RESUMEN
We report a unique and distinct clinical observation of a patient aged 52 years with acute reversible encephalopathy with late onset occurred 3 weeks after a mass poisoning of carbon monoxide [CO]. The clinical picture was dominated by cognitive associated with behavioral disorders, mood and judgment. Brain MRI [Magnetic resonance imaging] shows T2-weighted sequence Flair hyperintense extensive periventricular white matter and the centrum ovale and a bilateral hippocampal damage. The patient received hyperbaric oxygen therapy sessions. The evolution was marked by a dramatic improvement with complete disappearance of clinical and radiological signs. Finally, all isolated coma occurred in uncertain circumstances especially during winter and whose negative was etiology should encourage thinking about a toxic cause including carbon monoxide. Therefore, reflects a coma mass poisoning and should require very close clinical monitoring due to the subsequent development of a post-interval syndrome of neuropsychiatric order