Neuro-Otology
Neuro-Otology
What You'll Learn
- Peripheral vertigo = more symptomatic (severe spinning, nausea); central vertigo = more dangerous (stroke, subtle findings)
- HINTS exam has high sensitivity for posterior circulation stroke ONLY in acute vestibular syndrome (acute continuous dizziness/vertigo + spontaneous nystagmus + nausea/gait instability) AND when performed by a trained clinician; central or equivocal HINTS → MRI/MRA
- BPPV = most common cause of vertigo; posterior canal 80–90%; Dix-Hallpike → Epley maneuver
- Normal head impulse test in acute vertigo is alarming — suggests central cause (brainstem stroke)
- Vestibular migraine = most common episodic vertigo in young adults (after BPPV); can occur WITHOUT headache
- Meniere triad: episodic vertigo (20 min–12 h) + low-frequency SNHL + tinnitus ± aural fullness
- COWS: Cold Opposite, Warm Same (fast-phase direction of caloric nystagmus)
HighYield Pearls
- HINTS exam in acute vestibular syndrome (and only AVS): normal head impulse + direction-changing/vertical nystagmus + skew deviation → CENTRAL (stroke) until proven otherwise. Validated >98% sensitivity applies only when performed by trained clinicians (GRACE-3); central or equivocal HINTS → MRI/MRA.
- Normal head impulse test in a patient with prolonged spinning vertigo is a red flag — suggests posterior circulation stroke (PICA/AICA/basilar), not vestibular neuritis.
- BPPV: brief positional vertigo with rolling over/looking up + torsional upbeating nystagmus on Dix-Hallpike (delay, fatigue, reversal) → treat with Epley; horizontal canal → Lempert/BBQ roll.
- Vestibular neuritis: monophasic prolonged vertigo days, NO hearing loss, positive head impulse with catch-up saccade ipsilateral to lesion; vestibular rehab; steroids controversial.
- Ménière triad: episodic vertigo (hours) + low-frequency SNHL + tinnitus ± aural fullness. AAO-HNS: clinicians MAY offer diuretics ± betahistine for maintenance; MAY offer intratympanic steroids if not responsive to noninvasive therapy; SHOULD offer intratympanic gentamicin if not responsive to nonablative therapy.
- Vestibular migraine can occur WITHOUT headache — recurrent minutes-to-days vertigo + migraine criteria + photo/phonophobia; treat with migraine prevention.
- Vestibular schwannoma: slowly progressive asymmetric SNHL + tinnitus + imbalance; MRI IAC; bilateral = NF2.
- Superior canal dehiscence: autophony + Tullio phenomenon (sound-induced vertigo) + bony defect on temporal bone CT + abnormal VEMP → surgical plugging.
- Vestibular paroxysmia: brief recurrent seconds-long vertigo from neurovascular conflict at CN VIII → carbamazepine (like trigeminal neuralgia).
- Episodic ataxia type 2: autosomal dominant, CACNA1A → acetazolamide responsive.
🔍 Quick ReferenceClinical / triggers · Bedside exam · Treatment
Clinical / triggers
- Brief vertigo triggered by rolling over or looking up → BPPV (posterior canal)
- Sudden prolonged vertigo for days, no hearing loss, recent URI → Vestibular neuritis
- Episodic vertigo (hours) + low-frequency SNHL + tinnitus + aural fullness → Ménière disease
- Recurrent minutes-to-days vertigo ± headache + photo/phonophobia → Vestibular migraine
- Autophony (hearing own voice/heartbeat) + Tullio (sound-induced vertigo) → Superior canal dehiscence
- Progressive asymmetric SNHL + tinnitus + imbalance → Vestibular schwannoma (bilateral → NF2)
- Brief seconds-long recurrent vertigo, neurovascular conflict CN VIII → Vestibular paroxysmia
- Vertigo + ipsilateral Horner + crossed sensory loss + dysphagia → Wallenberg (lateral medullary / PICA)
- Vertigo + ipsilateral hearing loss + facial weakness + ataxia → AICA stroke
- Childhood-onset episodic vertigo/ataxia, AD inheritance → EA2 (CACNA1A)
Bedside / HINTS / exam
- Torsional upbeating nystagmus on Dix-Hallpike with latency, fatigue, reversal → Posterior canal BPPV (peripheral)
- Downbeating torsional nystagmus on Dix-Hallpike → Anterior canal BPPV (rare)
- Geotropic or apogeotropic horizontal nystagmus on supine roll test → Horizontal canal BPPV (peripheral)
- Unidirectional horizontal-torsional nystagmus + abnormal head impulse + no skew → Peripheral (vestibular neuritis)
- NORMAL head impulse + direction-changing/vertical nystagmus + skew deviation (INFARCT) → Central (posterior circulation stroke)
- Pure vertical or pure torsional nystagmus → Central until proven otherwise
- No fixation suppression of nystagmus → Central
- Downbeat nystagmus on chronic phenytoin/carbamazepine → Anticonvulsant cerebellar toxicity (central)
- Cannot sit/stand unsupported with acute vertigo → Cerebellar stroke/hemorrhage (central)
Treatment / maneuver
- Epley canalith repositioning maneuver → Posterior canal BPPV (Semont alternative)
- Lempert / BBQ roll maneuver → Horizontal canal BPPV
- Vestibular rehabilitation → Vestibular neuritis (recovery 1–3 wk)
- AAO-HNS Meniere ladder (graded recommendations): low-salt diet; diuretics ± betahistine (may offer) → intratympanic steroids (may offer if noninvasive-refractory) → intratympanic gentamicin (should offer if nonablative-refractory)
- Migraine prophylaxis (topiramate, propranolol, amitriptyline, CGRP) → Vestibular migraine
- Carbamazepine / oxcarbazepine → Vestibular paroxysmia
- Acetazolamide → Episodic ataxia type 2 (CACNA1A)
- Observation, stereotactic radiosurgery, or microsurgical resection → Vestibular schwannoma
- Surgical plugging / resurfacing of bony defect → Superior canal dehiscence
- Urgent MRI brain + posterior circulation stroke workup → Central HINTS pattern / suspected PICA/AICA/basilar stroke
Peripheral vs Central Vertigo
Master Comparison Table
| Feature | Peripheral | Central |
|---|---|---|
| Onset | Sudden | Sudden or gradual |
| Vertigo severity | Severe spinning | Mild-moderate (may be imbalance only) |
| Duration | Seconds to days (self-limited) | Variable; may be persistent |
| Nystagmus direction | Unidirectional (fast phase away from lesion); horizontal-torsional | Direction-changing, vertical, or purely torsional |
| Fixation suppression | Yes (nystagmus decreases) | No (nystagmus persists or worsens) |
| Hearing loss | May be present (labyrinthitis, Meniere) | Usually absent (except AICA stroke) |
| Nausea/vomiting | Prominent | Variable, often less severe |
| Neurologic signs | Absent | Present (diplopia, dysarthria, ataxia, weakness) |
| Gait | Unsteady but able to walk | Severe ataxia; may be unable to sit unsupported |
| Head impulse test | Abnormal (catch-up saccade) | Normal (no catch-up saccade) |
| Skew deviation | Absent | Present |
Red Flags for Central Vertigo
- Vertical nystagmus (downbeat or upbeat)
- Direction-changing nystagmus (changes with gaze direction)
- No fixation suppression
- Skew deviation (vertical misalignment on alternate cover test)
- New neurologic signs: diplopia, dysarthria, dysphagia, limb ataxia, weakness, numbness
- Normal head impulse test in acute sustained vertigo
- Inability to walk (cerebellar stroke/hemorrhage)
💎 Board Pearl
- Peripheral vertigo = more symptomatic; central vertigo = more dangerous — classic board teaching point
- Vertical nystagmus is always central until proven otherwise
HINTS Exam (Head Impulse, Nystagmus, Test of Skew)
HINTS Components
| Component | Peripheral (Vestibular Neuritis) | Central (Stroke) |
|---|---|---|
| Head Impulse Test (HIT) | Abnormal — catch-up saccade (positive) | Normal — no catch-up saccade |
| Nystagmus | Unidirectional (fast phase away from lesion) | Direction-changing or vertical |
| Test of Skew | Negative (no skew deviation) | Positive (vertical eye misalignment) |
Key Facts
- Sensitivity for posterior fossa stroke: >98% — superior to initial MRI (DWI can miss 12–20% within first 48 h)
- Only valid in acute vestibular syndrome (acute sustained vertigo + nystagmus + nausea/gait instability)
- Any ONE central finding = central until proven otherwise
InFARCT Mnemonic — Central Pattern
INFARCT = Impulse Normal, Fast-phase Alternating, Refixation on Cover Test — all 7 letters map to the 3 central HINTS findings:
| Letters | Component | Central Finding |
|---|---|---|
| I-N | Impulse Normal | Head impulse test normal (no catch-up saccade) |
| F-A | Fast-phase Alternating | Direction-changing nystagmus on lateral gaze |
| R-C-T | Refixation on Cover Test | Skew deviation present (vertical eye misalignment) |
Peripheral pattern (opposite of INFARCT): abnormal HIT (catch-up saccade), unidirectional nystagmus that does not change with gaze, and no skew deviation.
Clinical Pearl
HINTS sensitivity is operator-dependent. The >98% sensitivity figure was validated in trained neuro-otologists and stroke neurologists. Emergency physician sensitivity is much lower; HINTS performed by non-experts has not reliably outperformed clinical gestalt. Train the technique before relying on it.
⚠ Warning
A normal head impulse test in a patient with acute vertigo means the VOR is intact — the brainstem is likely the problem, NOT the inner ear. Do NOT be reassured by a normal HIT.
💎 Board Pearl
- HINTS beats early MRI for posterior fossa stroke detection — a classic board question
- INFARCT = Impulse Normal, Fast-phase Alternating, Refixation on Cover Test — all 3 central findings in one acronym; peripheral is the mirror image (abnormal HIT, unidirectional nystagmus, no skew)
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