Step 1: Take a breather. Look at the eyes! Confirm NIHSS 0. Confirm Posterior Stroke Screen Negative.
The elephant in the room is a posterior TIA or stroke, but less than 1% of posterior strokes are missed. Ensure a standard stroke screener (NIHSS) has been completed. The missed ones almost always are NIHSS <4 in which case urgent thrombolysis / clot retrieval would have likely not made a difference, though sometimes having earlier secondary prevention can have a significant benefit for patients. Eye findings are more useful than MRI, which are in turn more useful than CT Brain + neck angiogram. Note NIHSS is only a screening tool – a focused posterior stroke screener is still required to look for subtleties of a posterior stroke.
1a. Look for bidirectional or vertical nystagmus (instant dx CVA!)
1b. Confirm other cerebral vascular territories are intact – NIHSS 0 (link)
1c. Confirm no posterior stroke (link)
1d. Confirm dx actually vertigo (room spinning) – not lightheadedness. Ensure no symptomatic postural hypotension/tachycardia, and MAP > 60 on standing.
Step 2: Be Diagnostically Hungry
…assuming NIHSS 0, and all diagnositc criteria for the following differentials are met.
Triggered Positional Vertigo / BPPV:
– Patient reports it is (a) triggered by head movement, AND (b) relieved on keeping still.
– Positive dix/hallpike
— posterior canal (head over end of bed looking to L/R)
— horizontal canal (head roll to L and R)
— Nystagmus, which is often latent on head positioning (hold for at least 30s), must meet all three criteria below.
—– (1) Inducible
—– (2) Fatiguing – it must go away with keeping still,
—– (3) Typical vertical upbeating/rotating nystagmus on pos canal testing / or typical horizontal nystagmus on horizontal canal testing.
Intermittent Episodic Vertigo: Vestibular migraine
– formally diagnosed migraine (MRI negative, meeting IHS criteria)
– has had previous episodes of similar aura>>HA>>vertigo.
Acute Vestibular Syndrome (continuous nystagmus): Vestibular Neuritis / Labyrintitis
– Clear the HINTS exam
— Catch up saccades observed on head impulse to the ____. (vestibular-ocular reflex not equal because one side not functioning as well)
— Nystagmus fast beating to one horizontal direction only. Otherwise no pathological nystagmus (no rotational, vertical, or bidirectional vertigo)
— Negative test of skew.
– Alexander’s Law: Nystagmus worsens when looking in the direction of the fast beating. Fast beating away from the affected side.
– Able to walk: people with vestibular neuritis can usually walk – with some difficulty but they can walk. People with posterior strokes cannot comprehend their body’s position in time/space and will even have difficulty transferring from a chair to bed.
– Gross hearing test normal: any hearing deficit suggests a stroke.
Step 3: Posterior Stroke Workup
If unable to diagnose BPPV / Vestibular migraine / Vestibular Neuritis with all clinical criteria required.
1) Double check: Consider repeating a focused examination for posterior stroke signs.
2) Imaging
Acutely in ED, this would be a CT Brain + Neck/COW angiogram to identify major occlusions to the vertebrobasilar system / posterior circulation. Ultimately a MRI is required to look at the posterior circulation territories
3) Disposition Planning
Admit all patients with ongoing symptoms even if CT B + Neck/COW reported normal (CT is not sensitive for PCA strokes)
If symptoms completely resolved, treat per local TIA pathway (presumed central until proven otherwise)
Many pearls from this article were from the Vertigo Talk at ASM2024 by Stuart Swadron, FACEP, and a Vertigo Talk by senior vestibular physiotherapists at Peninsula University Hospital 2026.
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