title: Chronic exposure to carbon monoxide in two elderly patients using a kotatsu, a traditional Japanese charcoal-based heater.
abstract: We report on two elderly patients with cognitive impairments, for whom chronic carbon monoxide (CO) exposure was suspected based on elevated carboxyhaemoglobin levels in their serum. On their initial visits, cognitive impairment and brain magnetic resonance imaging findings in both patients were compatible with the diagnosis of Alzheimer's-type dementia. However, after discontinuation of the use of a kotatsu, a charcoal-based heater, their serum carboxyhaemoglobin levels normalized and their physical symptoms resolved. Their cognitive function also slightly improved. The causal relationship between physical symptoms and cognitive impairment after chronic CO poisoning is uncertain; however, it is possible that chronic exposure to low CO levels exacerbated the clinical manifestation in our patients.
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan. toshinaka@shinshu-u.ac.jp.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Azumi General Hospital, Azumino, Japan.
authors.forename: Koutaro
authors.initials: K
authors.lastname: Setsu
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Miyashita
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Sugiyama
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Washizuka
authors.affiliation: Azumi General Hospital, Azumino, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Murata
authors.affiliation: School of Health Sciences, Shinshu University, Matsumoto, Japan.
authors.forename: Tokiji
authors.initials: T
authors.lastname: Hanihara
authors.affiliation: Department of Psychiatry, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Naoji
authors.initials: N
authors.lastname: Amano
mesh_terms: D000369:Aged, 80 and over; D002248:Carbon Monoxide / Q000032:analysis* / Q000097:blood*; D002249:Carbon Monoxide Poisoning / Q000150:complications / Q000175:diagnosis*; D002263:Carboxyhemoglobin / Q000032:analysis; D002606:Charcoal; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D005260:Female; D006361:Heating / Q000295:instrumentation; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging; D008297:Male
chemical_list: D002606:Charcoal; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin
keywords: carbon monoxide; carboxyhaemoglobin; charcoal-based heater; cognitive impairment; poisoning