Vestibular Neuritis

1. Clinical Overview

Summary

Vestibular Neuritis is an acute peripheral vestibular disorder characterised by sudden onset of severe, prolonged rotational vertigo, nausea and vomiting, postural imbalance, and spontaneous horizontal-torsional nystagmus beating away from the affected ear. It represents inflammation of the vestibular nerve, most commonly attributed to viral aetiology, particularly reactivation of Herpes Simplex Virus Type 1 (HSV-1) within the vestibular ganglion. [1,2]

Critically, hearing is preserved in vestibular neuritis, distinguishing it from labyrinthitis which involves both vestibular and cochlear divisions of the vestibulocochlear nerve (cranial nerve VIII). Vestibular neuritis is one of the most common causes of acute vestibular syndrome (AVS), defined as acute onset of vertigo, nystagmus, postural instability, nausea/vomiting, and head-motion intolerance lasting more than 24 hours. [3]

The condition must be differentiated from central causes of AVS, particularly posterior circulation stroke, using the HINTS examination (Head Impulse, Nystagmus, Test of Skew), which demonstrates higher sensitivity than early MRI brain imaging for detecting stroke. [4] The acute vertiginous symptoms typically peak within 24-48 hours and gradually improve over 1-6 weeks as central vestibular compensation occurs through neuroplasticity mechanisms. [5]

Treatment is primarily supportive during the acute phase, with short-term vestibular suppressants and antiemetics. Vestibular rehabilitation represents the cornerstone intervention for promoting recovery, with high-quality evidence demonstrating accelerated and more complete compensation. [6] Corticosteroids administered within 3 days of symptom onset may improve long-term vestibular function recovery, though clinical benefit remains debated. [7]

Key Clinical Pearls

"Vertigo WITHOUT Hearing Loss = Vestibular Neuritis. WITH Hearing Loss = Labyrinthitis": This fundamental distinction guides diagnosis and investigation strategy. Acute hearing loss with vertigo should prompt consideration of labyrinthitis or central pathology.

"HINTS Exam Beats MRI in Acute Phase": The HINTS examination demonstrates 100% sensitivity and 96% specificity for stroke detection in acute vestibular syndrome, superior to MRI DWI performed within 48 hours of symptom onset. [4] Master this bedside assessment.

"Nystagmus Fast Phase Beats AWAY from the Lesion": The fast phase of spontaneous nystagmus beats toward the healthy side (away from the affected vestibular nerve). This reflects the tonic vestibular imbalance with reduced input from the damaged side.

"Limit Vestibular Suppressants to 3-5 Days Maximum": Prolonged use of vestibular suppressants (antihistamines, anticholinergics, benzodiazepines) impairs central vestibular compensation and delays recovery. Early mobilisation promotes neuroplasticity. [8]

"Vestibular Rehabilitation is Evidence-Based Cornerstone": Cochrane systematic reviews confirm that vestibular rehabilitation significantly improves subjective and objective outcomes, reduces symptom duration, and enhances quality of life. [6] Early referral to specialised physiotherapy is mandatory.

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2. Epidemiology

Demographics and Incidence

Epidemiological Context

Vestibular neuritis accounts for approximately 7-10% of all patients presenting to vertigo/dizziness clinics and represents the third most common cause of peripheral vertigo after benign paroxysmal positional vertigo (BPPV) and Ménière's disease. [12] It is the second most common cause of acute vestibular syndrome (AVS) after stroke in patients presenting to emergency departments. [3]

The condition predominantly affects middle-aged adults, though cases occur across all age groups including children and elderly. The seasonal variation observed in multiple epidemiological studies supports the viral aetiology hypothesis, with peak incidence coinciding with respiratory viral infection patterns. [11]

Recurrence is relatively uncommon, occurring in approximately 2-5% of patients, typically affecting the contralateral ear. [13] This low recurrence rate distinguishes vestibular neuritis from conditions like vestibular migraine or Ménière's disease where recurrent episodes are characteristic.

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3. Anatomy and Pathophysiology

Vestibular Nerve Anatomy

The vestibulocochlear nerve (cranial nerve VIII) comprises two functionally distinct divisions:

The vestibular nerve itself divides into:

Superior Vestibular Nerve Division:

• Innervates superior semicircular canal
• Innervates horizontal semicircular canal
• Innervates utricle
• Most commonly affected in vestibular neuritis (> 95% of cases) [14]

Inferior Vestibular Nerve Division:

• Innervates posterior semicircular canal
• Innervates saccule
• Less commonly affected in isolation

This anatomical division explains why posterior semicircular canal function is often relatively preserved in vestibular neuritis, resulting in characteristic patterns on caloric testing and video head impulse testing (vHIT). [14]

Viral Aetiology and Pathogenesis

The prevailing hypothesis for vestibular neuritis pathogenesis involves viral infection or reactivation within the vestibular ganglion (Scarpa's ganglion), analogous to herpes zoster involvement of sensory ganglia. [1]

Evidence for Herpes Simplex Virus Type 1 (HSV-1):

• Histopathological studies of temporal bones from patients with vestibular neuritis demonstrate HSV-1 DNA within vestibular ganglia and nerve tissue using polymerase chain reaction (PCR) techniques [1]
• Serological studies show elevated HSV-1 antibody titres in some patients with acute vestibular neuritis [2]
• Anatomical evidence of nerve degeneration predominantly in superior vestibular division, consistent with viral neuritis pattern [14]

Other Implicated Viral Pathogens:

• Varicella-Zoster Virus (VZV) - can cause Ramsay Hunt syndrome when affecting facial and vestibular nerves
• Cytomegalovirus (CMV)
• Epstein-Barr Virus (EBV)
• Adenovirus
• Influenza viruses

Approximately 50% of patients report a preceding upper respiratory tract infection in the 1-2 weeks before vestibular neuritis onset, supporting the viral hypothesis. [11]

Inflammatory Cascade and Nerve Damage

Following viral invasion or reactivation:

1. Viral Replication: HSV-1 replicates within vestibular ganglion neurons
2. Inflammatory Response: Host immune response triggers inflammatory cascade
3. Nerve Oedema: Inflammation causes oedema within the confined space of the bony vestibular canal (internal auditory meatus)
4. Vascular Compromise: Oedema may compress vasa nervorum, causing nerve ischaemia
5. Demyelination: Inflammatory mediators cause demyelination and axonal damage
6. Functional Denervation: Reduced or absent tonic vestibular input from affected side

The superior vestibular nerve travels through a narrower bony canal than the inferior division, potentially explaining its preferential involvement through compression-mediated ischaemia. [14]

Physiology of Vestibular Imbalance

The vestibular system functions through bilateral tonic activity from both labyrinths, with continuous firing of vestibular nerve afferents even at rest (approximately 100 spikes/second baseline). The central vestibular nuclei integrate input from both sides to maintain balance and spatial orientation.

Acute Unilateral Vestibular Hypofunction:

Nystagmus Generation: The spontaneous nystagmus in vestibular neuritis reflects the central nervous system's response to asymmetric vestibular input:

• Slow Phase Direction: Toward the affected (hypoactive) side - represents the pathological component (unopposed vestibular tone from healthy side)
• Fast Phase Direction: Away from affected side, toward healthy side - represents corrective saccade (conventionally defines nystagmus direction)
• Mechanism: Reduced tonic inhibition of contralateral oculomotor nuclei from affected vestibular nucleus

Alexander's Law: Nystagmus intensity increases when gaze is directed in the direction of the fast phase (toward healthy side), and decreases when gaze is directed opposite to the fast phase. This is characteristic of peripheral vestibular lesions. [15]

Vestibulo-Ocular Reflex (VOR) Dysfunction

The VOR stabilises vision during head movement by generating compensatory eye movements equal and opposite to head motion. The pathway involves:

• Semicircular canal → Vestibular nerve → Vestibular nucleus → Oculomotor nuclei → Eye muscles

In vestibular neuritis, VOR gain on the affected side is markedly reduced (typically less than 0.4, normal > 0.8), causing:

• Head Impulse Test Abnormality: Corrective saccades when head is rapidly turned toward affected side
• Oscillopsia: Visual blurring during head movement
• Gait Instability: Inability to maintain stable gaze during walking

Central Vestibular Compensation

Following acute unilateral vestibular injury, the central nervous system undergoes neuroplastic adaptation over days to weeks, termed vestibular compensation. [5]

Mechanisms of Compensation:

Key Sites of Compensation:

• Vestibular nuclei: Intrinsic neuronal plasticity
• Cerebellum (particularly nodulus and uvula): Supervises and tunes compensation
• Visual cortex: Enhanced visual-vestibular interactions
• Proprioceptive pathways: Increased weighting

Factors Promoting Compensation:

• Early mobilisation and physical activity [8]
• Vestibular rehabilitation exercises [6]
• Withdrawal of vestibular suppressants [8]
• Younger age (though compensation occurs at all ages)

Factors Impairing Compensation:

• Prolonged use of vestibular suppressants (benzodiazepines, antihistamines) [8]
• Immobility and inactivity
• Concurrent neurological disease (cerebellar pathology)
• Anxiety and psychological factors

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4. Clinical Presentation

Symptom Profile

Temporal Pattern

Prodromal Phase (0-2 weeks before):

• Approximately 50% of patients report recent upper respiratory tract infection [11]
• Mild non-specific symptoms in some cases

Acute Phase (First 24-72 hours):

• Sudden onset of severe vertigo, often upon waking
• Peak severity within 24-48 hours
• Severe nausea/vomiting may require hospital admission
• Spontaneous nystagmus most intense
• Complete inability to function normally

Subacute Phase (Days to 2-3 weeks):

• Gradual improvement in vertigo intensity
• Transition from continuous vertigo to head-motion-provoked symptoms
• Nystagmus intensity decreases
• Progressive mobilisation becomes possible

Recovery Phase (Weeks to months):

• Residual imbalance particularly with rapid head movements
• Oscillopsia may persist during vigorous activities
• Most functional recovery complete by 6-12 weeks
• Some patients experience chronic mild imbalance

Physical Examination Findings

General Appearance:

• Patient appears unwell, pale, anxious
• Preference to lie still with eyes closed
• Nausea/distress evident

Otoscopy:

• Normal tympanic membranes bilaterally
• No signs of acute otitis media or cholesteatoma
• External auditory canal normal

Spontaneous Nystagmus (Critical Finding):

Head Impulse Test (HIT) - Hallmark Finding:

Technique:

1. Patient fixates on examiner's nose
2. Examiner holds patient's head
3. Rapid, unpredictable head rotation ~15-20° to one side
4. Observe for corrective saccades

Interpretation:

• Abnormal (Positive): Eyes move with head then make corrective saccade back to target - indicates peripheral vestibular hypofunction on that side
• Normal (Negative): Eyes remain fixed on target despite head movement - suggests intact VOR (may indicate central pathology if in context of AVS)

In vestibular neuritis, HIT is abnormal when head is turned toward the affected ear and normal when turned toward the healthy ear. [4]

Video Head Impulse Test (vHIT):

• Quantitative assessment of VOR gain
• VOR gain less than 0.6 (normal > 0.8) on affected side confirms peripheral hypofunction [16]
• Can identify superior vs inferior division involvement
• Not required for diagnosis but useful in ambiguous cases

Romberg Test:

• Patient sways or falls toward affected side when eyes closed
• Less specific than HIT but supports lateralising diagnosis

Gait Assessment:

• Broad-based, unsteady gait
• Veering or falling toward affected side
• Difficulty with tandem (heel-to-toe) walking
• Normal cerebellar testing (no appendicular ataxia - would suggest central cause)

Hearing Assessment (Bedside):

If hearing loss detected: Consider labyrinthitis or central pathology rather than isolated vestibular neuritis.

Neurological Examination (Must be Normal):

Any abnormal neurological findings warrant urgent brain imaging to exclude stroke or other central pathology.

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5. HINTS Examination (Critical Clinical Tool)

The HINTS examination (Head Impulse, Nystagmus, Test of Skew) is a validated three-component bedside oculomotor assessment that differentiates peripheral vestibular causes (like vestibular neuritis) from central causes (particularly posterior circulation stroke) in patients presenting with acute vestibular syndrome. [4]

Landmark Study: Kattah et al. (2009) demonstrated that HINTS examination has 100% sensitivity and 96% specificity for detecting stroke in patients with acute vestibular syndrome, superior to MRI DWI performed within 48 hours of symptom onset (MRI sensitivity ~80-85% in first 48 hours). [4]

Component 1: Head Impulse Test (HIT)

Procedure:

1. Patient seated, fixates on examiner's nose at arm's length
2. Examiner holds patient's head with both hands
3. Rapid, small amplitude (10-20°) head rotation toward one side
4. Head movement must be unpredictable in timing and direction
5. Observe eyes during and immediately after head movement
6. Repeat multiple times, both directions

Interpretation:

Key Point: In acute vestibular syndrome, a normal HIT is concerning and suggests possible stroke, particularly if other HINTS components are also concerning. [4]

Component 2: Nystagmus Type and Direction

Assessment:

1. Observe spontaneous nystagmus in primary gaze (straight ahead)
2. Test nystagmus in all gaze directions (left, right, up, down)
3. Note direction, type (horizontal, vertical, torsional), and whether direction changes with gaze

Classification:

Fixation Suppression Test:

• Peripheral nystagmus suppresses with visual fixation (patient looks at target)
• Can enhance detection using Frenzel goggles (prevent fixation) or ophthalmoscopy (observe optic disc movement)
• Central nystagmus typically does not suppress with fixation

Key Point: Direction-changing or pure vertical nystagmus indicates central pathology and requires urgent imaging. [4]

Component 3: Test of Skew (Alternate Cover Test)

Procedure:

1. Patient fixates on examiner's nose at 3-4 feet distance
2. Examiner alternately covers one eye then the other
3. Observe for vertical refixation movement of the uncovered eye
4. Repeat multiple times

Interpretation:

Skew deviation reflects disruption of otolithic pathways in the brainstem and is virtually never seen in peripheral vestibular disorders. Its presence strongly suggests stroke or other central pathology. [4]

HINTS Algorithm for Risk Stratification

ACUTE VESTIBULAR SYNDROME
(Sudden vertigo + Nystagmus + Imbalance + Nausea lasting > 24h)
                    ↓
          PERFORM HINTS EXAMINATION
    (Head Impulse, Nystagmus, Test of Skew)
                    ↓
        ┌───────────┴───────────┐
        ↓                       ↓
   ALL THREE                ANY ONE
   "PERIPHERAL"            "CENTRAL"
   ↓                       ↓
   • Abnormal HIT          • Normal HIT, OR
   • Unidirectional        • Direction-changing
     nystagmus               or vertical nystagmus, OR
   • No skew               • Skew deviation present
   ↓                       ↓
   LOW stroke risk         HIGH stroke risk
   ↓                       ↓
   Vestibular Neuritis     URGENT MRI BRAIN
   or Labyrinthitis        Stroke Protocol
   (check hearing)         

HINTS Sensitivity and Specificity

Evidence from Kattah et al. (2009): [4]

• Sensitivity for stroke: 100% (95% CI: 94-100%)
• Specificity for stroke: 96% (95% CI: 92-98%)
• Superior to MRI DWI less than 48h: MRI sensitivity only 80-85% in first 48 hours of posterior circulation stroke

"Dangerous" HINTS Pattern (high stroke probability):

• Normal HIT (no corrective saccade)
• AND/OR direction-changing or vertical nystagmus
• AND/OR skew deviation present

Even one "central" finding warrants urgent brain imaging.

INFARCT Criteria (Adjunct to HINTS)

The INFARCT score adds clinical vascular risk factors to enhance stroke detection:

Impulse Normal (normal HIT) + Fast-phase Alternating (direction-changing nystagmus) + Refixation on Cover Test (skew deviation) + Plus vascular risk factors (age > 60, hypertension, diabetes, atrial fibrillation)

Presence of HINTS concerning features PLUS vascular risk factors significantly increases stroke probability. [17]

Limitations and Pitfalls

HINTS is only valid in:

• Acute vestibular syndrome (continuous vertigo > 24 hours)
• Presence of spontaneous nystagmus at time of examination
• Skilled examiner (requires training to perform and interpret correctly)

HINTS cannot be used for:

• Episodic vertigo (BPPV, vestibular migraine)
• No nystagmus present at examination
• Chronic dizziness

Common Errors:

• Performing HIT too slowly (must be rapid, high acceleration)
• Not ensuring patient fixation on target during HIT
• Mistaking saccadic pursuit for normal HIT
• Failing to test all gaze positions for nystagmus

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6. Differential Diagnosis

Acute Vestibular Syndrome Differentials

The key diagnostic challenge is distinguishing vestibular neuritis from other causes of acute vestibular syndrome, particularly posterior circulation stroke.

Focused Differential by Clinical Context

Age > 60 + Vascular Risk Factors + AVS

• High stroke risk - perform HINTS and urgent MRI
• Even with "peripheral" HINTS, lower threshold for imaging

Recurrent Episodes

• Vestibular migraine
• Ménière's disease
• BPPV (brief episodes)
• NOT typical of vestibular neuritis (recurrence less than 5%)

Hearing Loss Present

• Labyrinthitis
• Ménière's disease
• Acoustic neuroma (usually gradual onset)
• Central pathology affecting cochlear nucleus

Neurological Signs Present

• Stroke (posterior circulation)
• Multiple sclerosis
• Cerebellar pathology
• Brainstem lesion

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7. Investigations

Diagnostic Approach

Vestibular neuritis is a CLINICAL DIAGNOSIS based on:

1. History of acute vestibular syndrome (sudden vertigo, nausea, imbalance > 24h)
2. Examination findings (spontaneous unidirectional horizontal-torsional nystagmus, abnormal HIT, normal hearing, no neurological signs)
3. HINTS examination indicating peripheral vestibular pattern
4. Exclusion of central causes

Investigations serve to:

• Confirm clinical diagnosis (caloric testing)
• Exclude central pathology (MRI brain if HINTS concerning or atypical features)
• Exclude labyrinthitis (audiometry)
• Monitor recovery (vHIT, caloric testing)

Investigation Strategy

Caloric Testing - Gold Standard Vestibular Function Test

Principle: Irrigation of external auditory canal with warm/cold water creates temperature gradient in horizontal semicircular canal, inducing endolymph flow and nystagmus.

Procedure:

1. Warm water (44°C) and cold water (30°C) irrigation of each ear sequentially
2. Measure duration and slow-phase velocity of induced nystagmus
3. Calculate asymmetry between ears

Interpretation:

In vestibular neuritis:

• Acute phase: Marked reduction or absence of caloric response on affected side
• Recovery phase: Variable recovery; ~50% have persistent reduced response but clinical compensation [13]

Limitations:

• Not needed for acute diagnosis or management
• Uncomfortable for patient
• Requires specialist equipment and expertise
• Time-consuming

Video Head Impulse Test (vHIT) - Modern Alternative

Advantages over caloric testing:

• Rapid (few minutes vs 30-45 minutes)
• Well-tolerated
• Tests higher frequency VOR (more physiological)
• Can test all six semicircular canals individually
• Quantitative VOR gain measurement

Interpretation:

• VOR gain less than 0.6 indicates peripheral hypofunction (normal > 0.8)
• Can identify superior division vs inferior division involvement
• Covert saccades (during head movement) and overt saccades (after head movement) detected

Emerging role: Increasingly used in specialist vestibular clinics to confirm diagnosis and track recovery. [16]

MRI Brain - When Indicated

Indications for urgent MRI:

• Any "central" HINTS finding (normal HIT, direction-changing/vertical nystagmus, skew deviation)
• Neurological signs or symptoms
• Severe headache
• Age > 60 with vascular risk factors
• Atypical presentation (e.g., vertigo preceded by severe headache)
• Diagnostic uncertainty

MRI Protocol:

• DWI (Diffusion-Weighted Imaging): Most sensitive for acute stroke
• T2/FLAIR: Structural lesions, demyelination
• MRA (MR Angiography): If vascular dissection suspected
• Contrast: If concern for inflammatory/neoplastic process

Important Caveat: MRI DWI has only 80-85% sensitivity for posterior circulation stroke within first 48 hours. Small brainstem and cerebellar strokes can be missed. HINTS examination is more sensitive acutely. [4] If clinical suspicion for stroke remains high despite negative initial MRI, repeat MRI at 3-7 days or obtain MRA to assess vascular patency.

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8. Management

Management Algorithm

VESTIBULAR NEURITIS - CONFIRMED DIAGNOSIS
(Peripheral HINTS pattern + Normal hearing + No neurological signs)
                          ↓
    ┌─────────────────────┴─────────────────────┐
    ↓                                           ↓
ACUTE PHASE                              RECOVERY PHASE
(First 24-72 hours)                      (Days to weeks)
    ↓                                           ↓
┌───────────────────────────────────┐   ┌──────────────────────────────┐
│ SUPPORTIVE CARE                   │   │ VESTIBULAR REHABILITATION    │
│ • IV fluids if severe vomiting    │   │ (CORNERSTONE INTERVENTION)   │
│ • Rest in quiet, dark room        │   │ • Gaze stabilisation (VOR)   │
│ • Reassurance                     │   │ • Habituation exercises      │
│                                   │   │ • Balance retraining         │
│ VESTIBULAR SUPPRESSANTS           │   │ • Cawthorne-Cooksey protocol │
│ (SHORT-TERM ONLY: 3-5 days max)   │   │ • Referral to specialist PT  │
│ • Prochlorperazine 5mg TDS        │   │                              │
│ • Cyclizine 50mg TDS              │   │ EARLY MOBILISATION           │
│ • Cinnarizine 30mg TDS            │   │ • Encourage movement ASAP    │
│                                   │   │ • Promotes compensation      │
│ ANTIEMETICS                       │   │                              │
│ • Ondansetron 4-8mg PRN           │   │ STOP VESTIBULAR SUPPRESSANTS │
│ • Metoclopramide 10mg TDS         │   │ • After 3-5 days maximum     │
│                                   │   │ • Impair compensation        │
│ CORTICOSTEROIDS (Controversial)   │   │                              │
│ • Consider if less than 3 days onset       │   │ REASSURANCE                  │
│ • Methylprednisolone 100mg OD     │   │ • Expected timeline          │
│   for 3 days, OR                  │   │ • Benign prognosis           │
│ • Prednisolone 60mg tapering      │   │ • Likely full recovery       │
│ • Evidence: may improve vestib.   │   │                              │
│   function; unclear symptom benefit│   │ FOLLOW-UP                    │
│                                   │   │ • Review 2-4 weeks           │
│ AVOID                             │   │ • Assess compensation        │
│ • Antivirals (no proven benefit)  │   │ • Consider specialist referal│
│ • Prolonged vestibular suppressants│  │   if not improving           │
└───────────────────────────────────┘   └──────────────────────────────┘

Acute Phase Management (First 24-72 Hours)

Supportive Care:

Vestibular Suppressants (Use with Caution - Time-Limited):

Critical Principle: Limit to 3-5 days maximum. Prolonged use impairs central vestibular compensation and delays recovery. [8]

Avoid vestibular suppressants beyond 5 days - actively taper and discontinue to promote compensation.

Antiemetics:

Ondansetron is preferred if aiming to minimise vestibular suppression while controlling nausea.

Corticosteroids - Evidence and Controversy:

Rationale: Anti-inflammatory effect may reduce vestibular nerve inflammation and promote recovery of vestibular function.

Evidence:

Current Practice:

• Controversial - not universally recommended
• Consider if presenting within 3 days of symptom onset
• More commonly used in specialist neurology/ENT practice than general practice

Typical Regimen:

• Methylprednisolone 100mg IV or PO daily for 3 days, OR
• Prednisolone 60mg PO daily for 5 days, then taper over further 5 days

Contraindications: Diabetes (relative); peptic ulcer disease; infection; immunosuppression.

Antiviral Therapy - No Proven Benefit:

Despite viral aetiology hypothesis, antiviral agents (acyclovir, valacyclovir) have NOT demonstrated benefit in randomised controlled trials and are not recommended. [19]

Recovery Phase Management (Days to Weeks)

Vestibular Rehabilitation - Evidence-Based Cornerstone:

Cochrane Systematic Review (Hillier & McDonnell, 2011): [6]

• Strong evidence that vestibular rehabilitation improves subjective symptom resolution
• Accelerates functional recovery
• Reduces long-term disability
• High-quality evidence; strongly recommended

Components of Vestibular Rehabilitation:

1. Gaze Stabilisation Exercises (VOR Adaptation):
   • Patient focuses on stationary target while moving head side-to-side or up-down
   • Progressively faster head movements
   • Promotes VOR recalibration
   • Example: "X1 viewing"

• hold card with "X" at arm's length, move head horizontally while keeping X in focus

2. Habituation Exercises:

   • Repeated exposure to movements that provoke symptoms
   • Desensitises vestibular system
   • Example: Brandt-Daroff exercises (sitting to lying side-to-side movements)

3. Balance Retraining:

   • Static and dynamic balance tasks
   • Narrowing base of support (tandem stance, single-leg stance)
   • Foam pads, uneven surfaces
   • Visual deprivation (eyes closed)

4. Cawthorne-Cooksey Exercises:

   • Structured progressive exercise program
   • Combination of head movements, eye movements, bending, walking
   • Home-based program with graduated difficulty

Referral to Vestibular Physiotherapy:

• Should occur within 1-2 weeks of symptom onset
• Specialist physiotherapists with vestibular training ideal
• Individualised program based on assessment
• Typically 6-12 sessions over 6-12 weeks

Early Mobilisation:

• Encourage movement and activity as soon as tolerated (typically after 24-48h)
• Bed rest beyond initial acute phase is counterproductive
• Activity promotes neuroplasticity and compensation [8]

Discontinuation of Vestibular Suppressants:

• Stop after 3-5 days maximum
• Prolonged use actively impairs compensation
• Taper if used for several days

Reassurance and Education:

• Explain expected symptom trajectory (weeks to months for full recovery)
• Most patients achieve functional recovery
• Residual mild imbalance common but improves
• Avoid catastrophising and anxiety which impair compensation

Follow-Up:

• Review at 2-4 weeks to assess compensation
• Consider specialist referral (ENT/Neurology) if:
  • No improvement by 4 weeks
  • Severe ongoing symptoms
  • Diagnostic uncertainty
  • Request for formal vestibular testing

When to Refer to Specialist

ENT or Neurology Referral Indications:

• Diagnostic uncertainty
• Incomplete recovery by 6 weeks
• Severe persistent symptoms impacting function
• Request for vestibular function testing (caloric, vHIT)
• Recurrent episodes (suggests alternative diagnosis)
• Hearing symptoms develop (labyrinthitis, Ménière's disease)

Safety Netting and Red Flags

Advise patient to seek urgent reassessment if:

• New neurological symptoms (weakness, numbness, speech disturbance, double vision)
• Severe headache
• Hearing loss develops
• Symptoms dramatically worsen
• Fever develops (meningitis/encephalitis consideration)

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9. Complications

Acute Complications

Chronic Complications and Sequelae

Incomplete Central Compensation:

• Approximately 30-40% of patients have some residual mild imbalance or disequilibrium at 1 year [13]
• Most is mild and non-disabling
• Associated with:
  • Older age
  • Inactivity and avoidance behaviours
  • Anxiety and psychological factors
  • Inadequate vestibular rehabilitation
• Management: Continued vestibular rehabilitation; address anxiety; graded exposure

Post-Vestibular Neuritis BPPV:

• Develops in approximately 10-15% of patients following vestibular neuritis [20]
• Typically occurs weeks to months after acute episode
• Usually affects posterior canal of the affected ear
• Mechanism: Dislodged otoconia from damaged utricle
• Presentation: Episodic positional vertigo (distinct from initial continuous vertigo)
• Diagnosis: Dix-Hallpike manoeuvre positive
• Treatment: Epley repositioning manoeuvre (highly effective)

Persistent Postural-Perceptual Dizziness (PPPD):

• Functional dizziness syndrome that can develop after vestibular neuritis
• Criteria:
  • Persistent (> 3 months) non-vertiginous dizziness
  • Exacerbated by upright posture, movement, visual stimuli
  • Causes significant functional impairment
• Mechanism: Maladaptive compensation; over-reliance on visual input; high-threat postural control strategy
• Associated factors: Anxiety, depression, catastrophising
• Management:
  • Vestibular rehabilitation with cognitive-behavioural approach
  • Address anxiety/depression (SSRI if indicated)
  • Graded exposure to provocative stimuli
  • Multidisciplinary approach

Anxiety and Depression:

• Common psychological sequelae due to:
  • Severity and unpredictability of initial symptoms
  • Fear of recurrence
  • Impact on function and independence
  • Chronic symptoms
• Management:
  • Reassurance and education
  • Cognitive-behavioural therapy
  • Antidepressant/anxiolytic if indicated (SSRIs do not impair compensation)
  • Support groups

Chronic Unilateral Vestibular Hypofunction:

• Approximately 50% of patients have persistent reduced caloric response on affected side at 1 year [13]
• Most have compensated clinically despite persistent peripheral deficit
• May notice imbalance during:
  • Rapid head movements
  • Challenging balance situations (uneven ground, darkness)
  • Vigorous exercise
• Usually non-disabling with compensation

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10. Prognosis and Outcomes

Symptom Timeline and Recovery

Functional Outcomes

Short-Term (3 months):

• 70-80% of patients report substantial functional recovery [13]
• Return to work typically possible within 2-6 weeks
• Driving may be affected for 2-4 weeks (advise DVLA notification if persistent symptoms)

Long-Term (1 year):

• 60-70% report complete symptomatic recovery [13]
• 30-40% report mild residual symptoms (usually non-disabling)
• less than 10% report significant persistent symptoms requiring ongoing intervention

Vestibular Function Recovery

Caloric Testing Outcomes:

• ~50% recover some caloric response on affected side by 1 year
• ~50% have persistent vestibular areflexia on caloric testing despite clinical compensation [13]
• Clinical compensation occurs even without peripheral function recovery

VOR Gain Recovery (vHIT):

• Variable recovery patterns
• Some patients show improved VOR gain; others rely on compensatory mechanisms (covert saccades)

Factors Associated with Better Prognosis

Positive Prognostic Factors:

• Younger age (though compensation occurs at all ages)
• Early mobilisation and activity [8]
• Vestibular rehabilitation participation [6]
• Rapid discontinuation of vestibular suppressants
• Lower anxiety levels
• Good social support

Negative Prognostic Factors:

• Older age
• Prolonged vestibular suppressant use [8]
• Inactivity and bed rest beyond acute phase
• High anxiety and catastrophising
• Avoidance behaviours
• Concurrent neurological disease (impairs cerebellar compensation)

Recurrence

• Rare: Approximately 2-5% of patients experience recurrence [13]
• Recurrence typically affects contralateral ear
• Timing variable (months to years)
• Recurrent episodes may suggest alternative diagnosis (vestibular migraine, Ménière's disease)

Impact on Quality of Life

Acute Phase:

• Severe disruption to all activities of daily living
• Often requires time off work (median 1-2 weeks)
• Unable to drive during acute symptoms

Recovery Phase:

• Gradual return to normal activities
• May require workplace adjustments initially
• Psychological impact (anxiety about symptoms) can persist

Long-Term:

• Most patients return to full premorbid function
• Minority have ongoing impact on work, driving, sports
• Quality of life generally good with appropriate management and rehabilitation

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11. Evidence and Guidelines

Key Guidelines

Key Evidence

HINTS Examination Validation:

• Kattah et al. (2009) [4]: Landmark study demonstrating HINTS sensitivity 100%, specificity 96% for stroke detection in AVS; superior to MRI DWI less than 48h
• Revolutionised bedside assessment of acute vertigo

Vestibular Rehabilitation:

• Hillier & McDonnell (2011) Cochrane Review [6]: Strong evidence for benefit in unilateral peripheral vestibular dysfunction
• Multiple RCTs confirm acceleration of recovery and improved functional outcomes

Vestibular Suppressants:

• Strupp et al. (2006) [8]: Prolonged vestibular suppressant use delays compensation
• Recommendation to limit to 3-5 days maximum

Corticosteroids:

• Strupp et al. (2004) [7]: Methylprednisolone improved caloric recovery vs placebo
• Cochrane Review (2011) [18]: Modest evidence for functional recovery; unclear symptom benefit
• Remains controversial; not universally recommended

Antivirals:

• Hamann (2009) [19]: No benefit of acyclovir vs placebo
• Not recommended despite viral aetiology

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12. Patient and Layperson Explanation

What is Vestibular Neuritis?

Vestibular neuritis is inflammation of a nerve in your inner ear called the vestibular nerve, which is responsible for balance. When this nerve becomes inflamed, it sends abnormal signals to your brain, causing sudden, severe dizziness (called vertigo), where you feel like the room is spinning around you.

What Causes It?

Vestibular neuritis is usually caused by a viral infection, often the same virus that causes cold sores (herpes simplex virus). The virus affects the balance nerve, causing swelling and inflammation. About half of people with vestibular neuritis have had a cold or flu in the weeks beforehand.

What are the Symptoms?

• Sudden, severe dizziness (vertigo): Feels like you or the room is spinning; can be very intense
• Nausea and vomiting: Often severe
• Difficulty balancing: Trouble walking in a straight line; may fall to one side
• Vision problems: Things may appear blurry when you move your head

Important: Your hearing should NOT be affected. If you develop hearing loss or ringing in your ears with the dizziness, this may be a different condition called labyrinthitis, and you should inform your doctor.

What Tests Might I Need?

Vestibular neuritis is usually diagnosed based on your symptoms and a physical examination. Your doctor will:

• Check your eye movements
• Test your balance
• Check your hearing
• Perform a "head impulse test"
• moving your head quickly while you look at their nose

If there are any concerns about stroke or other serious causes, you may need a brain scan (MRI), though this is not needed in most cases.

How is it Treated?

First Few Days (Acute Phase):

• Rest: Stay in a quiet, dark room when symptoms are severe
• Medications:
  • Tablets to reduce dizziness (like prochlorperazine or cyclizine) - only for 3-5 days
  • Anti-sickness medication
  • Fluids through a drip if you cannot keep fluids down
• Steroids: Your doctor may offer steroid tablets if you present within the first few days, as there is some evidence these may help recovery, though this is not always given

After a Few Days - The Key to Recovery:

• Start moving as soon as you can tolerate it - even though it feels unpleasant at first, movement helps your brain adapt
• STOP dizziness medications after 3-5 days - they actually slow down recovery if used for longer
• Vestibular rehabilitation exercises: Specialised balance exercises with a physiotherapist - this is the most important treatment for getting better

How Long Will it Last?

• Severe symptoms: Usually last 1-3 days
• Gradual improvement: Over 1-6 weeks
• Full recovery: Most people feel back to normal by 3 months

Some people (about 1 in 3) have mild lingering imbalance for longer, but this usually improves with balance exercises.

Will it Come Back?

Recurrence is rare (only about 2-5 in 100 people). If you do get dizzy spells again, they may be a different type of dizziness (like BPPV, which can occur after vestibular neuritis and is easily treatable).

When Should I Seek Urgent Help?

Go to the Emergency Department or call 999 if you develop:

• Weakness in your arms or legs
• Numbness or tingling
• Difficulty speaking or slurred speech
• Double vision
• Severe headache
• Difficulty swallowing
• Hearing loss

These symptoms could indicate a stroke or other serious condition rather than vestibular neuritis.

What About Driving?

You should not drive while experiencing severe dizziness. You must inform the DVLA if symptoms persist for more than a few weeks. Most people can resume driving within 2-4 weeks once symptoms improve.

Self-Care and Recovery Tips

• Keep moving: Gentle activity promotes recovery
• Balance exercises: Practice exercises given by your physiotherapist
• Avoid prolonged bed rest: This delays recovery
• Stay hydrated: Drink plenty of fluids
• Avoid alcohol: Can worsen dizziness
• Be patient: Recovery takes time, but most people make a full recovery
• Don't worry: Vestibular neuritis is not dangerous and does not cause permanent damage in most cases

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13. Examination Focus and Viva Questions

Common MRCP/MRCS/FRCS Examination Questions

1. What is the HINTS Examination and Why is it Important?

Model Answer: "The HINTS examination stands for Head Impulse, Nystagmus type, and Test of Skew. It is a three-component bedside oculomotor assessment used to differentiate peripheral vestibular causes from central causes, particularly stroke, in patients presenting with acute vestibular syndrome.

The components are:

1. Head Impulse Test: Tests VOR function; abnormal (corrective saccade) suggests peripheral lesion
2. Nystagmus type: Unidirectional horizontal-torsional suggests peripheral; direction-changing or vertical suggests central
3. Test of Skew: Vertical ocular misalignment suggests brainstem pathology

The HINTS examination is critically important because it has higher sensitivity (100%) than MRI DWI performed within 48 hours of symptom onset (80-85%) for detecting posterior circulation stroke. A 'dangerous' HINTS pattern—normal HIT, direction-changing or vertical nystagmus, or skew deviation—requires urgent brain imaging."

2. How Do You Perform and Interpret the Head Impulse Test?

Model Answer: "The Head Impulse Test assesses the vestibulo-ocular reflex. Technique:

1. Patient seated at arm's length, fixates on my nose
2. I hold the patient's head with both hands
3. Make rapid, unpredictable, small-amplitude (10-20°) head rotation to one side
4. Observe if eyes remain fixed on target

Interpretation:

• Normal: Eyes remain locked on target throughout head movement
• Abnormal (positive): Eyes move with head then make a corrective saccade back to target—indicates peripheral vestibular hypofunction on that side

In vestibular neuritis, HIT is abnormal when head is turned toward the affected ear. Crucially, in acute vestibular syndrome, a normal HIT raises concern for central pathology and possible stroke."

3. Why Does the Nystagmus Fast Phase Beat AWAY from the Lesion in Vestibular Neuritis?

Model Answer: "The vestibular system normally has bilateral tonic activity maintaining balance. In vestibular neuritis, there is sudden loss of input from the affected vestibular nerve, creating asymmetric vestibular input.

The slow phase of nystagmus is the pathological component—it drifts toward the affected (hypoactive) side due to unopposed vestibular tone from the healthy side.

The fast phase is the corrective saccade bringing eyes back to midline, beating away from the lesion toward the healthy side. By convention, nystagmus is named by the fast phase direction.

This unilateral vestibular imbalance also explains why patients fall toward the affected side—the brain interprets reduced input as movement toward the healthy side and 'corrects' by tilting the body toward the lesion."

4. What is the Difference Between Vestibular Neuritis and Labyrinthitis?

Model Answer: "Both are acute peripheral vestibular disorders with similar presentations, but differ in anatomical involvement:

Vestibular Neuritis:

• Affects vestibular nerve only
• Vertigo, nausea, imbalance present
• Hearing is PRESERVED
• No tinnitus or aural fullness

Labyrinthitis:

• Affects both vestibular and cochlear divisions (entire labyrinth)
• Vertigo, nausea, imbalance present
• Hearing loss (sensorineural) present
• Tinnitus usually present

The distinction is clinically important because hearing loss suggests more extensive pathology, requires audiometry and potentially different investigation/follow-up, and has implications for differential diagnosis (e.g., stroke affecting both vestibular and auditory pathways)."

5. Why Should Vestibular Suppressants Be Limited to 3-5 Days?

Model Answer: "Vestibular suppressants (antihistamines like cyclizine, anticholinergics like prochlorperazine, and benzodiazepines) impair central vestibular compensation when used beyond the acute phase.

Central compensation is a neuroplastic process whereby the vestibular nuclei, cerebellum, and cortex recalibrate to asymmetric peripheral input. This requires:

• Sensory conflict (mismatch between vestibular, visual, proprioceptive input)
• Active movement and exposure to provocative stimuli
• Neuronal activity in vestibular nuclei

Vestibular suppressants reduce vestibular nucleus activity and sensory conflict, thereby delaying compensation and prolonging symptoms.

Evidence from Strupp et al. demonstrates that prolonged vestibular suppressant use is associated with incomplete compensation and chronic dizziness.

Therefore, they should be used only for symptomatic relief in the acute phase (first 3-5 days) and then stopped to promote recovery."

6. What is the Role of Vestibular Rehabilitation and What Does it Involve?

Model Answer: "Vestibular rehabilitation is the most important intervention for promoting recovery in vestibular neuritis. Cochrane systematic reviews provide Level I evidence that it accelerates symptomatic recovery, improves function, and reduces long-term disability.

Components:

1. Gaze stabilisation (VOR adaptation) exercises: Patient fixates on stationary target while moving head—promotes VOR recalibration
2. Habituation exercises: Repeated exposure to symptom-provoking movements to desensitise the system
3. Balance retraining: Static and dynamic balance tasks with progressive difficulty (foam surfaces, eyes closed, etc.)
4. Cawthorne-Cooksey exercises: Structured home-based program combining head movements, eye movements, and functional activities

Patients should be referred to specialist vestibular physiotherapy within 1-2 weeks. Early mobilisation is critical—prolonged bed rest beyond the acute phase impairs compensation. The exercises work by promoting neuroplasticity in vestibular nuclei, cerebellum, and cortex."

7. What is the Evidence for Corticosteroids in Vestibular Neuritis?

Model Answer: "Corticosteroid use in vestibular neuritis is controversial and not universally recommended.

Rationale: Anti-inflammatory effect may reduce vestibular nerve inflammation and promote recovery.

Evidence:

• Strupp et al. (2004): RCT showing methylprednisolone 100mg daily for 3 days improved caloric response recovery compared to placebo
• Cochrane Review (2011): Modest evidence for improved peripheral vestibular function on caloric testing; unclear whether this translates to clinically meaningful symptom improvement

Current Practice:

• May be considered if patient presents within 3 days of symptom onset
• More commonly used in specialist neurology/ENT settings
• Typical regimen: methylprednisolone 100mg daily for 3 days, or prednisolone 60mg with taper

Antivirals (acyclovir, valacyclovir) have been studied but show no benefit in RCTs despite the viral aetiology hypothesis, and are not recommended."

Viva Scenario

Examiner: "A 45-year-old woman presents to the Emergency Department with sudden onset of severe dizziness, nausea, and vomiting that started 6 hours ago. She feels the room is spinning. She has no headache, no hearing loss, and no neurological symptoms. How would you assess and manage her?"

Model Answer:

"This presentation is consistent with acute vestibular syndrome. My priorities are to:

1. Confirm AVS criteria
2. Differentiate peripheral (vestibular neuritis) from central (stroke) causes
3. Initiate appropriate management

Assessment:

History:

• Clarify symptom onset, duration, severity
• Vertigo character: rotational vs light-headedness
• Hearing symptoms: hearing loss or tinnitus would suggest labyrinthitis or Ménière's
• Neurological symptoms: diplopia, dysarthria, dysphagia, weakness, numbness would suggest central cause
• Vascular risk factors: age, hypertension, diabetes, atrial fibrillation, smoking—increase stroke probability
• Preceding viral illness

Examination:

• HINTS examination (critical):
  • "Head Impulse Test: Test VOR both directions"
  • "Nystagmus: Assess direction (unidirectional vs direction-changing), type (horizontal vs vertical)"
  • "Test of Skew: Alternate cover test for vertical deviation"
• Hearing assessment: Weber and Rinne
• Neurological examination: cranial nerves, cerebellar signs, motor/sensory
• Gait and Romberg

HINTS Interpretation:

• Peripheral pattern (vestibular neuritis): Abnormal HIT, unidirectional horizontal-torsional nystagmus, no skew deviation
• Central pattern (stroke concern): Normal HIT, direction-changing or vertical nystagmus, or skew deviation present

Investigations:

• If HINTS peripheral and no vascular risk factors: Clinical diagnosis, no imaging needed acutely; consider audiometry to exclude labyrinthitis
• If HINTS central or high vascular risk: Urgent MRI brain DWI (though sensitivity only 80-85% less than 48h, HINTS more sensitive)

Management if Vestibular Neuritis Confirmed:

Acute phase (first 3-5 days):

• Vestibular suppressants: prochlorperazine 5mg TDS or cyclizine 50mg TDS—limit to 3-5 days
• Antiemetics: ondansetron 4-8mg if severe nausea
• IV fluids if unable to tolerate oral
• Consider corticosteroids if less than 3 days onset (methylprednisolone 100mg daily × 3)

Recovery phase:

• Stop vestibular suppressants after 3-5 days
• Early mobilisation
• Referral to vestibular physiotherapy for rehabilitation (gaze stabilisation, habituation, balance exercises)
• Reassurance: expected gradual improvement over weeks

Safety netting: Advise patient to return if develops neurological symptoms, hearing loss, severe headache, or symptoms worsen."

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Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances and current best practice guidelines. Always consult appropriate specialists and consider individual patient factors when making diagnostic and therapeutic decisions.