Dizziness: BPPV vs Vestibular Neuritis vs Vertebrobasilar Insufficiency
Special Tests · 8 min read · 2025-11-08
Introduction
Dizziness is the third most common reason for outpatient medical visits. Three conditions represent the spectrum from benign to life-threatening: BPPV (the most common cause of vertigo), vestibular neuritis (an acute vestibular crisis), and vertebrobasilar insufficiency (a stroke warning).
BPPV (Benign Paroxysmal Positional Vertigo)
Pathology: Calcium carbonate crystals (otoconia) displaced into the semicircular canals — most commonly the posterior canal.
Presentation: Brief episodes of intense spinning vertigo (lasting <60 seconds) triggered by specific head positions — rolling over in bed, looking up, bending forward.
Key features:
- Vertigo is positional — always triggered by head movement
- Episodes are brief (seconds, not minutes or hours)
- No hearing loss, no tinnitus
- Between episodes, the patient feels normal
- Nausea during episodes, but no other neurological symptoms
Examination:
- Dix-Hallpike test: The gold standard. Rapidly move the patient from sitting to supine with head turned 45° to one side and extended over the table edge. A positive test produces rotational nystagmus (torsional, upbeating for posterior canal) with a 2–5 second latency, crescendo-decrescendo pattern, and fatigability (less intense with repetition).
Treatment: Epley maneuver — highly effective repositioning technique.
Vestibular Neuritis
Pathology: Viral or post-viral inflammation of the vestibular nerve. Affects the superior division more often.
Presentation: Sudden onset of severe, continuous vertigo lasting hours to days. The patient is often bedbound with nausea and vomiting. No hearing loss (if hearing loss is present, it's labyrinthitis).
Key features:
- Continuous vertigo (not positional)
- Horizontal nystagmus beating toward the unaffected ear
- Nausea and vomiting
- Unsteady gait, falling toward the affected side
- NO hearing loss (unlike labyrinthitis)
- NO other neurological symptoms
- Gradual improvement over days to weeks
Examination: Head impulse test is positive (corrective saccade when the head is rapidly turned toward the affected side) — this is a PERIPHERAL sign and is reassuring.
Vertebrobasilar Insufficiency (Posterior Circulation Stroke/TIA)
Pathology: Ischemia in the posterior fossa — brainstem, cerebellum, or vestibular nuclei.
Presentation: Vertigo with neurological symptoms. This is the one you cannot miss.
Red flags (the "D's"):
- Diplopia: Double vision
- Dysarthria: Slurred speech
- Dysphagia: Difficulty swallowing
- Dysmetria: Past-pointing, incoordination
- Drop attacks: Sudden falls without loss of consciousness
- Differential nystagmus: Direction-changing, vertical, or purely torsional nystagmus
Examination — HINTS exam (for acute continuous vertigo):
- HI (Head Impulse): Normal (negative) — concerning for central cause. A positive test (corrective saccade) suggests peripheral.
- N (Nystagmus): Direction-changing or vertical nystagmus = central. Unidirectional horizontal = peripheral.
- TS (Test of Skew): Vertical misalignment of the eyes during cover-uncover test = central.
A dangerous HINTS pattern: Normal head impulse + direction-changing nystagmus + skew deviation = posterior fossa stroke until proven otherwise.
Comparison
Clinical Pearl
A normal head impulse test in a patient with acute vertigo is paradoxically concerning. In peripheral vestibular disease, the head impulse test is positive (abnormal). When it's normal, it means the peripheral vestibular system is intact — and the vertigo is coming from somewhere central. Combined with direction-changing nystagmus and skew deviation, this pattern has >96% sensitivity for stroke.
Summary
Brief positional vertigo + positive Dix-Hallpike = BPPV (treat with Epley). Continuous vertigo + positive head impulse + no neuro signs = vestibular neuritis. Vertigo + neurological symptoms + dangerous HINTS pattern = posterior circulation stroke (emergency imaging).