TIA

Transient Ischemic Attack

• Defined classically as: focal neurologic deficit of ischemic origin of <24hrs duration.  (most <4hrs).
• Found that many "Classic TIAs" have MRI findings of infarcts.  These clinically silent infarcts thought to contribute to vascular dementia.
• New definition: No MRI findings of infarct.

• 2009 AHA/ASA Definition:  A transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction. (new definition does not define <24hrs, and requires neuroimaging)

• (new definition does not define <24hrs, and requires neuroimaging)
• Diagnosis:
  • Can use clinical judgement to diagnose, but can also use this criteria:

  • Asymptomatic Carotid Atherosclerosis Study team used criteria: Change in: Speech Visual loss diplopia numbness or tingling paralysis or weakness nonorthostatic dizziness. 80% agreement between criteria and expert panel review.

• Approach
  • ALL PATIENTS need urgent evaluation ASAP
  • MRI (with DWI) within 24hrs
• Risk Stratify
  • TIAs is an important risk factor - predicts 5.3% risk of stroke in 2 days and 10.5% stroke in 90 days.
    • ABCD2 score traditionally used to risk stratify (admission vs. outpatient and urgency of neurology referral), but no longer used.
    • Now many neurologists favour "high risk vs. low risk" stratification based on severity of deficit (unilateral hemiparesis, speech deficit etc.. are considered high risk).
    • Also risk depends on time of symptom onset (see below)
  • ABCD2 score is no longer used to risk stratify them.  The only thing that matter is timing of evaluation:

    • Time from Sympt. Onset	Risk	Recommended Timing of Evaluation in ER/Stroke Unit with stroke capability (CT, MRI, tPA)
      0-48hrs	HIGHEST	IMMEDIATE
      48hrs - 2w	INCREASED Risk	Within 24 hrs
      >2wk	LOWER Risk	Within 1 month

    • Symptoms without motor/speech (i.e. Sensory) are considered less urgent
• Hospitalization Criteria [Class IIa, C]
  • Within 72hrs of event AND
    • ABCD2 score of ≥3
    • ABCD2 score 0-2 + uncertain diagnostic w/u can be completed in <2 days
    • ABCD2 0-2 + other evidence event was caused by focal ischemia(???)
• Investigations:
  • Intra-Cranial Imaging within 24hrs of symptom onset
    • With MRI with DWI within 24hrs of symptom onset
    • If MRI not available, CT will suffice
  • Extra-Cranial Imaging  (Class IIa, B)
    • To look at cervicocephalic vessels
    • Any of: CUS/TCD, CTA or MRA of cervicocephalic vessels 
      (depends on patients and local expertise)
    • Often two investigations are needed before endarterectomy
      OR the gold standard, which is angiography
  • Cardiac
    • ECG STAT
    •  + cardiac monitoring (holter or telemetry)
    • Echo (ONLY if no other cause identified) [Class Iia, level B]
      • TTE reasonable, but TEE useful for PFOs, valve dz, arch atheroscerosis.
  • Bloodwork
    • CBC, Chemistry, PT, PTT, fasting lipids [Class Iia, B]
  • Other:
    • Screen for sleep apnea - Berlin Questionnaire or STOP-BANG score
• Management:
  • Risk Reduction!
  • Healthy, balanced diet as per Canada's Food Guide
    • (High fibre, proteins from fish/vegetables, unsaturated fats, whole grains, fruits)
  • Exercise
    • Moderate intensity (Brisk walking, jogging, cycling, swimming) --> 150min/week, ≥10min/session
  • Weight
    • BMI 18.5 - 24.9, waist 102cm (men) 88cm (women)
  • Smoking/drugs
  • Alcohol consumption
    • Max 15 drinks/week (men), 10 drinks/week (women), no more than 4 on on occasion
  • Hypertension --> CHEP guidelines
  • Oral contraceptives should be stopped
  • Diabetic control
    • HbA1c ≤ 7%, fasting glucose 4.0-7.0 mmol/L, 2hr post-prandial 5.0-10.0 (consider targeting 5.0-8.0 if unable to reach target HbA1c)
    • See CDA guidelines