Transtympanic intratympanic gentamicin injection for Meniere's disease works by which targeted mechanism?

• A Reducing endolymph production by destroying stria vascularis
• B Blocking histamine H1 receptors in the vestibular nuclei
• C Promoting endolymph resorption by the endolymphatic sac
• D Selectively destroying type I hair cells of the crista ampullaris, ablating vestibular function while relatively sparing cochlear function ✓

Explanation

Intratympanic gentamicin preferentially destroys type I vestibular hair cells (which are more sensitive to aminoglycosides than cochlear hair cells due to differences in uptake mechanisms and the MET channel properties). This vestibulotoxicity causes ipsilateral vestibular ablation, reducing the episodic vertigo attacks of Meniere's disease. However, there is a 10-30% risk of concurrent cochlear damage (SNHL worsening). Titration protocols (low-dose, low-frequency administration) reduce cochlear risk.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.