Spontaneous nystagmus and canalithiasis preceding a loss of vestibular function.

The patient, a 45-year-old female with Ménière's disease, was submitted to endolymphatic sac surgery because of frequent spells of vertigo. The day after surgery she became dizzy and lost the hearing in the operated ear. She presented with a brisk nystagmus towards the healthy ear; however, a remaining vestibular function on the operated side was still present. The head impulse test was normal and in the positioning test, when turning to the operated ear, the spontaneous nystagmus was replaced by a transient horizontal nystagmus in the opposite direction. It is likely that this geotropic nystagmus was elicited from the operated ear because of debris that had accumulated in the lateral semicircular canal. Due to a suspicion of post surgical edema, the patient was treated with prednisolone, but the progression of the lesion could not be arrested. The signs of canalithiasis disappeared, but the head impulse test became pathologic as did the caloric reaction. The patient remained deaf in the operated ear.