Urgent Evaluation and Management of Suspected Posterior Circulation Ischemia

Critical Diagnostic Approach

The American College of Radiology recommends brain MRI with diffusion-weighted imaging (DWI) as the examination of choice to identify acute ischemic lesions in the posterior circulation, which is superior to CT for detecting brainstem and cerebellar infarcts 1, 2
The American College of Radiology also recommends MRA or CTA of head and neck vessels to evaluate for vertebrobasilar insufficiency, carotid stenosis, or arterial dissection 1, 2
Bilateral visual symptoms with balance disturbance and wide-based gait represent a neurological emergency with high stroke risk in the vertebrobasilar territory, according to Praxis Medical Insights 2
The wide-based gait specifically suggests cerebellar involvement, which is supplied by the posterior circulation, as noted by Praxis Medical Insights 2

The American Academy of Ophthalmology suggests that temporal headache can accompany vertebrobasilar ischemia 3
Stroke risk is maximal within the first few days after symptom onset, making this time-critical, according to Praxis Medical Insights 2
Space-occupying lesion (posterior fossa tumor, cerebellar mass) causing increased intracranial pressure with cranial nerve involvement and ataxia should be considered, as noted by Praxis Medical Insights 4

The American Academy of Ophthalmology recommends complete visual acuity testing to detect vision-threatening pathology 4
Pupillary examination to identify afferent defects (suggesting optic nerve involvement) or efferent defects (suggesting third nerve palsy) is recommended by the American Academy of Ophthalmology 3, 4
Detailed sensorimotor examination demonstrating alignment in multiple gaze positions to localize which cranial nerve(s) are affected is suggested by the American Academy of Ophthalmology 3, 5

The American College of Radiology recommends ESR and CRP measurement if temporal headache raises concern for giant cell arteritis, though this is less common in younger patients 1, 2
Hemoglobin A1c and fasting glucose should be assessed to evaluate chronic glycemic control, according to the American Academy of Ophthalmology 3
ECG and echocardiography to assess for cardioembolic sources, particularly important in patients with risk factors, are recommended by Praxis Medical Insights 2

Reassurance alone is never appropriate for sudden-onset diplopia with neurological signs, according to Praxis Medical Insights 4
Attempting to complete a full ophthalmologic workup before neuroimaging risks missing time-sensitive diagnoses like stroke or tumor, as noted by Praxis Medical Insights 4
Nothing by mouth until swallow evaluation if brainstem involvement suspected to prevent aspiration, according to Praxis Medical Insights 2