Podcast # 499: Posterior Circulation Strokes Contributor: Neal O’Connor, MD Educational Pearls: Dizziness is a very common complaint in the emergency department, but how can we find patients with a dangerous cause of their symptoms, namely a posterior circulation stroke? Consider a posterior circulation stroke in those with an abrupt onset of headache with neck pain, balance problem, blurred vision, or dysphagia  Thorough cranial nerve exam can be important to screen for posterior circulation stroke, as much of the brainstem is supplied by the posterior circulation.  The most common posterior circulation stroke is a lateral medullary infarct (Wallenberg Syndrome), which produces dysphagia due to cranial nerve IX and XII involvement Other physical exam findings include truncal ataxia, extremity ataxia, visual field cuts, and Horner syndrome (Ptosis, Miosis, Anhidrosis)  The HINTS exam (Head Impulse - Nystagmus - Test of Skew)can be used to differentiate between peripheral and central causes of dizziness Concerning exam findings for central cause may include vertical nystagmus, gaze skew, or inability to track with head impulse References Áine Merwick, David Werring. Posterior circulation ischaemic stroke. BMJ 2014;348:g3175 doi: 10.1136/bmj.g3175 Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504–3510. doi:10.1161/STROKEAHA.109.551234 Nouh A, Remke J, Ruland S. Ischemic posterior circulation stroke: a review of anatomy, clinical presentations, diagnosis, and current management. Front Neurol. 2014;5:30. Published 2014 Apr 7. doi:10.3389/fneur.2014.00030   From CarePoint PA Academy, 2019