What pathophysiological change underlies Menière disease?

• A. Perilymphatic fistula
• B. Obstruction of the endolymphatic duct
• C. Degeneration of hair cells
• D. Endolymphatic hydrops (excess endolymphatic fluid in the labyrinth)

Answer: (D)

Endolymphatic hydrops—excess endolymphatic fluid in the labyrinth—is the key pathophysiological change in Menière disease. When endolymph accumulates, it distends the membranous labyrinth, altering the mechanical environment of vestibular and cochlear hair cells. This disruption produces the characteristic symptoms: episodic vertigo from vestibular disturbance, fluctuating sensorineural hearing loss with tinnitus from cochlear involvement, and aural fullness due to the swollen inner ear spaces. Other ideas like a perilymphatic fistula or obstruction of the endolymphatic duct relate to related processes or secondary contributors, but the defining change is the fluid imbalance causing endolymphatic hydrops. Degeneration of hair cells can occur with prolonged hydrops, but it is a downstream consequence rather than the initiating pathology.