Transient ischemic attack

(Redirected from TIA)

Background

  • Abbreviation: TIA
  • New Definition: a brief episode of neurologic dysfunction caused by focal brain 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

  • Focal weakness (Paralysis or paresis of the face, arm, or leg and typically unilateral)
  • Dysarthria or dysphasia or aphasia
  • Vision changes (Field deficits, blindness, or diplopia)
  • Changes in balance or coordination

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 (once hemorrhage ruled-out)
  • Consider dual antiplatelet therapy for high risk TIAs[7]
    • Load with ASA 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

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

ABCD2 Score[9]

  • 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%[10][11]

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[12]
    • 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

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 Attackfull 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. 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.
  10. 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.
  11. 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.
  12. 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.

Authors:

Ross Donaldson