Podcast #499: Posterior Circulation Ischemia

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