A patient with CSOM-safe (tubotympanic) type develops sudden onset severe vertigo, vomiting, and profound sensorineural hearing loss on the affected side. On examination, there is a fistula sign (positive Hennebert sign). Which complication has most likely occurred?

• A Labyrinthine fistula from cholesteatoma erosion of the lateral semicircular canal
• B Perilymph fistula through the round window membrane
• C Suppurative labyrinthitis with bacterial invasion of the cochlea ✓
• D Serous labyrinthitis from middle ear infection spreading

Explanation

Sudden onset severe vertigo, vomiting, and profound irreversible SNHL in a patient with CSOM indicates suppurative labyrinthitis — bacterial invasion of the labyrinth producing a labyrinthine abscess. This results in complete loss of cochlear and vestibular function. Serous labyrinthitis produces milder hearing loss without profound vertigo. Labyrinthine fistula due to cholesteatoma is seen in the unsafe (atticoantral) type, not the safe type. The positive fistula sign (pressure-induced nystagmus) confirms labyrinthine involvement.

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

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Written and medically reviewed by the StethoPrep medical team.