Transient Ischemic Attacks Transient Ischemic Attacks Rodney W. Smith, MD Rodney W. Smith, MD Clinical Assistant Professor Clinical Assistant Professor Department of Emergency Medicine Department of Emergency Medicine University of Michigan University of Michigan Ann Arbor, MI Ann Arbor, MI
58
Embed
Transient Ischemic Attacks Rodney W. Smith, MD Clinical Assistant Professor Department of Emergency Medicine University of Michigan Ann Arbor, MI.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
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
• 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
Rodney Smith, MD
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
• 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