Transient ischemic attack

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A transient ischemic attack (TIA) is a type of transient neurological attack. In a TIA, the focal area of brain cells were not killed, but only transiently deprived of blood supply and the signs of what seems to be a stroke, (or black-out), pass quickly and completely. A TIA is often a warning sign of an impending stroke, however, and like a true stroke, is a neurological emergency. None the less, a TIA is not a true stroke.

Diagnosis

History and physical examination

The history and physical examination of patients with a possible TIA is difficult to interpret. Two neurologists interviewing the same patient have statistically 'substantial' but imperfect agreement about whether the patient had a TIA.[1] Disagreement may occur even when a 'standardized' patient is trained to give identical histories to each neurologist.[2]

Differential diagnosis

Other disorders that may cause similar symptoms are syncope, seizure, migraine, vestibulopathy, and conversion disorder.[3]

Treatment

Anti-platelet drugs

The most effective anti-platelet treatment is probably to combine aspirin, 25 mg twice a day with extended-release dipyridamole 200 mg twice a day according to the ESPRIT[4]

The combination of aspirin and clopidogrel should probably be avoided according to the MATCH[5] and CHARISMA[6] studies.

Invasive treatment

Carotid endarterectomy may prevent stroke in patients with more than 70% stenosis of the carotid artery.[7]

Expedited care protocol

A before and after comparison study found reduced mortality fell from 10% to 2% with the following protocol started the day the patient presents for medical care:[8]

  • "antiplatelet therapy: aspirin in patients not already on antiplatelet therapy (75 mg daily), or clopidogrel if aspirin was contraindicated" (loading dose of clopidogrel 300 mg).
    • * "In patients seen within 48 h of their event, or those seen within 7 days who were thought to be at particularly high early risk", clopidogrel (75 mg daily, to be stopped after 30 days; loading dose of clopidogrel 300 mg) was recommended in addition to aspirin."[9]
    • However, as noted above combining aspirin 25 mg twice a day with extended-release dipyridamole 200 mg twice a day might be a better choice than either aspirin alone or aspirin combined with clopidogrel.
  • simvastatin 40 mg daily
  • "blood pressure lowering unless systolic blood pressure was below 130 mm Hg on repeated measurement (either by increases in existing medication, or by commencement of perindopril 4 mg daily with or without indapamide 1·25 mg daily)"
  • anticoagulation as required
  • "Brain imaging was required before starting combination antiplatelet treatment or anticoagulation after a minor stroke"

Prognosis

A meta-analysis of 18 cohort studies found the risk of stroke after 7 days varies from 0% to 13%. The lowest rates were in studies of emergency treatment by specialist stroke services.[10]

The risk of stroke among patients presenting to the emergency room with a TIA is approximately 3% to 5% in the next 2 days and 4% to 7% over the next week according to a second meta-analysis.[11] This meta-analysis thought the ABCD2 (below) provided the best estimate.

Calculating estimated prognosis

The ABCD2 score is a clinical prediction rule that can predict likelihood of subsequent stroke.[12][13]

The score is calculated as:

  • Age ≥ 60 years = 1 point
  • Blood pressure at presentation ≥ 140/90 mm Hg = 1 point
  • Clinical features
unilateral weakness = 2 points
speech disturbance without weakness = 1 point
  • Duration of attack
≥ 60 minutes = 2 points
10–59 minutes = 1 point
  • Diabetes = 1 point

Interpretation of score, the risk for stroke:

  • Score 0-3 (low)
    • 2 day risk = 1.0%
    • 7 day risk = 1.2%
  • Score 4-5 (moderate)
    • 2 day risk = 4.1%
    • 7 day risk = 5.9%
  • Score 6–7 (high)
    • 2 day risk = 8.1%
    • 7 day risk = 11.7%

References

  1. ↑ Kraaijeveld CL, van Gijn J, Schouten HJ, Staal A (1984). "Interobserver agreement for the diagnosis of transient ischemic attacks". Stroke 15 (4): 723–5. PMID 6464066. [e]
  2. ↑ Koudstaal PJ, Gerritsma JG, van Gijn J (1989). "Clinical disagreement on the diagnosis of transient ischemic attack: is the patient or the doctor to blame?". Stroke 20 (2): 300–1. PMID 2919420. [e]
  3. ↑ Johnston SC (2007). "Transient Neurological Attack: A Useful Concept?". JAMA 298 (24): 2912–2913. DOI:10.1001/jama.298.24.2912. PMID 18159062. Research Blogging.
  4. ↑ Halkes PH, van Gijn J, Kappelle LJ, Koudstaal PJ, Algra A (2006). "Aspirin plus dipyridamole versus aspirin alone after cerebral ischaemia of arterial origin (ESPRIT): randomised controlled trial". Lancet 367 (9523): 1665–73. DOI:10.1016/S0140-6736(06)68734-5. PMID 16714187. Research Blogging.
  5. ↑ Diener HC, Bogousslavsky J, Brass LM, et al (2004). "Aspirin and clopidogrel compared with clopidogrel alone after recent ischaemic stroke or transient ischaemic attack in high-risk patients (MATCH): randomised, double-blind, placebo-controlled trial". Lancet 364 (9431): 331–7. DOI:10.1016/S0140-6736(04)16721-4. PMID 15276392. Research Blogging.
  6. ↑ Bhatt DL, Fox KA, Hacke W, et al (2006). "Clopidogrel and aspirin versus aspirin alone for the prevention of atherothrombotic events". N. Engl. J. Med. 354 (16): 1706–17. DOI:10.1056/NEJMoa060989. PMID 16531616. Research Blogging.
  7. ↑ (1991) "Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators". N. Engl. J. Med. 325 (7): 445–53. PMID 1852179. [e]
  8. ↑ Rothwell PM, Giles MF, Chandratheva A, et al (2007). "Effect of urgent treatment of transient ischaemic attack and minor stroke on early recurrent stroke (EXPRESS study): a prospective population-based sequential comparison". Lancet 370 (9596): 1432–42. DOI:10.1016/S0140-6736(07)61448-2. PMID 17928046. Research Blogging.
  9. ↑ Markus HS, Droste DW, Kaps M, et al (2005). "Dual antiplatelet therapy with clopidogrel and aspirin in symptomatic carotid stenosis evaluated using doppler embolic signal detection: the Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic Carotid Stenosis (CARESS) trial". Circulation 111 (17): 2233–40. DOI:10.1161/01.CIR.0000163561.90680.1C. PMID 15851601. Research Blogging.
  10. ↑ Giles MF, Rothwell PM (2007). "Risk of stroke early after transient ischaemic attack: a systematic review and meta-analysis". Lancet Neurol 6 (12): 1063–72. DOI:10.1016/S1474-4422(07)70274-0. PMID 17993293. Research Blogging.
  11. ↑ Shah KH, Kleckner K, Edlow JA (2008). "Short-term prognosis of stroke among patients diagnosed in the emergency department with a transient ischemic attack". Ann Emerg Med 51 (3): 316-23. DOI:10.1016/j.annemergmed.2007.08.016. PMID 18282526. Research Blogging.
  12. ↑ Johnston SC, Rothwell PM, Nguyen-Huynh MN, et al (2007). "Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack". Lancet 369 (9558): 283-92. DOI:10.1016/S0140-6736(07)60150-0. PMID 17258668. Research Blogging.
  13. ↑ Rothwell PM, Giles MF, Flossmann E, et al (2005). "A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack". Lancet 366 (9479): 29-36. DOI:10.1016/S0140-6736(05)66702-5. PMID 15993230. Research Blogging.
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