A patient with CSOM develops sudden complete ipsilateral sensorineural hearing loss, severe vertigo, and nystagmus while being treated for an acute exacerbation. CT shows erosion of the horizontal semicircular canal. The most likely complication is:
- A Labyrinthine fistula (perilymph fistula) ✓
- B Labyrinthitis ossificans
- C Serous labyrinthitis
- D Suppurative labyrinthitis
Correct answer: A. Labyrinthine fistula (perilymph fistula)
Explanation
Cholesteatoma most commonly erodes the horizontal (lateral) semicircular canal, creating a labyrinthine fistula. This is confirmed by the positive fistula sign (Hennebert's sign): nystagmus and vertigo induced by pneumatic pressure in the EAC. Sudden worsening of hearing and vertigo during an acute exacerbation suggests perilymph leakage through the fistula. CT evidence of canal erosion confirms the diagnosis. Suppurative labyrinthitis would indicate bacteria entering the inner ear with total cochlear destruction.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.