## Pathophysiology of Meniere Disease **Key Point:** Endolymphatic hydrops (abnormal accumulation of endolymph) is the hallmark pathophysiological finding in Meniere disease, causing increased pressure within the membranous labyrinth. ### Mechanism The condition results from either: - Overproduction of endolymph by the stria vascularis, OR - Impaired absorption/drainage of endolymph through the endolymphatic duct and sac This increased pressure leads to: 1. Distension of the membranous labyrinth 2. Rupture of Reissner membrane (vestibular membrane) 3. Mixing of endolymph and perilymph 4. Transient changes in ion concentration affecting hair cell function ### Clinical Consequences - **Vertigo:** Sudden onset, severe, rotatory; lasts 20 minutes to several hours - **Hearing loss:** Fluctuating initially, becomes permanent over time - **Tinnitus:** Low-frequency, roaring quality - **Aural fullness:** Sensation of pressure in the affected ear **High-Yield:** The classic triad is **fluctuating sensorineural hearing loss + episodic vertigo + tinnitus** in a single ear. **Clinical Pearl:** Early in the disease, hearing loss is reversible because it is functional (due to ion imbalance); later it becomes permanent due to hair cell degeneration from repeated ruptures. 
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