A patient with disabling unilateral Meniere's disease refractory to medical therapy is offered intratympanic gentamicin. The intended mechanism and the major risk of this treatment are:

• A Selective vestibulotoxicity reducing endolymphatic pressure; risk of additional sensorineural hearing loss ✓
• B Restores Eustachian tube function; risk is ossicular chain damage
• C Anti-inflammatory effect on endolymph; risk of tympanic membrane perforation
• D Reduces endolymph production by inhibiting stria vascularis; risk of round window niche obliteration

Explanation

Intratympanic gentamicin for Meniere's disease exploits the selective vestibulotoxicity of aminoglycosides. The type I hair cells of the vestibular maculae and cristae are more sensitive to aminoglycoside toxicity than cochlear hair cells at the doses and frequency used, reducing abnormal vestibular signalling and vertigo attack frequency. The major risk is cochlear hair cell damage causing permanent sensorineural hearing loss, occurring in approximately 15–25% of cases depending on dosing protocol (titration method has lower 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.