Recurrence of acute disseminated encephalomyelitis after a 12-year symptom-free interval.

We report a patient with recurrent acute meningoencephalitis who had three episodes of headache, fever and unconsciousness; the first episode was at age 6 and the second, at age 7. After a 12-year symptom-free interval, she had a relapse, exhibiting the same symptoms as those in the previous two episodes. Head magnetic resonance imaging also revealed the recurrence of lesions in the basal ganglia and medial portion of the temporal lobe. The occurrences of stereotyped symptoms with meningoencephalitis and the same lesions in the basal ganglia observed in each episode favor the diagnosis of recurrent acute disseminated encephalomyelitis (ADEM) rather than multiple sclerosis or multiphasic disseminated encephalomyelitis. The occurrence of this rare case suggests that ADEM can relapse after a very long symptom-free interval.