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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.

It may first be seen by an emergency physician, who will obtain neurological consultation.

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"

Another approach is based on the ABCD2 score (see below). If score 6-7, hospitalize patient If score 4-5, image carotids and admit if significant stenosis.[10]

Prognosis

Overall, about 10% of patients will have a stroke within 7 days.[11] This is especially true in patients with TIA due to small-vessel disease (SVD) etiology with motor weakness (capsular warning syndrome).[11]

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.[12]

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.[13] This meta-analysis thought the ABCD2 (below) provided the best estimate.

Prognosis is worse if the carotid artery has a greater than 70% obstruction.[14]

Calculating estimated prognosis

History and physical

"The simpler FAST scale could replace the more complex ROSIER for the initial assessment of patients with suspected acute stroke in the emergency department.". [15]

ABCD2

The ABCD2 score (http://www.stroke.org/site/DocServer/NSA_ABCD2_tool.pdf) is a clinical prediction rule that can predict likelihood of subsequent stroke over short term[16][17][18][19] or long term[20].

The risk of stroke depends on the study setting and how the data for the score was collected.[21] It may not work as well in a group with only a 2% risk of stroke within one week.[22]

Calculation of score

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 from the original study:

  • 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%
Improvements to the ABCD2

The ABCD2 score may be improved by adding the results of diffusion-weighted magnetic resonance imaging (MRI) to look for infarction.[23]

The score may be improved by the ABCD3 score which adds a point for 'dual' attacks within 7 days.[24]

The ABCD and ABCD2 may be improved by adding hyperglycemia and a history of hypertension.[25]

Diagnostic imaging

The rule may be improved by adding the presence of brain infarction visualized on diagnostic imaging using either brain infarction on either diffusion-weighted magnetic resonance imaging or computed tomography[26] or brain imaging combined with imaging of the carotid artery (ABCD3-I).[24]

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. Olivot JM, Wolford C, Castle J, Mlynash M, Schwartz NE, Lansberg MG et al. (2011). "TWO ACES: Transient Ischemic Attack Work-Up as Outpatient Assessment of Clinical Evaluation and Safety.". Stroke 42 (7): 1839-43. DOI:10.1161/STROKEAHA.110.608380. PMID 21617143. Research Blogging.
  11. 11.0 11.1 Paul NL, Simoni M, Chandratheva A, Rothwell PM (2012). "Population-based study of capsular warning syndrome and prognosis after early recurrent TIA.". Neurology 79 (13): 1356-62. DOI:10.1212/WNL.0b013e31826c1af8. PMID 22972645. PMC PMC3448742. Research Blogging.
  12. 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.
  13. 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.
  14. Ois A, Cuadrado-Godia E, Rodríguez-Campello A, Jimenez-Conde J, Roquer J (2009). "High risk of early neurological recurrence in symptomatic carotid stenosis.". Stroke 40 (8): 2727-31. DOI:10.1161/STROKEAHA.109.548032. PMID 19498196. Research Blogging.
  15. Whiteley WN, Wardlaw JM, Dennis MS, Sandercock PA (2011). "Clinical scores for the identification of stroke and transient ischaemic attack in the emergency department: a cross-sectional study.". J Neurol Neurosurg Psychiatry 82 (9): 1006-10. DOI:10.1136/jnnp.2010.235010. PMID 21402744. Research Blogging.
  16. Asimos AW, Johnson AM, Rosamond WD, Price MF, Rose KM, Catellier D et al. (2010). "A multicenter evaluation of the ABCD2 score's accuracy for predicting early ischemic stroke in admitted patients with transient ischemic attack.". Ann Emerg Med 55 (2): 201-210.e5. DOI:10.1016/j.annemergmed.2009.05.002. PMID 19556026. Research Blogging.
  17. 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.
  18. 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.
  19. Chandratheva A, Mehta Z, Geraghty OC, Marquardt L, Rothwell PM (June 2009). "Population-based study of risk and predictors of stroke in the first few hours after a TIA". Neurology 72 (22): 1941–7. DOI:10.1212/WNL.0b013e3181a826ad. PMID 19487652. Research Blogging.
  20. Wijnhoud AD, Maasland L, Lingsma HF, Steyerberg EW, Koudstaal PJ, Dippel DW (2010). "Prediction of major vascular events in patients with transient ischemic attack or ischemic stroke: a comparison of 7 models.". Stroke 41 (10): 2178-85. DOI:10.1161/STROKEAHA.110.580985. PMID 20814011. Research Blogging.
  21. Giles MF, Rothwell PM (2010). "Systematic review and pooled analysis of published and unpublished validations of the ABCD and ABCD2 transient ischemic attack risk scores.". Stroke 41 (4): 667-73. DOI:10.1161/STROKEAHA.109.571174. PMID 20185786. Research Blogging.
  22. Perry JJ, Sharma M, Sivilotti ML, Sutherland J, Symington C, Worster A et al. (2011). "Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack.". CMAJ 183 (10): 1137-45. DOI:10.1503/cmaj.101668. PMID 21646462. PMC PMC3134721. Research Blogging.
  23. Giles MF, Albers GW, Amarenco P, Arsava EM, Asimos AW, Ay H et al. (2011). "Early stroke risk and ABCD2 score performance in tissue- vs time-defined TIA: A multicenter study.". Neurology 77 (13): 1222-8. DOI:10.1212/WNL.0b013e3182309f91. PMID 21865578. PMC PMC3179650. Research Blogging.
  24. 24.0 24.1 Merwick A, Albers GW, Amarenco P, Arsava EM, Ay H, Calvet D et al. (2010). "Addition of brain and carotid imaging to the ABCD² score to identify patients at early risk of stroke after transient ischaemic attack: a multicentre observational study.". Lancet Neurol 9 (11): 1060-9. DOI:10.1016/S1474-4422(10)70240-4. PMID 20934388. Research Blogging.
  25. Fothergill A, Christianson TJ, Brown RD, Rabinstein AA (2009). "Validation and refinement of the ABCD2 score: a population-based analysis.". Stroke 40 (8): 2669-73. DOI:10.1161/STROKEAHA.109.553446. PMID 19520983. Research Blogging.
  26. Giles MF, Albers GW, Amarenco P, Arsava MM, Asimos A, Ay H et al. (2010). "Addition of brain infarction to the ABCD2 Score (ABCD2I): a collaborative analysis of unpublished data on 4574 patients.". Stroke 41 (9): 1907-13. DOI:10.1161/STROKEAHA.110.578971. PMID 20634480. Research Blogging.