A 42-year-old woman from Mumbai presents with a 6-month history of episodic vertigo lasting 20–30 minutes, accompanied by severe tinnitus and a sensation of fullness in the left ear. She reports progressive hearing loss in the low frequencies. During the current episode, she has horizontal nystagmus with the fast component toward the right. Audiometry shows sensorineural hearing loss at 500 Hz and 1000 Hz. Caloric testing reveals reduced response on the left. What is the most likely diagnosis?

Explanation

## Diagnosis: Meniere Disease ### Clinical Presentation This patient presents with the classic tetrad of Meniere disease: **Key Point:** The four cardinal features are: 1. Episodic vertigo (20 min to several hours) 2. Fluctuating sensorineural hearing loss (low frequencies initially) 3. Tinnitus 4. Aural fullness (sensation of pressure in the ear) ### Audiometric Findings **High-Yield:** Early Meniere disease shows sensorineural hearing loss at **low frequencies (500–1000 Hz)**, which is pathognomonic. This contrasts with noise-induced or age-related hearing loss, which affects high frequencies first. ### Vestibular Findings **Clinical Pearl:** The horizontal nystagmus with fast component toward the right (away from the affected left ear) is consistent with left-sided vestibular hypofunction. Caloric testing showing reduced response on the left confirms peripheral vestibular involvement. ### Pathophysiology **Key Point:** Meniere disease results from endolymphatic hydrops—abnormal accumulation of endolymph within the membranous labyrinth. This causes: - Distortion of the basilar membrane (hearing loss) - Displacement of the cupula (vertigo) - Increased pressure sensation (aural fullness) ### Diagnostic Criteria (Modified Diagnostic Criteria for Meniere Disease) | Feature | Meniere Disease | BPPV | Acoustic Neuroma | |---------|-----------------|------|------------------| | **Vertigo duration** | 20 min–several hrs | Seconds to minutes | Rarely vertigo | | **Hearing loss** | Fluctuating, low-freq | Normal | Progressive, high-freq | | **Tinnitus** | Present | Absent | Often unilateral | | **Aural fullness** | Yes | No | No | | **Nystagmus** | Horizontal/rotatory | Positional | Rare | **Mnemonic:** FAINT = **F**luctuating hearing loss, **A**ural fullness, **I**ntermittent vertigo, **N**ystagmus, **T**innitus ### Investigations 1. **Audiometry:** Sensorineural pattern, low-frequency loss 2. **Caloric test:** Reduced vestibular response on affected side 3. **MRI:** Rules out retrocochlear pathology; may show endolymphatic hydrops on 3D-FLAIR sequences 4. **Electrocochleography (ECG):** Elevated summating potential/action potential ratio (supportive but not diagnostic) ### Management Approach ```mermaid flowchart TD A[Meniere Disease Suspected]:::outcome --> B{Acute Attack?}:::decision B -->|Yes| C[Acute Management]:::action C --> C1[Antiemetics: Prochlorperazine/Metoclopramide] C --> C2[Vestibular suppressants: Diazepam] C --> C3[Rest in dark room] B -->|No| D[Maintenance Therapy]:::action D --> D1[Dietary sodium restriction] D --> D2[Diuretics: Hydrochlorothiazide] D --> D3[Betahistine] D --> D4[Vestibular rehabilitation] A --> E{Refractory?}:::decision E -->|Yes| F[Intratympanic Gentamicin/Corticosteroids]:::action E -->|Still Refractory| G[Surgical: Endolymphatic sac decompression]:::action E -->|Severe| H[Labyrinthectomy/Vestibular neurectomy]:::urgent ``` **High-Yield:** First-line management is **conservative**: sodium restriction, diuretics (hydrochlorothiazide 25 mg daily), and betahistine (16 mg TID). Intratympanic gentamicin or corticosteroids are reserved for refractory cases.