What are the clinical features, examination findings, investigations, and management options for a patient with suspected Meniere's disease, presenting with episodic vertigo, tinnitus, hearing loss, and aural fullness?

Meniere's Disease: Comprehensive Clinical Overview

Etiology

Meniere's disease results from increased endolymphatic fluid volume in the inner ear, causing distortion of the membranous labyrinth (endolymphatic hydrops), though the precise underlying mechanism remains incompletely understood. 1

• The condition involves multiple biochemical pathways including the endocrine system, innate immune response, and autonomic nervous system 2
• Genetic susceptibility plays a role, with epidemiologic and genomic evidence supporting hereditary factors 2
• Potential triggers include allergens, infectious agents, vascular events, or genetic factors that disrupt inner-ear homeostasis 2
• Bilateral involvement occurs in 10-25% of cases over time, which significantly impacts surgical decision-making 3

Clinical Features

Definite Meniere's disease requires two or more spontaneous vertigo attacks lasting 20 minutes to 12 hours each, audiometrically documented fluctuating low- to mid-frequency sensorineural hearing loss, and fluctuating aural symptoms (hearing loss, tinnitus, or fullness) in the affected ear. 1

Classic Symptom Tetrad:

• Episodic vertigo: Rotational spinning sensation lasting specifically 20 minutes to 12 hours per attack 1
• Fluctuating sensorineural hearing loss: Initially affects low- to mid-frequencies but may eventually involve all frequencies as disease progresses 1, 3
• Tinnitus: Fluctuating in nature, associated with the affected ear 1
• Aural fullness: Sensation of pressure or fullness in the affected ear 1

Additional Clinical Considerations:

• Headache commonly occurs during attacks 2
• Drop attacks (Tumarkin's otolithic crisis) may develop in later disease stages—sudden falls without loss of consciousness during discrete MD attacks 1, 3
• Imbalance (distinct from vertigo) may be ongoing rather than episodic 1
• High co-occurrence rate with migraine should prompt specific history-taking 4

Examination Findings

Physical examination findings are typically unremarkable between attacks, making Meniere's disease primarily a clinical diagnosis based on history and audiometric testing. 1

• Neurological examination should be normal; any abnormalities suggest alternative diagnoses 1
• During acute attacks: nystagmus may be present, with profound nausea and vomiting 5
• Between attacks: examination is generally normal 1

Critical Red Flags Requiring Emergency Neuroimaging:

• Dysarthria or dysphagia 3
• Visual blurring or drop attacks 3
• Motor or sensory deficits 3
• Horner's syndrome 3
• Direction-changing nystagmus without head position changes 3
• Downbeating nystagmus 3
• Severe imbalance disproportionate to vertigo 3

Investigations

Essential Diagnostic Testing:

Audiometry is mandatory for documenting the characteristic low- to mid-frequency sensorineural hearing loss pattern. 3

• Pure tone audiometry must demonstrate fluctuating low- to mid-frequency SNHL in the affected ear on at least one occasion before, during, or after a vertigo episode 1
• Regular audiometric testing is recommended to monitor hearing progression 3
• Word recognition/discrimination scores help define "usable hearing" for surgical planning 1

Usable Hearing Classification (AAO-HNS Scale):

• Class A: Discrimination 70-100%; PTA <30 dB (usable) 1
• Class B: Discrimination 50-69%; PTA 31-50 dB (usable) 1
• Class C: Discrimination 50-69%; PTA >50 dB (usable) 1
• Class D: Discrimination <50%; any PTA (non-usable) 1, 3

Imaging and Additional Workup:

• Contrast-enhanced MRI of internal auditory canals to exclude cerebellopontine angle tumors, vestibular schwannoma, and other structural lesions 4
• Conventional imaging is typically normal in Meniere's disease 1

Differential Diagnosis Exclusion:

Must exclude conditions that mimic Meniere's disease 4:

• Otosyphilis
• Autoimmune inner ear disease
• Perilymphatic fistula
• Superior semicircular canal syndrome
• Lyme disease
• Multiple sclerosis
• Vestibular paroxysmia
• Temporal bone tumors

Management

The American Academy of Otolaryngology-Head and Neck Surgery recommends a stepwise approach starting with conservative measures and progressing to more invasive interventions only after failure of less aggressive therapies. 3

Tier 1: Conservative Management (First-Line)

Begin with lifestyle modifications and medical therapy, as up to 60% of patients show improvement with conservative measures. 3

• Low-sodium diet (cornerstone of dietary management) 3, 4
• Avoidance of dietary triggers: caffeine, alcohol, nicotine 4, 6
• Stress reduction and sleep hygiene 4
• Diuretic therapy as first-line medical treatment 3, 4
• Continue conservative measures for several months before escalating 3

Tier 2: Medical Interventions for Active Disease

For patients failing conservative management after several months, intratympanic steroid injections should be considered before ablative therapies. 3

• Intratympanic corticosteroid injections for active disease not responsive to conservative measures 3
• Betahistine may be considered (though efficacy is debated) 4, 2
• Vestibular suppressants and antiemetics for symptomatic control during acute attacks (benzodiazepines, antiemetics) 4

Tier 3: Ablative Therapies

Intratympanic gentamicin is indicated for patients with debilitating vertigo who have failed medical management and have non-usable hearing or are willing to accept hearing risk. 7, 8

• Low-dose intratympanic gentamicin protocol reduces vestibular function without requiring complete ablation 7, 8
• Goal: control vertigo by partially destroying vestibular system while maintaining hearing 8
• Transtympanic injection is quick, easy, well-tolerated, ambulatory, and cost-effective 8
• Drug concentration should depend on frequency, intensity, and duration of vertigo spells, plus degree of existing hearing loss 8

Tier 4: Surgical Options

For patients with usable hearing (Class A, B, or C), non-ablative procedures such as endolymphatic sac decompression may preserve auditory function. 3

• Endolymphatic sac surgery: efficacy is controversial but may be considered for usable hearing preservation 3, 4
• Vestibular nerve section: rarely considered for severe symptoms unresponsive to gentamicin 4
• Labyrinthectomy: reserved for patients with non-usable hearing and severe refractory symptoms 4

Important Surgical Considerations:

• Recognize that 10-25% of cases may eventually affect both ears, making destructive procedures potentially problematic 3
• Positive pressure therapy (Meniett device) is NOT recommended 3

Rehabilitative and Hearing Management

Vestibular rehabilitation/physical therapy should be offered for patients with unilateral vestibular weakness who have failed less definitive therapy. 3

Hearing Rehabilitation Options:

• Conventional hearing aids for patients with usable hearing 3
• CROS (Contralateral Routing of Signal) hearing aids for severely compromised speech discrimination 3
• Cochlear implants for severe hearing loss where amplification provides limited benefit 3, 2

Monitoring and Follow-up

• Regular audiometric testing to monitor hearing progression 3
• Quality of life assessment as part of ongoing management 3
• Documentation of changes in hearing loss, tinnitus, and vertigo after treatment 3

Critical Pitfalls to Avoid

• Do not assume vertigo >12 hours is Meniere's disease—this duration suggests vestibular neuritis, labyrinthitis, or stroke 5
• Do not proceed to ablative therapy without adequate trial of conservative management (several months minimum) 3
• Do not overlook bilateral disease potential when planning destructive procedures 3
• Recognize that hearing loss often worsens over time despite treatment—complete restoration is not currently possible 3
• Do not rely on placebo-controlled trial data alone—up to 60% show placebo response, making treatment efficacy assessment challenging 3
• Always exclude other causes (otosyphilis, autoimmune disease, tumors) before confirming diagnosis 4