A 40-year-old woman with multidrug-resistant tuberculosis is started on an aminoglycoside. She develops bilateral high-frequency sensorineural hearing loss and tinnitus after 3 weeks of therapy. The ototoxic effect of aminoglycosides primarily damages which structure?
- A The inner hair cells at the apex of the cochlea
- B The outer hair cells at the base of the cochlea ✓
- C The stria vascularis
- D The tectorial membrane
Correct answer: B. The outer hair cells at the base of the cochlea
Explanation
Aminoglycoside ototoxicity primarily damages the outer hair cells, starting at the base of the cochlea where high-frequency sounds are processed. This explains why high-frequency hearing loss occurs first. The outer hair cells are more vulnerable than inner hair cells to aminoglycoside toxicity due to higher drug accumulation and greater metabolic activity. The stria vascularis and tectorial membrane are not the primary targets of aminoglycoside ototoxicity.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
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Written and medically reviewed by the StethoPrep medical team.