Serious delayed encephalopathy and cognitive sequelae following acute carbon monoxide
intoxication constitutes a rare and a distinct entity. A case of delayed encephalopathy and cognitive sequelae
after acute carbon monoxide poisoning is presented. The patient is a 50-year-old Thai female with a history of
carbon monoxide poisoning during her vacation tour in Arizona in winter. She developed encephalopathy 4
weeks after recovery from the acute stage. Her MRI-brain found abnormal white matter change of cerebral
hemispheres bilaterally and abnormal signal intensity at both putamens and caudate nuclei. She regained
some improvement in her memory and other cognitive function after 4 weeks of treatment including hyperbaric
oxygen therapy (HBOT).

Keywords: Carbon monoxide poisoning, Delayed encephalopathy, Cognitive sequelae