Tickborneencephalitisimmunization
Rifampinprophylaxis
Correctanswer:D
Rationale:
ThisbiphasicillnessisaclassiccaseoftickborneencephalitiswhichoccursinWesternandEastern
Europe.Therearedifferenttypesoftick‐borneflavivirusmeningitisandencephalitisinother
geographicareas(dividedintoEuropean,FarEastern,andSiberian).Typicallypatientswith
EuropeanTBEhavefeverduringtheviremicstage,recover,andthenseveraldayslaterdevelopa
moresevereneuroinvasivesyndromecharacterizedbyencephalitis,meningitis,ormyelitis.Fatality
rateandrateofneurologicsequelaevaryaccordingtothevirusstraininvolved.
ThereisaneffectivevaccineforEuropeantick‐borneencephalitisthatislicensedinEurope,butnot
intheUnitedStates.Mostshort‐termtravelershavenoneedforthisunlesstheyareplanningon
somehighriskactivity.ThevaccineavailableforEuropeanTickborneencephalitisisnot
necessarilyactiveagainstothertickborneencephalitides.Keepinmindthatthistickborne
encephalitisisNOTthesameasJapaneseBencephalitiswhichistransmittedbyamosquito,nota
tick,andhasaneffectivevaccinethatisavailableintheUnitedStates.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Doxycyclinecouldhavepreventedleptospirosis,butleptospirosisisnotthebestanswerhere.
AsepticmeningitiscouldbeduetoleptospirosiswhichthispatientcouldhaveacquiredinSweden:
theincubationperiodhereislong(typicallyleptospirosishasanincubationperiodof10days)but
canbeaslongas28days.However,abiphasicillnessisnottypicalofleptospirosis,andthispatient
lackedtheacuteonset,myalgias,thrombocytopenia,orLFTorrenalabnormalitiestomakethisa
likelydiagnosis.
Thisisunlikelytoberabiessincethepatientrecovered.
Influenzacanrarelycauseencephalitisorasepticmeningitis,buttheincubationperiodistoolong
sincethequestionaskedaboutdiseasesacquiredinEurope:theincubationperiodofinfluenzais
typically1‐2days.
Rifampinprophylaxismighthavereducedthelikelihoodofmeningococcalmeningitis,butthe
clinicalcourseandCSFmakethisanunlikelycauseofthissyndrome.
DiseasesoftravelersareeasytotestforandthiscaseisderivedfromMMWR2010,soit’s
somethingyoumightbeexpectedtoknow.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#23
InAugust,a40‐year‐oldmalefromruralSouthEastVirginiadevelopedfever,headaches,myalgias,
andarthralgias.Multipleescharsonhislowerextremitiesantedatedthefeverby2days.Hedenied
travel,tickbites,orexposuretomice.Hehadseveraldogsandcats.Overthenext12hours,he
developedanerythematousmaculopapularrashonhistrunkthatspreadtohisextremities.
Treatmentwithcephalexindidnotimprovehissymptoms.
WBC3300;Platelets149,000;Hgb13.5;LDH1502U/L;Bilirubin2.4mg/dL;ALT195U/L
Whichofthefollowingisthemostlikelyagentcausingthisinfection?
A. Babesiamicroti
B. Borreliaburgdoferi
C. Scrubtyphus(Orientiatsutsugamushi)
D. Murinetyphus(Rickettsiatyphi)
E. Rickettsiaparkeri
Correctanswer:E
Rationale:
Thispatientcouldhaveawidevarietyofinfections,butinthisquestionweneedtofindthebest
answer.
AdiffusemaculopapularrashwouldbeunusualforbabesiosisorLymedisease,andVirginiawould
notbeacommonlocaleforbabesiosis.
Scrubtyphus(Orientalistsutsugamushi)doesnotoccurintheUnitedStates:thisoccursinAsia
includingChinaandIndiaandJapan,inthePacific.R.conori,R.africaeandO.tsutsugamushiare
associatedwitheschars;however,R.typhiisworldwide.Theorganismisspreadwhenfleafecesare
rubbedintoskinwounds.Thisisamildillness,seendomesticallymostlyinthesouthwestUnited
States.Thus,thispatientisnotgeographicallytypical.
ThiscasecouldbeRtyphiexceptthegeographyisatypical,andprominentescharsshouldpoint
youtoR.parkeriifthecasewasacquiredintheUnitedStates.
Rickettsiaparkeri(ticksandrodents)isarecentlyrecognizedcauseofhumanillnessintheUnited
States.ThisspottedfeverrickettsiaistransmittedbytheGulfCoasttick(Amblyommamaculatum).
ItistheorizedthatsomecasesofR.parkeriinfectionhavebeenmisidentifiedasRMSF.The
presenceofaneschar,andoftenmorethanone,maybeadistinguishingfeaturefromRMSF.
2012BoardPrepBook|©2012InfectiousDiseaseBoardReview
Question#24
A35‐year‐oldmaleagriculturalspecialistvisitedZimbabwefor3weekstoassessfarm
productivity.OnedayafterhisreturntotheUnitedStates,hedevelopedfever,headache,diffuse
myalgiesandjointpainsinhishands,elbows,shoulders,knees,andfeet.Hehadamacular
nonpruriticrashonhisfaceandneckthatfadedoverseveraldays.Hisfingersandwristswere
swollenbutnoterythematous.Hiswristsweresosorehecouldnotusehiscomputerorcarryhis
briefcase.
Hestayedhomefromworkfor4daysuntilhisfeverabatedwithouttherapy,buthisjointpains
persist3weekslater,andheconsultsyou.
HerelatesthathetookmefloquineweeklyduringhisstayinIndiabutstoppeditwhenthefever
andrashbegan.Onhisexamheisnotfebrileandhehasnorash,jointfindings,orother
abnormalitiesyoucandetect.
Laboratory:
CBCandbloodchemistriesarenormal.
Malariasmearispending.
Themostlikelycauseofthisman’sillnesswaswhichofthefollowing:
A.
B.
C.
D.
E.
Nipahvirus
HepatitisA
Chikungunya
Mefloquinehypersensitivity
Dengue
Correctanswer:C
Rationale:
Arthritisorarthralgiasthatpersistforweeksormonthsafterafebrileillnessshouldmakeyou
suspectChikungunyaoroneofseveralotheralphaviruses.ThisvirusistransmittedbytheAedes
mosquito(severalspecies)andhasbeenreportedintravelersfromIndia,islandsintheIndian
Ocean(e.g.Reunion)andSubsaharanAfrica(e.g.Zimbabwe),includingtravelersreturningtoItaly
andtheUnitedStates.
DiagnosisismadebysendingserumtoCDCforIgMElisaandPCR.Thereisnospecifictherapy.
Anophelesmosquitostransmitmalaria,filariaanddirofilaria,butthesediseasesdonotfitthe
symptomsofthispatient.
NipahvirushasbeenseeninAsia(includingIndiaandMalaysiaasacauseofencephalitisin
individualshavingclosecontactwithpigs.
HepatitisAisnotlikelyinapatientwhohasnormalliverfunctiontests3weeksaftertheonsetof
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symptoms,althoughhepatitisAorBcanbeassociatedwitharthralgias.
Mefloquinecancauseneuropsychiatricsymptomsbutnotarthralgias
Dengueisamosquitoborneillness(severalspeciesofAedes)withheadache,highfever,rashand
myalgias,butpersistentarthralgiasorarthritiswouldnotbetypical.
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