High mimic rate among recipients of intravenous thrombolysis for acute minor ischemic stroke presenting with disabling symptoms

This single-center, retrospective study reviewed patients with NIHSS scores of ≤5 and disabling symptoms who received IV thrombolytics for suspected acute ischemic stroke from March 2018 to March 2023. Univariate analysis compared demographics and characteristics between stroke and stroke mimic groups using Chi-square or Fisher's exact test for categorical variables and Wilcoxon's rank-sum test for continuous variables. Among 61 patients identified, 29 % (n = 18) were classified as stroke mimics. There were no significant differences in age, gender, presenting symptoms. Hypertension, hyperlipidemia and diabetes mellitus was more predominant among stroke patients. Although not statistically significant, the rate of adverse events was higher among stroke patients compared to stroke mimics (9 % vs 0 %, p = 0.30). One patient developed symptomatic intracerebral hemorrhage, two patients experienced asymptomatic intracerebral hemorrhage and one patient had gross hematuria while no adverse events were observed in the stroke mimic group. Stroke mimics were more likely to achieve a good functional outcome at discharge (mRS <1) compared to stroke patients (89 % vs 37 %, p = 0.008). The final discharge diagnoses for stroke mimics included migraine(50 %), toxic-metabolic encephalopathy (27 %), seizures (17 %) and somatoform disorders (5 %). None of the stroke mimic patients experienced adverse events post-IV thrombolysis. In contrast, 1 stroke patient (2 %) developed symptomatic intracranial hemorrhage, two patients (4.6 %) had asymptomatic intracranial hemorrhage and one patient(2 %) had minor extracranial bleeding (gross hematuria) CONCLUSIONS: The high percentage of stroke mimics among patients with NIHSS ≤5 despite disabling features suggests a need for improved diagnostic tools to distinguish true strokes from mimics. Importantly, thrombolytic therapy was not associated with significant adverse events in stroke mimic patients, who had a better functional outcome at discharge.