Delayed neuropsychiatric syndrome after acute Carbon Monoxide poisoning

Abstract

The clinical presentation of Carbon Monoxide (CO) poisoning is highly variable and unspecific. Late manifestations can occur in up to 40% of the cases. These may be observed days or months after the acute poisoning. The diagnosis is based on clinical suspicion, on imaging features and
neuropsychological tests. It is important to exclude differential diagnoses.
The authors describe a case of a 44-year-old man admitted with confusion, altered behavior and psychomotor agitation during 4 days, with no previous trauma or fever. He presented a history of severe CO poisoning
three months prior to admission, without sequelae. On hospital admission
the patient was disoriented, agitated, with attention deficit and hallucinatory activity. The cerebral CT scan revealed the presence of bilateral nonspecific pallidal hypodensities, suggestive of old lesions, consistent with
CO poisoning on brain MRI. Metabolic, endocrine, toxic and infectious
causes and also vitamin deficiencies were excluded. The neuropsychological screening tests revealed an impairment of higher brain functions, compatible with a Delayed neuropsychiatric syndrome.
The authors emphasize the importance of early recognition and treatment
of acute CO poisoning highlighting the need for long term monitoring of
these patients in order to identify late manifestations as early as possible.