question 1 (18 marks) - litfl · § lp → 90% < 10 cells/ml, mainly t lymphocytes, ↑ igg,...

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UNIVERSITY HOSPITAL, GEELONG FELLOWSHIP WRITTEN EXAMINATION WEEK 15– TRIAL SHORT ANSWER QUESTIONS Suggested answers PLEASE LET TOM KNOW OF ANY ERRORS/ OTHER OPTIONS FOR ANSWERS Please do not simply change this document - it is not the master copy ! Question 1 (18 marks) a. Complete the table to distinguish between the clinical features of Guillain-Barré Syndrome and Multiple Sclerosis. (4 marks) History Guillain-Barré Syndrome Multiple sclerosis Age at onset Typical onset : 20-40 yr old Onset Insidious Post infection/ Sx/ Immunisation/ malignancy Episodic, relapsing, remitting Distribution Ascending motor paralysis Glove & stocking loss Random, eyes often 1 st Limb pain Passive movement/ calf pain common Electric shock sensations in legs, worse with neck flexion Visual disturbance Opthalmoplegia rare Optic neuritis Painful eye movements VA/ field defects Cerebral Fx Intellectual demise Seizures Natural course > 90% recovery Stabilise & improve Progressive Sex Female : male 2:1 b. Complete the table to distinguish between the examination features of Guillain-Barré Syndrome and Multiple Sclerosis. (4 marks) Examination Guillain-Barré Syndrome Multiple sclerosis CN 50% facial n or bulbar Common, esp eyes ION, RAPD Cerebellar signs Rare May be present Gait weakness Spastic Tone ↑ , clonus Reflexes ↓ / flaccid (LMN) ↑ (UMN) Autonomic Common Rare- sensory - Bladder dysfunction Respiratory compromise ↓ FEV1 Respiratory support may be required Rare c. List the two (2) investigations of choice to assist with the diagnosis of Multiple Sclerosis. State two (2) diagnostic findings that are supportive of Multiple Sclerosis for each investigation. (6 marks) Investigation of choice 1: CSF examination Supportive findings: (90%) < 10 cells/ml- T lymphocyte predominance Normal protein Iggy (↑ in 80%) o Oligoclonal bands (85-90% of clinical MS) Investigation of choice 2: MRI Brain Supportive findings: Subcortical and periventricular plaques (50%) Enhancement indicates activity/ resolves with remission d. Assuming the diagnosis of Guillain-Barré Syndrome, which drug must not be given if intubation is required? (2 marks) Sux Precipitation of life threatening hyperkalaemia (absolutely contraindicated in patients with GBS. There have been a number of case reports of severe hyperkalaemia, life threatening arrhythmias, and cardiac arrest after its administration in GBS) e. List the two (2) options for treatment of Guillain-Barré Syndrome. (2 marks) IV Immunoglobulin Plasmaphoresis (usually not both together, it’s an either/ or) “List” = 1-3 words “State”= short statement/ phrase/ clause

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Page 1: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

UNIVERSITYHOSPITAL,GEELONGFELLOWSHIPWRITTENEXAMINATION

WEEK15–TRIALSHORTANSWERQUESTIONSSuggestedanswersPLEASELETTOMKNOWOFANYERRORS/OTHEROPTIONSFORANSWERSPleasedonotsimplychangethisdocument-itisnotthemastercopy!

Question1(18marks)

a. CompletethetabletodistinguishbetweentheclinicalfeaturesofGuillain-BarréSyndromeandMultipleSclerosis.(4marks)

History Guillain-BarréSyndrome MultiplesclerosisAgeatonset Typicalonset:20-40yroldOnset Insidious

Postinfection/Sx/Immunisation/malignancyEpisodic,relapsing,remitting

Distribution AscendingmotorparalysisGlove&stockingloss

Random,eyesoften1st

Limbpain Passivemovement/calfpaincommon Electricshocksensationsinlegs,worsewithneckflexion

Visualdisturbance Opthalmoplegiarare OpticneuritisPainfuleyemovementsVA/fielddefects

CerebralFx IntellectualdemiseSeizures

Naturalcourse >90%recovery Stabilise&improveProgressive

Sex Female:male2:1b. CompletethetabletodistinguishbetweentheexaminationfeaturesofGuillain-BarréSyndromeandMultiple

Sclerosis.(4marks)Examination Guillain-BarréSyndrome Multiplesclerosis

CN 50%facialnorbulbar Common,espeyesION,RAPDCerebellarsigns Rare MaybepresentGait weakness SpasticTone ↓ ↑,clonusReflexes ↓/flaccid(LMN) ↑(UMN)Autonomic Common Rare-sensory-BladderdysfunctionRespiratorycompromise ↓FEV1

RespiratorysupportmayberequiredRare

c. Listthetwo(2)investigationsofchoicetoassistwiththediagnosisofMultipleSclerosis.Statetwo(2)diagnostic

findingsthataresupportiveofMultipleSclerosisforeachinvestigation.(6marks)Investigationofchoice1: CSFexaminationSupportivefindings:

• (90%)<10cells/ml-Tlymphocytepredominance• Normalprotein• Iggy(↑in80%)

o Oligoclonalbands(85-90%ofclinicalMS)Investigationofchoice2: MRIBrainSupportivefindings:

• Subcorticalandperiventricularplaques(50%)• Enhancementindicatesactivity/resolveswithremission

d. AssumingthediagnosisofGuillain-BarréSyndrome,whichdrugmustnotbegivenifintubationisrequired?(2

marks)• Sux • Precipitationoflifethreateninghyperkalaemia(absolutelycontraindicatedinpatientswithGBS.There

havebeenanumberofcasereportsofseverehyperkalaemia,lifethreateningarrhythmias,andcardiacarrestafteritsadministrationinGBS)

e. Listthetwo(2)optionsfortreatmentofGuillain-BarréSyndrome.(2marks)• IVImmunoglobulin• Plasmaphoresis(usuallynotbothtogether,it’saneither/or)

“List”=1-3words“State”=shortstatement/phrase/clause

Page 2: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

GuillainBarreSyndrome§ Commonestcauseofrapidonsetparalysisinpreviouslyhealthyperson.§ Bothsexes.Allages§ Acutepolyneuropathy1-4weekspost:

§ 70%postviralURTI/gastro§ Postoperative§ Postimmunisation§ Intercurrentmalignancy

§ Pathology→neuronitiswithmyelindestructionand∴Walleriandegenerationofneurones

ClinicalfeaturesSensory§ Initialparaesthesiainhandsandfeet→minorgloveandstockingloss(sensoryneuropathyisusuallyminimal)§ Posteriorcolumnvibration/proprioception>spinothalamicMotor§ Progressiveascendingmotorweaknessaffecting>1limb→distalmmweaknesswithoutatrophy(25%prox>distal)§ Areflexia/markedhyporeflexia§ Limbpainonpassivemovement/calfpain§ CNin~50%→usuallyfacialnnorbulbar(allexceptI,II,VIII,extraocularmmrarelyinvolved) -MillerFischervarianthaspredominantCNinvolvementOther§ Nofever/neckstiffness,normalmentalstate§ Autonomicdysfunction -Badprognosticindicator -Verysensitivetocardiacdrugs→mayarrestonintubation -Ileus,retention,assoc.SIADH

Investigations Dx -CSFprotein↑in90% >0.4g/l -CSFcountnormal

-FET→monitorprogress Tx -ABG -RFT -Excludeothercauses

Management§ CVS,Respsupport§ SUXAMETHONIUMASSOCIATEDWITHSUDDENDEATH§ Nutrition→enteral,parenteral§ Plasmaphoresis -Superiortosupportivealone -Bestifcommenced<7daysafteronset -↑speedofrecovery -Nochangetoultimatemortality§ ImmunoglobulinRx -ProbablyasusefulasplamaphoresisPrognosis§ Good→mostfullrecovery§ Worseprognosisif: -autonomicinvolvement

-deficitnot↓in3/52§ 2%mortality→resp.failure§ 10%majorresidualdeficitDDxofacuteascendingmotorparalysis§ Rhabdomyolysis§ Tick/snakebite§ Diphtheria/polio/botulism§ PANDDXautonomicneuropathy

§ DM§ ETOH§ Amyloid

Page 3: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Multiplesclerosis§ Commonestchronicneurologicalcondition§ Onset30-40’s,60%F§ 20%asymptomaticthroughlife§ HigherincidenceinTas,lowerasgonorthinAus§ Pathology→ Extensivewhitematterplaques,lossofoligodendrocytes,axonalsparing Conductiondisturbedbyfever,stress,electrolyteimbalance(lossofsuppressorTcellsb4attacks)

Clinicalfeatures

§ Episodicattacksoffocalneurologicaldeficit→sensory,motororsphincter§ Predilectionforspinalcord,brain,opticnerves§ Over2-14/7thenremission§ ~½presentassinglesignorsymptom§ Common→limbweakness,opticneuritis(painwiteyemovements,↓VA),sensorysymptoms,diplopia

1. Spinalcord→ commonestmanifestation§ limbweaknessin40%,UMNsigns(spasticgait,↑tone,clonus,↑reflexes),postcolumnloss§ painfulspasms§ bladderdysfunction,constipation§ Lhermittessign→painfulelectricshocksdownlegs↑byneckflexion

2. Opticneuritis→40%atsomestage,presentingsymptomin20%Significantpainwitheyemovementispresentinnearlyeverycaseofdemyelinatingopticneuropathy

§ VAoverdays,centralscotoma,usuallyunilateral§ disturbedcolourperceptionearlysign§ visualfielddefects§ painoneyemovement§ Ex:50%papillitisonfundoscopy,relativeafferentpupilliarydefect§ 40%goontoMS§ 1/3completelyrecover,partially,notatall§ Uhthoff’sphenomenon→↓visiondtexercise,hotmeal/bath

3. Brainstem→ common§ Diplopia,III,IV,VICNlesions§ InternuclearopthalmoplegiaalmostDxofMSorSLE AbnoofMLF→ipsilateraladductioninability,contralaterallat.gazenystagmus§ Bell’spalsy§ Vestibularneuronitis→vertigo,vomiting,nystagmus§ Cerebellarsigns

4. Cerebral→ Intellectualdemise§ Depression§ Seizures~5%§ Rare→dysphasia,hemiparesis,homonymoushemianopia

Diagnosis§ Involvementofdifferentpartsofnervoussystem,2separateoccasions,lasting>24/24orslowprogressionover6/12§ Requires2anatomicallyseparatelesions§ Delayedvisual/auditory/somatosensoryevokedpotentials§ LP→ 90%<10cells/ml,mainlyTlymphocytes,↑IgG,proteinnormal§ MRI→detectsdemyelinatedareas,subcorticalandperiventricularplaquesvisualisedin50% Enhancementindicatesactivityofdisease

DDxEye Retinala/vocclusion Opticnerveglioma MethanolingestionSCdisease Cxspondylosis Subacutedegeneration

Hereditaryataxias SCcompressionCerbral HIV

PosteriorfossaSOL SLE Sarcoid

Mx

§ Acute→highdosemethylpred,ACTH80U,PNL§ Preventrelapses→Azathioprine,cylophosphamide,interferon,plasmaphoresis§ Symptomatic→baclofenforspasms,carbamazepineforpain,urinarycatheter,boweltraining

Page 4: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Opticneuritis

§ Mono-ocularvisionchanges,especiallyinayoungfemaleshouldpromptyoutothinkingaboutthiscondition.§ Opticneuritis(decreasedvisualacuity,relativeafferentpupillaryafferentdefect)caneasilybemistakenforpapilledema

(visualacuityandpupillaryreflexesarenormal)§ Makingthediagnosiscanbedifficultinthatthemajorityofpatientsmayactuallyhaveanormalfundoscopicexambutgivea

classichistoryfor"retrobulbarneuritis"(visionchangesandpainespeciallywitheyemovement).§ Theclinicalpresentationofdemyelinatingopticneuropathyvaries.§ PatientsfrequentlypresenttotheEDwithanacutelossofvision.§ ThenaturalhistoryofMS-relatedvisionlossisrapidlyprogressiveacuitylossforaperiodof10days,whichthen

stabilisesandimproves.§ Additionalocularsignsincludeeyepain,tendernessoftheglobe,dyschromatopsia,decreasedbrightnesssense,decreased

colourperception,arelativeafferentpupillarydefect,assortedvisualfielddefects(altitudinalandcentral/cecocentral),phosphenesuponeyemovementandopticdiscswellingwithorwithoutvitreouscells.Often,theopticnerveisnormalinappearanceandthedysfunctionisconsideredretrobulbar.

§ Demyelinatingopticneuropathycandamagethefibersinboththevisualandpupillarypathways.Thisdamageinterruptsnerveimpulseswithinthepathways,producingdecreasedvisionaswellasanafferentpupillarydefect.

§ Systemicsignsandsymptomsmayincludeheadache,nausea,Uhtoff’ssign(decreasedvisionwithorwithoutlimbweakness

followingexposuretoincreasedtemperaturesi.e.,abathorexercise),Romberg’ssign(patientfallswhentheyclosetheireyes),Pulfrich’sstereophenomenon(beerbarrelappearancetotheenvironment)andfever.

§ Asrecordedinthethree-yearfollow-upofpatientsRxwithintravenousmethylprednisolonefollowedbyoralcorticosteroid

regimensreducedthetwo-yearrateofdevelopmentofclinicalMS,particularlyinpatientswithsignalabnormalitiesconsistentwithdemyelinationonMRIofthebrainatthetimeofstudyentry.Serioussideeffectsofglucocorticoidtherapyareinfrequent.Therefore,outpatientadministrationofhigh-doseintravenousglucocorticoidsmayberecommended.

ClinicalPearls

• AnumberofothertypesofdemyelinatingdisordershavebeenassociatedwithON.Theyare: acutetransversemyelitis

Guillain-BarrésyndromeDevic’sneuromyelitisopticalCharcot-Marie-Toothsyndromemultifocaldemyelinatingneuropathyacutedisseminatedencephalomyelitis.

• Diseasessuchassyphilis,toxoplasmosis,histoplasmosis,tuberculosis,hepatitis,rubella,humanimmunodeficiencyvirus(HIV),Lymeborreliosis,familialMediterraneanfever,Epstein-Barrvirus,herpeszosterophthalmicus,paranasalsinusdisorder,sarcoidosis,systemiclupuserythematosus,Bechet’sdisease,anddiabetesmaycauseopticneuropathyandshouldbeconsideredbeforeprematurelydiagnosingdemyelinatingopticneuropathy.

• Incasesofopticneuropathypresumablysecondarytodemyelinatingdisease,MRIcanassistinsystemicdiagnosisbyidentifyingbotholdandacutedemyelinatingplaqueswithinperiventricularwhitematter.

• Significantpainwitheyemovementispresentinnearlyeverycaseofdemyelinatingopticneuropathy.• Asthevisualdysfunctionisduetoautoimmunedestructionofmyelinandnotdirectinflammationoftheopticnerve

tissue,thisdiseaseentityisbesttermeddemyelinatingopticneuropathy.

Papilloedema

Optic neuritis

Page 5: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question2(11marks)

A35yearoldmanisbroughtintoyouremergencydepartmentafteranisolatedinjurytotheleftanklesustainedinamotorcycleaccident.Hisobsare:BP160/50mmHgsupineHR110/minGCS15

a. State(4)featuresshownonthisxraythatsuggestasevereinjury.(4marks) • Complete#throughtheneckoftalus• Severecomminutionoftalus• Separationofthemajorfragments>1cm• MarkedanteriordisplacementofdistalfragmentNB:notdislocation/subluxationasanklejointisintact

Heisdeliveredbyambulanceandhasreceivedonlypenthraneenroute.Hedoesnothaveintravenousaccessonarrival.Heisextremelydistressedwithpain.Helastate2hoursago.Hisweightis70kg.

b. Listseven(7)analgesicoptionsforthispatientwhileheisintheemergencydepartment.Includedosesandrouteswhereapplicable.Includeinitialdosesandroutewhereappropriate.(7marks)• Initialoptions:

§ IMketamine3-5mg/kg§ INfentanyl1mcg/kg§ N20

• IVmorphine-5-10mg• Sedationforreduction:

§ IVketamine1-1.5mg/kg§ IVmidazolam3-5mg

• Reduction/immobilisation• Elevation• Ankleblock10-20mlx0.5%plainbupivacaine• PCA• Oraloxycodone/paracetamol

Page 6: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question3(12marks)A65yearoldfemale,non-Englishspeaking,Italianladypresentswithabout1cupofhaemoptysis.Youare

unabletoobtainanymedicalhistory.Herobservationsare:BP135/65mmHgHR80/minGCS15a. Listfour(4)likelydifferentialdiagnosesforthispresentation.(4marks)• TB• PE• Pneumonia-severewithinfarction• LungCa-primary/secondary• Pulmonaryabscess• Coagulopathy/overanticoagulation• Thrombocytopaenia• Pulmonarycontusion• InhaledFB

b. OtherthanaCXR,listthree(3)keyinvestigationsthatyouwouldconsiderorderinginthe

emergencydepartment.(3marks)NB:listonly-noqualificationneeded

• INR• Sputum-AFB,MCS• CTChest• CTPA • ECG,FBE,UE,LFT,QuanteferonGold,ECHO

AChestXrayshowsunilateralchanges.Sheexperiencesalargevolumehaemoptysis(estimatedbloodloss500ml).

c. Listfive(5)keystepsinthetreatmentofthispatientoverthenext30minutes.(6marks)NB:500mlismassive/lifethreateninghaemoptysis• Communication-Interpreter-obtainfocussedHx/explaintopt• Nursewithaffectedsidedown-Preserveunaffectedlung• Ventilationsupport-Mainstemintubationorcombitube/duallumentubetononaffected

sideonly(anaestheticassistance)• Circulation-Volumereplacement-blood-massivetransfusionifindicated• Reverseanticoagulation-FFP/VitK/Prothrombinex/Tranaxemicacid• Rxunderlyingconditions-PneumoniaIVabs/PE-anticoagulation• Isolation-IfTbexpectedNB:ReferinterventionalXR-Ifbleedingpersistswillprobablybeafter30min

Page 7: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question4(17marks)A64yearoldmanisbeingevaluatedinyouremergencydepartmentafteranepisodeofchestpainwhichhasnowresolved.Heisgivenaspirinonlyenroutetohospital.2010/1/6.Hisobservationsare:BP140/85mmHgRR20/minO2saturation97%roomair

a. Statefour(4)abnormalfindingsshowninthisECG. (4marks) • Bradycardia~48bpm• Mobitztype1(Wenchebach)2nddegreeHB• STE1mmII,V2-V6• BiphasicTWIIIVi

b. Listfour(4)likelycausesforthesefindings.(4marks)

• Ischaemia• Drugs--vechronotropes(BB,CCB,Digoxin)-therapeutic• Drugs-ODegsameasabove• Cardiomyopathy• Myocarditis

Thepatientbecomessuddenlyunwell.He is lightheadedwithnochestpain. HisBP is70/50mmHg.He isgivena500mlfluidboluswithnoimprovement.

c. Statefive(5)abnormalfindingsshowninthisECG.(5marks)• Rate25-30• CHB• Ventricular/IdioventricularescapeorQRSprolongation• RAD• TWIII,III,V1-V3

(ForQwavestobesignificanttheyneedtobe: >40msec&>2mmdeep&>25%depthofQRS)

d. List in order of escalation, your choice of drug treatment for this patient. Specify dose and route. (4marks)

Drugtreatment Dose1stline Isoprenalineor

AdrenalineBolus20-40mcgIVFollowedbyinfusion0.5-20mcg/min

2ndline Atropine 300mcg-600mcgIV(rarelyeffective)

Page 8: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question5(14marks)

Aseriesofthree(3)Xraysfromthree(3)differentpatientsareshowninthepropsbooklet

a. ForXray1,statewheretheforeignbodylies.(1mark)

• Loweroesophagusatthegastro-oesophagusjunction. b. ForXray1,listtwo(2)optionsforthenature/compositionoftheforeignbody.(2marks)

• Coin• Roundmetalobject

c. Listtwo(2)factorsthatwouldmandateurgentremovaloftheforeignbody.(2marks)• Excessivesymptoms

o Unabletoswallowo Severepain

• Complicationso Haematemesiso Featuresofperforation

d. ForXray2,wheretheforeignbodylies.(1mark)

• Oesophagus-upper e. ForXray2,whatisthenature/compositionoftheforeignbody?(1mark)

• Buttonbattery f. ForXray2,stateyourdisposition.Providetwo(2)pointsofjustificationforthischoice.(2marks)

• Disposition:Theatre-AdmitGastro/ENT• Justification: Immediateremovalrequired(MANDATORY)(<2/24)

Extensivesurroundingtissuedamagecommences<30min Toolargetoallowwaitandseeifpassageoccursspontaneously

g. ForXray3,wheredoestheforeignbodylie?(1mark)• Upperoesophagus

h. ForXray3,stateyourdisposition.Providetwo(2)pointsofjustificationforthischoice.(3marks)Disposition:AdmitGastro/ENT

Justification: Toolargetopassspontaneously Timingofremovaldependsonsymptoms

Page 9: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question6(12marks)A45yearoldmanwithtype1diabetesmellitusisbroughtinbyambulancewithanalteredconsciousstate.Hisobservationsare:BP90/70mmHgHR120bpmTemperature36.8 °COxygensaturation97%on8LbyHudsonmaskGCS12E4,V3,M5

a. Providethree(3)calculationstohelpyoutointerprettheseresults.(3marks)

1. CorrectedNa(NeedtocorrectNapriortoAGcalculation)• TrueNa= measuredNa+ + glucose-10/3

Or measuredNa+ + glucose-7/3.5 Or measuredNa+ + glucose/4

2. AnionGap=21∴↑3. Deltagap∆ratio:~1.7∴PureHAGMA 4. Others:

o ExpectedCO2o A-agradient274-247=27∴normalforageo SeOsmo

b. Provideaunifyingexplanationforthisclinicalpicturebasedontheseresults.(3marks)

• HAGMetabolicacidosis-LikelyDKA• 1°respiratoryacidosis-Likelyhypoventilation• Renalimpairment-slightlyincreasedUr:Crlikelypartlyprerenalfromdehydration

c. Complete the following table demonstrating three (3) key specific treatment tasks in the first 2 hours of the

emergencydepartmentstay.Statehowyouwouldachieveeachofthesetasks.

Keytreatmenttask Howwillyouachievethetask?

1 Establish U/O/ correcthypovolaemia

Fluid1LNSStat~250ml/hrfornext4/24MonitorU/OwithFBC(avoidIDC)CVPmonitoring

2 Correcthypoglycaemia FluidsInsulin0.1U/kg/hr(max15U/hr)Followlocalprotocol3-5U/hr

Kbalance ReplaceKasglucosefallsandKfalls Airwayprotection Carefulobservationgivenalteredconsciousstate Treatprecipitant EgSepsis

Page 10: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

DeltaratioThisDeltaRatioissometimesusefulintheassessmentofmetabolicacidosis.Asthisconceptisrelatedtotheaniongap(AG)andbuffering,itwillbediscussedherebeforeadiscussionofmetabolicacidosis.TheDeltaRatioisdefinedas:

Deltaratio=(IncreaseinAnionGap/Decreaseinbicarbonate)Howisthisuseful?Inordertounderstandthis,considerthefollowing:Ifonemoleculeofmetabolicacid(HA)isaddedtotheECFanddissociates,theoneH+releasedwillreactwithonemoleculeofHCO3

-toproduceCO2andH2O.Thisistheprocessofbuffering.TheneteffectwillbeanincreaseinunmeasuredanionsbytheoneacidanionA-(ieaniongapincreasesbyone)andadecreaseinthebicarbonatebyone.Now,ifalltheaciddissociatedintheECFandallthebufferingwasbybicarbonate,thentheincreaseintheAGshouldbeequaltothedecreaseinbicarbonatesotheratiobetweenthesetwochanges(whichwecallthedeltaratio)shouldbeequaltoone.Thedeltaratioquantifiestherelationshipbetweenthechangesinthesetwoquantities.ExampleIftheAGwassay26mmols/l(anincreaseof14fromtheaveragevalueof12),itmightbeexpectedthattheHCO3

-wouldfallbythesameamountfromitsusualvalue(ie24minus14=10mmols/l).IftheactualHCO3

-valuewasdifferentfromthisitwouldbeindirectevidenceofthepresenceofcertainotheracid-basedisorders(seeGuidelinesbelow).ProblemAproblemthough:theaboveassumptionsaboutallbufferingoccurringintheECFandbeingtotallybybicarbonatearenotcorrect.Fiftytosixtypercentofthebufferingforametabolicacidosisoccursintracellularly.ThisamountofH+fromthemetabolicacid(HA)doesnotreactwithextracellularHCO3

-sotheextracellular[HCO3-]willnotfallasfarasoriginallypredicted.Theacidanion(ieA-)howeverischargedandtendsto

stayextracellularlysotheincreaseintheaniongapintheplasmawilltendtobeasmuchaspredicted.Overall,thissignificantintracellularbufferingwithextracellularretentionoftheunmeasuredacidanionwillcausethevalueofthedeltaratiotobegreaterthanoneinahighAGmetabolicacidosis.Caution:Inaccuraciescanoccurforseveralreasons,forexample:• Calculationrequiresmeasurementof4electrolytes,eachwithameasurementerror• Changesareassessedagainst'standard'normalvaluesforbothaniongapandbicarbonateconcentration.Sometimestheseerrorscombinetoproducequiteanincorrectvaluefortheratio.Asanexample,patientswithhypoalbuminaemiahavealower'normal'valueforaniongapsousingthestandardvalueof12tocompareagainstmustleadtoanerror.Donotoverinterpretyourresultandlookforsupportiveevidenceespeciallyifthediagnosisisunexpected.GuidelinesforUseoftheDeltaRatioSomegeneralguidelinesforuseofthedeltaratiowhenassessingmetabolicacid-basedisordersinprovidedinthetablebelow.OverallAdvice:Beverywaryofover-interpretation-Alwayscheckforotherevidencetosupportthediagnosisasanunexpectedvaluewithoutanyotherevidenceshouldalwaysbetreatedwithgreatcaution.

DeltaRatio AssessmentGuideline

<0.4 Hyperchloraemicnormalaniongapacidosis

0.4-0.8 ConsidercombinedhighAG&normalAGacidosisBUTnotethattheratioisoften<1inacidosisassociatedwithrenalfailure

1to2 Usualforuncomplicatedhigh-AGacidosisLacticacidosis:averagevalue1.6DKAmorelikelytohavearatiocloserto1duetourineketoneloss(espifpatientnotdehydrated)

>2 Suggestsapre-existingelevatedHCO3levelsoconsider:• aconcurrentmetabolicalkalosis,or• apre-existingcompensatedrespiratoryacidosis

Warning:Beverywaryofover-interpretation-Alwayscheckforotherevidencetosupportthediagnosisasanunexpectedvaluewithoutanyotherevidenceshouldalwaysbetreatedwithgreatcaution.AhighratioAhighdeltaratiocanoccurinthesituationwherethepatienthadquiteanelevatedbicarbonatevalueattheonsetofthemetabolicacidosis.Suchanelevatedlevelcouldbeduetoapre-existingmetabolicalkalosis,ortocompensationforapre-existingrespiratoryacidosis(iecompensatedchronicrespiratoryacidosis).Withonsetofametabolicacidosis,usingthe'standard'valueof24mmol/lasthereferencevalueforcomparisonwhendeterminingthe'decreaseinbicarbonate'willresultinanoddresult.AlowratioAlowratiooccurswithhyperchloraemic(ornormalaniongap)acidosis.Thereasonhereisthattheacidinvolvediseffectivelyhydrochloricacid(HCl)andtheriseinplasma[chloride]isaccountedforinthecalculationofaniongap(iechlorideisa'measuredanion').Theresultisthatthe'riseinaniongap'(thenumeratorinthedeltarationcalculation)doesnotoccurbutthe'decreaseinbicarbonate'(thedenominator)doesriseinnumericalvalue.Thenetofofboththesechangesthenistocauseamarkeddropindeltaratio,commonlyto<0.4LacticacidosisInlacticacidosis,theaveragevalueofthedeltaratioinpatientshasbeenfoundtobeis1.6duetointracellularbufferingwithextracellularretentionoftheanion.Asageneralrule,inuncomplicatedlacticacidosis,theriseintheAGshouldalwaysexceedthefallinbicarbonatelevel.DiabeticketoacidosisThesituationwithapurediabeticketoacidosisisaspecialcaseastheurinarylossofketonesdecreasestheaniongapandthisreturnsthedeltaratiodownwardstowardsone.Afurthercomplicationisthatthesepatientsareoftenfluidresuscitatedwith'normalsaline'solutionwhichresultsinaincreaseinplasmachlorideandadecreaseinaniongapanddevelopmentofa'hyperchloraemicnormalaniongapacidosis'superimposedontheketoacidosis.Theresultisafurtherdropinthedeltaratio.

Page 11: Question 1 (18 marks) - LITFL · § LP → 90% < 10 cells/ml, mainly T lymphocytes, ↑ IgG, protein normal § MRI → detects demyelinated areas, subcortical and periventricular

Question7(12marks)

A65yearoldmanpresentswithalefthandinjury.

a. Listtwo(2)factorsthatarisefromthisimage,thatwouldsuggestapoorprognosisforsuccessful

reimplantation.(2marks)• Site-throughmiddlephalanyxorDIP• Tendonavulsion• Macerationofedges• (Paletiporavulsedpartsnotstoredappropriatelyatpresent-clutchingstraws)

b. Listsix(6)historicalfactorsthatwouldsuggestapoorprognosisforsuccessfulreimplantation.(6marks) • Timeofinjury/delaytorepairWarmischaemia>6badandcoldischaemiatime>12bad• Age• SmokingHx Mostimportant• PVD • Diabetes• Steroiduse• Delay/incorrectcoolingofamputatedparts• Hypotension• Proximalinjurytoarm/forearm

c. Howwouldyoustoretheamputatedpartspendingadecisionforpotentialreimplantation?List

two(2)pointsinyouranswer.(2marks)• Doublesealedbag(orbottomshelffridge)• Iceslurry

d. Whatisthemostappropriateregionalanaesthesiatechniqueforthispatient?(1mark)• Combinedradialandmediannnblock• orUSguidedscaleneblock• orvolarplateblock

NB:Notringblock-maypranganartery

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Amputations

Careofamputatedparts Xray WashgrosscontaminationwithsterileNS→wrapinsterilegauzelightlysoakedinNS→doubleplasticbaginice/water Orlowertrayfridge Aimtokeepcoolavoidfreezing

Careofstump RemoveanytorniquetappliedbyMAS Directpressurewithsteriledressings-combine Novascularclamping Directedtemporarytourniquet

-onlyifuncontrollablebleedingenroutetotheatre

Timetoreimplantation-ishaemiatime Warm6-8hrs Cool12hrs(upto24hrs)

PrognosticfactorsforfavourableoutcomeAmputatedpartfactors Cleancutvscrush/shear/degloving Durationoftimebetweeninjuryandsurgery Minimalcontamination/infection Minimalwater/shrinkageeffectatedges Site/musclecontent →wristbetterthanforearm→tendonsrepairbetterthanmuscle →fingersdowellifamputateddistaltoFDPorproxFDSinsertion(worstbetDIP&PIP) →worstiftwolevelinjuryPatientfactors Age→childrendobetter Preexistinghealth(DM,PVD,steroidsdoworse) →smokerspoorsuccessrate

Relativecontraindicationstoimplantation Longdurationbetweentimeofinjury→Sx(>6/24warm,>12coldischemiatime) CrushwithextensiveSTI Peripheralvasculardisease Grosslycontaminated/infectedwound Devitalisedtissue Otherlife-threateninginjurieswhichtakeprecendence Siteofamputationinpresenceofsignificantneurologicalinjury(egBPdisruption)

Don'tforgetIVAbsTetanusprophylaxis-toxoid+/-TIGAnalgesiaSplintFastManagementofotherinjuries-Secondarysurvey

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Question8(12marks)

A6yearoldboypresentswithaleftsupracondylarhumeralfracture.

a. Listtwo(2)typeofpainscoringsystemsthatyoucouldapplytothischild.(2marks)• WongBakerFaces (3-18)• FLACC (2/12-18)• Visualanalogue (6-18)NB:Numerical (8+yrs)

b. Listtwo(2)reasonswhyapainscoreisused.(2marks)

• Objectiveassessmentofpainispoor• Allowsassessmentofefficacyofanalgesia

c. Listfour(4)indicationsforGAMPinthispatient.(4marks)

• Distalneurocompromise• Distalvascularcompromise• Skincompromise• Capitellumposteriortoanteriorhumeralline(dorsalangulation>10°)• <50%bonycontact• Medial/lateralangulationEspif>10°• Anteriordisplacement

d. Listfour(4)piecesofadvicethatyouwouldgivetothisboy’sparentifthepatientisabletobe

dischargedfromtheemergencydepartment.(4marks) • Postsedationadvice• PostPOPadvice

§ Indicationstoreturnforreview• POPcheckplan• Analgesiaadvice• Followuparrangements

ClickontheimagebelowtoviewtheentirePDF(&print/saveifnecessary)

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Question9(12marks)

A46yearmanisbroughttoyouremergencydepartmentwithsuspectedalcoholwithdrawal.

a. List seven (7) of the 10 scale domains that form theAlcoholWithdrawal Assessment Scale (7marks) • N&V• Tactiledisturbance• Tremor• Paroxysmalsweating• Auditorydisturbance• Visualdisturbance• Anxiety• Agitation• Headache• Orientationandcloudingofsensorium

A35yearoldmaleisidentifiedashaving“verysevere”alcoholwithdrawal.

b. Statefive(5)keymanagementstepsforthispatientoverthenext1hour.(5marks)• Nonstimulatingenvironment• Provideadequatehydration• RxThiamine&multivitamins• Rxhypoglycaemia• IVdiazepam5mg-repeatto4xover1st30minthen30minutelyasrequired

This resource is produced for the use of University Hospital, Geelong Emergency staff for preparation for the Emergency Medicine Fellowship written exam. All care has been taken to ensure accurate and up to date content. Please contact me with any suggestions, concerns or questions. Dr Tom Reade (Staff Specialist, University Hospital, Geelong Emergency Department) Email: [email protected] November 2017

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