Characteristics and Predictors of Stroke Mimics in Young Patients in The Norwegian Tenecteplase Stroke Trial (NOR-TEST)

Abstract Background: Several studies have shown that stroke mimics occur more often among young patients. Our aims were to identify the common mimics in young patients under the age of 60 years who received thrombolysis, to analyze the risk of hemorrhage after treatment with thrombolysis, and to identify risk factors and clinical parameters that might identify mimics in this group. Methods: Norwegian Tenecteplase Stroke Trial was a phase-3 trial investigating safety and efficacy of tenecteplase vs alteplase in patients with acute ischemic stroke. Patients diagnosed with either acute cerebral ischemia or transient ischemic attack were categorized as stroke group, and patients with any diagnosis other than ischemic stroke or transient ischemic attack as mimics group. Patients were grouped post-hoc into young (<60 years) and old (≥60 years). Logistic regression analyses were performed with mimics vs stroke as dependent variable to identify predictors of mimics. Results: Of the 1091 patients included in the trial, 211 patients (19.3%) were under the age of 60 years. Sixty-nine patients (32.7%) out of the 211 patients under the age of 60 were diagnosed as mimic. Mimics were significantly more frequent among the young (OD=3.3, 32.7% vs 12.8%, p=<.001). The most frequent mimics diagnoses among patients under 60 years of age were migraine (11.8%), no definite diagnosis (11.4%) and peripheral vertigo (3.3%). Mimics were independently associated with age <50 years (OR=4.97, p=<0.001), not currently working/studying (OR=3.39, p=0.002) and not having aphasia on admission (OR=2.95, p=0.025). None of the mimics under the age of 60 years had a symptomatic or asymptomatic intracerebral hemorrhage as a complication to thrombolysis. Conclusion: We found significantly more mimics in the young, of which migraine was the most predominant diagnosis. Thrombolysis of mimics with alteplase or tenecteplase were both safe. It is not possible to identify mimics reliably using risk factors and clinical parameters alone.