Background: Carbon monoxide (CO) poisoning is the leading cause of accidental poisoning worldwide. This study undertook a meta-analysis to examine differences in neuropsychological functioning in patients with CO poisoning as compared to healthy controls, and examined the longer-term neuropsychological effects of CO poisoning. Methods: Studies performed between the years 1995 and 2016 were identified through a search of the electronic databases Medline and PsycInfo. Data from the papers identified were pooled to determine standard mean differences using a random-effects model. Results: Ten studies were included in the analysis, with healthy controls performing significantly better than CO poisoned participants on the domains of divided attention, immediate memory, and processing speed. No statistically significant differences were found for sustained attention, recent memory, working memory, visuospatial/constructional ability, and expressive language. Performance by participants with CO poisoning for the domains of sustained attention, recent memory, visuospatial/constructional abilities, and working memory significantly improved over time after initial exposure, demonstrating recovery of these functions over time. No statistically significant differences were evident for divided attention or expressive language. Conclusions: This evidence indicates that healthy controls perform better than do individuals with CO poisoning on a range of neuropsychological domains; however, it also indicates that performance in some domains does improve over time. (JINS, 2018, 24, 405–415)

Objective: We evaluated emergency department (ED) data, emergency medical services (EMS) data, and public utilities data for describing an outbreak of carbon monoxide (CO) poisoning following a windstorm.

Methods: Syndromic ED data were matched against previously collected chart abstraction data. We ran detection algorithms on selected time series derived from all 3 data sources to identify health events associated with the CO poisoning outbreak. We used spatial and spatiotemporal scan statistics to identify geographic areas that were most heavily affected by the CO poisoning event.

Results: Of the 241 CO cases confirmed by chart review, 190 (78.8%) were identified in the syndromic surveillance data as exact matches. Records from the ED and EMS data detected an increase in CO-consistent syndromes after the storm. The ED data identified significant clusters of CO-consistent syndromes, including zip codes that had widespread power outages. Weak temporal gastrointestinal (GI) signals, possibly resulting from ingestion of food spoiled by lack of refrigeration, were detected in the ED data but not in the EMS data. Spatial clustering of GI-based groupings in the ED data was not detected.

Conclusions: Data from this evaluation support the value of ED data for surveillance after natural disasters. Enhanced EMS data may be useful for monitoring a CO poisoning event, if these data are available to the health department promptly.

(Disaster Med Public Health Preparedness. 2011;5:37-45)

This case report describes carbon monoxide toxicity from prolonged shisha (water-pipe) smoking. The evidence base for the source and pathway of toxicity is discussed. This practice has been increasing in the UK in recent years, and emergency physicians need to be aware of the high levels of CO, with the consequent risk of clinical poisoning from water-pipe smoking.

ClarkeSFJ, StephensC, FarhanM, WardP, KeshishianC, MurrayV, ZennerD. Multiple Patients with Carbon Monoxide Toxicity from Water-Pipe Smoking. Prehosp Disaster Med. 2012;27(6):1-3.

This study tested the hypothesis that carbon monoxide poisoning would produce a deficit of attentional control, the supervisory attention system, as indexed by attention switching and attentional scheduling, and that routine attentional orienting would be unaffected. Seventy-three cases of carbon monoxide poisoning were assessed at 3 days and 1 month post poisoning on tasks of attentional orienting, and tasks of the supervisory attention system. The results were compared to a group of 53 healthy community participants. A deficit of the supervisory attentional system was documented on a task of attention switching in survivors of both deliberate and accidental CO poisoning, leaving attentional scheduling intact. There was no deficit of attentional orienting in the current study. Alteration of consciousness was found to predict subsequent supervisory attention system impairment in correlation analyses, and the deficit was persistent for a 1 month follow-up period. (JINS, 2004, 10, 843–850.)

Exposure to carbon monoxide is a well-recognized cause of morbidity and mortality. Both acute accidental poisoning and chronic exposure are associated with a range of adverse health effects. We report two cases of carbon monoxide poisoning with the associated phenomenon of sensorineural hearing loss. Although hearing loss as a result of acute carbon monoxide exposure has previously been described, here we emphasize the need to consider chronic exposure to carbon monoxide as a potentially reversible cause of sensorineural hearing loss if diagnosed and treated early.

Magnetic resonance (MR) images and neuropsychological testing data of 69 carbon monoxide (CO) poisoned patients were prospectively obtained within 1 day of CO poisoning, two weeks and six months. CO patients' Day 1 cross-sectional fornix surface area measurements, corrected for head size by using a fornix-to-brain ratio (FBR), were compared to normal age and gender-matched controls. Additionally, a within-subjects analysis was performed comparing the mean areas between CO patients' Day 1, 2 weeks and 6-month FBR. The FBR was correlated with patients' neuropsychological data. There were no significant differences between CO patients' Day 1 fornix measurements compared to normal control subjects. However, significant atrophic changes in the fornix of CO poisoned patients occurred at two weeks with no progressive atrophy at 6 months. By 6 months, CO patients showed significant decline on tests of verbal memory (when practice effects were taken into account), whereas visual memory, processing speed and attention/concentration did not decline. This study indicates that CO results in brain damage and cognitive impairments in the absence of lesions and other neuroanatomic markers. (JINS, 2001, 7, 640–646.)

We report a case of carbon monoxide poisoning where symptoms of Neuroleptic Malignant Syndrome developed following use of neuroleptic medication. Literature review has failed to reveal a previous report of neuroleptic malignant syndrome following carbon monoxide insult.