Gentamicin has a well-known potential for damaging the peripheral vestibular organs. However, it is considered to be innocuous to the CNS as it crosses the blood-brain barrier poorly. Here, we describe central neuro-otological abnormalities developed by a patient after deployment of gentamicin into his spinal space.

A 61-year-old male unintentionally received gentamicin during spinal locoregional anesthesia for a urological procedure. During the first 48 hours the patient presented upper extremity dysmetria, dysarthria, and bilateral abducens nerve paralysis from which he recovered completely. He remained asymptomatic from day 3 to 10 after the incident. On day 11 he presented an acute vestibular syndrome. Severe bilateral vestibulopathy was confirmed by means of video head impulse testing. From day 14 onwards, he presented a persistent horizontal left-beating nystagmus, showing no variation or signs of compensation after 14 months, not responding to intensive vestibular rehabilitation or vestibular suppressant drugs. During follow-up, intercurrent gaze-evoked/direction-changing nystagmus has been recorded in various opportunities.

We interpreted these findings as signs of both severe peripheral bilateral vestibulopathy and cerebellar and/or midbrain late-onset neurotoxicity, which can be explained by the intrinsic neurotoxic capability of high doses of gentamicin in the CNS.