Dementia with a seasonal onset secondary to carbon monoxide poisoning

Air Pollution: A Silent Key Driver of Dementia

In 2017, the Lancet Commission on Dementia Prevention, Intervention, and Care included air pollution in its list of potential risk factors for dementia; in 2018, the Lancet Commission on Pollution concluded that the evidence for a causal relationship between fine particulate matter (PM) and dementia is encouraging. However, few interventions exist to delay or prevent the onset of dementia. Air quality data are becoming increasingly available, and the science underlying the associated health effects is also evolving rapidly. Recent interest in this area has led to the publication of population-based cohort studies, but these studies have used different approaches to identify cases of dementia. The purpose of this article is to review recent evidence describing the association between exposure to air pollution and dementia with special emphasis on fine particulate matter of 2.5 microns or less. We also summarize here the proposed detailed mechanisms by which air pollutants reach the brain and activate the innate immune response. In addition, the article also provides a short overview of existing limitations in the treatment of dementia.

Chronic exposure to carbon monoxide in two elderly patients using a kotatsu, a traditional Japanese charcoal-based heater

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.