A 38-year-old woman with a 3-year history of recurrent episodes of vertigo, fluctuating low-frequency hearing loss, tinnitus, and aural fullness in the right ear presents with acute worsening. During the current episode, she has severe vertigo with spontaneous nystagmus (fast phase to the left), nausea, and vomiting lasting 4 hours. Caloric testing shows reduced vestibular response on the right. Audiometry confirms sensorineural hearing loss at 250–1000 Hz on the right. What is the most likely diagnosis?

Explanation

## Diagnosis: Menière Disease with Acute Endolymphatic Hydrops ### Classic Tetrad of Menière Disease **Key Point:** Menière disease is an idiopathic inner ear disorder characterized by **endolymphatic hydrops** (excessive fluid accumulation in the endolymphatic space). The diagnosis requires **at least two of four symptoms**: vertigo, hearing loss, tinnitus, and aural fullness. ### Diagnostic Criteria Met | Criterion | Finding | Significance | |-----------|---------|---------------| | **Vertigo** | Recurrent, episodic, severe | Spontaneous attacks lasting hours | | **Hearing loss** | Fluctuating, low-frequency SNHL | Pathognomonic pattern for Menière | | **Tinnitus** | Present, chronic | Correlates with endolymphatic pressure | | **Aural fullness** | Present, unilateral right | Indicates inner ear pressure | | **Caloric response** | Reduced on right | Confirms vestibular involvement | | **Audiometry** | Low-frequency SNHL (250–1000 Hz) | Classic Menière pattern | | **Duration** | 3-year history with acute exacerbation | Chronic relapsing course | ### Pathophysiology of Endolymphatic Hydrops ```mermaid flowchart TD A["Impaired endolymphatic fluid reabsorption"]:::outcome --> B["Accumulation of endolymph in scala media"]:::action B --> C["Increased pressure in membranous labyrinth"]:::action C --> D{"Pressure exceeds threshold?"}:::decision D -->|Yes| E["Rupture of Reissner membrane"]:::urgent D -->|No| F["Chronic distension of vestibular/cochlear structures"]:::action E --> G["Mixing of endolymph and perilymph"]:::urgent G --> H["Acute vertigo, hearing loss, tinnitus"]:::outcome F --> I["Fluctuating symptoms between episodes"]:::outcome ``` **High-Yield:** The **low-frequency sensorineural hearing loss** (250–1000 Hz) is pathognomonic for Menière disease. This contrasts with noise-induced or age-related hearing loss, which affects high frequencies first. ### Mechanism of Symptoms 1. **Vertigo**: Rupture of Reissner membrane allows endolymph to mix with perilymph, causing sudden deflection of the cupula and intense vertigo lasting 20 minutes to several hours. 2. **Hearing Loss**: Pressure on the cochlear duct distorts the organ of Corti; early in the disease, hearing recovers between episodes (fluctuating pattern). 3. **Tinnitus & Aural Fullness**: Direct consequence of increased endolymphatic pressure and membrane distension. ### Diagnostic Approach **Mnemonic: FVTA** - **F**luctuating hearing loss (low-frequency SNHL) - **V**ertigo (episodic, spontaneous) - **T**innitus (chronic) - **A**ural fullness (unilateral) ### Management Algorithm ```mermaid flowchart TD A["Suspected Menière disease"]:::outcome --> B["Confirm with audiometry + caloric test"]:::action B --> C{"Acute episode?"}:::decision C -->|Yes| D["Acute management"]:::action D --> E["Antiemetics: prochlorperazine, metoclopramide"]:::action D --> F["Vestibular suppressants: meclizine, diazepam"]:::action C -->|No| G["Prophylactic management"]:::action G --> H["Sodium restriction + diuretics"]:::action H --> I["Betahistine or venlafaxine"]:::action I --> J{"Refractory to medical management?"}:::decision J -->|Yes| K["Surgical options: endolymphatic sac decompression, vestibular nerve section"]:::urgent J -->|No| L["Long-term symptom control"]:::outcome ``` **Clinical Pearl:** **Sodium restriction** (< 1500 mg/day) and **loop diuretics** (furosemide) are first-line prophylactic treatments, as they reduce endolymphatic fluid volume. **Betahistine** (a histamine analogue) improves microcirculation in the inner ear and is widely used in Europe and Asia. ### Why Not Vestibular Neuritis? - Vestibular neuritis causes **unilateral peripheral vestibular loss** but does NOT cause hearing loss or tinnitus. - Hearing is normal in vestibular neuritis; this patient has documented SNHL. - The 3-year history of recurrent episodes is inconsistent with a single acute viral event. ### Why Not Sudden Sensorineural Hearing Loss (SSHL) with Viral Labyrinthitis? - Viral labyrinthitis causes **acute hearing loss and vertigo simultaneously**, but hearing loss is typically **high-frequency or flat**, not low-frequency. - The **fluctuating pattern over 3 years** is not consistent with SSHL, which is typically permanent after the acute episode. - Tinnitus and aural fullness are less prominent in viral labyrinthitis. ### Why Not Perilymphatic Fistula? - Perilymphatic fistula presents with **progressive vertigo and hearing loss triggered by pressure changes** (Hennebert sign, Tullio phenomenon). - The **fluctuating hearing loss pattern** is not typical of PLF; hearing loss is usually progressive and unidirectional. - Caloric testing may show reduced response, but the combination of low-frequency SNHL + aural fullness + tinnitus is more specific to Menière disease. [cite:Harrison 21e Ch 21, Gupta & Gupta Physiology Ch 11]