Transient ischemic attack

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Background

  • Abbreviation: TIA
  • New Definition: a brief episode of neurologic dysfunction caused by focal brain, spinal cord or retinal ischemia, with clinical symptoms typically lasting less than one hour, and without evidence of acute infarction. [1]
    • Should be viewed as analogous to unstable angina
  • Classic Definition: A sudden, focal neurologic deficit that lasts for less than 24 hours, is presumed to be of vascular origin, and is confined to an area of the brain or eye perfused by a specific artery[1]
  • Since 15% of strokes are preceded by TIA, timely eval of high risk conditions like Atrial Fibrillation and Carotid Stenosis is important

Clinical Features

Differential Diagnosis

Stroke-like Symptoms

Evaluation

Stroke Work-Up

  • Labs
    • POC glucose
    • CBC
    • Chemistry
    • Coags
    • Troponin
    • T&S
  • ECG
    • In large ICH or stroke, may see deep TWI and prolong QT, occ ST changes
  • Head CT (non-contrast)
    • In ischemia stroke CT has sensitivity 42%, specificity 91%[2]
    • In acute ICH the sensitivity is 95-100%[3]
    • The goal of CTH is to identify stroke mimics (ICH, mass lesions, etc .)[4]
  • Also consider:
    • CTA brain and neck
      • To check for large vessel occlusion for potential thrombectomy
      • Determine if there is carotid stenosis that warrants endarterectomy urgently
    • Pregnancy test
    • CXR (if infection suspected)
    • UA (if infection suspected)
    • Utox (if ingestion suspected)

MR Imaging (for Rule-Out CVA or TIA)

  • MRI Brain with DWI, ADC (without contrast) AND
  • Cervical vascular imaging (ACEP Level B in patients with high short-term risk for stroke):[5]
    • MRA brain (without contrast) AND
    • MRA neck (without contrast)
      • May instead use Carotid CTA or US (Carotid US slightly less sensitive than MRA)[6] (ACEP Level C)

Management

  • Little acute management (given normally resolution of symptoms)
  • Consider Aspirin 325 mg PO (once hemorrhage ruled-out) for low risk TIA (ABCD2 score < 4)
  • Consider dual antiplatelet therapy for high risk TIA (ABCD2 score ≥ 4)[7]
    • Load with Aspirin 325 mg chewed, followed by ASA 81 mg PO daily
    • Load with Clopidogrel 300 mg PO followed by 75 mg daily for 3 weeks only

Medication Dosing

Aspirin 325mg chewed, then 81mg PO daily PO Clopidogrel 300mg PO load, then 75mg daily x 3 weeks PO"Clopidogrel Dual antiplatelet for high-risk TIA (ABCD2 >" contains a listed ">" character as part of the property label and has therefore been classified as invalid.

Disposition

ACEP Guidelines[5]

  • Level B: In adult patients with suspected TIA, do not rely on current existing risk stratification instruments (eg, age, blood pressure, clinical features, duration of TIA and presence of diabetes [ABCD2] score) to identify TIA patients who can be safely discharged from the ED.
    • In contrast to the 2009 AHA/ASA recommendations that were based on limited research, the ABCD2 does not sufficiently identify the short-term risk for stroke to use alone as a risk-stratification instrument.
    • Multiple other risk-stratification instruments have been evaluated less frequently than the ABCD2 score. None have demonstrated the ability to identify individual patients at sufficiently low short-term risk for stroke to use alone as a risk-stratification instrument.
  • Level B: A rapid ED based diagnostic protocol can be used to safely identify patients at short-term risk for stroke.
    • Study based on observation units and outpatient TIA clinics[8]
Example of a rapid ED protocol for TIA

Prognosis

Canadian TIA Score

  • The score offers better performance than ABCD2 in predicting stroke risk after TIA, particularly low risk. [9]

Item Scoring

  • Clinical Findings:
    • 1. First TIA (in lifetime) (2 pt)
    • 2. Symptoms ≥10 minutes (2 pt)
    • 3. Past history of carotid stenosis (2 pt)
    • 4. Already on antiplatelet therapy (3 pt)
    • 5. History of gait disturbance (1 pt)
    • 6. History of unilateral weakness (1 pt)
    • 7. History of vertigo (-3 pts)
    • 8. Initial triage diastolic blood pressure ≥110 mm Hg (3 pt)
    • 9. Dysarthria or aphasia (history or examination) (3 pt)
  • Investigations in the emergency department:
    • 1.Atrial fibrillation on electrocardiogram (2 pt)
    • 2.Infarction (new or old) on computed tomography (1 pt)
    • 3.Platelet count≥400×109/L (2 pt)
    • 4.Glucose ≥15 mmol/L (3pt)
Points Stroke Risk Risk of Stroke or Carotid Revascularization in 7 Days
-3-3 Low .5%
4-8 Medium Risk 2.3%
≥9 High 5.9%

ABCD2 Score[10]

  • Risk of stroke at 2d, 7d, and 90d from TIA
  • Although prognostic, evidence-based admission thresholds have not been determined
  • None with score <3 had CVA within one week in study
  • Studies have failed to validate the ABCD2 score, and may cause physicians to incorrectly classify ~8% of patients as low risk, with sensitivity of the score for high risk patients only ~30%[11][12]

Scoring

  • Age >60yr (1 pt)
  • BP (SBP >140 OR diastolic >90) (1 pt)
  • Clinical Features
    • Isolated speech disturbance (1 pt)
    • Unilateral weakness (2 pts)
  • Duration of symptoms
    • 10-59 min (1 pt)
    • >60 min (2 pts)
  • Diabetes mellitus (1 pt)
Points Stroke Risk Two Days Seven Days 90 Days
0-3 Low 1.0% 1.2% 3.1%
4-5 Moderate 4.1% 5.9% 9.8%
6-7 High 8.1% 11.7% 17.8%
  • According to the 2018 Canadian Heart and Stroke Guideline, the Clinical component of the ABCD2 score is the most important prognostic feature[13]
    • Very high risk for recurrent stroke are the following symptoms that have occurred within the last 48 hours
      • Transient, fluctuating or persistent unilateral weakness (face, arm and/or leg)
      • Transient, fluctuating or persistent language/speech disturbance
      • And/or fluctuating or persistent symptoms without motor weakness or language/speech disturbance

Calculators

ABCD2 Score for TIA

ABCD2 Score — TIA Stroke Risk
Criteria Select
A — Age 1 <60 years (0)   ≥60 years (+1)
B — Blood Pressure 1 SBP <140 and DBP <90 (0)   SBP ≥140 or DBP ≥90 (+1)
C — Clinical Features 1 Other symptoms (0)   Speech disturbance without weakness (+1)   Unilateral weakness (+2)
D — Duration of symptoms 1 <10 minutes (0)   10–59 minutes (+1)   ≥60 minutes (+2)
D — Diabetes 1 No (0)   Yes (+1)
ABCD2 Score / 7
Interpretation — 2-Day Stroke Risk After TIA
0–3 Low risk — 1.0% risk of stroke within 2 days.
4–5 Moderate risk — 4.1% risk. Consider urgent workup and admission.
6–7 High risk — 8.1% risk. Admit for urgent evaluation and treatment.
References
  • Johnston SC, Rothwell PM, Nguyen-Huynh MN, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet. 2007;369(9558):283-292. PMID 17258668.

External Links

See Also

References

  1. ↑ 1.0 1.1 Albers GW, et al. The TIA Working Group. Transient ischemic attack: proposal for a new definition. N Engl J Med. 2002; 347:1713–1716.
  2. ↑ Mullins ME, Schaefer PW, Sorensen AG, Halpern EF, Ay H, He J, Koroshetz WJ, Gonzalez RG. CT and conventional and diffusion-weighted MR imaging in acute stroke: study in 691 patients at presentation to the emergency department. Radiology. 2002 Aug;224(2):353-60.
  3. ↑ Suarez JI, Tarr RW, Selman WR. Aneurysmal subarachnoid hemorrhage. N Engl J Med. 2006; 354(4):387–396.
  4. ↑ Douglas VC, Johnston CM, Elkins J, et al. Head computed tomography findings predict short-term stroke risk after transient ischemic attack. Stroke. 2003;34:2894-2899.
  5. ↑ 5.0 5.1 ACEP Clinical Policy: Suspected Transient Ischemic Attack full text
  6. ↑ Nederkoorn PJ, Mali WP, Eikelboom BC, et al. Preoperative diagnosis of carotid artery stenosis. Accuracy of noninvasive testing. Stroke. 2002;33:2003-2008.
  7. ↑ Johnston SC, Easton JD, Farrant M, Barsan W, Conwit RA, Elm JJ, Kim AS, Lindblad AS, Palesch YY. Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA. N Engl J Med. 2018 Jul 19;379(3):215-225.
  8. ↑ Ross MA, Compton S, Medado P, et al. An emergency department diagnostic protocol for patients with transient ischemic attack: a randomized controlled trial. Ann Emerg Med. 2007;50:109-119
  9. ↑ Perry JJ et al. Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study.BMJ 2021 Feb 4.
  10. ↑ Johnston SC, et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack.Lancet. 2007; 369(9558):283-92.
  11. ↑ Stead LG, Suravaram S. An assessment of the incremental value of the ABCD2 score in the emergency department evaluation of transient ischemic attack. Ann Emerg Med. 2011 Jan;57(1):46-51.
  12. ↑ Ghia D, Thomas P. Low positive predictive value of the ABCD2 score in emergency department transient ischaemic attack diagnoses: the South Western Sydney transient ischaemic attack study. Intern Med J. 2012 Aug;42(8):913-8.
  13. ↑ Boulanger JM, Lindsay MP, Gubitz G, et al. Canadian Stroke Best Practice Recommendations for Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care, 6th Edition, Update 2018. Int J Stroke. 2018;:1747493018786616.
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