Medicine for the Outdoors
Medicine for the Outdoors

Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.

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Drowning in People with Epilepsy

With summer upon us in the northern hemisphere, greater numbers of people are in the water - swimming, boating, diving, etc. Summer camps are booming, and children are being taught to swim, kayak, windsurf, and do all of the other activities that are so much fun. Of course, most of them are being watched closely by parents, camp counselors, lifeguards and the like. The supervisors should be aware that there is a group at higher risk for drowning than the baseline, namely, persons who suffer from epilepsy (seizures).

An article appeared in 2008 in the journal Neurology (2008;71:578-582), published by the American Academy of Neurology. It is entitled "Drowning in people with epilepsy. How great is the risk? The authors are G. S. Bell, MD, A. Gaitatzis, MD, C. L. Bell, A. L. Johnson, PhD and J. W. Sander, PhD, FRCP. The paper is from the Department of Clinical & Experimental Epilepsy (G.S.B., A.G., J.W.S.), UCL Institute of Neurology, and National Hospital for Neurology and Neurosurgery, UCL Hospitals NHS Foundation Trust, Queen Square, London; Bristol Medical School (C.L.B.); MRC Biostatistics Unit (A.L.J.), Institute of Public Health, University Forvie Site, Cambridge, UK; and SEIN–Epilepsy Institutes of the Netherlands Foundation (J.W.S.), The Netherlands.

From the abstract that accompanies the article, we learn that people with epilepsy are known to be at increased risk of death by drowning but until the authors undertook this project, there were few data available regarding the size of the risk. Their goal was to quantify the risk using meta-analysis, which is a method in which multiple data sets were reviewed and the data pooled and analyzed to draw conclusions.

The authors undertook a literature search whereby they identified 51 cohorts of people with epilepsy in whom the number of deaths by drowning in people with epilepsy and the number of person-years at risk could be estimated. Population data were taken from the World Health Organization (WHO) Statistical Information Service or from the UK Office for National Statistics where available. Standardized mortality ratios (SMRs) with 95% confidence intervals (CIs) were calculated for each cohort, for groups of cohorts, and for the total population. Additionally, an SMR for drowning in people with epilepsy in England and Wales (1999–2000) was calculated using National Registries.

The results showed that 88 drowning deaths were observed, compared with 4.70 expected, giving an SMR of 18.7 (95% CI 15.0 to 23.1). Compared with community-based incident studies (SMR 5.4), the SMR was significantly raised in prevalent epilepsy (SMR 18.0), in people with epilepsy and learning disability (SMR 25.7), in those in institutional care (SMR 96.9), and in those who had a temporal lobe excision surgical procedure (SMR 41.1). The SMR for people with epilepsy in England and Wales was 15.3.

The authors concluded from this analysis that the risk of drowning in people with epilepsy is raised 15- to 19-fold compared with people in the general population. It is important that people with epilepsy and their caretakers be informed of these risks so that deaths can be prevented.

How might one prevent such deaths? The most obvious method would be enhanced supervision, so that a person suffering a seizure in the water would be rescued promptly before a drowning episode. Close attention to medication doses might be helpful, and enforcement of safety rules, including the wearing of lifejackets, could potentially be helpful. If possible, no person with epilepsy should ever be left alone in or near the water, particularly when swimming or boating. Analysis of individual drownings and deaths might lead to further recommendations.

Preview the Annual Meeting of the Wilderness Medical Society, which will be held in Snowmass, Colorado July 24-29, 2009.

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About the Author

Dr. Paul S. Auerbach is the world’s leading authority on wilderness medicine.