Meniere Disease

Detailed Overview

The underlying pathological mechanism is endolymphatic hydrops, an accumulation of endolymph fluid leading to distension of the membranous labyrinth. The attacks are episodic, severely debilitating, and last from 20 minutes to several hours. Over time, the fluctuating hearing loss becomes a permanent, progressive decline in low-frequency hearing. Management ranges from conservative dietary restrictions and diuretics to destructive surgical procedures for refractory vertigo.

Epidemiology & Demographics

Prevalence is approximately 190 per 100,000 in the US. Typically presents between the ages of 40 and 60. Slightly more common in females.

Etiological Mechanism

Primarily idiopathic. It is thought to result from impaired resorption of endolymphatic fluid in the endolymphatic sac, leading to increased pressure.

Primary Causes

Unknown (idiopathic). Secondary causes of endolymphatic hydrops (Meniere's syndrome) include viral infections (HSV, VZV), head trauma, and autoimmune inner ear disease.

• Genetics: About 10-20% of cases have a familial predisposition.
• Autoimmune Disease: Higher incidence in patients with autoimmune disorders like Rheumatoid Arthritis or SLE.
• Dietary Triggers: High sodium intake, caffeine, and alcohol can precipitate acute attacks.

Defective absorption of endolymph in the endolymphatic sac causes the endolymphatic volume and pressure to increase (Endolymphatic Hydrops). This ballooning distorts the structures of the inner ear. The acute vertigo attacks are hypothesized to occur when Reissner's membrane ruptures, mixing potassium-rich endolymph with sodium-rich perilymph. This sudden chemical imbalance depolarizes the vestibular nerve, firing an intense false signal of movement (vertigo) to the brain. Healing of the membrane halts the attack, but repeated ruptures eventually destroy the delicate cochlear hair cells, causing permanent sensorineural hearing loss.

Characteristic Clinical Presentation

• Episodic Vertigo: Severe spinning sensation accompanied by nausea and vomiting, lasting 20 minutes to 12 hours.
• Fluctuating Hearing Loss: Decreased hearing primarily in low pitches, which may improve after an attack but worsens progressively over years.
• Tinnitus and Aural Fullness: A roaring or buzzing sound and a feeling of pressure or 'fullness' in the affected ear.

Physical Examination Signs

• Spontaneous horizontal-torsional nystagmus during an acute attack (beating away from the affected ear)
• Positive Romberg test during acute phase
• Normal tympanic membrane on otoscopy

• Permanent Sensorineural Hearing Loss: Eventual profound deafness in the affected ear.
• Tumarkin's Otolithic Crisis: Sudden 'drop attacks' where the patient falls to the ground without loss of consciousness due to abrupt vestibular failure.

Diagnostic Criteria & Guidelines

Clinical diagnosis defined by the Barany Society: 1) Two or more spontaneous episodes of vertigo lasting 20 mins to 12 hours. 2) Audiometrically documented low- to medium-frequency sensorineural hearing loss in one ear. 3) Fluctuating aural symptoms (tinnitus, fullness) in the affected ear. 4) Not better accounted for by another diagnosis.

Differential Diagnosis

• Vestibular Schwannoma (Acoustic Neuroma)
• Vestibular Migraine
• Benign Paroxysmal Positional Vertigo (BPPV)
• Transient Ischemic Attack (TIA) / Stroke

Laboratory Tests & Biomarkers

• Audiometry: Low-frequency up-sloping sensorineural hearing loss (classic pattern).
• Videonystagmography (VNG): Unilateral vestibular weakness on caloric testing in the affected ear.
• Electrocochleography (ECochG): Elevated SP/AP ratio (>0.4), indicating increased inner ear pressure.

Imaging Modalities & Findings

• MRI Brain with Gadolinium: Not for diagnosing Meniere's, but ABSOLUTELY REQUIRED to rule out a Vestibular Schwannoma or MS. (Recent high-resolution MRI protocols can visualize endolymphatic hydrops, but are not strictly required for diagnosis).

• Early Stage
  Intense, frequent vertigo attacks. Hearing loss fluctuates and returns to normal between episodes.
• Middle Stage
  Vertigo attacks may become less severe, but tinnitus and hearing loss become constant and gradually worsen.
• Late Stage
  Vertigo attacks often cease ('burnt-out Meniere's'), but the patient is left with severe, irreversible hearing loss and chronic balance issues.

Second-Line & Adjunctive Therapy

Intratympanic Corticosteroid Injections (Dexamethasone) for refractory vertigo with preserved hearing. Meniett device (delivers pressure pulses to the ear).

Surgical & Procedural Management

For severe refractory cases: Endolymphatic sac decompression (hearing-sparing). If hearing is already poor and vertigo is disabling: Intratympanic Gentamicin ablation, Vestibular Nerve Section, or complete Labyrinthectomy (destructive procedures).

Recommended Lifestyle Changes

• Strict adherence to a 1,500 mg/day sodium limit to reduce fluid retention.
• Manage stress, which is a known trigger for acute attacks.
• Avoid driving or working at heights when symptoms are active or unpredicted.

Patient Counseling & Advice

Warn the patient that the disease causes permanent hearing loss over time. Assure them that while the vertigo attacks are terrifying, they are not life-threatening. Discuss the risks of 'drop attacks' (falling).

Follow-Up & Monitoring Schedule

Annual audiograms to track the progression of hearing loss. Frequent evaluations to assess the efficacy of dietary and diuretic therapies in controlling vertigo.

Preventive Strategies

Attacks can be minimized by strict dietary control, but the underlying progression of the disease cannot be entirely prevented.

Highly variable. About 50-70% respond to conservative medical management. Ultimately, vertigo 'burns out' after many years, leaving the patient with significant unilateral hearing loss and potential chronic imbalance.