Neuropsychological and magnetic resonance imaging findings in five patients after carbon monoxide poisoning.

Introduction. Carbon monoxide (CO) poisoning has been shown to result in cognitive impairments. These disorders have rarely been reported. The present study aimed to evaluate these disturbances in five patients with a neuroanatomical study. Methods. There were two men and three women with an average of 25 years old. Patients were explored several months after acute CO poisoning. Neuropsychological testing was administered to assess memory, intellectual, executive, visual-spatial and constructional functions, language, praxis and gnosis. Cerebral magnetic resonance imaging (MRI) was performed in all patients using axial, sagittal and coronal slides with T1 and T2 weighted and flair images. None of the subjects had hyperbaric oxygen. They received 7, 5 mg bromocriptine per day. Results. All patients presented cognitive disorders including marked impairment in long term memory with a severe defect in recall performance in comparison to recognition memory Visual memory was more affected than the verbal one. There were also moderate disturbances in intellectual, executive, visual-spatial and constructional functions. One patient presented alexia agraphia, severe visual disturbances, constructional and dressing apraxia. Four patients had depression and one psychic akinesia. Cerebral MRI studies revealed that all patients had bilateral pallidal necrosis, bilateral hippocampal and moderate cortical atrophy. Fornix atrophy was found in 2 patients and corpus mammillary atrophy in 3 patients. Others lesions were also found: bilateral cerebellar in two cases and cortical in three cases. Treatment with bromocriptine was effective in three cases. There was no improvement in the patients treated 14 months and 5 years following CO poisoning. Conclusion. Neuropsychological impairments in CO poisoned subjects include memory, intellectual, executive, and visuospatial defects. In addition to pallidal necrosis, which is a typical feature of CO poisoning, hippocampal and cortical atrophy are often present. Bromocriptine can improve the cognitive disorders.