Stroke Mimics in a Stroke Care Pathway Based on MRI Screening

Abstract

Background: Since the use of tissue plasminogen activator for acute ischemic stroke (IS), stroke care pathways have been developed for patients with suspicion of acute stroke. The aim of this prospective observational study was to analyze the stroke mimic (SM) characteristics in patients who were part of our stroke care pathway. Methods: All consecutive patients admitted in the code stroke within a 1-year period were prospectively enrolled in this study. Patients with a sudden onset of neurological focal deficit in a time window less than 4H30 as indicated for intravenous thrombolysis, had been accepted in the pathway by a neurologist who was directly contactable by the prehospital emergency medical service 24 h per day. Patients arrived directly on the MRI site without passing by the emergency department. A clinical neurological evaluation and a brain MRI with tri-dimensional time-of-flight magnetic resonance angiography were performed. The FAST score was calculated a posteriori. The final discharge diagnosis was concluded either immediately after both neurological examination and cerebrovascular neuroimaging or after other relevant investigations. We classified the discharge diagnosis into neurovascular diseases (NVDs) and into SM. Results: There were 1,361 consecutive patients admitted for suspicion of acute stroke. Sixty-two percent (n = 840) had an NVD including IS (n = 529), transient ischemic attacks (n = 236), intracranial hemorrhages (n = 68), cerebral venous thrombosis (n = 3) and neurovascular medullar pathologies (n = 4). SM represented 38% of cases (n = 521) and the most frequent discharge diagnosis was defined as headaches (18.6%), psychological disorders (16.7%), peripheral vertigo (11.9%) and epilepsy (10.6%). The comparison between the characteristics of the NVD and those of the SM groups showed some significant differences: in the SM group, women were more represented, patients were younger and the NIHSS was lower than in the NVD group. All cardiovascular risk factors were more represented in the NVD group. Concerning the symptoms, motor deficit, speech disturbances, homonymous lateral hemianopia and head and gaze deviation were more represented in the NVD group, whereas vertigo, non-systematized visual trouble, headache, confusion, weakness, neuropsychological symptoms, seizure and chest pain were significantly more frequent in the SM group. The negative predictive value of the FAST score was 64% and the positive predictive value was 76%. Conclusions: A rate of SM up to 38% of the code stroke system confirms the difficulty to distinguish clinically a stroke from another diagnosis. In this study, using cerebral MRI in first intention was of special interest in patients with acute neurological symptoms to differentiate an NVD from an SM.