transient ischemic attacks rodney w. smith, md clinical assistant professor department of emergency...
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Transient Ischemic Attacks Transient Ischemic Attacks
Rodney W. Smith, MDRodney W. Smith, MD
Clinical Assistant ProfessorClinical Assistant ProfessorDepartment of Emergency MedicineDepartment of Emergency Medicine
University of MichiganUniversity of MichiganAnn Arbor, MIAnn Arbor, MI
Rodney Smith, MD
Example CaseExample Case
• A 55 year old male presents to the emergency department with acute onset of– Left arm weakness: Unable to lift left
arm off of lap– Symptoms improved on the way to the
hospital
Rodney Smith, MD
Example CaseExample Case
• PMHx: Hypertension– Takes enalapril
• ROS:– No headache– No other neurologic symptoms
• Social Hx:– Smokes 1 ppd
Rodney Smith, MD
Example CaseExample Case
• Physical Exam– Overweight, in NAD– 160/90, 80, 14, 37.5C– Right carotid bruit– Heart with regular rate and rhythm; No
murmur
Rodney Smith, MD
Example CaseExample Case
• Neuro exam– Oriented to person, place, and time– Fluent speech– CN II-XII intact– Motor 4/5 strength in left upper extremity– Sensory subjective decrease in pinprick in left
upper extremity compared to the right– DTR +2 except at left biceps +3– Gait steady– Cerebellar intact finger to finger and finger to nose– No extensor plantar response.
Rodney Smith, MD
Summary
• Importance of distinguishing TIA from other causes of transient “spells”
• Essential elements include a careful history, physical exam, and CT scan
• ED treatment and disposition are directed toward prevention of subsequent stroke
• Incidence of early stroke after TIA justifies hospital admission for further evaluation
Rodney Smith, MD
Risk Factors/EpidemiologyRisk Factors/Epidemiology
• 300,000 TIAs per year in US• 5-year stroke risk after TIA 29%
– 43.5% in 2 years with >70% carotid stenosis treated medically
• Many stroke patients have had TIA– 25% - 50% in large artery atherothrombotic
strokes– 11% - 30% in cardioembolic strokes– 11% to 14% in lacunar strokes
Rodney Smith, MD
Risk Factors/EpidemiologyRisk Factors/Epidemiology• Risk factors are the same as stroke
– Increasing age– Sex– Family history / Race– Prior stroke / TIA– Hypertension– Diabetes– Heart disease– Carotid artery / Peripheral artery disease– Obesity– High cholesterol– Physical inactivity
Rodney Smith, MD
ED PresentationED Presentation
• What is a TIA?– Acute loss of focal cerebral function– Symptoms last less than 24 hours– Due to inadequate blood supply
• Thrombosis• Embolism
Rodney Smith, MD
ED PresentationED Presentation
• Acute loss of focal cerebral function– Motor symptoms
• Weakness or clumsiness on one side• Difficulty swallowing
– Speech disturbances• Understanding or expressing spoken
language• Reading or writing• Slurred speech• Calculations
Rodney Smith, MD
ED PresentationED Presentation
• Acute loss of focal cerebral function– Sensory symptoms
• Altered feeling on one side• Loss of vision on one side• Loss of vision in left or right visual field• Bilateral blindness• Double vision• Vertigo
Rodney Smith, MD
ED PresentationED Presentation
• Non-focal Symptoms (Not TIA)– Generalized weakness or numbness– Faintness or syncope– Incontinence – Isolated symptoms (symptoms occurring
alone)• Vertigo or loss of balance• Slurred speech or difficulty swallowing• Double vision
Rodney Smith, MD
ED PresentationED Presentation
• Non-focal Symptoms (Not TIA)– Confusion
• Disorientation• Impaired attention/concentration• Diminution of all mental activity• Distinguish from
– Isolated language or visual-spatial perception problems (may be TIA)
– Isolated memory problems (transient global amnesia)
Rodney Smith, MD
TIA Symptoms RelatedTIA Symptoms Relatedto Cerebral Circulationto Cerebral Circulation
Symptom Anterior Either PosteriorDysphasiaUnilateral weakness UsuallyUnilateral sensory disturbance UsuallyDysarthria Plus otherHomonymous hemianopiaUnsteadiness/ataxia Plus otherDysphagia Plus otherDiplopia Plus otherVertigo Plus otherBilateral simultaneous visual lossBilateral simultaneous weaknessBilateral simultaneous sensory disturbanceCrossed sensory/motor loss
Circulation Involved
Rodney Smith, MD
ED PresentationED Presentation
• Acute loss of focal cerebral function– Abrupt onset – Symptoms occur in all affected areas
at the same time– Symptoms resolve gradually– Symptoms are “negative”
Rodney Smith, MD
ED PresentationED Presentation
• Symptoms last less than 24 hours– Most last less than one hour– Less than 10 percent > 6 hours– Amaurosis fugax up to five minutes
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ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Migraine with aura– Positive symptoms– Spread over minutes– Visual disturbances– Somatosensory or motor disturbance– Headache within 1 hour
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Aura without Headache– 98% Visual symptoms– 30% with other symptoms
• 26% sensory• 16% aphasia• 6% dysarthria• 10% weakness
– Mean age 48.7 (vs. 62.1)– Fewer cardiovascular risk factors
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
Duration of symptoms
0%
20%
40%
60%
80%
15 15 to 60 > 60
Time in minutes
Time to maximum symptoms
0%
10%
20%
30%
40%
50%
< 1 1 to 5 6 to 30 >30
Time in minutes
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Partial (focal) seizure– Positive sensory or motor symptoms– Spread quickly (60 seconds)– Negative symptoms afterward (Todd’s
paresis)– Multiple attacks
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Transient global amnesia– Sudden disorder of memory– Antegrade and often retrograde– Recurrence 3% per year– Etiology unclear
• Migraine• Epilepsy (7% within 1 year)• Unknown
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Transient global amnesia– No difference in vascular risk factors
compared with general population– Fewer risk factors when compared
with TIA patients– Prognosis significantly better than TIA
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Structural intracranial lesion– Tumor
• Partial seizures• Vascular steal• Hemorrhage• Vessel compression by tumor
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Intracranial hemorrhage– ICH rare to confuse with TIA– Subdural hematoma
• Headache • Fluctuation of symptoms• Mental status changes
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Multiple sclerosis– Usually subacute but can be acute
• Optic neuritis• Limb ataxia
– Age and risk factors– Signs more pronounced than
symptoms
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Labyrinthine disorders– Central vs. Peripheral vertigo– Ménière's disease– Benign positional vertigo– Acute vestibular neuronitis
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Metabolic– Hypoglycemia– Hyponatremia– Hypercalcemia
• Peripheral nerve lesions– Entrapments– Painful quality
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
O xfordshire C om m unity S troke Pro ject
52 (10%) M igra ine 33 (6%) V ertigo
48 (9%) S yncope 29 (6%) E pi lepsy
46 (9%) Poss . T IA 17 (3%) T G A
45 (9%) F unny turn 47 (9%) O ther
317 O thers 195 (38%) w ith T IA
512 Pa tients re fe rredfor suspec ted T IA
Rodney Smith, MD
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
ED PresentationED PresentationDifferential DiagnosisDifferential Diagnosis
• Patient evaluation by senior neurologists with interest in stroke
• Agreement on 48 of 56 patients (85.7%)– 36 with TIA– 12 Not TIA– 8 of 56 disagreement
• 4 of these, both listed firm diagnosis
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and Evaluation
• History– Characteristics of the attack– Associated symptoms– Risk factors
• Vascular Disease• Cardiac Disease• Hematologic Disorders• Smoking
– Prior TIA
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and Evaluation
• Physical Examination– Neurologic Exam– Carotid Bruits– Cardiac Exam– Peripheral Pulses
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and Evaluation
• EKG
• CBC, Coags, and Chemistries
• Chest Xray
• Head CT without contrast
• Expedite if early presentation
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and Evaluation
• Symptom vs. Disease– Significant carotid artery stenosis– Cardiac embolism
• Admission vs. Discharge– Traditional approach– Trend toward outpatient evaluation
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and EvaluationED Diagnosis and EvaluationED Diagnosis and Evaluation
• Stroke Rate After TIA– Percent (95% CI)
Oxfordshire Rochester
1 month 4.4 (1.5 - 7.3) 8 (4.2 - 11.8)
6 months 8.8 (4.7 - 12.9) 10 (6.7 - 14.3)
12 months 11.6 (6.9 - 16.3) 13 (8.1 - 17.9)
5 years 29.3 (21.3 - 37.3) 29 (22.0 - 36.0)
Rodney Smith, MD
ED Diagnosis and EvaluationED Diagnosis and Evaluation
• Stroke Rate After TIA• Johnston, et al. JAMA 284:2901,
2000.
– Follow-up of 1707 ED patients diagnosed with TIA
– Stroke rate at 90 days was 10.5%– Half of these occurred in the first 48
hours after ED presentation
Rodney Smith, MD
ManagementManagement
• Goal: Prevention of Stroke• Expedited Evaluation
– Carotid Artery Disease– Cardioembolism– Inpatient vs. Observation Unit vs. Outpatient
• Antiplatelet Therapy• Risk Factor Modulation
Rodney Smith, MD
ManagementManagementED DispositionED DispositionManagementManagement
ED DispositionED Disposition
• Discharge– Further testing will not change
treatment– Prior workup– Not a candidate for CEA or
anticoagulation
Rodney Smith, MD
ManagementManagementED DispositionED DispositionManagementManagement
ED DispositionED Disposition
• Admission– Clear indication for anticoagulation– Severe deficit– Crescendo symptoms– Other indication for admission
• Admission or observation unit evaluation – All others
Rodney Smith, MD
ManagementManagementDiagnosis of Carotid StenosisDiagnosis of Carotid Stenosis
Carotid bruit related to stenosis
0%
10%
20%
30%
40%
Normal 1 - 24 25 - 49 50 - 74 75 - 99 Occluded
Percent stenosis of symptomatic ICA
Pe
rce
nt
of
pa
tie
nts
No Bruit Bruit
Rodney Smith, MD
ManagementManagementDiagnosis of Carotid StenosisDiagnosis of Carotid Stenosis
• Carotid Duplex Ultrasound– Sensitivity of 94 - 100% for > 50% stenosis– May overdiagnose occlusion– Non-invasive
Rodney Smith, MD
ManagementManagementDiagnosis of Carotid StenosisDiagnosis of Carotid Stenosis
• Magnetic Resonance Angiography– Similar sensitivity to carotid
ultrasound– Overestimates degree of stenosis– Gives information about
vertebrobasilar system– Accuracy of 62% in detecting
intracranial pathology– Cost and claustrophobia
Rodney Smith, MD
ManagementManagementDiagnosis of Carotid StenosisDiagnosis of Carotid Stenosis
• Cerebral Angiography– Gold standard for diagnosis– Invasive, with risk of stroke of up to 1%– For patients with positive ultrasound– For patients with occlusion on ultrasound– First test if intracranial pathology
suspected
Rodney Smith, MD
ManagementManagementCardiogenic EmbolismCardiogenic Embolism
• Major risk factors: Anticoagulation Indicated
– Atrial fibrillation– Mitral stenosis– Prosthetic cardiac valve– Recent MI– Thrombus in LV or LA appendage– Atrial myxoma– Infective endocarditis (No anticoagulation)– Dilated cardiomyopathy
Rodney Smith, MD
ManagementManagementCardiogenic EmbolismCardiogenic Embolism
• Minor risk factors: Best treatment unclear
– Mitral valve prolapse– Mitral annular calcification– Patent foramen ovale– Atrial septal aneurysm– Calcific aortic stenosis– LV regional wall motion abnormality– Aortic arch atheromatous plaques– Spontaneous echocardiographic contrast
Rodney Smith, MD
ManagementManagementEchocardiogramEchocardiogram
• Yield < 3% in undifferentiated patients• Higher with risk factors• TEE preferred• Specific treatment of many
abnormalities unknown
Rodney Smith, MD
ManagementManagementEchocardiogramEchocardiogram
• Indications– Age < 50– Multiple TIAs in more than one arterial
distribution– Clinical, ECG, or CXR evidence suggests
cardiac embolization
Rodney Smith, MD
Management Management TIA with Atrial FibrillationTIA with Atrial Fibrillation
• INR 2.5 (Range 2 to 3)• Aspirin if Warfarin contraindicated• Timing of onset of AC not proven in RCT• AC in other causes of cardioembolic
stroke not proven in RCT
EAFT Study Group, Lancet, 1993
Rodney Smith, MD
ManagementManagementAntiplatelet TherapyAntiplatelet Therapy
• Aspirin– Compared with placebo in patients with
minor stroke/TIA• Relative risk of composite endpoint reduced
by 13% to 17%
– Dose of aspirin probably not important– Lower dose gives lower incidence of GI
side effects.
Rodney Smith, MD
ManagementManagement
• Ticlopidine– Small absolute risk reduction
compared with ASA– Side effects preclude use in up to 5%– Serious adverse effects
• Neurtropenia• Thrombotic thrombocytopenic purpura
Rodney Smith, MD
ManagementManagement
• Clopidogrel– Similar to Ticlopidine in reducing
composite endpoint– Reduction in risk of stroke alone less
than with Ticlopidine– Similar side effect profile to ASA
Rodney Smith, MD
ManagementManagement
• Dipyridamole plus ASA– Small absolute risk reduction for
stroke compared with ASA alone– Risk reduction for composite endpoint
due to stroke reduction alone– Safe side effect profile
Rodney Smith, MD
ManagementManagement
• Discharged patients should receive ASA 50 - 325 mg/day– Based on cost and small absolute benefit of
other agents
• Patients with TIA on ASA should have change in agent– Dipyridamole plus ASA– Clopidogrel– Increase dose of ASA to 1300 mg/day
Rodney Smith, MD
Expected OutcomeExpected Outcome
• 70% stenosis or greater
• Best medical therapy vs. CEA
Medical SurgicalIpsilateral stroke 26.0% 9.0%Major or fatal ipsilateral stroke 13.1% 2.5%Stroke or death 32.3% 15.8%
Rodney Smith, MD
Expected OutcomeExpected Outcome
• 50 - 69% stenosis
• Best medical therapy vs. CEA
Medical SurgicalIpsilateral stroke 22.2% 15.7%Stroke or death 43.3% 33.2%
Rodney Smith, MD
Expected Outcome Expected Outcome TIA with Atrial FibrillationTIA with Atrial Fibrillation
• Rate of stroke– Placebo - 12% per year– Aspirin - 10% per year– Warfarin - 4% per year
• Major bleed in 2.8% per year• No increase in ICH occurrence
EAFT Study Group, Lancet, 1993
Rodney Smith, MD
Future directionsFuture directions
• Treatment of PFO in patients with TIA– ASA; Warfarin; Surgery
• Ongoing trials of Warfarin vs. ASA for secondary stroke prevention
• Ongoing trials of carotid artery angioplasty and stents
Rodney Smith, MD
Outcome of CaseOutcome of Case
• Patient was evaluated in an Observation Center– Carotid ultrasound demonstrated 80% stenosis of R
ICA– Underwent R CEA, without complication– Patient discharged with plan for risk modification
• Diet for weight reduction• Smoking cessation program• Optimized antihypertensive regimen
Rodney Smith, MD
SummarySummary
• Importance of distinguishing TIA from other causes of transient “spells”
• Essential elements include a careful history, physical exam, and CT scan
• ED treatment and dispostition are directed toward prevention of subsequent stroke
• Incidence of early stroke after TIA justifies hospital admission for further evaluation