Unknown Onset Stroke: Differences Between Patients with Wake-Up Stroke and Daytime-Unwitnessed Stroke

Objectives: Patients with unknown onset stroke (UOS) can be categorized as wake-up stroke (WUS) and daytime-unwitnessed stroke (DUS). We sought to determine whether decisions for initial imaging modalities, frequency of mismatch findings, resulting treatment decisions and outcome differ between WUS and DUS patients. Materials and Methods: In a retrospective analysis, all patients with UOS admitted to our Stroke Unit from January to December 2018 were evaluated and classified as either WUS or DUS. Results: 180 patients were included (74.4 % WUS, 25.6 % DUS). Compared to WUS patients, DUS patients received more often a non-contrast computed tomography initially (43.5 % vs. 24.6 %, p = 0.016). MR imaging was performed more frequently in WUS patients (53.7% vs. 34.8%, p = 0.027). The rate of mismatch findings in patients examined with either multimodal CT or MRI (126 patients, 101 WUS and 26 DUS) did not differ between the groups. Likewise, the rate of intravenous thrombolysis or mechanical thrombectomy was similar in both groups. DUS patients had more often severe neurological deficits at admission as defined by the National Institutes of Stroke Scale score (14.2 vs. 8.6, p < 0.001). Conclusions: Patients with DUS had disadvantages in mismatch-based treatment options due to initial imagingmodalities. Current data do not support different treatment concepts in WUS and DUS patients. All UOS patients should initially be evaluated by either multimodal CT or MRI to open a chance to receive reperfusion therapy.