Copyright (c) 2026 Fernando Pérez, Fernando Gracia, María Lucia De León
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Acute disseminated encephalomyelitis (ADEM) is a rare, usually monophasic, immune-mediated demyelinating disease that appears after viral infections or, to a lesser extent, after vaccination.
Its development after a snake bite is exceptional, with few cases documented in the world literature. We present the case of a previously healthy 28-year-old male patient who was bitten by a Bothrops asper snake on the medial malleolus of his left foot. Ten minutes after the accident, he lost consciousness, followed by a generalized tonic-clonic seizure lasting approximately ten minutes, with relaxation of the urinary sphincter and tongue biting. He was transferred to the hospital 45 minutes later, admitted in a comatose state; the airway was secured by endotracheal intubation and 30 vials of polyvalent antivenom serum were administered. During his hospital stay, he had a second seizure, which was controlled with intravenous diazepam. Physical examination revealed coagulopathy with epistaxis, gingival bleeding, and hematuria. Cerebral magnetic resonance imaging showed multiple hyperintense lesions on T2/FLAIR sequences located in both cerebral hemispheres, thalami, and periventricular regions, consistent with an acute demyelinating process. Treatment was initiated with intravenous methylprednisolone (1 g daily for five days), followed by a gradual decrease with oral prednisone. The patient showed progressive neurological recovery, was extubated after 72 hours, and discharged on the ninth day without sequelae. This case highlights an exceptional neurological complication following a Bothrops asper bite and underscores the importance of early recognition and timely treatment with corticosteroids to achieve complete recovery.
