The chart below dividing "Dizziness" into vertigo, unsteadiness & presyncope is the classic teaching. However it is not evidence-based, and type of dizziness is not a trustworthy predictor of cause. Keep a broad differential and consider CVA & cardiac etiologies in all forms of dizziness.
Vertigo: Is it transient or persistent?
[ ] EKG for ?cardiac arrythmias
[ ] Hearing loss, tinnitus / roaring, ear fullness? Attacks lasting minutes to a few hours?
- Supports Meniere's, or endolymphatic hydrops, believed to be too much inner ear fluid but exact pathophyz debated
- Will need ENT f/u, MRI to r/o other causes such as schwannoma
[ ] Dix-Halpike: only positive if markedly reproduces symptoms that fatigue over 20-30 seconds, and a/w torsional (rotational) nystagmus that also fatigues. Usually 5-10 seconds of latency prior symptoms. Supports BPPV.
[ ] If c/f TIAs, may need head / neck imaging, admission
- Note that vascular supply to the inner ear derives from posterior cerebellar circulation, so hearing loss alone is not definitive for peripheral process
Persistent = Acute Vestibular Syndrome
Main differential is CVA vs. peripheral process
[ ] Abrupt onset? Recurrent seconds-to-minutes episodes over preceding weeks / months?
[ ] H/o trauma? Age > 50? Vascular risk factors? Auditory symptoms?
- These all suggest a CVA. Trauma and/or neck pain raise c/f vertebral dissection. Note that 1 in 4 dissections have no pain or headache.
[ ] HINTS testing
- More sensitive for stroke than MRI!
[ ] No Dix-Halpike indicated in a //persistent AVS situation
[ ] Neuro exam should also include
- finger-to-nose, heel-to-shin, rapid-alternating movements
- truncal ataxia (patient can sit still with arms crossed on chest)
- Head Impulse: Quick deviations of head to R or L (unpredictably) while patient looks at nose, watch for a catchup-saccad. It should occur when head turned to side of a peripheral process.
- Nystagmus: Observe for in primary, R, and L gaze. Unidirectional supports a peripheral process.
- Test of Skew: Alternate covering each eye, watching for any vertical eye refixations
INFARCT: mnemonic for remembering red flags on HINTS testing:
- Impulse Normal: If no catch-up saccads noted, this is concerning for stroke. (But there are rare pontine strokes that do also cause a catchup saccad, so a catchup saccad on HI test does not alone rule out stroke.)
- Fast-Phase Alternating: Nystagmus should not be direction-changing (i.e. left-beating when looking L and right-beating when looking R).
- Refixation on Cover Test: If one or other eye has to keep refixating vertically when uncovered, c/f brain stem stroke
A brain-stem stroke can appear clinically stable but over the next 1-3 days deteriorate with increased swelling / bleeding, so needs managed at a neurosurgery-capable center.