The brain lesion responsible for parkinsonism after carbon monoxide poisoning

Background: Parkinsonism is a common neurological sequela of carbon monoxid e (CO) poisoning, but its pathophysiological mechanism has yet to be clarif ied. Objectives: To describe a married couple who were both affected by CO poiso ning, but only 1 of whom developed GO-induced parkinsonism, and to discuss the possible underlying pathophysiological mechanism of CO-induced parkinso nism by comparing the neuroimaging findings of these patients. Design and Setting: Case report from a clinical neurology department. Patients: A married couple experienced CO poisoning simultaneously. One mon th later, only the husband gradually developed delayed sequelae, including parkinsonism and intellectual impairment. On detailed neurological examinat ion, the husband showed mild but definite rigidity and bradykinesia, while no parkinsonian signs were observed in the wife. neuropsychological examina tion revealed impaired memory and attention in both patients, but they were more severe in the husband than in the wife. Magnetic resonance imaging sc ans of the patients' brains disclosed diffuse high-intensity white matter s ignals in both patients and bilateral pallidal necrosis in the wile. Dopami ne transporter imaging showed that the degree of dopamine neuronal loss was comparable between these patients. Magnetic resonance spectroscopy reveale d more severe white matter damage in the husband than in the wife. Thirteen months later, neurological and neuropsychological examinations showed comp lete recovery from parkinsonism as well as intellectual impairment. Follow- up magnetic resonance spectroscopy also suggested remarkable improvements i n white matter damage. Conclusion: These results support the role of white matter damage in produc ing parkinsonism after CO poisoning and highlight the possible usefulness o f magnetic resonance spectroscopy in predicting delayed sequelae in patient s after CO poisoning.