[Wake up stroke: Overview on diagnostic and therapeutic options for ischemic stroke on awakening].

Up to 25 % of all acute ischemic strokes (AIS) occur during sleep with the patients or relatives becoming aware of their neurological deficits as they wake up. Because of the unclear time of stroke onset patients with stroke on awakening are usually not considered for acute therapies and excluded from most treatment trials. We give an overview of the published data regarding ischemic wake up strokes (WUS). In particular we focused on baseline characteristics, imaging methods and therapy strategies. Comparing WUS patients and patients with known stroke onset there were no major differences found regarding patient characteristics, etiology, clinical and radiological characteristics. Even though there is no existing gold standard multiparametric neuroimaging (CT; MRI) appears to be helpful for decision making whether to treat a WUS patient with thrombolysis or not. Especially multiparametric MRI which proved to be safe in patients within an extended time window might serve as an adequate diagnostic tool. The results of first pilot studies analyzing treatment of WUS demonstrate that a substantial number of these patients can be treated with IV thrombolysis (IVT) successfully. Large randomized, controlled, prospective clinical trials for patients with WUS are needed to test safety and efficacy of IVT and to evaluate the assumed benefit of multiparametric neuroimaging techniques in this patient group. The results of first pilot studies may be instrumental to help plan and design such trials.