Management of Vestibular Disturbance from Posterior Fossa Lesion

Initial Clinical Assessment

The American College of Radiology recommends MRI brain without IV contrast as the initial imaging modality in patients with vestibular disturbance suspected to be related to a posterior fossa lesion, with urgent neuroimaging indicated when there are abnormal neurologic findings, abnormal HINTS examination by a trained specialist, or high vascular risk factors 1
The initial clinical assessment should categorize the vestibular syndrome pattern, which drives the diagnostic and imaging approach, including acute vestibular syndrome, triggered episodic syndrome, spontaneous episodic syndrome, and chronic vestibular syndrome 2

MRI head without IV contrast is the most sensitive test for posterior circulation infarcts and posterior fossa pathology, superior to CT, which misses a significant proportion of posterior fossa lesions 1
In patients with chronic recurrent vertigo and brainstem neurologic deficits suggesting vertebrobasilar insufficiency, MRA head and neck or CTA head and neck are useful for evaluating the posterior circulation vasculature 1, 4

Approximately 25% of patients with acute vestibular syndrome have cerebrovascular disease, rising to 75% in high vascular risk cohorts, and 75-80% of patients with posterior circulation infarct have no focal neurologic deficits on standard examination 3
Older age, hypertension, atrial fibrillation, nonwhirling type of dizziness, and combined neurological symptoms are vascular risk factors that require a lower threshold for imaging 1

Posterior circulation stroke accounts for 3.6% of patients presenting with dizziness who have acute lesions, and isolated transient vertigo may precede vertebrobasilar stroke by weeks or months 1, 2
Vestibular schwannoma and other tumors should be considered in patients with chronic recurrent vertigo and unilateral hearing loss or tinnitus, and MRI head and internal auditory canal without and with IV contrast is useful for excluding vestibular schwannoma 1

Normal neurologic examination should not be relied upon to exclude stroke, as 75-80% of posterior circulation strokes present without focal deficits 3
CT should not be used as definitive imaging, as it is insensitive for posterior fossa infarcts, and imaging should not be delayed in high vascular risk patients, even with peripheral-appearing symptoms 1