A case of acute disseminated encephalomyelitis mimicking leukodystrophy.

Acute disseminated encephalomyelitis (ADEM) is a monophasic, immune-mediated demyelinating disorder that can follow immunizations or more often infections including rubeola, rubella, varicella, herpes zoster, mumps, Mycoplasma pneumoniae, or, more commonly, other nonspecific upper respiratory tract infections. Documentation of a preceding illness is not required to make this diagnosis. This report examines the case of a 9-month-old male patient presenting with the features of an acute leukodystrophy following innoculation with the mixed vaccine Pentaxim (Sanofi Pasteur, Lyon- France) while suffering from a lower respiratory tract infection, and who was eventually diagnosed as ADEM. The case is presented as a reminder that ADEM can sometimes be linked to lower respiratory tract infection and vaccination, and that the features in such cases can be confused with leukodystrophy.