Transient ischemic attack

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

ABCD2 Score[8]

  • 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%[9][10]

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[11]
    • 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

AHA/ASA Guidelines[12]

  • Reasonable to hospitalize patients with TIA who present within 72 hr of symptom onset and have:
    • ABCD2 score of ≥ 3
    • ABCD2 score of 0-2 and uncertainty that diagnostic workup can be completed within 2d as outpatient
    • ABCD2 score of 0-2 and other evidence that event was caused by focal ischemia

NSA Guidelines[13]

  • Hospitalization for patients with first TIA within past 24-48hr
  • Recommended admission for patients with the following:
    • Crescendo TIA (more than three TIAs in 72hr period)
    • Duration of symptoms >1hr
    • Symptomatic carotid stenosis >50%
    • Known cardiac source of embolus
    • Known hypercoaguable state
    • High risk of early stroke after TIA

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[14]
Example of a rapid ED protocol for TIA

Urgent Cardiac Workup

  • Urgent echocardiogram and/or holter monitor may be needed to identify patients requiring conditions requiring anticoagulation (such as atrial fibrillation not seen during ED workup)
  • Two groups that may require inpatient or urgent outpatient workup
    • Known heart disease including CHF, severe valvular disease, severe CAD, history of MI, rheumatic heart disease
    • Patients with no clear cause of TIA and no classic risk factors (such as paroxysmal atrial fibrillation, severe valvular disease, PFO)

External Links

MDCalc ABCD2 Score

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. 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.
  9. 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.
  10. 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.
  11. 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.
  12. Easton JD, et al. Definition and evaluation of transient ischemic attack. A scientific statement for healthcare professionals from the American Heart Association/American Stroke Association Stroke Council; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular Radiology and Intervention; Council on Cardiovascular Nursing; and the Interdisciplinary Council on Peripheral Vascular Disease. Stroke. 2009; 40:2276-2293.
  13. Johnston SC, et al. National Stroke Association guidelines for the management of transient ischemic attacks. Ann Neurol. 2006; 60(3):301-13.
  14. 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