21-year-old female with an acute onset of a unilateral sixth cranial nerve deficit. Brain MRI showed at least a dozen white matter lesions, one of them contrast-enhancing. Sensory evoked potentials showed a bilateral increase in latency. Multiple sclerosis was diagnosed, and the patient was treated by corticosteroids, followed by improvement of symptoms. The first follow-up revealed no focal neurological signs with a history of a transitory unilateral lower limb hyposthenia. On the second visit, a horizonto-rotatory nystagmus and irregular paraesthesia in the right toes are documented.