Transient Ischemic Attack

Aka: Transient Ischemic Attack, TIA, CITS, Cerebral Infarction with Transient Signs, Reversible Ischemic Neurologic Deficit, RIND, Acute Neurologic Syndrome

advertisement

II. Definitions

  1. Transient Ischemic Attack (TIA)
    1. Transient neurologic deficit with spontaneous clinical resolution (not a radiographic diagnosis)

III. Epidemiology

  1. Incidence: 200,000 to 500,000 per year in United States

IV. Pathophysiology

  1. General
    1. Vascular related focal cerebral dysfunction
    2. Acute Neurologic Syndrome is analogous to Acute Coronary Syndrome
      1. Coronary syndrome evaluation is differentiating Myocardial Ischemia from infarction with Troponin
      2. Acute Neurologic Syndrome evaluation is differentiating cerebral ischemia from infarction with Brain MRI
  2. Spectrum
    1. Acute Neurologic Syndrome or Transient Ischemic Attack (TIA)
      1. Temporary neurologic dysfunction
        1. Focal cerebral ischemia or
        2. Focal spinal ischemia or
        3. Retinal ischemia
      2. No Cerebral Infarction (based on imaging)
        1. Previously defined as duration less than 24 hours (usually <10 minutes)
    2. Cerebral Infarction with Transient Signs (CITS)
      1. Partially reversible, non-disabling stroke (minor stroke)
    3. Ischemic Cerebrovascular Accident
      1. Non-reversible stroke

V. Causes

  1. See Transient Ischemic Attack Causes

VI. Risk Factors

  1. See TIA Risk Factors

VII. Precautions

  1. Urgently evaluate new onset TIA within hours to days
    1. See Prognosis below for studies regarding risk
    2. Stroke follows TIA within 90 days in 20-25% of cases
    3. Odds Ratio for Stroke following TIA
      1. At 1 month: 30.4 Odds Ratio
      2. At 1-3 months: 18.9 Odds Ratio
      3. At 4-6 months: 3.16 Odds Ratio
      4. After 5 years: 1.87 Odds Ratio
      5. Thacker (2010) Stroke 41(2): 239-43 [PubMed]

VIII. Evaluation

  1. History
    1. Obtain history from witnesses who observed episode
    2. Evaluate differential diagnosis (see Ischemic CVA)
    3. Evaluate TIA Risk Factors
    4. Determine anterior or Posterior Circulation (above)
    5. Determine probable source (see causes above)
    6. Ask about conditions associated with TIA mimics (conditions on differential diagnosis)
      1. Cognitive disorder
      2. Seizure Disorder
      3. Postural Hypotension
      4. Vertigo
  2. Examination
    1. Thorough cardiovascular examination
      1. Assess for Carotid Bruit
      2. Funduscopic Examination
      3. Assess for Atrial Fibrillation
      4. Assess for Heart Murmur
      5. Assess for Hypertension
        1. CVA commonly presents with Hypertension
    2. Thorough Neurologic Examination
      1. Often normal if TIA has completely resolved
      2. See Neurologic Exam
      3. See NIH Stroke Scale

IX. Symptoms

  1. Symptoms most suggestive of TIA or CVA
    1. Sudden onset
    2. Recurrent focal symptoms (higher risk for future CVA)
    3. Diplopia
    4. Transient Monocular Blindness
    5. Unilateral Paresis (Hemiparesis)
    6. Speech disturbance (Dysarthria)
  2. Symptoms most suggestive of alternative diagnosis (TIA mimic or non-TIA)
    1. Precaution
      1. Presence of these symptoms does not exclude TIA
      2. These symptoms are still present in TIAs, but at a lower percentage than in TIA mimics
    2. Most suggestive of mimic over TIA
      1. Gradual onset of symptoms
      2. Non-specific neurologic symptoms
        1. Memory Loss or Amnesia
        2. Headache
        3. Blurred Vision
    3. Other findings more suggestive of mimic than TIA (if isolated symptom or sign)
      1. Generalized weakness
      2. Dizziness (especially if not Vertigo)
      3. Confusion
      4. Loss of consciousness
      5. Tinnitus
      6. Dysphagia
      7. Scintillating Scotoma
      8. Headache
      9. Eye Pain
      10. Chest Pain
      11. Drop attacks (sudden spontaneous fall)

X. Signs

  1. Findings most suggestive of TIA or CVA
    1. Unilateral Motor Weakness
      1. May be associated with spasticity, Clonus or rigidity
    2. Speech deficits
  2. Cranial Nerve deficits: General
    1. Facial drooping
    2. Lateral Tongue movement
    3. Dysphagia
  3. Cranial Nerve deficits: Vision
    1. Diplopia
    2. Hemianopia
    3. Monocular Blindness
    4. Disconjugate gaze
  4. Cerebellar deficits and vestibular dysfunction
    1. Ataxia
    2. Nystagmus

XI. Symptoms and Signs: Localizing findings

  1. Timing
    1. Carotid TIAs resolve within 14 minutes
    2. Vertebral TIA resolve within 8 minutes
    3. Symptoms persisting >1 hour: 2-14% resolve in 24 hours
    4. Albers (2002) N Engl J Med 347(21):1713-6 [PubMed]
  2. Anterior Circulation symptoms (Carotid Artery)
    1. See Anterior Cerebral Artery CVA
    2. See Middle Cerebral Artery CVA
    3. Transient Monocular Blindness (Amaurosis Fugax)
    4. Clumsiness, weakness or numbness of hand
    5. Speech changes
  3. Posterior Circulation symptoms (Vertebro-basilar)
    1. See Posterior Inferior Cerebellar Artery CVA
    2. See Vertebro-Basilar CVA
    3. See Posterior Cerebral Artery CVA
    4. Binocular Vision changes or Diplopia
    5. Vertigo, Ataxia or Light Headedness
    6. Dysarthria
    7. Generalized weakness
    8. Loss of consciousness
    9. Transient Global Amnesia

XII. Labs

  1. Initial
    1. Complete Blood Count (CBC)
    2. Serum Glucose
      1. Urgent bedside, finger stick Glucose on presentation
    3. Serum Electrolytes
    4. ProTime with INR
    5. Partial Thromboplastin Time (aPTT)
  2. Labs during admission or outpatient
    1. Fasting Serum Lipids
    2. Serum Vitamin B12
  3. Other labs to consider in young patients (age <50 years)
    1. See Hypercoagulable for clotting predisposition evaluation
    2. See Altered Level of Consciousness for evaluation
    3. Lumbar Puncture
      1. Evaluate for CNS Infection (Meningitis or Encephalitis)
    4. Urine Drug Screen
    5. Blood Alcohol Level
    6. Rapid plasmin reagin (RPR for Syphilis)

XIII. Diagnostics

  1. Electrocardiogram (EKG)
    1. Among the highest yield tests in the TIA evaluation arsenal
    2. Identifies new Arrhythmias (especially Atrial Fibrillation)
    3. Telemetry rarely identifies additional conditions (important in TIA) not identified on the EKG
  2. Echocardiogram
    1. Evaluate for cardiac anomaly (esp. Patent Foramen Ovale)

XIV. Imaging: First Line Evaluation (emergent, immediate)

  1. Head CT
    1. Head CT is the recommended study in acute CVA if Thrombolysis is being considered
    2. Identifies prior infarction or Hemorrhagic CVA
    3. Identifies Brain Tumor and other CNS masses
    4. MRI may be performed instead, if readily available without significant delay
  2. Other studies to consider at time of initial TIA evaluation
    1. CTA Head and Neck (consider reflexing from CT, if GFR normal)
      1. Typically done in concert with Head CT at emergency department evaluation for CVA
      2. Identifies high grade stenotic lesions with little added evaluation time (contrast with MRA)
      3. If outpatient, non-ED evaluation, then MRI with MRA is often performed (see below)

XV. Imaging: Second Line Evaluation

  1. Typical evaluation in first 24-48 hours
    1. MRI Brain (with diffusion weight imaging or DWI)
      1. Non-contrast, diffusion weighted MRI is fast (10 min) and sufficient to identify ischemia and infarction
      2. Patients presenting with TIA and demonstrate infarction on MRI have a 20% chance of in-hospital CVA
        1. Ay (2005) Ann Neurol 57(5): 679-86 [PubMed]
      3. Identifies ischemic regions (in up to 25% of TIA patients), a high risk finding
        1. Ischemia on MRI is high risk for new CVA in short-term (as high as 10% in next 72 hours)
        2. Prabhakaran (2007) Arch Neurol 64(8):1105-9 +PMID: 17698700 [PubMed]
        3. Redgrave (2007) Cerebrovasc Dis 24(1):86-90 +PMID: 17519549 [PubMed]
    2. Magnetic Resonance Angiography (MRA) of Brain and Neck
      1. If CT Angiogram not done or non-diagnostic
      2. MRA or CTA are preferred over carotid Ultrasound
    3. Transthoracic Echocardiogram
      1. Consider Transesophageal Echocardiogram if emboli suspected and negative echo
      2. Primary conditions to identify in TIA cases
        1. Cardioembolic source
        2. Patent Foramen Ovale
        3. Valvular heart disease
  2. Studies to consider on discharge
    1. Holter Monitor
      1. Identify suspected intermittent Atrial Fibrillation and not found on inpatient telemetry
  3. Other studies
    1. Carotid Ultrasound for Anterior Circulation
      1. CTA and MRA has largely replaced carotid Ultrasound in post-CVA assessment
      2. Carotid Ultrasound is a good alternative when dictated by expense or MRI Contraindications
      3. Carotid Stenosis <50% suggests other source
      4. Carotid Stenosis >50% (especially if >80%)
        1. Obtain carotid arteriogram or MRA
        2. Arteriogram or MRA confirms >70% stenosis: Surgery
        3. Arteriogram or MRA suggests 50-69% stenosis
          1. Consider surgery in lower risk patient
          2. Medical therapy in high risk patient
    2. Transcranial Ultrasound for Posterior Circulation
    3. Arteriography
      1. Gold standard for pre-endarterectomy evaluation

XVI. Differential Diagnosis

  1. See Ischemic CVA
  2. Findings making TIA mimic more likely
    1. See symptoms above
    2. See history above
  3. Common TIA mimics (alternative diagnoses)
    1. Metabolic disturbance (e.g. Hypoglycemia)
      1. Hypoglycemia is always considered but
        1. However Hypoglycemia not expected to resolve spontaneously
        2. Contrast with TIA resolution without any intervention
    2. Complicated Migraine Headache (including aura)
    3. Seizure Disorder (including post-ictal period)
      1. May present with Todd's Paralysis
    4. Syncope
      1. Syncope is a a global hypoperfusion event
      2. Acute Neurologic Syndrome (Tranient Ischemic Attack) is a loss of a neurologic function
  4. Other alternative diagnoses
    1. CNS tumor
    2. CNS Infection (Meningitis, Encephalitis)
    3. Multiple Sclerosis
    4. Subarachnoid Hemorrhage
    5. Vertigo

XVII. Management

  1. See Risk Factor Modification Following Transient Ischemic Attack
  2. Early diagnosis and risk factor management can recurrent Ischemic CVA by as much as 80%
    1. Rothwell (2007) Lancet 370(9596): 1432-42 [PubMed]
  3. Immediate management of suspected TIA
    1. Antiplatelet agent
      1. Do not start until CT Head negative for Hemorrhage
      2. Antiplatelet agents reduce CVA risk 15%
      3. Patient not on Aspirin when TIA occurred
        1. Start Aspirin 81 mg orally daily
      4. Patient on Aspirin when TIA occurred
        1. Increase Aspirin dose to 325 mg
        2. Add Clopidogrel 75 mg daily to Aspirin if high grade stenosis (>70%)
        3. Previously, switch to Aggrenox (Aspirin with Dipyridamole) might be recommended
          1. Aggrenox does not appear more effective for CVA Prevention than Aspirin alone
    2. Do not lower Blood Pressure acutely in most cases
      1. See CVA Blood Pressure Control for special circumstances
    3. ER evaluation if symptom onset <48 hours ago
      1. See labs and radiology above
      2. See CVA Management if ongoing symptoms
        1. Consider for Thrombolytic management in CVA (if persistent significant deficit meeting criteria)
    4. Urgent outpatient evaluation if >48 hours
      1. See labs and radiology above
      2. See Carotid Stenosis for Endarterectomy Indications
      3. See Prevention of Ischemic Stroke
  4. Inpatient evaluation criteria (other cases may be managed outpatient)
    1. ABCD2 Score-based criteria (not typically recommended for disposition planning)
      1. Interrater reliability is inconsistent
        1. Ishida (2015) J Stroke Cerebrovasc Dis 24(6):1174-8 +PMID:25816725 [PubMed]
      2. ABCD2 Score: 5 or higher
      3. ABCD2 Score: 4 and
        1. MRA head and neck with symptomatic lesion
      4. ABCD2 Score: 3 and
        1. Symptoms resolved within prior 72 hours and
        2. Focal ischemia signs and
        3. Neurovascular imaging not available (e.g. MRA)
      5. References
        1. Olivot (2011) Stroke 42(7): 1839-43 [PubMed]
    2. Cardioembolic source with Anticoagulation considered
      1. Acute MI with large wall motion abnormality
      2. Mural thrombus
      3. Valvular vegatations or suspected emboli
      4. Significant valvular heart disease
      5. Atrial Fibrillation or other significant Arrhythmia
    3. Cerebrovascular Accident
      1. All CVAs are typically admitted
      2. TIA symptoms recurring at increasing frequency or with escalating symptoms
    4. Vascular or neurosurgery Consultation may be required
      1. MRI with ischemia (high risk for near-term CVA)
      2. High grade Carotid Stenosis suspected
      3. Possible Subarachnoid Hemorrhage
    5. Other significant risk factors
      1. Multiple TIAs prior to presentation or recurrent symptoms during emergency evaluation
      2. TIA despite full Anticoagulation
    6. High risk for CVA or TIA complications
      1. Aspiration Pneumonia

XVIII. Precautions

  1. Transient Ischemic Attacks are not outpatient problems (evaluate in emergency or inpatient setting)
  2. Evaluate and manage TIA underlying causes (e.g. severe Carotid Stenosis) within 2 weeks of event
  3. Ambulatory follow-up (neurology or primary care) from emergency department evaluation within 1 week

XIX. Prevention

  1. See Carotid Stenosis for Endarterectomy Indications
  2. See Prevention of Ischemic Stroke
  3. Tobacco Cessation is the single most effective prevention measure in CVA Prevention

XX. Prognosis

  1. Risk of Cerebrovascular Accident within 2 days of Acute Neurologic Syndrome (Transient Ischemic Attack)
    1. See ABCD2 Score
  2. Adverse Acute ischemic strokvents occur in 20-25% with TIA within 90 days
    1. Acute Ischemic Stroke represents 10% of these adverse events
    2. Roughly half of Ischemic Strokes occur within 48 hours of TIA (4.8% of TIA patients)
      1. Proper evaluation and management decreases stroke risk by 80%
  3. Carotid Stenosis
    1. Carotid Stenosis >50% predicts future Cerebrovascular Accidents
    2. Carotid Stenosis >70% in TIA is an indication for early carotid endarterectomy
    3. Barnett (1991) N Engl J Med 325(7):445-53 +PMID:1852179 [PubMed]
    4. Ferguson (1999) Stroke 30:1751-8 [PubMed]
  4. Annual CVA risk of TIA
    1. Typically 2-4% annual risk (as high as 20% in some populations)
  5. References
    1. Coull (2004) BMJ 328:326-8 [PubMed]
    2. Johnston (2000) JAMA 284:2901-6 [PubMed]

XXI. References

  1. Du Pont and Abboud (2021) Crit Dec Emerg Med 35(1): 25
  2. Orman, Swaminathan and Berg in Herbert (2016) EM:Rap 16(8): 13-5
  3. Pruitt in Goroll (2000) Primary Care, p. 970-4
  4. Beauchamp (1999) Radiology 212(2):307-24 [PubMed]
  5. Adams (2007) Stroke 38(5): 1655-711 [PubMed]
  6. Bernheisel (2011) Am Fam Physician 84(12): 1383-88 [PubMed]
  7. Biller (2000) Am Fam Physician 61(2):400-6 [PubMed]
  8. Eugene (1999) Geriatrics 54(5):24-33 [PubMed]
  9. Flemming (2000) Postgrad Med 107(6):55-80 [PubMed]
  10. Hemphill (2000) Geriatrics 55(3):42-52 [PubMed]
  11. Riggs (1998) Surg Clin North Am 78(5):881-900 [PubMed]
  12. Ryan (1999) Am Fam Physician 60(8):2329-41 [PubMed]
  13. Sacco (1998) Neurology 51:S27-30 [PubMed]
  14. Simmons (2012) Am Fam Physician 86(6): 521-6 [PubMed]
  15. Simmons (2012) Am Fam Physician 86(6): 527-32 [PubMed]
  16. Solenski (2004) Am Fam Physician 69:1665-80 [PubMed]
  17. Swain (2008) BMJ 337:a786 [PubMed]

Images: Related links to external sites (from Bing)

These images are a random sampling from a Bing search on the term "Transient Ischemic Attack." Click on the image (or right click) to open the source website in a new browser window. Search Bing for all related images

Related Studies

Related Topics in Cardiovascular Medicine

advertisement