Residency · Residency · Otolaryngology

Meniere Disease and Endolymphatic Hydrops

Overview

Meniere disease is an idiopathic inner ear disorder characterized by episodic vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural fullness. The underlying pathophysiology involves endolymphatic hydrops -- distension of the endolymphatic space. Management ranges from dietary and medical therapy to destructive procedures in refractory cases.

Pathophysiology

Endolymphatic Hydrops

Distension of the endolymphatic compartment (scala media, saccule, utricle). Proposed mechanisms: impaired endolymph absorption in the endolymphatic sac, overproduction of endolymph, or disrupted ion homeostasis. Histopathologic hallmark: ballooning of Reissner membrane into scala vestibuli. Hydrops is necessary but not sufficient for clinical Meniere disease -- hydrops found in asymptomatic temporal bones. Rupture theory: periodic rupture of Reissner membrane causes potassium-rich endolymph to mix with perilymph, depolarizing vestibular and cochlear nerve fibers.

Endolymph Physiology

Produced primarily by stria vascularis (cochlea) and dark cells (vestibule). High potassium (~150 mEq/L), low sodium -- unique extracellular fluid. Absorbed by the endolymphatic sac. Endocochlear potential (~+80 mV) maintained by stria vascularis.

Epidemiology

Prevalence: 50-200 per 100,000. Peak onset: 4th-6th decade. Slight female predominance. Bilateral involvement in 25-40% over time (increases with disease duration). Familial cases reported (~8-10%); possible autosomal dominant with incomplete penetrance.

Diagnostic Criteria (AAO-HNS 2015 / Barany Society)

Definite Meniere Disease

Two or more spontaneous episodes of vertigo, each lasting 20 minutes to 12 hours. Audiometrically documented low- to mid-frequency sensorineural hearing loss in the affected ear on at least one occasion before, during, or after one of the episodes. Fluctuating aural symptoms (hearing loss, tinnitus, fullness) in the affected ear. Not better accounted for by another vestibular diagnosis.

Probable Meniere Disease

Two or more episodes of vertigo or dizziness lasting 20 minutes to 24 hours. Fluctuating aural symptoms in the affected ear, Not better accounted for by another diagnosis.

Clinical Presentation

Symptom Profile

Vertigo: episodic, rotational, lasting 20 minutes to several hours; associated with nausea, vomiting, and nystagmus. Hearing loss: initially low-frequency SNHL, fluctuating; progresses to flat moderate-severe loss over years. Tinnitus: typically low-pitched, roaring; worsens before or during attacks. Aural fullness: pressure sensation in the affected ear, often a prodrome of attacks. Tumarkin crisis (otolithic crisis): sudden drop attacks without loss of consciousness (late disease).

Natural History

Episodic phase: recurrent vertigo attacks with fluctuating hearing. "Burnout" phase: vertigo attacks diminish over years as vestibular function is destroyed, but hearing loss and imbalance persist. Hearing stabilizes at moderate-to-severe levels after 5-10 years.

Workup

Audiometry

Low-frequency SNHL is characteristic early pattern, Serial audiograms document fluctuation and progression. Speech discrimination preserved early, deteriorates with disease progression.

Electrocochleography (ECoG)

Measures summating potential (SP) and action potential (AP) ratio. SP/AP ratio >0.4-0.5 suggests endolymphatic hydrops. Can be performed with tympanic membrane electrode (non-invasive) or transtympanic electrode (more accurate).

Vestibular Testing

Caloric testing: may show unilateral weakness on the affected side (reduced vestibular response). VEMPs: may show reduced or absent cVEMP on affected side. vHIT: may be normal early; abnormal in late disease.

MRI

Gadolinium-enhanced inner ear MRI (3T with delayed contrast) can visualize endolymphatic hydrops directly. Useful for research and in diagnostic uncertainty. MRI of the IAC to rule out vestibular schwannoma in asymmetric SNHL.

Medical Management

Lifestyle and Dietary Modifications

Sodium restriction (<1500-2000 mg/day) -- mainstay of management. Adequate hydration, Caffeine and alcohol limitation, Stress reduction and adequate sleep, Avoid known triggers.

Pharmacotherapy

Diuretics: hydrochlorothiazide/triamterene (Dyazide) most commonly used; limited RCT evidence but widely prescribed. Betahistine: histamine analog; used extensively in Europe and Canada; 16-48 mg TID; may improve endolymphatic circulation; debated efficacy. Vestibular suppressants: meclizine, diazepam, promethazine -- for acute attacks only (not for prophylaxis). Antiemetics: ondansetron, prochlorperazine for nausea during attacks.

Intratympanic Therapy

Intratympanic Dexamethasone

Office-based injection through the tympanic membrane, 10-24 mg/mL concentration; 0.4-0.8 mL per injection, Series of 3 injections over several weeks, or as needed, Vertigo control in ~70-80% of patients, Hearing preservation (no ototoxic risk), First-line intratympanic therapy in most protocols.

Intratympanic Gentamicin [CONTROVERSY]

Chemical vestibular ablation via selective hair cell toxicity. Preferential toxicity to type I vestibular hair cells over cochlear cells. Vertigo control rates: 80-90%. Risk of sensorineural hearing loss: 10-30% (dose-dependent). Protocols: low-dose titration (single injection, wait and observe) vs. fixed-schedule dosing. Low-dose titration protocol preferred to minimize hearing loss risk. Controversy: intratympanic gentamicin vs. dexamethasone -- gentamicin more effective for vertigo control but carries hearing loss risk; dexamethasone is safer but may require repeated treatments.

Surgical Management

Endolymphatic Sac Decompression/Shunt

Cortical mastoidectomy with decompression of the endolymphatic sac. Shunt placement into the mastoid or subarachnoid space (evidence debated). Vertigo control: 60-75% (controversial; challenged by the Danish Sham Surgery Study). Hearing preservation procedure, Low morbidity; often used before destructive procedures. Controversy: efficacy questioned since the 1981 Thomsen et al. sham surgery trial; subsequent studies have shown benefit, and the sham study itself has been criticized for methodology.

Vestibular Nerve Section

Selective sectioning of the vestibular nerve via middle fossa or retrosigmoid approach. Vertigo control: 90-95%. Hearing preservation possible. Requires craniotomy -- higher morbidity than intratympanic procedures. Rarely performed today due to effectiveness of intratympanic gentamicin.

Labyrinthectomy

Transmastoid or transcanal destruction of the vestibular labyrinth. Vertigo control: >95%. Results in complete ipsilateral hearing loss -- reserved for non-serviceable hearing. Definitive treatment when hearing is already lost.

Bilateral Meniere Disease

Occurs in 25-40% over disease course. Challenging management: avoid bilateral destructive procedures. Bilateral hearing loss may require hearing aids or cochlear implantation. Medical management and vestibular rehabilitation are mainstays. Cochlear implantation can be considered in severe bilateral cases.

<image>Histopathologic cross-section of the cochlea comparing a normal cochlea with one showing endolymphatic hydrops in Meniere disease. Normal side shows the scala vestibuli, scala media (cochlear duct) with Reissner membrane in normal position, and scala tympani with the organ of Corti labeled. Hydropic side shows massive distension of the scala media with Reissner membrane ballooning into the scala vestibuli. Labels for stria vascularis, tectorial membrane, basilar membrane, and endolymphatic and perilymphatic spaces.</image>

<image>Diagram illustrating the step-by-step technique of intratympanic injection for Meniere disease. Panel A shows patient positioned supine with head turned 45 degrees away, external ear canal with the tympanic membrane visible. Panel B shows a spinal needle inserted through the posteroinferior quadrant of the tympanic membrane into the middle ear space, with dexamethasone or gentamicin being injected. Panel C shows the medication pooling in the round window niche for absorption into the inner ear. Anatomical landmarks including the round window, oval window, promontory, and umbo are labeled.</image>

<image>Treatment algorithm flowchart for Meniere disease management. Starting with lifestyle modifications and sodium restriction, progressing to oral diuretics and betahistine, then intratympanic dexamethasone, followed by intratympanic gentamicin for refractory cases, and finally surgical options (endolymphatic sac surgery, vestibular nerve section, or labyrinthectomy) based on hearing status. Decision points and vertigo control rates at each level are indicated.</image>

Clinical Pearls

Low-frequency SNHL that fluctuates is the audiometric hallmark; this pattern differentiates early Meniere disease from presbycusis or noise-induced hearing loss. Always rule out vestibular schwannoma with MRI in cases of unilateral SNHL and vestibular symptoms. Sodium restriction is the most universally recommended first-line treatment, despite limited high-quality evidence. Intratympanic dexamethasone is first-line intratympanic therapy because it preserves hearing; reserve gentamicin for failures. The "burnout" phenomenon means vertigo often improves with time, but at the cost of progressive vestibular and hearing loss. Bilateral disease develops in a significant minority and alters the treatment strategy -- avoid bilateral destructive procedures. Tumarkin crises (drop attacks) are particularly dangerous and may warrant more aggressive treatment. Electrocochleography (elevated SP/AP ratio) supports the diagnosis but is neither perfectly sensitive nor specific.

References

• Lopez-Escamez JA, Carey J, Chung WH, et al. "Diagnostic criteria for Meniere disease." J Vestib Res. 2015;25(1):1-7.
• Pullens B, van Benthem PP. "Intratympanic gentamicin for Meniere disease." Cochrane Database Syst Rev. 2011;(3):CD008234.
• Patel M. "Intratympanic corticosteroids in Meniere disease." J Neurol. 2017;264(Suppl 1):S58-S64.
• Thomsen J, Bretlau P, Tos M, Johnsen NJ. "Placebo effect in surgery for Meniere's disease." Arch Otolaryngol. 1981;107(5):271-277.
• Sajjadi H, Paparella MM. "Meniere's disease." Lancet. 2008;372(9636):406-414.

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