

These patients are misdiagnosed twice as often as those with anterior events. 6 The physical examination to detect them is more nuanced the National Institutes of Health Stroke Scale (NIHSS) is weighted toward the anterior circulation 7 and patients with posterior circulation strokes can have a NIHSS of zero with disabling deficits. 1- 4 Common posterior circulation stroke symptoms, including dizziness, clumsiness or imbalance, visual symptoms (diplopia, field cuts, or blurred vision), anisocoria, confusion and altered mental status, vomiting, headache and neck pain, problems with speech and swallowing, and decreased hearing, 5 are less specific than typical anterior circulation stroke symptoms. Posterior circulation strokes represent 20% of all ischemic strokes. Strategies to avoid misdiagnosis include establishing an abrupt onset of symptoms, awareness of the nonspecific presentations, consideration of basilar stroke in altered patients and using a modern approach to diagnosis of the acutely dizzy patient. We present a symptom-based review of posterior circulation ischemia focusing on the subtler presentations with a brief discussion of basilar stroke, both of which can be missed by the emergency physician. Understanding important anatomic variants, the clinical presentations, relevant physical examination findings, and the limitations of acute brain imaging may help reduce misdiagnosis. Misdiagnosed patients likely have worse outcomes than correctly diagnosed patients because they are at risk for complications of the initial stroke as well as recurrent events due to lack of secondary stroke prevention and failure to treat the underlying vascular pathology. Posterior circulation stroke patients are misdiagnosed twice as often compared to those with anterior events.

Posterior circulation strokes represent 20% of all acute ischemic strokes.
