I often have trouble wrapping my head around the concept of TIA. Thinking about it on a continuum with stroke, like the "unstable angina of the brain", caused by the same disease processes and modifiable risk factors as ischemic strokes, has helped me a lot. I have organized the main points into this graphic. I hope it helps you too.
1. TIA exists on a continuum with stroke:
-Even symptoms that resolve after 24 hrs may have abnormality on diffusion-weighted MRI (much more advanced imaging than we had when 24 hr cutoff was developed)
-think of it like “unstable angina of the brain”
-15% of pt’s with TIA go on to have a larger stroke in next 3 months (and HALF of those happen in the first 48 hrs – so start treatment right away!)
-Treatment is same for TIA as for small strokes – namely, to prevent major stroke in future
2. Alternative nomenclature:
Stroke
Persistent deficits
Infarction on imaging
Transient Symptoms with Infarction (TSI)
Deficits resolve
Infarction (stroke) on imaging
Transient Ischemic Attack (TIA)
Deficits resolve
No Infarction (stroke) on imaging
3. Three key elements of TIA history:
-symptoms onset is SUDDEN
-symptom is a DEFICIT (or loss of something – such as sensation or strength)
– the presence of a paresthesia or abnormal smell etc. is more likely intracranial or migraine or seizure
-deficit is FOCAL and makes sense anatomically (correlates to a specific area of the brain or spinal cord – that’s right, the spinal cord can infarct too!)
- multiple/generalized symptoms is usually something else.
4. Exam:
-always perform a complete neuro exam beyond just NIH scale
-thorough cardiac exam (afib? Pulse defecits?)
5. Unique stroke etiologies (other than most common atherosclerotic thromboembolic disease):
-Endocarditis > give IV Abx
-Carotid artery dissection > give AC
-Aortic arch dissection > CT surgery
-Temporal arteritis > corticosteroids
6. TIA mimics:
-focal/partial seizure
-todd’s paralysis
-complex migraine
-recrudescence triggered by other acute illness
-cardiac syncope
-metabolic (glucose, sodium, calcium)
-brain lesion
-demyelinating disease
-acute vestibular syndrome
-peripheral nerve lesion/neuropathy
-CNS infection
-psychogenic
7. Initial evaluation/workup:
-Cardiac monitor (pick up Afib)
-EKG
-Labs (CBC, coags, often a troponin is warranted)
-CT head
-CTA head & neck for large vessel territory
-MRI (does not need to happen this second, but should be urgent, is often needed to confirm the diagnosis, which serves to encourage treatment (e.g. aspirin, statin, smoking cessation) so get it in the ER if you can)
8. Initial treatment in ER:
-162mg aspirin if no bleed on initial CT
-clopidogrel if ASA allergy
-neurology may recommend other anti-platelets (e.g. both ASA & plavix) but you dont have to start both yourself
-markedly elevated BP can be very slowly lowered (like really slowly. Like over days. PO meds not IV). Permissive hypertension is okay acutely because you want to make sure that ischemic brain gets perfused!
9. Who gets admitted?
-AHA says those who have symptoms <72 hrs ago, ABCD2 score >3, and those who are unable to get rapid evaluation as an outpt should be admitted
-Unfortunately, ACEP says that there is not adequate validation of ABCD2 score to make it a reliable SOLO tool for disposition, and I agree, but I figured I would still include it for you guys because it can be used in concert with other risk factors/circumstances (such as co-morbidities, access to quick followup) to determine who should stay to have their MRI/carotid doppler/echo/cardiac monitoring ASAP vs. who can followup w/neuro and cards in the office.
10. Who gets anticoagulation?
-Afib
-ventricular thrombi on echo
-CHADS-VAsc 1 or more in men, 2 or more in women
11. Other treatment (not in ER):
-assess and treat modifiable risk factors (HTN, HLD, DM, smoking)
-carotid stenosis imaging can indicate need for carotid endarterectomy which greatly reduces future TIA/stroke risk, this is probably the most important f/u test to get!
-echo can find Left side thrombus that requires long-term AC. Can also find PFO.
References:
https://www.emrap.org/episode/c3tia/c3tia
Blum CA, Kasner SE. Transient Ischemic Attacks Presenting with Dizziness or Vertigo. Neurol Clin 33 (2015) 629–642. PMID: 26231276
Coutts SB. Diagnosis and Management of Transient Ischemic Attack. Continuum (Minneap Minn) 2017;23(1):82–92.PMID: 28157745
Lo BM, Carpenter CR. Clinical Policy: Critical Issues in the Evaluation of Adult Patients With Suspected Transient Ischemic Attack in the Emergency Department Ann Emerg Med. 2016;68:354-370.PMID: 27568419
Tarnutzer AA, Lee S, et al. ED misdiagnosis of cerebrovascular events in the era of modern neuroimaging. Neurology 2017;88:1468–1477.PMID: 28356464
Easton JD, Saver JL, Albers GW, et al. Definition and evaluation of transient ischemic attack. Stroke. 2009 Jun 1;40(6):2276-93.PMID: 19423857
Prabhakaran S, Silver AJ, Warrior L, et al. Misdiagnosis of transient ischemic attacks in the emergency room. Cerebrovascular Diseases. 2008;26(6):630-5.PMID: 18984948