Epilepsy-related Injuries

Epilepsia, 47(Suppl. 1):79 86, 2006 Blackwell Publishing, Inc. C International League Against Epilepsy Epilepsy-related Injuries Elaine C. Wirrell Division of Neurology, Department of Pediatrics, Alberta Children s Hospital, Calgary, Alberta, Canada Summary: Only one prospective, controlled study has compared the risk of accidental injury in persons with epilepsy to controls without seizures. A mildly increased risk in the epilepsy group was found, predominantly due to injuries that result directly from a seizure. With regard to injury type, this study found significantly higher rates of only head and soft tissue injury; however, most injuries were minor. Several retrospective, populationbased studies have suggested increased rates of more serious injury types. Submersion injury has a high mortality; the risk of submersion in children with epilepsy is 7.5 13.9 fold higher than in the general population. The risk of fracture is elevated approximately twofold, either resulting directly from seizure-induced injury or predisposed by drug-induced reduction in bone mineral density. Burns due to seizures account for between 1.6% and 3.7% of burn unit admissions. The risk of motor vehicle accidents in drivers with epilepsy also appears increased, albeit marginally. Several factors predispose to a higher risk of injury among those with epilepsy. Seizures resulting in falls increase the risk of concussion and other injuries. Higher seizure frequency, lack of a prolonged seizure-free interval, comorbid attention deficit disorder, or cognitive handicap may also increase the risk of injury. While some restrictions are necessary to protect the safety of the person with epilepsy, undue limitations may further limit achievement of independence. Given the high morbidity and mortality of submersion injury, those with active epilepsy should bathe or swim only with supervision; however, showering is a reasonable option. Appropriate vitamin D and calcium supplementation and periodic measurement of bone mineral density in those at risk for osteopenia are recommended. Key Words: Epilepsy Seizures Accidental injury Submersion. Persons with epilepsy are believed to be at higher risk of incurring accidental injury than those without seizures. The increased risk may occur directly as the result of a seizure or due to other comorbid conditions that predispose to injury. First, seizures may lead to abrupt falls that occur without warning. The patient is unable to utilize their protective reflexes to brace their fall and may consequently suffer head, orthopedic, or soft tissue injury. In addition, they may fall onto a hot surface or into water, and sustain burns or submersion injury. Second, absence or partial complex seizures lead to loss of awareness, preventing the patient from realizing and responding to dangerous situations. Even in the absence of obvious clinical seizure activity, paroxysmal EEG discharge has been shown to affect alertness and mental speed (1). Third, antiepileptic medications may impair cognition, although this effect is probably minimal in most cases. While newer medications are felt to have less cognitive impact, this may not be the case for all agents (2). Finally, epilepsy is known to be associated with a number of comorbid conditions which Address correspondence and reprint requests to Dr. Elaine C. Wirrell at Division of Neurology, Department of Pediatrics, Alberta Children s Hospital, 2888 Shaganappi Tr NW, Calgary, Alberta, Canada T3B 6A8. E-mail: elaine.wirrell@calgaryhealthregion.ca doi: 10.1111/j.1528-1167.2006.00666.x may also play an additional role in increasing injury risk. Attention deficit disorder is much more common in children with epilepsy (37% compared to 5% in healthy controls) (3), and has clearly been associated with an increased risk of accidental injury (4,5). Approximately one-third of persons with epilepsy have some degree of cognitive impairment, and consequently may be less able to perceive potential harm and make appropriate judgments. A higher proportion of patients also have motor impairment including cerebral palsy, which may place them at increased risk of falls, and may impair their ability to quickly remove themselves from a dangerous situation. As the result of the enhanced injury risk, persons with epilepsy are subject to limitations on driving, certain sports or activities, and employment. While it is appropriate to mandate appropriate restrictions to reduce injury, excessive limitations may lead to loss of independence, impaired social development, and potentially increased psychiatric comorbidity. WHAT IS THE EVIDENCE FOR INCREASED INJURY? Various studies have reported on accidental injury rates in cohorts with epilepsy (Table 1). 79

80 E. C. WIRRELL TABLE 1. Reported accidental injury rates in patients with epilepsy Number Author Study type and population of patients Injury rate Beghi 2002 (6) Nakken 1993 (8) Neufeld 1999 (9) Buck 1997 (10) Lawn 2004 (34) Kirby 1995 (44) Appleton 2002 (11) Kirsch 2001 (12) Wirrell 1996 (13) Ziegler 1994 (45) Prospective, case-control, children 5 years and adults, general hospital and university centers Prospective study of 62 multihandicapped adults in nursing homes followed for 13 months Retrospective survey of adults with epilepsy regarding past injuries during seizures, epilepsy clinic Retrospective, population-based survey of injuries sustained in past year in adults with active epilepsy but without severe physical or learning disabilities Retrospective chart review of patients diagnosed with epilepsy over a 10-year period to determine injuries severe enough to seek medical attention or to be determined during the course of medical care Prospective study of all adults with seizures presenting to the ERs in a regional area Prospective identification of newly diagnosed children 1 16 yr attending one of seven U.K. hospitals Retrospective case-control study of cognitively normal children 5 16 yr attending a pediatric neurology clinic and their best friends Population-based, retrospective study of childhood and juvenile absence epilepsy and juvenile myoclonic epilepsy Retrospective study of children with epilepsy without motor or mental handicap 951 cases 909 controls At 12 months: injury in 17% of cases and 12% of controls At 24 months: injury in 27% of cases and 17% of controls (p < 0.0001) 62 cases 32.3% sustained a seizure-related injury in a 13-month period 298 cases 30% reported prior trauma associated with seizures 696 (71% response rate) 35% sustained injury in the preceding year as the result of a seizure 247 adults 62 seizure-related injuries identified in 39 patients over 2,714 patient-years one injury every 44 person-years 560 cases 14% injury rate with seizures that present to an ER 198 children 12.6% experienced a seizure-related injury before the diagnosis of epilepsy was established 25 cases Median injury rate was 1 over the past year, and 3 even for 25 controls both cases and controls 59 cases 27% had sustained at least one injury during an absence seizure 198 cases Six injuries over 11 year follow-up period The largest investigation of this topic was done in a multicenter, European cohort of 951 children and adults with idiopathic, cryptogenic, or remote symptomatic epilepsy followed prospectively for 17,484 person-months, and compared to a cohort of 909 matched controls (6). Cases were recruited from both general hospital and university settings and followed between 1 and 2 years. Children less than 5 years of age were excluded, as were those with acute or progressing epileptogenic conditions. Partial epilepsies accounted for 55% of the cohort and seizure frequency at study entry was less than monthly in 70%. Controls were relatives or friends of the patient and were age and gender matched. Cases with epilepsy had a significantly higher cumulative probability of an accident than controls both at 12 (17% vs. 12%, p < 0.0001) and 24 months (27% vs. 17%, p < 0.0001). In the epilepsy group, 24% of accidents were seizure related, but after exclusion of these, the overall accident rate of the epilepsy group at 12 and 24 months (14% and 22%) was similar to controls (p = 0.056). However, further analysis did show that, even after controlling for seizure-related accidents, cases with epilepsy have a higher rate of domestic, street, and work accidents than controls. The overall injury rate was neither significantly correlated with seizure frequency nor etiology. However, those with generalized epilepsy had significantly more concussions, and abrasions were less common in patients with inactive epilepsy (7). Most accidents were minor, with contusions and wounds being the most commonly reported injuries. However, cases with epilepsy reported higher rates of hospitalization (3% vs. 1%) and medical action after an accident (16% vs. 10%), compared to controls. Not surprisingly, adults with intractable epilepsy have higher rates of injury. In a prospective study of 62 multihandicapped adults residing in nursing homes in Norway, most of whom had refractory seizures, Nakken and Lossius found that 32.3% sustained a seizure-related injury over a 13-month period (8). Eighty injuries were seen with 6,889 clinical seizures, for a seizure-related injury risk of 1.2%. While most injuries were mild, 6 of 80 were more severe (five fractures and one subdural hematoma). Several retrospective, questionnaire-based studies suggest rates of injury due to seizures of 30 35%, over varied time periods ranging from the past year to lifetime (9,10). Several studies have also been done in the pediatric age group. Using a structured questionnaire, Appleton collected information on seizure-related injury in 198 children 1 16 years of age, presenting with two or more newly diagnosed, afebrile seizures at several centers in the United Kingdom and found seizure-induced injury to be uncommon (11). Only 25 (12.6%) had experienced an injury prior to the diagnosis of epilepsy, with 4 of these requiring medical attention for this injury. Similar to previous studies, most injuries were seen in patients with tonic-clonic or myoclonic seizures. In a small, case-control study comparing cognitively normal children with epilepsy to age- and gender-matched controls, Kirsch found no increased rate of injury in those

EPILEPSY-RELATED INJURIES 81 with epilepsy (12). However, the small number of children with comorbid attention deficit disorder did have a higher rate of injury. Finally, in a retrospective study of 59 young adults with typical absence epilepsy, 27% reported sustaining at least one injury during a seizure (13). Compared to controls, both bicycle and car accidents were significantly more common in cases with absence epilepsy. In summary, the only prospective, controlled study on this topic shows a mild, but definite, increased injury risk in persons with epilepsy, but suggests that injuries directly resulting from seizures are the major reason for this increased risk. WHAT TYPES OF INJURIES ARE MOST CONCERNING? Submersion Injury Submersion injury is a major concern in persons with epilepsy and appears the most likely injury type that leads to death. Using data from the National Center for Health Statistics of Centers for Disease Control and Prevention, Sheth et al. found the proportionate mortality ratio for accidental drowning in adults with epilepsy was 4.4 (95% confidence interval [CI] 2.7 6.1) (14). In a retrospective study of adults with epilepsy who were asked to complete a questionnaire on prior injuries, 44 of 313 (14%) reported sustaining a seizure while bathing or swimming in the preceding 12 months (10) (Table 2). A retrospective, population-based cohort study of all submersion injuries in children and teens in a single county in Washington State also noted a strikingly high risk of submersion injury in children with epilepsy. Those with epilepsy had a relative risk of 13.9 for submersion, and of 13.8 for fatal drowning compared to children without epilepsy, and were more likely to be 5 years of age or older at time of injury. The most common sites for submersion were the bathtub or a swimming pool, with a relative risk of 96 for drowning in a bath, and of 23.4 for drowning in a pool (15). A second survey from the United Kingdom found that children with epilepsy were 7.5 times more likely to experience submersion injury or death than those without seizures (16). Nearly all deaths resulted from bathing or swimming unsupervised. Ryan also noted that most drownings in persons with epilepsy occurred in the bath, without direct supervision, but also reported one case in a shower when the drain was obstructed by the patient s body (17). Burns Although the prospective, European cohort study did not demonstrate a significantly greater risk of burns in persons with epilepsy (7), other retrospective studies suggest an increased risk of burns. In two similarly designed studies, 1.6% and 3.7% of burn unit admissions resulted from epileptic seizures (18,19). Most burns occurred at home, with scald injuries and contact burns with radiators, irons, or hair dryers being the most common. In surveys of adults with epilepsy, 3.7 15.9% reported sustaining a burn as the result of a seizure (9,10). Fractures Persons with epilepsy may be at increased risk of fractures due to seizure-induced injury as well as antiepileptic drug-induced reduction in bone mineral density. Drugs which are inducers of the cytochrome p450 system, such as phenobarbital, phenytoin, primidone, and carbamezepine are most commonly associated with reduction in bone mineral density (20), presumably due to increased catabolism of vitamin D and decreased calcium absorption, resulting in secondary hyperparathyroidism, although valproic acid has also been implicated (21). While lamotrigine appears to be safer (22), there are few studies addressing this question in relation to the newer agents. In the only prospective study done to date, no increased risk of fractures was seen in persons with epilepsy (7), although, fractures did account for 11% of accidents in the epilepsy cohort (6). In contrast, several retrospective studies have shown an increased fracture rate in persons with epilepsy. Using the General Practice Research Database, which comprises computerized medical records of approximately 650 general practices in the United Kingdom, the incidence of fractures was compared between persons with epilepsy and nonepileptic controls (23). Those with epilepsy had a nearly twofold higher risk of fracture, with the relative fracture risk being highest for hip and femur fractures. Those with epilepsy, however, also had significantly greater rates of fractures of the hand or radius/ulna, tibia, fibula, ankle or foot, and other fractures. In a retrospective, neurology-clinic-based study of adult outpatients with epilepsy, Persson et al. documented the incidence of fractures to be 23.8 per 1,000 person-years, a 2.39 increased risk compared to regional fracture rates (24). In a retrospective, population-based survey of fractures, Annegers et al. found that those with epilepsy had a 2.3-fold increased risk of sustaining a hip fracture (25). Head Injuries The European prospective cohort study found that concussion accounted for 10% of accidents seen in those with epilepsy (6) and was significantly more common than in controls (odds ratio 2.6, 95% CI 1.2 5.8) (7). In another prospective study of 298 adults with chronic, long-term epilepsy, 27,934 seizures were recorded, 45.2% of which were associated with falls (26). A total of 766 head injuries resulted, 45% of which required suturing. Only three more serious head injuries occurred, one with skull fracture and one each with extradural and subdural hemorrhage. Other studies have reported higher rates of serious injury, but are derived from highly selected populations. In a study of 22 adults with head injuries resulting from falls due to

82 E. C. WIRRELL TABLE 2. Types of injuries resulting from seizures Injury type Study Design Findings Submersion Ryan 1993 (17) Diekema 1993 (15) Quan 1989 (46) Kemp 1993 (16) Burns van den Broek 2004 (7) Fractures Head injuries Soft tissue injuries Spitz 1992 (18) Josty 2000 (19) van den Broek 2004 (7) Souverein 2005 (23) Persson 2002 (24) Annegers 1989 (25) Vestergaard 1999 (47) Desai 1996 (48) van den Broek 2004 (7) Russell-Jones 1989 (26) Zwimpfer 1997 (27) van den Broek 2004 (7) Nakken 1993 (8) Deekollu 2005 (28) Dental injuries Buck 1997 (10) Nakken 1993 (8) Retrospective, population-based cohort Retrospective, population-based cohort Retrospective, population-based cohort Retrospective, population-based cohort Prospective, cohort study of persons with epilepsy and nonepileptic controls followed for 17,484 and 17,206 person-months, respectively Retrospective, hospital-based review of burn unit admissions Retrospective, hospital-based review of burn unit admissions Prospective, cohort study of persons with epilepsy and nonepileptic controls followed for 17,484 and 17,206 person-months, respectively Retrospective review of U.K. General Practice Research Database Retrospective, neurology-clinic-based review of fractures in adults with epilepsy Retrospective, population-based review of fractures Self-completed questionnaires on fractures completed by noninstitutionalized patients with epilepsy and randomly selected controls Retrospective review of fractures sustained in 185,066 seizures over 4,521 patient-years compared to normal population Prospective, cohort study of persons with epilepsy and nonepileptic controls followed for 17,484 and 17,206 person-months, respectively Prospective study of 298 patients with chronic long-term epilepsy Prospective cohort of adults with head injury admitted to a neurosurgical service Prospective, cohort study of persons with epilepsy and nonepileptic controls followed for 17,484 and 17,206 person-months, respectively Prospective study of staff recorded injuries due to seizures in multihandicapped adults in nursing homes followed for 13 months Retrospective study of 33 children with intractable seizures leading to falls Retrospective, population-based survey of adults with active epilepsy but without severe physical or learning disabilities, of injuries sustained in past year Prospective study of staff recorded injuries due to seizures in multihandicapped adults in nursing homes followed for 13 months 5% of 482 drowning deaths over a 10-year period were related to seizures Relative risk for children with epilepsy of drowning in bathtub or pool was 96 and 23.4, respectively 7.5% of 199 submersions occurred in children with a history of prior seizures Children with epilepsy were 7.5-fold more likely to drown Relative of risk of burn in the epilepsy group: 0.9 (95% CI 0.4 2.0) 10/267 (3.7%) of burn unit admissions had epilepsy and sustained a burn due to a seizure 111/6,940 (1.6%) of burn unit admissions were secondary to a seizure Relative risk of fracture in the epilepsy group: 1.3 (95% CI 0.8 2.4) Persons with epilepsy had an overall risk of fracture 1.89 times higher than controls, and risk of femur and hip fractures 2.79 times higher Overall risk ratio of fracture in patients with epilepsy was 2.39. 43% of fractures were definitely or possibly seizure-related Hip fractures were 2.3-fold more common in patients with epilepsy Relative risk of fracture in those with epilepsy 2.0. Seizures accounted for 33.9% of all fractures in the epilepsy group 4.3-fold increased risk for all fractures and 3.2-fold increased risk for fractures unrelated to seizures. Biggest risk for fractures of intertrochanteric region and ankle (9.9 for each) Relative risk of concussion in epilepsy: 2.6 (95% CI 1.2 5.8). Excluding seizure-related concussions: 1.4 (95% CI 0.6 3.5) 766 significant head injuries seen in 27,934 seizures (45.2% of which led to falls). 45% of head injuries required sutures. 1/9,311 seizures led to skull fracture, extradural, or subdural hemorrhage 20/22 (91%) patients had an intracranial hematoma, 18 of whom required surgical drainage Relative risk of contusion in epilepsy: 1.5 (95% CI 1.0 2.2) Excluding seizure-related contusions: 1.2 (95% CI 0.8 1.8) Relative risk of wound in epilepsy: 1.9 (95% CI 1.2 3.1) Excluding seizure-related wounds: 1.5 (95% CI 0.9 2.5) Relative risk of abrasion in epilepsy: 2.1 (95% CI 1.1 4.0) Excluding seizure-related abrasions: 1.9 (95% CI 0.9 3.7) Relative risk of sprain in epilepsy: 1.3 (95% CI 0.6 2.8) Excluding seizure-related sprains: 0.9 (95% CI 0.2 3.8) Soft tissue injuries accounted for 59/80 (74%) injuries Lacerations and bruises to the face and scalp accounted for 43/59 (73%) of injuries 9.7% reported a dental injury (loss of teeth or fracture of jaw in 86% of these cases) Dental injuries occurred in 4/80 (5%) seizure-related injuries (continued)

EPILEPSY-RELATED INJURIES 83 TABLE 2. Continued. Injury type Study Design Findings Motor vehicle accidents Sheth 2004 (14) Taylor 1996 (29) Hansotia 1991 (30) Lings 2001 (33) Epidemiological study on driving fatalities in persons using data from the Centers for Disease Control and Prevention Self-completed questionnaires on motor vehicle accidents in the preceding 3 years in adults with and without a history of epilepsy and single seizures Population-based, retrospective cohort study of all licensed drivers Retropective cohort study of drivers with epilepsy and healthy controls Seizure-related fatal crashes accounted for 0.2% of total fatal crashes Higher disease-specific fatal crash rate for patients with seizures (8.6 per 100,000) compared to cardiovascular disease (3.74 per 100,000) or diabetes (1.88 per 100,000) No difference in accident rates between those with and without epilepsy; however, those with epilepsy had marginally increased risk of accident with serious physical injury Drivers with epilepsy were 1.33 times as likely to be involved in an accident (p = 0.04) Drivers with epilepsy were 7.01-fold (95% confidence interval 2.18 26.13) more likely to be involved in an injury following which they sought treatment in a casualty department seizures admitted to a neurosurgical service over an 8-year period, intracranial hematomas were present in 20 (91%), 18 of whom required neurosurgical evacuation (27). Soft-tissue Injuries Soft-tissue injuries are the most common type of injury sustained as the result of a seizure. In the prospective European cohort study, contusions, wounds, and abrasions accounted for 26%, 23%, and 11% of accidents in persons with epilepsy (6) and all of these injury types were more prevalent in the cohort with epilepsy than controls (7). In all cases, once seizure-related events were excluded, there were no significant differences between cases and controls. However, sprains and strains were not more prevalent in the group with epilepsy, even prior to excluding injuries sustained during a seizure. Five percent of cases required medical attention following a contusion and 4% following a wound. In a prospective study of multihandicapped patients with seizures, soft-tissue injuries accounted for 59 of 80 (74%) seizure-related injuries (8). In a retrospective study of 33 children who had been prescribed helmets for intractable seizures resulting in falls, Deekollu et al. documented a seizure-related injury risk of 0.4%; scalp and facial bruises and lacerations were the most commonly seen injury type (28). Interestingly, in this study, helmets did not appear to reduce the risk of facial or scalp injury 21 of 31 (68%) of accidents occurring when a helmet was worn versus 16 of 28 (57%) of those seen when a helmet was not worn resulted in injuries to the face and scalp. Dental Injuries Not all studies have looked specifically at dental injury. In one retrospective survey of adults with seizures, 9.7% of patients reported sustaining a dental injury as the result of a seizure, and in 86% of these cases, the injury resulted in either loss of teeth or fracture of the jaw (10). In a prospective study of multihandicapped adults with epilepsy, dental injuries accounted for only 4 of 80 seizure-related accidents (8). Motor Vehicle Accidents Driving restrictions, specified by law are nearly universal for persons with epilepsy; however, there is variation in the seizure-free period required to obtain a license. The risk of seizure-related motor vehicle accidents varies widely in the literature. In a large epidemiological study which was limited to driving fatalities, Sheth et al. studied mortality data, obtained by the National Center for Health Statistics of Centers for Disease Control and Prevention, for the years 1995 1997 to determine the risk to public safety posed by drivers with epilepsy (14). Seizure-related driving fatalities were rare, accounting for only 86 (0.2%) of the total 44,027 annual driving fatalities in the United States. However, drivers with epilepsy had an increased risk of fatal crashes (8.6 per 100,000) compared to those with other medical conditions such as cardiovascular and hypertensive disease (3.74 per 100,000) or diabetes (1.88 per 100,000). Taylor et al. compared accident rates in two large cohorts in the United Kingdom: a normal population of 12,324 persons surveyed through the Transport Research Laboratory, and a population with epilepsy or single seizures comprising 24,000 individuals applying for license renewal to the licensing authority, and 468 persons reported to the licensing authority because they suffered a recent seizure (29). Potential subjects were mailed a questionnaire asking about motor vehicle accidents in the previous 3 years. Seventy-two percent of the normal population and 71% of those with seizures returned the questionnaire. There was no evidence of an increased risk of accidents in the population of drivers with epilepsy (mean number of accidents in the prior 3 years 0.25 in those with epilepsy vs. 0.29 in controls). However, those with epilepsy had a marginally increased risk of an

84 E. C. WIRRELL accident resulting in serious physical injury (odds ratio 1.33, 95% CI 1.01 1.76). Patients who had been seizurefree for longer than 3 years had a lower rate of accident than those with more recent seizures (odds ratio 0.74, 95% CI 0.62 0.87). In an earlier, population-based, retrospective cohort study of all 30,420 licensed drivers, both with and without epilepsy in a regional area, Hansotia et al. found a modest but significantly higher accident rate in those with seizures (rate ratio 1.33, 95% CI 1.00 1.73, p = 0.04) (30). Interestingly, those with epilepsy also had significantly greater rates of violations regarding careless driving (standard mishap ratio 1.57, 95% CI 1.05 2.25) and alcohol and drugs (standard mishap ratio 2.75, 95% CI 1.50 4.62). In a second study, the same authors report that the risks are highest with a history of multiple seizures and in those not treated with antiepileptic drugs (31). Krauss et al. performed a retrospective case-control study comparing 50 patients with epilepsy who were involved in motor vehicle accidents during a seizure and 50 age- and gender-matched controls with epilepsy who had not crashed (32). Groups were comparable for hours of driving per month and total years of driving. Factors significantly correlated with a lower rate of crashes included being seizure-free 12 months (odds ratio 0.075), 6 months (odds ratio 0.147), reliable auras with every seizure (odds ratio 0.077), recent reduction or change in antiepileptic drugs (odds ratio 0.111), and total fewer nonseizure related accidents in the past (odds ratio 0.465). Of note, over half of patients who crashed in this study were driving illegally, with seizure-free intervals shorter than legally permitted. A small retrospective Danish study, comparing injuryassociated accidents in persons with epilepsy to healthy controls documented a sevenfold increased accident risk in those with seizures (33). However, only accidents where the driver sought treatment at a casualty department were included. Children with absence seizures may be at higher risk for bicycle accidents (13); however, not all studies have documented this increased risk (11). In summary, minor soft tissue injuries are most commonly seen following seizures. Rare, but potentially much more serious injuries include drownings, severe burns, severe head injuries, and severe motor vehicle accidents. WHERE DO INJURIES OCCUR? The European prospective cohort study recorded circumstances/location for each injury sustained, subdivided into home, street, work, school, or sport (7). Compared to controls, persons with epilepsy had significantly more home, street, and work accidents, and this difference persisted even after excluding seizure-related events. The home was the most common place of injury, consistent with findings in other studies (9,11), likely, at least in part, due to the time spent at home versus at other locations. WHAT RISK FACTORS PREDISPOSE TO INJURY? Several epilepsy-specific variables have been correlated with higher risks of injury. Seizure type has been a factor in most studies. Patients with generalized onset seizures, particularly tonic clonic, atonic, or myoclonic seizures leading to falls, are at higher risk of concussion (7) as well as other injuries (9 11). In a study of risk factors for motor vehicle accidents, Krauss noted a lower risk in patients who had a reliable aura, presumably as they are able to stop driving before a seizure impairs their ability to do so (32). High seizure frequency also increases risk of injury (10,34) and in the European prospective cohort study, correlated with an increased risk of abrasions (7). Seizure-free intervals of 12 months correlate with lower crash rates in drivers with epilepsy (32). In children, attention-deficit disorder is a common comorbidity in epilepsy, being present in approximately 37% of cases (3). Attention-deficit /hyperactivity disorder is a known risk factor for injury in children (4,5). While no study has specifically examined the effect of comorbid attention-deficit disorder on the risk of injury, one study did note a higher rate of injury in children who had been diagnosed with this comorbidity, however, was limited by very small study numbers (12). Comorbid cognitive handicap may also increase risk of injury (35). One small study of cognitively normal children with epilepsy documented a similar rate of injury to their nonepileptic peers (12). However, children with lower cognitive function are often also those with more refractory seizures. WHAT ARE REASONABLE RECOMMENDATIONS TO MINIMIZE INJURY RISK AND MAXIMIZE INDEPENDENCE AND SOCIAL DEVELOPMENT? Having epilepsy poses inherent challenges to maintaining independence and participating fully in social interactions. While some restrictions are necessary to protect both the patient s and public s safety, restrictions themselves further limit independence and social development. Carpay et al. found that parents reported disability due to restrictions in 83% of children with active epilepsy (36). Higher disability was seen in children whose neurologist had recommended at least some restrictions, emphasizing that physicians need to be aware of the impact of their recommendations when they counsel patients. Evidence from the literature would suggest that injury risk is not the same in all patients. Those with generalized seizures, particularly those leading to repetitive falls, appear to be at higher risk, as do those with more frequent

EPILEPSY-RELATED INJURIES 85 seizures. Comorbid attention deficit and cognitive impairment likely also increase the risk. Seizures that occur exclusively at night, in the safety of one s bed, probably also lead to less injury than those occurring predominantly during the day. Given the high mortality and morbidity resulting from submersion injuries, it is imperative that persons with epilepsy be advised to bathe and swim only with supervision. Showering is a reasonable option, as the risk of drowning in a shower is exceeding low. To minimize the risk of scald injuries, patients should be advised to regulate the temperature of their hot water. In addition to hot water safety devices, in order to minimize risk of burns, patients with poorly controlled seizures should minimize the use of electric irons, handheld hairdryers, and stove top cooking or have supervision for these activities. Utilization of microwaves, insulated plastic kettles, and self-sealing deep fryers pose lesser risk (37). Fire and radiator guards may also reduce risk of contact burns. To minimize fracture risk, patients taking antiepileptic medications, particularly phenytoin, phenobarbital, primidone, and probably carbamazepine and valproate, should be counseled to ensure adequate vitamin D and calcium intake (38). Periodic bone mineral density assessments should be strongly considered in those at risk for osteopenia/osteoporosis, based on gender or age (postmenopausal women) or in those on long-term phenytoin, phenobarbital, or primidone (39). Limited physical activity, due to factors such as cerebral palsy, or limited sun exposure may also increase the risk of bone disease. Head injuries are most prominent in patients with poorly controlled generalized seizures leading to repetitive falls. While protective helmets are often recommended for this population, a recent study noted a high proportion of injuries even when helmets were worn (28). Further work is needed to find a helmet design that is well tolerated and is effective at prevention of injury. Persons with epilepsy should be encouraged to participate in regular physical activity. Contact sports are not precluded, as there is no evidence they induce seizures. Swimming and water sports, harnessed rock climbing, horseback riding, and gymnastics are safe with appropriate supervision. However, certain sports such as free climbing, sky-diving, hang-gliding, and scuba diving could be particularly dangerous if a seizure occurred, and should be avoided. In determining appropriate driving restrictions, we must balance public safety with the employment, social, and psychological impact to the individual with seizures (40). The available data suggest that drivers with epilepsy have only a marginally increased risk of accidents, with only 1/500 1/10,000 accidents related to epilepsy (14,41). In contrast, alcohol was responsible for 1/10 of accidents. The use of cellular phones while driving increases the risk of a collision fourfold (42), suggesting that drivers who use these devices regularly pose a greater risk to public safety than drivers with epilepsy. There is insufficient data to make a clear recommendation regarding the optimal period of seizure-freedom prior to obtaining a license, and this issue has been addressed by an international joint commission (43). In Krauss s study, the strongest predictor of not having a collision was a seizure-free period of at least 12 months (32). However, in patients who had been seizure free for at least 6 months, the odds of crashes were also reduced by 85% compared to those with shorter seizure-free intervals. 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