Introduction

Research and clinical experience suggest that people with epilepsy are more likely than the general population to have accidents and related injuries, including bone fractures, wounds and lacerations, abrasions, head trauma, concussion, drowning, burns, sprains/strains, broken teeth and eye lesions.^{1, 7}

The home, street and workplace are, in decreasing order, the leading sites where accidents and injuries occur.¹ Most accidents and injuries are fairly mild to moderate in severity and uncomplicated. In rare circumstances, these events can be fatal, mostly motor vehicle accidents, drownings, severe falls and burns.¹ Even injuries that do not prove lethal can be the cause of disability, missed work or school, health care expenses and indirect costs.

Some of the accidents and injuries can be directly attributed to seizures (Figure 7.1). Indeed, seizures can be associated with alterations or impairment of consciousness and loss of motor control. Additional injuries may be the consequence of seizures themselves, as for example shoulder dislocation due to muscle contraction during a generalized tonic-clonic seizure or tongue biting from contraction of masseter muscles.^{8, 9}

Figure 7.1 Risk factors for accidents and injuries in patients with epilepsy.

Comorbid conditions and concurrent handicaps, neurological and cognitive deficits, behavioural and psychiatric disorders as well as side effects of antiepileptic medications, like drowsiness, ataxia, blurred vision and diplopia, may be present in patients with epilepsy and act as independent putative causes of accidents and injuries; impaired judgement or vigilance, impulsiveness, sleepiness and poor balance are potential underlying mechanisms (Figure 7.1).^{1, 10–12}

Motor Vehicle Accidents in Patients with Epilepsy

There is considerable variation across individual studies in the rates of motor vehicle accidents reported in patients with epilepsy. In a recently published systematic review that included 30 observational studies, the prevalence of traffic accidents ranged from 0 to 61%.¹³ Remarkably, studies recruited patients with a wide range of seizure disorders and baseline characteristics, including first seizure, childhood onset epilepsy, drug-resistant epilepsy, people collected by a free ambulance service, patients on at least one antiepileptic agent or dependent on psychoactive drugs.¹³ One third of the studies specified the time frame considered to estimate prevalence, which covered the past 1, 2, 3, 4, 5 or 10 years.¹³ Only half of the study authors described whether the traffic accidents were seizure-related or not, and the proportion of accidents due to an actual seizure versus a driver error remained difficult to ascertain in many cases.¹³ Studies were predominantly performed in high-income settings, limiting the generalizability of the evidence to middle and low-income countries, which are characterized by higher incidence of epilepsy and road traffic fatality rate.^{14, 15} Furthermore, in high-income countries about 90% of patients with epilepsy drive before and near all hold a driver’s licence ten years after the disease onset, whereas only 20–30% of people with epilepsy drive in middle-income countries.^16–18

The existing literature suggests that people with epilepsy are overall more likely to be involved in motor vehicle accidents than the unaffected population with a risk that ranges from 1.2 to 2.1 in different study populations.^{1, 11, 19–23} By contrast, no difference in risk of accidents was found between epileptic and non-epileptic drivers in a retrospective questionnaire survey in the UK.²⁴ Potential underestimation bias could explain such discrepancy as drivers in the UK are required to self-report to the authorities any medical condition that can affect driving ability.

It is worth noting that people with epilepsy also have a 2.2- and 1.7-fold increased risk of pedestrian and bicycle accidents, respectively in comparison to controls.¹⁹

Some studies tried to elaborate on the nature of motor vehicle accidents in people with epilepsy. In this regard, accidents related to epilepsy have been reported to produce more minor injuries, and to be more likely to involve a single vehicle, carry a sole occupant, begin mostly with an ‘out of control movement’, to be a collision with a fixed object, involve an ‘off path, on straight’ mechanism and occur in less densely populated areas than non-seizure related crashes.^{25, 26} Moreover, crashes related to generalized epilepsy have been shown to involve younger drivers and seizure-provoking factors and occur earlier during the day in comparison to focal epilepsy.²⁶

Protective factors against motor vehicle accidents include a prolonged seizure-free interval, epilepsy surgery, presence of reliable auras, history of few non-seizure related crashes and regular adjustment of antiepileptic therapy.^{27, 28} Patients with a seizure-free interval of 6 months have a 85% reduced risk of accident compared to subjects with shorter intervals, and the risk is reduced by more than 90% in patients with >12 months of freedom from seizures.²⁸ Conversely, non-adherence and poor compliance to the antiepileptic drug regimen and driving in violation of restrictions are associated with a higher risk of traffic crashes.^{26, 29–31}

The use of newer versus older antiepileptic drugs, namely lamotrigine or levetiracetam versus carbamazepine or oxcarbazepine, did not affect the risk of serious motor vehicle accidents in a Swedish nationwide cohort study. This suggests how adherence to antiepileptic therapy may be emphasized over the choice of a specific agent in counselling patients about driving to minimize the risk of seizures and car crashes.¹⁹ A nested case–control study performed in the Australian state of Victoria also identified that, although 20% of patients with epilepsy had a car accident before the diagnosis, approximately one fifth of seizure-induced crashes were attributable to non-compliance to antiepileptic treatment once prescribed.²⁶ A retrospective open-cohort study using Medicaid claims data from Florida, Iowa and New Jersey found that non-adherence to therapy was associated with a significantly higher incidence of motor vehicle injuries than adherence in adult patients who had a diagnosis of epilepsy and had been prescribed antiepileptic drugs.³²

Driving restriction is a major critical issue in patients with epilepsy. Worldwide, in order to balance the economic and social relevance of having a driving licence with the hazard to public safety, the main assumption that inspires current legislation is to reduce rather than avoid risks by allowing people with an acceptable low likelihood of a seizure-related traffic accident to drive.² Seizure-free interval is the main measure and dominating factor to establish fitness to drive and the time since the last seizure represents the major or sole criterion employed most widely by driver-licencing authorities.³³ A great variability, however, exists in the specific rules and driving restrictions across countries and even within states in the USA and European Union. Additional variables that can predict the risk of seizure recurrence and seizure-related accidents include age, seizure type, diurnal pattern, seizure duration and electroencephalographic abnormalities.^34–36

Treatment withdrawal may be indicated in people with epilepsy in remission. In this regard, the Medical Research Council antiepileptic drug withdrawal study, which involved 1,021 patients with epilepsy, found a risk of 30% for seizure recurrence in the next 12 months immediately following drug taper.³⁷ Further, the risk of seizure after drug tapering decreases with the increasing of the seizure-free interval.^37–39 In the case of seizure recurrence, when treatment was reinstated, the risk of a seizure in the following 12 months was 26%, 18% and 17% after 3, 6 and 12 months spent without seizures.³⁷ These figures should be born in mind when advising time off driving after discontinuation of antiepileptic drugs. In the UK, people with epilepsy are advised to not drive during drug tapering and for the next 6 months⁴⁰; in the USA, no laws exist about driving restriction during or after drug tapering, but 80% of epilepsy specialists would advise to not drive for 3 months after treatment withdrawal.⁴¹

There is converging evidence that people with epilepsy who are compliant with local driving restrictions have a risk of traffic accidents that is similar to that observed in the general population, and most epilepsy patients causing motor vehicle crashes did not fulfil the criteria established by law.^42–44 It is, hence, of great concern to know that only around half of patients with epilepsy are aware of the rules regarding driving privileges,^{45, 46} and up to two-fifths of people with seizures drive without meeting the seizure freedom requirement.^{47, 48}

Seizure-related Injuries

Seizure-related injuries have been classified into burns, head trauma, dental traumas, fractures, major body injuries, penetrating traumas, road injuries and drowning.^{12, 49, 50} Noteworthy, a patient could have one or more injuries at different body locations during a seizure or multiple injuries with different seizures.

A number of studies have shown that head traumas are the most frequent types of injury, followed by fractures.^50–54 In a recent study by Lagunju et al., 57 children (46%) had a seizure-related injury and 31 (25%) of them presented multiple injuries; higher seizure frequency was reported as the main risk factor for seizure-related injuries.⁵²

Head injuries usually result from falls occurring during seizures. The patient can fully recover from trauma, but cognitive and psychological symptoms may persist over time. The risk of fractures has been also shown to be increased in patients with epilepsy. The risk of fractures of the extremities due to seizures has been reported to be 2.4 times higher in patients with epilepsy, and bone fractures showed a rate of 19%.^{9, 55} In addition, patients with epilepsy can further become more prone to have fractures due to the osteopenic effects of some antiepileptic medications, mainly those of the first generation.⁵⁵

A recent study showed that patients with epilepsy tend to have multiple injuries and most of these injuries occur during everyday activities at home.⁵⁴ The most common type of seizure-related injury that happens at home is dental trauma, followed by burns and head traumas. The most common injuries occurring outdoor result in fractures, followed by head and body traumas, including lacerations and soft tissue injuries.⁵⁴ In a multicentre prospective study, the probability of seizure-related injuries was significantly greater in the domestic environment than on the street or at work.⁵⁶ These results may be, at least partly, attributed to the decreased level of alertness and attention to safety in domestic places as well as to the tendency of epileptic patients to spend more time at home and isolate themselves due to the fear of presenting seizures in public. The evidence that home is the main setting of possible serious injuries also highlights the need to take adequate preventive measures to minimize risks.

Conclusion

Quality of life is defined as the individual’s perception of physical health, psychological state and level of independence, social relationships and personal beliefs. Accidents and injuries that occur during seizures may require hospitalization, cause disability, influence the ability to drive and restrict holding a driving licence, increase loss of work productivity, increase indirect costs, decrease self-esteem, contribute to social stigmatization and, hence, affect the overall quality of life in patients with epilepsy.⁹

The knowledge of the nature and risk factors for accidents and injuries that most commonly occur in people with epilepsy represents the key step to adequately counsel and inform both patients and their families or caregivers and adopt reliable preventive measures. Most accidents and injuries occur within the first 2 years of the diagnosis of epilepsy, which is the period associated with the most significant adjustment in management and the greatest risk of seizure recurrence.^{10, 11} Lower educational level has been demonstrated to be a meaningful risk factor of having seizure-related injuries.⁵⁴ The remarkable prevalence of seizure-related injuries among patients with poor education is a further signal that epilepsy-related risks are still overlooked and their underappreciation can have major socioeconomic impact. Awareness-raising campaigns and education need to be boosted among both health care professionals and lay population to promote and increase the knowledge on epilepsy-related issues.