A 42-year-old woman presents to the ENT clinic with a 6-month history of episodic vertigo lasting 20 minutes to 3 hours, accompanied by unilateral tinnitus and aural fullness in the left ear. She reports progressive hearing loss in the same ear over the past 4 months. Audiometry shows low-frequency sensorineural hearing loss (SNHL) on the left. Caloric test reveals reduced response on the left side. MRI of the internal acoustic meatus is normal. 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 of Meniere disease are: 1. Episodic vertigo (20 min to several hours) 2. Unilateral tinnitus 3. Aural fullness (sensation of pressure in the ear) 4. Fluctuating unilateral sensorineural hearing loss ### Audiological Findings **High-Yield:** Low-frequency SNHL is pathognomonic for Meniere disease. This contrasts with noise-induced or age-related hearing loss, which typically affects high frequencies first. ### Vestibular Findings The reduced caloric response on the left indicates vestibular hypofunction ipsilateral to the affected ear, consistent with endolymphatic hydrops. ### Pathophysiology ```mermaid flowchart TD A[Endolymphatic Hydrops]:::outcome --> B[Increased endolymph volume] B --> C[Rupture of Reissner membrane] C --> D[Mixing of endolymph and perilymph] D --> E[Vertigo + SNHL] A --> F[Increased pressure in cochlea] F --> G[Cochlear dysfunction] G --> H[Low-frequency hearing loss] ``` ### Diagnostic Criteria (Modified American Academy of Otolaryngology) | Feature | Meniere Disease | BPPV | Acoustic Neuroma | |---------|-----------------|------|------------------| | Vertigo duration | 20 min–several hours | Seconds to minutes | Continuous/progressive | | Tinnitus | Unilateral, fluctuating | Absent | Often present | | Hearing loss | Fluctuating, low-freq | Absent | Progressive, high-freq | | Aural fullness | Present | Absent | Absent | | Imaging | Normal or endolymphatic hydrops | Normal | Mass on CPA | **Clinical Pearl:** The fluctuating nature of hearing loss in early Meniere disease is crucial — it may recover between episodes, unlike progressive SNHL from other causes. ### Why MRI Is Normal MRI may show endolymphatic hydrops on high-resolution imaging (3 Tesla with contrast), but a normal MRI does NOT exclude Meniere disease. The diagnosis is clinical, based on the symptom complex. **Warning:** Do not require imaging abnormality to diagnose Meniere disease — the diagnosis is clinical, not radiological.