Study objective: It is now clear that transient ischemic attacks and strokes are different manifestations of the same disease and transient ischemic attacks are often warning signs of an impending stroke. Unfortunately, it is unclear when the next event will occur in an individual patient. It is critical for emergency physicians to know what the true risk of stroke is for patients who present to the emergency department (ED) with a transient ischemic attack and a normal neurologic examination result. We perform an evidence-based emergency medicine shortcut review of the short-term outcome of stroke among patients diagnosed in the ED with a transient ischemic attack.
Methods: We searched PubMed for articles that studied patients with transient ischemic attack and reported their risk of stroke up to 30 days. We used standard criteria to appraise the quality of prognostic studies.
Results: Eight studies met the inclusion criteria; 5 were conducted prospectively and 3 had a retrospective design. Of the 5 prospective studies, only 2 enrolled patients from the ED. The 48-hour risk of stroke after transient ischemic attack ranged from 1.4% to 9.9% and the 7-day risk ranged from 3.8% to 12.8%. However, the 2 ED-based studies suggest that the short-term risk of having a stroke after a transient ischemic attack in the next 48 hours is approximately 3% to 5% and during the next week is 4% to 7%.
Conclusion: According to studies assessing the short-term prognosis of patients diagnosed with transient ischemic attack in the ED, approximately 1 in 20 patients will have a stroke during the following 48 hours.