A 42-year-old woman from Mumbai presents with a 6-month history of episodic severe vertigo lasting 4–6 hours, accompanied by tinnitus and a sensation of fullness in the right ear. She reports progressive hearing loss in the low frequencies. Between episodes, she is symptom-free. Audiometry shows sensorineural hearing loss predominantly at 500–2000 Hz. Caloric testing reveals reduced response on the right. MRI of the internal auditory canal is normal. What is the most likely diagnosis?

Explanation

## Diagnosis: Meniere Disease ### Clinical Presentation This patient presents with the classic tetrad of Meniere disease: 1. **Episodic vertigo** — severe, spontaneous, lasting hours (4–6 hours in this case) 2. **Tinnitus** — often low-frequency roaring or buzzing 3. **Aural fullness** — sensation of pressure in the affected ear 4. **Fluctuating sensorineural hearing loss** — initially at low frequencies (500–2000 Hz), may progress to all frequencies **Key Point:** The **fluctuating nature** of hearing loss in early Meniere disease is pathognomonic. Unlike acoustic neuroma (progressive, unidirectional) or BPPV (no hearing loss), Meniere disease shows reversible low-frequency SNHL that may recover between attacks. ### Pathophysiology **High-Yield:** Meniere disease is caused by **endolymphatic hydrops** — excessive accumulation of endolymph in the membranous labyrinth. This leads to: - Increased pressure in the cochlea → fluctuating hearing loss - Increased pressure in the semicircular canals → vertigo attacks - Distension of the cochlear duct → tinnitus and aural fullness ### Diagnostic Criteria (Modified American Academy of Otolaryngology–Head and Neck Surgery) | Criterion | Finding | |-----------|----------| | **Vertigo episodes** | Spontaneous, severe, 20 min to 24 hours | | **Hearing loss** | Audiometrically documented, fluctuating or fixed SNHL | | **Tinnitus or aural fullness** | Present during or between attacks | | **Affected ear** | Unilateral (90% of cases) | | **Exclusion** | Other causes ruled out (MRI normal, no retrocochlear pathology) | **Clinical Pearl:** The **low-frequency predominance** of hearing loss is a distinguishing feature. High-frequency loss suggests noise-induced or age-related hearing loss. ### Investigations 1. **Audiometry** — sensorineural, low-frequency loss (500–2000 Hz) 2. **Caloric testing** — may show reduced vestibular response (as in this case) 3. **MRI of IAC** — normal (rules out acoustic neuroma, retrocochlear pathology) 4. **Electrocochleography (ECoG)** — elevated summating potential (SP/AP ratio > 0.4) suggests endolymphatic hydrops 5. **Videonystagmography (VNG)** — documents nystagmus during attacks **Mnemonic:** **FVATH** — Fluctuating hearing loss, Vertigo, Aural fullness, Tinnitus, Hydrops (endolymphatic). ### Management Algorithm ```mermaid flowchart TD A[Meniere Disease Diagnosed]:::outcome --> B{Frequency & Severity?}:::decision B -->|Mild, infrequent| C[Conservative: Low-salt diet, diuretics]:::action B -->|Moderate| D[Betahistine or Vestibular rehab]:::action B -->|Severe, refractory| E{Hearing preserved?}:::decision E -->|Yes| F[Intratympanic steroid or gentamicin]:::action E -->|No| G[Surgical: Labyrinthectomy or vestibular nerve section]:::action C --> H[Symptom control]:::outcome D --> H F --> H G --> H ``` ### Why Normal MRI Rules Out Acoustic Neuroma **Clinical Pearl:** Acoustic neuroma (vestibular schwannoma) presents with **progressive, unidirectional** hearing loss (typically high-frequency), not fluctuating low-frequency loss. MRI would show a mass at the cerebellopontine angle. The normal MRI in this patient excludes retrocochlear pathology. ## Summary **High-Yield:** Meniere disease = **Episodic vertigo + fluctuating low-frequency SNHL + tinnitus + aural fullness + endolymphatic hydrops**. The combination of episodic severe vertigo, fluctuating low-frequency hearing loss, tinnitus, aural fullness, and normal MRI is diagnostic.