Transient Ischemic Attacks Rodney W Transient Ischemic Attacks Rodney W. Smith, MD Clinical Assistant Professor Department of Emergency Medicine University of Michigan Ann Arbor, MI 54 1 54

Example 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

Example Case PMHx: Hypertension ROS: Social Hx: Takes enalapril No headache No other neurologic symptoms Social Hx: Smokes 1 ppd

Example Case Physical Exam Overweight, in NAD 160/90, 80, 14, 37.5C Right carotid bruit Heart with regular rate and rhythm; No murmur

Example 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.

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

Risk 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

Risk 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

ED Presentation What is a TIA? Acute loss of focal cerebral function Symptoms last less than 24 hours Due to inadequate blood supply Thrombosis Embolism

ED 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

ED 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

ED 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

ED 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)

TIA Symptoms Related to Cerebral Circulation

ED 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”

ED 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

ED Presentation Differential Diagnosis Migraine with aura Positive symptoms Spread over minutes Visual disturbances Somatosensory or motor disturbance Headache within 1 hour

ED Presentation Differential 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

ED Presentation Differential Diagnosis

ED Presentation Differential Diagnosis Partial (focal) seizure Positive sensory or motor symptoms Spread quickly (60 seconds) Negative symptoms afterward (Todd’s paresis) Multiple attacks

ED Presentation Differential 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

ED Presentation Differential 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

ED Presentation Differential Diagnosis Structural intracranial lesion Tumor Partial seizures Vascular steal Hemorrhage Vessel compression by tumor

ED Presentation Differential Diagnosis Intracranial hemorrhage ICH rare to confuse with TIA Subdural hematoma Headache Fluctuation of symptoms Mental status changes

ED Presentation Differential Diagnosis Multiple sclerosis Usually subacute but can be acute Optic neuritis Limb ataxia Age and risk factors Signs more pronounced than symptoms

ED Presentation Differential Diagnosis Labyrinthine disorders Central vs. Peripheral vertigo Ménière's disease Benign positional vertigo Acute vestibular neuronitis

ED Presentation Differential Diagnosis Metabolic Hypoglycemia Hyponatremia Hypercalcemia Peripheral nerve lesions Entrapments Painful quality

ED Presentation Differential Diagnosis

ED Presentation Differential 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

ED Diagnosis and Evaluation History Characteristics of the attack Associated symptoms Risk factors Vascular Disease Cardiac Disease Hematologic Disorders Smoking Prior TIA

ED Diagnosis and Evaluation Physical Examination Neurologic Exam Carotid Bruits Cardiac Exam Peripheral Pulses

ED Diagnosis and Evaluation EKG CBC, Coags, and Chemistries Chest Xray Head CT without contrast Expedite if early presentation

ED Diagnosis and Evaluation Symptom vs. Disease Significant carotid artery stenosis Cardiac embolism Admission vs. Discharge Traditional approach Trend toward outpatient evaluation

ED Diagnosis and Evaluation Stroke Rate After TIA Percent (95% CI)

ED 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

Management Goal: Prevention of Stroke Expedited Evaluation Carotid Artery Disease Cardioembolism Inpatient vs. Observation Unit vs. Outpatient Antiplatelet Therapy Risk Factor Modulation

Management ED Disposition Discharge Further testing will not change treatment Prior workup Not a candidate for CEA or anticoagulation

Management ED Disposition Admission Clear indication for anticoagulation Severe deficit Crescendo symptoms Other indication for admission Admission or observation unit evaluation All others

Management Diagnosis of Carotid Stenosis

Management Diagnosis of Carotid Stenosis Carotid Duplex Ultrasound Sensitivity of 94 - 100% for > 50% stenosis May overdiagnose occlusion Non-invasive

Management Diagnosis 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

Management Diagnosis 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

Management Cardiogenic 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

Management Cardiogenic 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

Management Echocardiogram Yield < 3% in undifferentiated patients Higher with risk factors TEE preferred Specific treatment of many abnormalities unknown

Management Echocardiogram Indications Age < 50 Multiple TIAs in more than one arterial distribution Clinical, ECG, or CXR evidence suggests cardiac embolization

Management TIA 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

Management Antiplatelet 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.

Management Ticlopidine Small absolute risk reduction compared with ASA Side effects preclude use in up to 5% Serious adverse effects Neurtropenia Thrombotic thrombocytopenic purpura

Management Clopidogrel Similar to Ticlopidine in reducing composite endpoint Reduction in risk of stroke alone less than with Ticlopidine Similar side effect profile to ASA

Management 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

Management 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

Expected Outcome 70% stenosis or greater Best medical therapy vs. CEA

Expected Outcome 50 - 69% stenosis Best medical therapy vs. CEA

Expected Outcome TIA 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

Future 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

Outcome 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

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 dispostition are directed toward prevention of subsequent stroke Incidence of early stroke after TIA justifies hospital admission for further evaluation