Bobbing oscillopsia from gentamicin toxicity

A series of 15 patients had been studied, all of whom suffered severe labyrinthine damage from gentamicin. All subjects were patients in a renal unit and had been in renal failure. The antibiotic was administered, either intramuscularly, intravenously or into the dialysate. In most of the patients there was a history of previous or simultaneous administration of another ototoxic agent, either another aminoglycoside, or a loop diuretic. None of the patients developed severe vertigo. They consistently complained, when they eventually were able to get out of bed, a vertical bouncing of their surroundings, when they walked, coinciding with each step. This sensation is made worse if the patient runs, or drives on a bumpy road, and stops as soon as the patient stands still. Caloric tests revealed non-functioning labyrinths on both sides. Gradual improvement in the symptom occurred over a period of months. No cochleotoxic effect was observed. The probable mechanism of this phenomenon is discussed.