Vestibular Neuritis
Vestibular neuritis is an acute unilateral vestibulopathy and the second most common cause of peripheral vertigo after BPPV. It presents with sudden-onset severe prolonged vertigo, nausea, and postural instability caused by inflammation of the vestibular nerve, most likely from reactivation of herpes simplex virus type 1 (HSV-1) in the vestibular (Scarpa) ganglion. The critical clinical challenge lies in distinguishing vestibular neuritis from posterior circulation stroke, a task at which the bedside HINTS examination outperforms early MRI. Early vestibular rehabilitation — not prolonged use of vestibular suppressants — is the single most important intervention for long-term recovery.
Bottom Line
- Acute vestibulopathy: Sudden severe vertigo lasting hours to days, horizontal-torsional nystagmus beating away from the affected ear, and NO hearing loss (hearing loss indicates labyrinthitis, not neuritis)
- HINTS examination is essential: In the acute vestibular syndrome, the 3-component HINTS test (Head Impulse, Nystagmus type, Test of Skew) is more sensitive than early MRI for detecting stroke (sensitivity >96% vs ~70% for DWI-MRI in first 48 hours)
- Peripheral HINTS pattern: Positive head impulse test (catch-up saccade) + unidirectional nystagmus + no skew deviation = peripheral cause (reassuring)
- Vestibular suppressants are SHORT-TERM only: Use for no more than 48–72 hours; prolonged use delays central compensation
- Vestibular rehabilitation is paramount: Early initiation of vestibular physical therapy is the most effective intervention for functional recovery
- Corticosteroids: Methylprednisolone within 72 hours of onset may improve caloric recovery but evidence for symptomatic benefit is modest
Pathophysiology
The prevailing theory attributes vestibular neuritis to reactivation of latent HSV-1 residing in the vestibular ganglion (Scarpa ganglion), analogous to herpes zoster reactivation in shingles. Temporal bone studies have demonstrated HSV-1 DNA in the vestibular ganglia of patients with vestibular neuritis.
Superior vs Inferior Division
The vestibular nerve has two divisions, and their anatomy explains the clinical patterns:
| Feature | Superior Division | Inferior Division |
|---|---|---|
| Innervates | Superior and horizontal canals; utricle | Posterior canal; saccule |
| Bony canal | Longer, narrower → more susceptible to edema and ischemia | Shorter, wider → less vulnerable |
| Frequency of involvement | Most common (~70% of cases are superior division only) | Less common (~15% isolated inferior; ~15% both divisions) |
| Head impulse test | Positive for horizontal head impulse | May have normal horizontal HIT; abnormal vertical HIT in posterior canal plane |
| Caloric testing | Canal paresis (reduced or absent response) | May be normal (calorics test horizontal canal) |
| VEMP testing | Abnormal cVEMP (saccular) may be normal or abnormal depending on involvement | Abnormal cVEMP (saccule); preserved oVEMP (utricle) |
Clinical Presentation
Vestibular neuritis presents as an acute vestibular syndrome (AVS) — the sudden onset of severe vertigo, nausea, vomiting, and postural instability lasting continuously for hours to days. Key clinical features include:
- Vertigo: Severe, continuous (not episodic), worsened by head movement but present at rest; typically peaks within hours and gradually improves over days to weeks
- Nystagmus: Horizontal-torsional, beating away from the affected ear (toward the intact side); follows Alexander law (increases in intensity when gazing in the direction of the fast phase); suppressed by visual fixation
- Nausea and vomiting: Often severe in the first 24–48 hours
- Postural instability: Falls toward the affected side; Romberg positive with fall toward the lesion
- Head impulse test: Positive (corrective catch-up saccade) on rapid head rotation toward the affected ear
- NO hearing loss: Hearing is preserved because the cochlear nerve is unaffected
- NO focal neurological deficits: No diplopia, dysarthria, dysphagia, weakness, or sensory loss
Vestibular Neuritis vs Labyrinthitis
- Vestibular neuritis: Inflammation of the vestibular nerve alone → vertigo WITHOUT hearing loss
- Labyrinthitis: Inflammation of the vestibular nerve AND cochlea (or entire labyrinth) → vertigo WITH acute sensorineural hearing loss and/or tinnitus
- The bedside examination and management approach are otherwise identical
- Labyrinthitis carries a worse prognosis for hearing recovery
The HINTS Examination
The HINTS examination (Head Impulse, Nystagmus type, Test of Skew) is the single most important bedside tool for distinguishing peripheral vestibular neuritis from posterior circulation stroke in the acute vestibular syndrome. In the landmark study by Kattah et al. (2009), HINTS had >96% sensitivity and ~99% specificity for identifying stroke — outperforming initial DWI-MRI, which misses up to 12–20% of posterior fossa strokes in the first 48 hours.
HINTS Components
| Component | Technique | Peripheral (Reassuring) | Central (Dangerous) |
|---|---|---|---|
| Head Impulse (HI) | Rapidly rotate the head ~20° while the patient fixates on the examiner’s nose; observe for corrective saccade | Positive: Catch-up saccade (eyes cannot maintain fixation, then snap back) — indicates ipsilateral vestibular hypofunction | Negative: Normal (no saccade) — a normal HIT in the setting of acute vertigo and nystagmus is concerning for stroke |
| Nystagmus (N) | Observe nystagmus in primary gaze and with gaze in each direction | Unidirectional: Nystagmus beats in the same direction regardless of gaze direction (intensity changes per Alexander law but direction does not) | Direction-changing: Nystagmus changes direction with gaze (gaze-evoked nystagmus) or is purely vertical |
| Test of Skew (TS) | Alternate cover test: cover one eye, then quickly uncover and cover the other; observe for vertical correction | No skew: No vertical refixation movement when alternating cover | Skew deviation: Vertical refixation present (indicates brainstem or cerebellar lesion) |
Dangerous Central HINTS Patterns — Do NOT Miss
- Normal (negative) head impulse test: In a patient with acute vestibular syndrome and nystagmus, a normal HIT means the vestibulo-ocular reflex is intact bilaterally → the problem is NOT in the peripheral vestibular system → think stroke
- Direction-changing nystagmus: Nystagmus that reverses direction with gaze (e.g., right-beating in right gaze, left-beating in left gaze) indicates a central lesion, most often cerebellar
- Skew deviation: Vertical ocular misalignment on alternate cover test strongly suggests a brainstem lesion
- Any ONE dangerous sign: If any single component is “central,” the sensitivity for stroke exceeds 96%; urgent neuroimaging and vascular workup are required
- HINTS Plus: Addition of bedside hearing assessment — new unilateral hearing loss in AVS suggests AICA stroke (labyrinthine artery territory), even if other HINTS components appear peripheral
HINTS Caveats and Limitations
- Applies ONLY to acute vestibular syndrome: HINTS is validated only for patients with acute continuous vertigo, nystagmus, and gait instability — NOT for episodic vertigo or isolated dizziness
- Requires examiner training: The head impulse test requires practice to perform and interpret correctly; subtle saccades (covert saccades) can be missed without video head impulse testing (vHIT)
- Timing: Most accurate in the first 24–72 hours of symptom onset
- Small strokes: Rarely, small lateral medullary strokes may produce a “peripheral-appearing” HINTS pattern
Differential Diagnosis
| Feature | Vestibular Neuritis | Labyrinthitis | Posterior Circulation Stroke |
|---|---|---|---|
| Onset | Acute, often preceded by viral illness | Acute, may follow otitis media | Acute, often with vascular risk factors |
| Vertigo | Severe, continuous, lasting days | Severe, continuous, lasting days | Severe, continuous |
| Hearing | Normal | Sensorineural hearing loss | Usually normal; loss suggests AICA stroke |
| Nystagmus | Unidirectional, horizontal-torsional | Unidirectional, horizontal-torsional | Direction-changing, or purely vertical |
| Head impulse test | Positive (abnormal) | Positive (abnormal) | Normal (negative) — dangerous sign |
| Skew deviation | Absent | Absent | May be present |
| Neurological signs | None | None | May have dysarthria, ataxia, weakness |
| HINTS pattern | Peripheral (benign) | Peripheral (benign) | Central (dangerous) |
| MRI | Normal | May show labyrinthine enhancement | DWI restriction (may be negative <48h) |
Diagnostic Workup
In most cases, vestibular neuritis is a clinical diagnosis based on the acute vestibular syndrome presentation and a peripheral HINTS pattern. Additional testing may be helpful or necessary in certain situations:
- MRI brain with DWI: Indicated when any HINTS component is central, when vascular risk factors are prominent, or when clinical uncertainty exists. Note that DWI may be falsely negative in the first 24–48 hours for posterior fossa strokes
- Video head impulse test (vHIT): Quantifies VOR gain; detects covert saccades missed on bedside examination; useful for confirming the diagnosis and monitoring recovery
- Caloric testing: Demonstrates unilateral canal paresis; not necessary acutely but useful for documentation and medicolegal purposes
- Audiometry: Normal in vestibular neuritis; essential to rule out labyrinthitis or AICA stroke if hearing loss is suspected
- VEMP testing: Helps localize the affected division (superior vs inferior) of the vestibular nerve
Treatment
Acute Phase (First 48–72 Hours)
Acute Management of Vestibular Neuritis
- Vestibular suppressants (SHORT-TERM ONLY):
- Meclizine 25–50 mg every 8 hours
- Dimenhydrinate 50 mg every 6–8 hours
- Diazepam 2–5 mg every 8–12 hours (most potent vestibular suppression)
- Antiemetics: Ondansetron 4–8 mg, promethazine 12.5–25 mg, or prochlorperazine 5–10 mg
- IV fluids: If dehydrated from vomiting
- CRITICAL: Discontinue all vestibular suppressants after 48–72 hours — continued use inhibits central vestibular compensation and prolongs disability
Corticosteroids
The role of corticosteroids remains debated. The most cited evidence comes from Strupp et al. (2004), showing that methylprednisolone (initial dose 100 mg, tapered over 3 weeks) initiated within 3 days of onset significantly improved caloric function recovery compared to placebo. However, the evidence for symptomatic benefit is modest, and subsequent studies have yielded mixed results. Current practice varies:
- If used, initiate within 72 hours of onset for maximal benefit
- Typical regimen: prednisone 60 mg daily tapered over 10–14 days, or methylprednisolone taper
- Antivirals (valacyclovir) have NOT shown benefit and are not recommended
Vestibular Rehabilitation Therapy (VRT)
Vestibular Rehabilitation — The Most Important Intervention
- Timing: Begin as soon as acute nausea/vomiting subsides (typically by day 2–3); earlier initiation correlates with better outcomes
- Gaze stabilization exercises: VOR ×1 (fixate on a target while moving the head) and VOR ×2 (move head and target in opposite directions); promotes VOR adaptation
- Habituation exercises: Repeated exposure to movements that provoke dizziness to promote central desensitization
- Balance training: Progressive static and dynamic balance exercises; gradually reducing the base of support and adding visual/surface challenges
- Mechanism: VRT promotes central vestibular compensation — the brainstem and cerebellum recalibrate to rely on the intact side and use visual/proprioceptive inputs
- Evidence: Cochrane review confirms moderate-to-strong evidence that VRT improves symptoms and function in unilateral vestibular hypofunction
Vestibular Suppressants Beyond 48–72 Hours: A Common Error
- Continued use of meclizine, benzodiazepines, or anticholinergics beyond the acute phase actively impairs central vestibular compensation
- These drugs suppress the very neural signals required for the brain to recalibrate
- Patients discharged with “as-needed meclizine” prescriptions often self-medicate chronically, leading to prolonged disability
- Counsel patients explicitly: vestibular suppressants are for the first 2–3 days ONLY
- If symptoms persist beyond 4–6 weeks, the priority is aggressive vestibular rehabilitation, NOT medication
Natural History and Prognosis
The natural history of vestibular neuritis follows a predictable course:
- Acute phase (days 1–3): Severe vertigo, nystagmus, nausea; largely bed-bound
- Subacute phase (days 3–14): Gradual improvement; nystagmus decreases; patients begin to ambulate; head movement still provokes dizziness
- Compensation phase (weeks to months): Central compensation progressively reduces symptoms; most patients achieve functional recovery by 6–12 weeks
- Long-term outcomes:
- ~50% have persistent caloric weakness on testing (canal paresis) despite clinical recovery
- 10–15% develop secondary BPPV (otoconia displaced from damaged utricle)
- Some patients report persistent mild unsteadiness, especially in visually complex environments or darkness
- Incomplete compensation may result from elderly age, concomitant CNS disease, sedentary lifestyle, or prolonged vestibular suppressant use
Recurrence
True recurrence of vestibular neuritis affecting the same ear is rare (<2%). When “recurrent” vestibular episodes occur, consider:
| Alternative Diagnosis | Key Distinguishing Feature |
|---|---|
| Vestibular migraine | Episodic vertigo (minutes to hours), migraine features, normal hearing |
| Meniere disease | Episodic vertigo (20 min–12 hours) with hearing loss, tinnitus, aural fullness |
| BPPV | Brief positional vertigo (<60 seconds), provoked by specific head positions |
| Vestibular schwannoma | Progressive unilateral hearing loss, asymmetric caloric response |
| Recurrent vestibulopathy | Repeated acute episodes without hearing loss; may be migrainous variant |
| Contralateral vestibular neuritis | Rare; new symptoms lateralize to the opposite side |
Special Considerations
Vestibular Neuritis and Driving
Patients should be counseled not to drive during the acute and early subacute phase. Return to driving is typically appropriate when the patient can walk without assistance, can maintain visual fixation during head movement, and has sufficient dynamic visual acuity. In most cases, this occurs within 1–4 weeks.
Incomplete Compensation
Approximately 10–20% of patients experience incomplete central compensation with persistent symptoms. Risk factors include older age, concomitant central nervous system disease (particularly cerebellar), anxiety and avoidance behavior, and continued use of vestibular suppressants. Management involves intensified vestibular rehabilitation, cognitive behavioral therapy for anxiety-related avoidance, and cessation of suppressant medications.
Bilateral Vestibulopathy
Bilateral vestibular neuritis is exceedingly rare. Bilateral vestibular hypofunction more commonly results from ototoxic medications (aminoglycosides), autoimmune inner ear disease, or bilateral Meniere disease. Bilateral loss presents with oscillopsia (visual blurring during head movement) and severe imbalance rather than vertigo.
References
- Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009;40(11):3504–3510.
- Strupp M, Zingler VC, Arbusow V, et al. Methylprednisolone, valacyclovir, or the combination for vestibular neuritis. N Engl J Med. 2004;351(4):354–361.
- Baloh RW. Clinical practice. Vestibular neuritis. N Engl J Med. 2003;348(11):1027–1032.
- McDonnell MN, Hillier SL. Vestibular rehabilitation for unilateral peripheral vestibular dysfunction. Cochrane Database Syst Rev. 2015;(1):CD005397.
- Newman-Toker DE, Kerber KA, Hsieh YH, et al. HINTS outperforms ABCD2 to screen for stroke in acute continuous vertigo and dizziness. Acad Emerg Med. 2013;20(10):986–996.
- Tarnutzer AA, Berkowitz AL, Robinson KA, Hsieh YH, Newman-Toker DE. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ. 2011;183(9):E571–E592.
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- Fishman JM, Burgess C, Waddell A. Corticosteroids for the treatment of idiopathic acute vestibular dysfunction (vestibular neuritis). Cochrane Database Syst Rev. 2011;(5):CD008607.
- Herdman SJ, Hall CD, Delaune W. Variables associated with outcome in patients with unilateral vestibular hypofunction. Neurorehabil Neural Repair. 2012;26(2):151–162.
- Lee H, Sohn SI, Cho YW, et al. Cerebellar infarction presenting isolated vertigo: frequency and vascular topographical patterns. Neurology. 2006;67(7):1178–1183.