Differential Diagnosis of Positional Vertigo

PERIPHERAL CAUSES

1. Benign Paroxysmal Positional Vertigo (BPPV) ★ Most Common

• Mechanism: Free-floating otoconia (calcium carbonate crystals) dislodged from the utricular macula into a semicircular canal (posterior > horizontal > anterior)
• Duration: < 1 min per episode (typically 15–20 s)
• Triggers: Lying down, rolling over in bed, rising supine → sitting, head extension ("looking up")
• Nystagmus: Posterior canal → upbeat + torsional (top poles toward affected ear); horizontal canal → horizontal nystagmus bilaterally
• Diagnosis: Dix-Hallpike test (posterior canal); supine roll test (horizontal canal)
• Distinguishing feature: Brief, fatigable, latency of 1–5 s before nystagmus onset, suppressed by fixation
• Treatment: Epley maneuver (posterior canal); barbecue roll (horizontal canal)

2. Vestibular Neuritis

• Vertigo worsens with movement but is not exclusively positional; can mimic BPPV after the acute phase
• Associated small-angle persistent nystagmus; no hearing loss

3. Perilymph Fistula

• Abnormal opening between middle and inner ear
• Positional or straining-provoked vertigo
• History of trauma, barotrauma, heavy lifting

4. Labyrinthitis

• Vertigo + sensorineural hearing loss (differentiates from vestibular neuritis)
• Movement exacerbates symptoms

5. Ménière Disease

• Triad: Episodic vertigo + fluctuating sensorineural hearing loss + tinnitus ± aural fullness
• Episodes last 20 min–hours (not seconds)
• Mechanism: endolymphatic hydrops

6. Acoustic Neuroma (Vestibular Schwannoma)

• Usually progressive unilateral sensorineural hearing loss over months; vertigo uncommon as dominant symptom
• Can occasionally present with positional symptoms

7. Other Peripheral

• Otitis media, foreign body in canal, labyrinthine concussion/trauma

CENTRAL CAUSES (Red Flags — Must Not Miss)

8. Central Positional Vertigo / Central Positional Nystagmus

• Lesions of the dorsolateral fourth ventricle or dorsal cerebellar vermis
• Nystagmus: typically downbeating, short latency, non-fatigable, atypical direction, not responsive to Epley
• Causes: cerebellar infarction, Chiari malformation, cerebellar tumors, MS, cerebellar degeneration

9. Vestibular Migraine (Migrainous Vertigo) ★ Underdiagnosed

• One of the most common central mimics of BPPV
• Vertigo lasts minutes to hours (longer than BPPV)
• May occur with or without headache; photophobia, phonophobia common
• Nystagmus may be of central or peripheral pattern
• History of migraine is key

10. Vertebrobasilar Insufficiency (VBI) / TIA

• Ischemia in posterior circulation (PICA, AICA, basilar)
• Head turning compresses vertebral artery → positionally triggered vertigo
• Associated diplopia, dysphagia, dysarthria, ataxia, facial numbness, drop attacks
• Risk factors: HTN, DM, atrial fibrillation, age, prior stroke

11. Vertebral Artery Dissection

• Neck pain + positional vertigo ± occipital headache
• Most frequent symptom = dizziness (58% of presentations); neck pain may be absent
• Can lead to lateral medullary (Wallenberg) syndrome

12. Cerebellar Infarction / Hemorrhage

• Severe sudden vertigo, vomiting, gait ataxia
• Cerebellar hemorrhage can mimic peripheral vertigo early, but rapidly progresses
• Absence of brainstem signs does NOT exclude this diagnosis

13. Multiple Sclerosis

• Demyelinating plaques in vestibular pathways or cerebellum
• Positional nystagmus often downbeat, persistent
• Other neurological symptoms and signs

14. Posterior Fossa Tumor

• Space-occupying lesions near the fourth ventricle
• Persistent, non-fatigable positional nystagmus
• Progressive course

15. Chiari Malformation

• Tonsillar herniation → compression of dorsal brainstem/cerebellum
• Downbeat positional nystagmus; exacerbated by Valsalva

16. Temporal Lobe Epilepsy

• Rare; vertiginous aura preceding seizure activity

KEY DIFFERENTIATING FEATURES: Peripheral vs. Central

DIAGNOSTIC APPROACH

1. Dix-Hallpike test → positive (upbeat-torsional nystagmus, fatigable) → BPPV confirmed
2. Atypical nystagmus or negative Dix-Hallpike → perform supine roll test (for horizontal BPPV) and head impulse test (HIT)
3. HINTS exam (Head Impulse, Nystagmus, Test of Skew) for acute vestibular syndrome — central if: normal HIT + direction-changing nystagmus + skew deviation
4. Timing and triggers: < 1 min episodic = BPPV; 20 min–hours = Ménière; persistent = neuritis or central
5. MRI brain/posterior fossa with DWI for suspected central cause or stroke