Acute disseminated encephalomyelitis following spider bite

Acute disseminated encephalomyelitis (ADEM) is an inflammatory, demyelinating disease of the central nervous system that occurs as an immunological response to a viral or bacterial infection or an immunization. We describe a patient with clinical presentation and radiological features of ADEM that appeared after a spider bite. Corticosteroid therapy did not produce satisfied treatment response. The patient recovered after five days of immunoglobulin therapy. The cross-reactivity between spider toxin and myelin could explain pathophysiological mechanism of demyelination. ADEM should be considered as a possible complication of a spider bite.