Disabling wake up stroke without lesions on initial diffusion weighted imaging - Case report and clinical implications.

An 86-year-old lady presented after waking up with left sided paresis and neglect. Right hemispheral stroke was suspected, but initial MRI with Diffusion Weighted Imaging (DWI) was negative and there was no large vessel occlusion. We accordingly withheld intravenous thrombolysis. She did not improve clinically and follow-up MRI after three days showed a marked lesion compatible with acute ischemic stroke in the right middle cerebral artery territory. This case shows that even with a disabling stroke in the anterior circulation initial DWI may be negative. Former studies established that thrombolysis can be safe in these cases when there is no doubt about the clinical diagnosis of acute ischemic stroke.