Abstract 146: Symptomatic Basilar Stenosis Presenting as Focal Tonic Posturing and Wrong Way Eyes

Introduction A common encounter for the Vascular Neurologist assessing emergent neurological complaints is recognition of stroke mimics and stroke chameleons. Unlike mimics, stroke chameleons are presentations that masquerade as an alternative neurological entity when they are truly ischemic in nature. We present a rare case of bilateral pontine infarcts masquerading as a presumptive focal tonic seizure with gaze deviation in a patient with transient decorticate posturing and wrong way eyes secondary to symptomatic basilar stenosis. Materials/Methods Case Report Results We report a case of a 77‐year‐old gentleman with a medical history of coronary artery disease, atrial fibrillation, prior liver transplant, and B‐cell lymphoma in remission who was recently discharged from an outside facility after an episode of right‐sided hemiparesis in the context of several months of kaleidoscopic‐like vision changes where electroencephalogram (EEG) showed left temporal sharp waves. Patient subsequently presented to our emergency department (ED) with fluctuating onset of alternating laterality of facial paralysis over several days and eventually left‐sided hemiparesis. On admission, magnetic resonance imaging (MRI) of the brain showed no evidence of ischemic stroke. While in the ED, the patient had a two‐minute episode of tonic flexion contraction of the left upper extremity, leftward gaze, and intact awareness, with cessation after 2 milligrams of intravenous (IV) lorazepam. He was subsequently loaded with IV lacosamide with suspicion for focal motor seizure resulting in a post‐ictal Todd's paralysis. Follow‐up vessel imaging subsequently showed a severely stenotic basilar artery with intraluminal thrombus, raising concern of brainstem hypoperfusion. EEG the following morning was normal. On day 3, given clinical concern persisted, repeat MRI Brain revealed bilateral pontine infarcts. The patient was treated with IV heparin and blood pressure support. He was ultimately discharged ambulatory with a walker with mild facial palsy. Conclusion With much attention placed on stroke mimics in clinical practice, stroke chameleons require a high index of suspicion for the prompt identification of patients presenting with acute ischemic stroke. Brainstem ischemia warrants close attention, with decorticate posturing presenting similarly to a focal tonic motor seizure and a paramedian pontine reticular formation lesion presenting with wrong way eyes (i.e. gaze deviation towards the affected limb), exhibiting high potential for misdiagnosis. This case highlights the complexities of brainstem anatomy, places focus on the variability of the presenting features of stroke and underscores the caliber clinical suspicion carries in patients with MRI‐negative strokes.