Postmortem changes in blood concentrations of phenytoin and carbamazepine: an experimental study

[Sudden unexpected death in epilepsy (SUDEP) : Epidemiology, cardiac and other risk factors]

Sudden unexpected death in epilepsy (SUDEP) is one of the most frequent epilepsy-related causes of death. The incidence of SUDEP is estimated to be approximately 1.2/1000 person-years (PY); however, it varies considerably depending on disease-specific and demographic factors. The estimated incidence of SUDEP in children seems to be significantly lower (0.22/1000 PY) than in adults but recent studies in children (>12 years) indicated a similar incidence to that of adults. Based on these estimations, approximately 700 SUDEP cases would be expected in Germany annually but no reliable data or epidemiological studies on SUDEP are available. Various risk factors and predictors for SUDEP have been investigated, e.g. age, seizure frequency, number of antiepileptic drugs, non-compliance and comorbidities, with sometimes contradictory results. This is understandable given that the exact mechanisms of SUDEP are unclear; however, it is very likely that the frequency of (nocturnal) generalized tonic-clonic seizures is the most important risk factor. Nocturnal monitoring of seizures (using devices) or the presence of another person at night may represent important factors to reduce the risk of SUDEP. Thus, seizure control and seizure monitoring are, according to current knowledge, the most important factors to avoid SUDEP. Some recent studies have contributed to a better understanding of possible pathomechanisms of SUDEP; however, further research is needed to identify predictive clinical factors and biomarkers and in particular to prevent SUDEP.

National Association of Medical Examiners Position Paper: Recommendations for the Investigation and Certification of Deaths in People with Epilepsy

Sudden unexpected death of an individual with epilepsy (SUDEP) can pose a challenge to death investigators, as most deaths are unwitnessed and the individual is commonly found dead in bed. Anatomic findings (e.g., tongue/lip bite) are commonly absent and of varying specificity, limiting the evidence to implicate epilepsy as a cause of or contributor to death. Thus, it is likely that death certificates significantly underrepresent the true number of deaths in which epilepsy was a factor. To address this, members of the National Association of Medical Examiners, North American SUDEP Registry, Epilepsy Foundation SUDEP Institute, American Epilepsy Society, and the Centers for Disease Control and Prevention convened an expert panel to generate evidence-based recommendations for the practice of death investigation and autopsy, toxicological analysis, interpretation of autopsy and toxicology findings, and death certification to improve the precision of death certificate data available for public health surveillance of epilepsy-related deaths. The recommendations provided in this paper are intended to assist medical examiners, coroners, and death investigators when a sudden, unexpected death in a person with epilepsy is encountered.

National Association of Medical Examiners position paper: Recommendations for the investigation and certification of deaths in people with epilepsy

Sudden unexpected death of an individual with epilepsy can pose a challenge to death investigators, as most deaths are unwitnessed, and the individual is commonly found dead in bed. Anatomic findings (eg, tongue/lip bite) are commonly absent and of varying specificity, thereby limiting the evidence to implicate epilepsy as a cause of or contributor to death. Thus it is likely that death certificates significantly underrepresent the true number of deaths in which epilepsy was a factor. To address this, members of the National Association of Medical Examiners, North American SUDEP Registry, Epilepsy Foundation SUDEP Institute, American Epilepsy Society, and the Centers for Disease Control and Prevention constituted an expert panel to generate evidence-based recommendations for the practice of death investigation and autopsy, toxicological analysis, interpretation of autopsy and toxicology findings, and death certification to improve the precision of death certificate data available for public health surveillance of epilepsy-related deaths. The recommendations provided in this paper are intended to assist medical examiners, coroners, and death investigators when a sudden unexpected death in a person with epilepsy is encountered.

SUDEP: The First Case Series in Turkey

INTRODUCTION

Sudden unexpected death in epilepsy (SUDEP) is defined as the sudden, unexpected, witnessed or unwitnessed, non-traumatic, and non-drowning death of patients with epilepsy with or without evidence of a seizure, excluding documented status epilepticus, and in whom postmortem examinations do not reveal a toxicological or anatomic cause for death. In this study, data on patients who passed away under observation in the epilepsy clinic due to sudden, unexpected death have been compiled, and we also aim to emphasize the importance of SUDEP in Turkey.

METHODS

This study was performed with a total of nine cases. Data were obtained from hospital records, information given by the families of patients, the database of the General Directorate for Civil Services of the Ministry of Internal Affairs of Turkey, and from the Ankara Metropolitan Municipality Cemetery Information System. As the basis of classification and definition, the proposals suggested by Nashef et al., which were made to the International League Against Epilepsy (ILAE) in 2011, were taken into consideration.

RESULTS

Eight of the patients were classified as probable SUDEP and one of them as possible SUDEP; the mean age at SUDEP was 33 years, and the average follow-up period was 19.7 years. In these cases, except for known risk factors (generalized tonic-clonic seizures, nocturnal seizures, severe epilepsy, more frequent seizures, younger age at the onset of epilepsy, unwitnessed seizures, polytherapy, and mental handicap), a different risk factor was not identified.

CONCLUSION

This study is the first case series on SUDEP in Turkey. Postmortem studies are the most important shortcoming of the study. However, the importance of the topic is highlighted by presenting the available data. SUDEP deserves more attention during the daily practice of neurologists, pediatric neurologists, forensic physicians, and family physicians. If death is sudden and unexpected in a patient with epilepsy, SUDEP should be considered, regardless of the clear causes of death.

Sudden unexpected death in epilepsy: some approaches for its prevention and medico-legal consideration

Worldwide, mortality associated with epilepsy is a matter of grave concern. The mortality rate in epileptic population is two to three times more than that of the general population. Sudden unexplained death in epilepsy, better known as sudden unexpected death in epilepsy (SUDEP), is a mysterious and rare condition, in which typically young or middle-aged people with epilepsy die without a clearly defined cause. At times, this may raise a strong suspicion of foul play and raise several medico-legal issues. There may be several different underlying mechanisms but most research has focused on seizure-related cerebral and respiratory depression, cardiac arrhythmia and autonomic dysfunction. In recent years, some significant risk factors have been recognized and strategies have been suggested that could be useful in prevention of SUDEP. Present communication provides some of the updates on new advances in prevention of SUDEP as well as highlights related medico-legal issues.

Investigation of Deaths in Seizure Patients

Epilepsy is commonly encountered in forensic pathology and is ultimately determined to be the cause of death in 1–2% of medicolegal death investigations. Epilepsy is a risk factor for death from external causes, including accidents and drowning. More commonly, deaths result from the underlying epilepsy pathology, including intracranial neoplasms, cerebrovascular disease, status epilepticus, and sudden unexpected death in epilepsy (SUDEP). SUDEP refers to the sudden death in an epilepsy patient that lacks an alternative anatomic or toxicological cause of death. At autopsy, intracranial pathology is present in the majority of epilepsy-related deaths and is more likely to be identified following brain fixation. Common findings include brain tumors, mesial temporal sclerosis, and malformations of cortical development. Death investigators should pay particular attention to clinical history to establish a clear history of epilepsy and to determine seizure type, frequency, underlying etiology, and prior medical and surgical treatments as well as other comorbid medical conditions. A complete autopsy with toxicology is necessary to identify other causes of death, particularly in cases of suspected SUDEP. While toxicology may be helpful in some cases, caution must be taken in interpreting postmortem antiepileptic drug concentrations as levels decrease postmortem.

Sudden unexpected death in epilepsy. Potential role of antiepileptic drugs

Among people with epilepsy, there is a 20-fold higher risk of dying suddenly and unexpectedly compared with the general population. This phenomenon is called sudden unexpected death in epilepsy (SUDEP) and the term is used when sudden death occurs in an otherwise reasonably healthy person with epilepsy and the autopsy is unrevealing. In most cases, SUDEP occurs during sleep and is unwitnessed. Risk factors for SUDEP include the presence or number of generalized tonic-clonic seizures (GTCS), nocturnal seizures, young age at epilepsy onset, longer duration of epilepsy, dementia, absence of cerebrovascular disease, asthma, male gender, symptomatic aetiology of epilepsy and alcohol abuse. Suggested factors predisposing to SUDEP have included long-QT-related mutations, impaired serotonergic brain stem control of respiration, altered autonomic control and seizures with a pronounced postictal suppression and respiratory compromise. Final events that may lead up to SUDEP are a postictal CNS shutdown with pronounced EEG suppression, ictal or postictal apnoea, and ictal cardiac arrhythmia. It is unknown whether antiepileptic drugs (AEDs) modify the risk for SUDEP. Studies have consistently found that the presence or number of GTCS is associated with an increased risk for SUDEP. Since continued presence of GTCS clearly necessitates the use of AEDs, both factors must be taken into account to determine whether one or both increases the risk for SUDEP. Some studies suggest that AEDs, such as lamotrigine and carbamazepine, may increase the risk of SUDEP, but rarely adjust for GTCS. Other studies, which have found that AEDs are associated with a decreased SUDEP risk, either adjust for the number of GTCS or are meta-analyses of randomized clinical trials. Studies assessing the impact of AEDs on the risk for SUDEP are limited because SUDEP is a rare event, making randomized clinical trials impossible to conduct. Observational studies focus on whether or not an AED was prescribed. When postmortem AED concentrations are assessed they are usually low or absent, perhaps due to sampling in deceased individuals, making it difficult to fully resolve whether AEDs increase or decrease SUDEP risk. Despite these caveats, the evidence suggests that AEDs are not associated with an increased risk for SUDEP on a population level, although some individuals may be susceptible to effects of AEDs. Recent evidence from a meta-analysis of randomized clinical trials of adjunctive AEDs at efficacious doses provides strong support for AED treatment as mono- or polytherapy to increase seizure control and protect against SUDEP in patients with refractory epilepsy. For patients for whom seizure control is unattainable, supervision or monitoring may prevent SUDEP, though this has never been formally tested.

Forensic antiepileptic drug levels in autopsy cases of epilepsy

A 1-year retrospective coroner-based forensic examination of causes of death among persons with a history of epilepsy was conducted at the Allegheny County Coroner's Office to evaluate the phenomenon of sudden unexplained/unexpected death in epilepsy (SUDEP), a diagnosis of exclusion. All cases at the Coroner's Office from January 1, 2001 through December 31, 2001, were examined. Review of a total of 1200 autopsied deaths revealed 12 cases with a past medical history of seizure disorder on the death certificate, which listed seizure disorder as the immediate cause of death or contributory cause of the death. Of the 7 men with seizure disorders, 5 were categorized as definite SUDEP and 2 as possible SUDEP. Of the 5 women with seizure disorders, 2 were listed as definite SUDEP, 2 as possible, and 1 as non-SUDEP because the convulsive seizures developed from a grade II glial tumor. Postmortem findings were evaluated for 11 cases; 1 body was decomposed. Toxicological screens were carried out on blood, bile, urine, and eye fluid for all 12. Antiepileptic drug (AED) levels detected in postmortem toxicological analysis were examined. AED levels were determined in 7 cases. Four of 7 had subtherapeutic AED levels, 2 had therapeutic levels, and only 1 victim of SUDEP had levels above the therapeutic range. Five cases had no detectable AED levels. AED levels at autopsy were either absent or subtherapeutic in 9 of 10 SUDEP cases, findings consistent with the likelihood of poor AED compliance. Subtherapeutic levels of AEDs may be a risk factor for SUDEP that could contribute to increased interictal and/or ictal epileptiform activity with associated autonomic dysfunction leading to disturbance of heart rate, heart rhythm, and/or blood pressure.

Increased risk of sudden unexpected death in epilepsy in females using lamotrigine: a nested, case-control study

PURPOSE

To estimate the incidence of sudden unexpected death in epilepsy (SUDEP) in Rogaland County, Norway, in the period August 1 1995-July 31 2005, and to investigate whether use of lamotrigine (LTG) was associated with increased risk in female patients or other subgroups.

METHODS

SUDEP victims were identified from autopsy reports and data from the Norwegian Cause of Death Registry. In all cases where SUDEP was considered as a possible cause of death, the hospital records were also reviewed. For each deceased, at least three living patients with epilepsy were randomly selected as controls. The market share in defined daily doses was collected for each year to estimate the number of patient-years at risk on each antiepileptic drug.

KEY FINDINGS

We identified 26 cases of SUDEP: 16 definite, 3 probable, and 7 possible; 15 patients were female and 11 were male. Of these, 10 patients (38.5%) were treated with LTG: 9 of these patients were female. The incidence of SUDEP was estimated as 1.0 per 1,000 patient-years when all cases were included, and 0.7 per 1,000 patient-years for definite and probable SUDEP. Seven of 12 (58.3%) of female patients with definite and probable SUDEP and 10 of 41 (24.4%) of controls matched on age and gender were on LTG (p = 0.038). The incidence of definite and probable SUDEP in women on LTG, was estimated as 2.5 per 1,000 patient-years and 0.5 per 1,000 patient-years in female who were not taking LTG (p = 0.007).

SIGNIFICANCE

The incidence of SUDEP was significantly higher among female patients with epilepsy who were being treated with LTG than among female patients with epilepsy who were not taking LTG, and a significantly higher proportion of female SUDEP cases than controls were taking LTG. Our findings may have implications for treatment of epilepsy in female patients.

Sudden unexpected death in epilepsy: current knowledge and future directions

Although largely neglected in earlier literature, sudden unexpected death in epilepsy (SUDEP) is the most important epilepsy-related mode of death, and is the leading cause of death in people with chronic uncontrolled epilepsy. Research during the past two to three decades has shown that incidence varies substantially depending on the epilepsy population studied, ranging from 0.09 per 1000 patient-years in newly diagnosed patients to 9 per 1000 patient-years in candidates for epilepsy surgery. Risk profiles have been delineated in case-control studies. These and other studies indicate that SUDEP mainly occurs in the context of a generalised tonic-clonic seizure. However, it remains unclear why a seizure becomes fatal in a person that might have had many similar seizures in the past. Here, we review SUDEP rates, risk factors, triggers, and proposed mechanisms, and critically assess potential preventive strategies. Gaps in knowledge are discussed and ways forward are suggested.

Risk factors in sudden death in epilepsy (SUDEP): the quest for mechanisms

People with epilepsy may die suddenly and unexpectedly without a structural pathological cause. Most SUDEP cases are likely to be related to seizures. SUDEP incidence varies and is <1:1,000 person-years among prevalent cases in the community and approximately 1:250 person years in specialist centres. Case-control studies identified certain risk factors, some potentially amenable to manipulation, including uncontrolled convulsive seizures and factors relating to treatment and supervision. Both respiratory and cardiac mechanisms are important. The apparent protective effect of lay supervision supports an important role for respiratory factors, in part amenable to intervention by simple measures. Whereas malignant tachyarrhythmias are rare during seizures, sinus bradycardia/arrest, although infrequent, is well documented. Both types of arrhythmias can have a genetic basis. This article reviews SUDEP and explores the potential of coexisting liability to cardiac arrhythmias as a contributory factor, while acknowledging that at present, bridging evidence between cardiac inherited gene determinants and SUDEP is lacking.

Lamotrigine in idiopathic epilepsy - increased risk of cardiac death?

OBJECTIVES

Lamotrigine (LTG) has recently been shown to inhibit the cardiac rapid delayed rectifier potassium ion current (Ikr). Ikr-blocking drugs may increase the risk of cardiac arrhythmia and sudden unexpected death. With this background, it may be of importance that in our outpatient clinic between August 1, 1995 and August 1, 2005 we registered four consecutive cases of sudden unexpected death in epilepsy (SUDEP) in non-hospitalized patients that were all being treated with LTG in monotherapy. Here we describe and discuss these cases, the relevant literature, and the reasons to question whether these events were as a result of coincidence alone.

METHODS

All the cases were collected consecutively at the outpatient clinic, Department of Neurology, Stavanger University Hospital, Norway. Clinical and pathological data were obtained and the relevant literature reviewed.

RESULTS

All were females with idiopathic epilepsy.

CONCLUSIONS

A systematic study is needed to reveal whether LTG may increase the risk of SUDEP in certain groups of patients.

Variability of antiepileptic medication taking behaviour in sudden unexplained death in epilepsy: hair analysis at autopsy

BACKGROUND

Variable compliance with antiepileptic drugs (AEDs) is a potentially preventable cause of sudden unexplained death in epilepsy (SUDEP). Hair AED concentrations provide a retrospective insight into AED intake variability.

METHODS

We compared hair AED concentration variability in patients with SUDEP (n = 16), non-SUDEP epilepsy related deaths (n = 9), epilepsy outpatients (n = 31), and epilepsy inpatients (n = 38). AED concentrations were measured in 1 cm hair segments using high performance liquid chromatography. Individual patient hair AED concentration profiles were corrected for "washout" using linear regression analysis. The coefficient of variation (CV) of the corrected mean hair AED concentration provided an index of variability of an individual's AED taking behaviour. Hair sample numbers varied between subjects, and so weighted regression estimates of the CV were derived for each group.

RESULTS

The CV regression estimates for each group were: SUDEP 20.5% (standard error 1.9), non-SUDEP 15.0% (3.9), outpatients 9.6% (1.4), and inpatients 6.2% (2.7). The SUDEP group therefore showed greater hair AED concentration variability than either the outpatient or the inpatient groups (p<0.0001).

CONCLUSION

Observed variability of hair AED concentrations, reflecting variable AED ingestion over time, is greater in patients dying from SUDEP than in either epilepsy outpatients or inpatients. SUDEP, at least in a proportion of cases, appears preventable.

Sudden Unexpected Death in Epilepsy: A Review of Incidence and Risk Factors

Sudden unexpected death in epilepsy (SUDEP) is the most important direct epilepsy-related cause of death. However, SUDEP is rare in patients with new onset epilepsy and in patients in remission. Incidence is about 0.35 cases/1,000 person-years in population-based incidence cohort of epilepsy. Incidence is considerably higher in patients with chronic epilepsy, 1-2/1,000 person-years, and highest with severe, refractory seizures, 3-9/1,000. The highest rates occur from 20 to 40 years. Most SUDEP appears seizure-related. When witnessed, the fatal event generally occurred in association with generalized tonic-clonic seizure. Two recent case-control studies suggest that seizure frequency is the strongest risk factor for SUDEP: relative risk = 23 (95% CI = 3.2-170) for persons with > or =1 seizure during the year of observation versus seizure-free patients. Onset of epilepsy at an early age and long duration of the disorder are other risk factors. Although SUDEP has not been associated with the use of any particular antiepileptic drugs (AEDs), some case-control studies have pointed to an association between SUDEP and polytherapy with AEDs and frequent dose changes independent of seizure frequency. Although recent epidemiological studies have been helpful in identifying patients at risk for SUDEP, providing clues to mechanisms behind SUDEP, no single risk factor is common to all SUDEP, suggesting multiple mechanisms or trigger factors. Seizure control seems of paramount importance to prevent SUDEP. Further large-scale case-control studies are needed to assess the role of AEDs in order to form a basis for treatment strategies aiming at seizure control and prevention of SUDEP.

Do antiepileptic drugs play a role in sudden unexpected death in epilepsy?

Sudden unexpected death in epilepsy (SUDEP) accounts for approximately 2% of deaths in population-based cohorts of epilepsy, and up to 25% of deaths in cohorts of more severe epilepsy. When it occurs, SUDEP usually follows a generalised tonic-clonic seizure. Unresponsiveness, apnoea, and cardiac arrest occur in SUDEP, rather than the typical gradual recovery. The great majority of tonic-clonic seizures occur without difficulty and how the rare seizure associated with SUDEP differs from others is unknown.Three mechanisms have been proposed for SUDEP: cardiac arrhythmia, neurogenic pulmonary oedema, and postictal suppression of brainstem respiratory centres leading to central apnoea. Recent studies have found that the incidence of SUDEP increases with the severity of epilepsy in the population studied. The duration of epilepsy, number of tonic-clonic seizures, mental retardation, and simultaneous treatment with more than two antiepileptic drugs are independent risk factors for SUDEP. Some studies have reported that carbamazepine use, carbamazepine toxicity, and frequent, rapid changes in carbamazepine levels, may be associated with SUDEP. Other evidence indicates that carbamazepine could potentially increase the risk for SUDEP by causing arrhythmia or by altering cardiac autonomic function. However, this evidence is tenuous and most studies have not found an association between the use of carbamazepine or any other individual antiepileptic drug and SUDEP. There is little information regarding antiepileptic drugs other than phenytoin and carbamazepine. The incidence of SUDEP with gabapentin, tiagabine, and lamotrigine clinical development programmes is in the range found in other populations with refractory epilepsy. This suggests that these individual antiepileptic drugs are no more likely to cause SUDEP than antiepileptic drugs in general. Best current evidence indicates that the risk of SUDEP can be decreased by aggressive treatment of tonic-clonic seizures with as few antiepileptic drugs as necessary to achieve complete control. At present there is no strong reason to avoid any particular antiepileptic drug. Further studies are needed to elucidate the potential role of individual antiepileptic drugs in SUDEP and establish clinical relevance, if any. These studies may be challenging to conduct and interpret because SUDEP is relatively uncommon and large numbers will be necessary to narrow confidence intervals to determine the clinical relevance. Also adjustments will be needed to account for the potent risks associated with other independent factors.

Mortality in epilepsy in the west of Ireland: a 10-year review

BACKGROUND

Sudden and unexpected death is not an uncommon event in otherwise healthy epileptics.

AIMS

To study the autopsied cases of sudden death in known epileptic patients in the West of Ireland.

METHODS

A retrospective study was carried out which involved the review of 3,103 autopsy reports over a 10-year period in Galway University Hospital.

RESULTS

Twenty-two cases were classified as sudden, unexpected death in epilepsy (SUDEP). Forty-five per cent had been found dead in bed. The mean age was 38 years and 68% were males. Of 16 cases with data about antiepileptic drug (AED) levels, 68% had absent or low levels at postmortem. Eighty-eight per cent of the cases had a past history of a generalised seizure. Pulmonary oedema was present in 86% of cases at postmortem.

CONCLUSIONS

Compliance with treatment and frequent nightly observations to those at high risk of sudden death may help to minimise its incidence. The patients and their families should be aware of this potential outcome.

Mortality in pediatric epilepsy

Mortality in pediatric epilepsy is the subject of this review. Epilepsy in both adults and children increases the risk of premature death. Conditions that are comorbid with epilepsy may carry an increased mortality risk. Patients with neurologic compromise may be at risk for aspiration and critical respiratory disease. Epilepsy per se enhances the risks of accidents, particularly drowning. Epilepsy may result in unwitnessed or, less frequently, witnessed sudden death. Witnessed sudden death frequently involves an observed seizure. Cardiac and respiratory mechanisms for epileptic sudden death have been proposed. Reducing the number of seizures should reduce the risk for sudden death. Awareness of the increased risk for premature death associated with epilepsy may enhance patients' and parents' cooperation with therapy.

Antiepileptic drug therapy and its management in sudden unexpected death in epilepsy: a case-control study

PURPOSE

Because frequent seizures constitute a major risk factor for sudden unexpected death in epilepsy (SUDEP), the treatment with antiepileptic drugs (AEDs) may play a role for the occurrence of SUDEP. We used data from routine therapeutic drug monitoring (TDM) to study the association between various aspects of AED treatment and the risk of SUDEP.

METHODS

A nested case-control study was based on a cohort consisting of 6,880 patients registered in the Stockholm County In Ward Care Register with a diagnosis of epilepsy. Fifty-seven SUDEP cases, and 171 controls, living epilepsy patients, were selected from the cohort. Clinical data including data on TDM were collected through medical record review.

RESULTS

The relative risk (RR) of SUDEP was 3.7 (95% CI, 1.0-13.1) for outpatients who had no TDM compared with those who had one to three TDMs during the 2 years of observation. RR was 9.5 (1.4-66.0) if carbamazepine (CBZ) plasma levels at the last TDM were above and not within the common target range (20-40 microM). High CBZ levels were associated with a higher risk in patients receiving polytherapy and in those with frequent dose changes. Although the subgroup of patients with high CBZ levels was small (six cases of 33 with CBZ therapy), and the result should be interpreted with caution, no similar associations were demonstrated for phenytoin plasma levels and risk of SUDEP. No association was found between SUDEP risk and within-patient variation in AED levels over time.

CONCLUSIONS

Polytherapy, frequent dose changes, and high CBZ levels as identified risk factors for SUDEP all point to the risks associated with an unstable severe epilepsy. It is unclear whether high CBZ levels per se represent a risk factor or just reflect other unidentified aspects of a severe epilepsy. Our results, however, prompt further detailed analyses of the possible role of AEDs in SUDEP in larger cohorts and suggest that reasonable monitoring of the drug therapy may be useful to reduce risks.

Sudden unexpected death in epilepsy (SUDEP): risk factors and case control studies

Sudden unexpected death is an important category of mortality in the population with epilepsy. Possible risk factors have been identified from an epidemiological study of this phenomenon, but the exact mechanisms remain unclear. Some of these factors include: male sex; age 20-40 years; generalized seizures; poor seizure control; poor compliance with medication. Case-control studies now being undertaken are the next step in the elucidation of these factors. The results of one study to date reinforce the view that, in the majority of cases, sudden unexpected death in epilepsy (SUDEP) is a seizure-related event. This suggests that improvement in seizure control and the avoidance of polytherapy may be important in risk reduction. An ongoing exploratory case-control study in the UK has identified 154 cases of SUDEP, each of which will have four controls, matched for age and geographical location, in order to examine the influence of various parameters on the risk of sudden death.

Sudden unexpected deaths in epileptics--a literature review

In summary, SUDEP accounts for death in approximately 8% of the young epileptic population. It is commoner in young male epileptics with a long history of generalised seizures, who have a history of head trauma and alcohol excess, and who are taking more than one antiepileptic drug. Most deaths are unwitnessed and occur at home, usually in bed and presumably overnight. Subtherapeutic AED levels do not necessarily imply non compliance, and may simply reflect drug degradation in the plasma after death. Many victims have pulmonary oedema on postmortem examination, and some show ischaemic damage of the heart despite normal coronary arteries. This possibly arises as a result of repeated episodes of vasoconstriction from seizure related catecholamine bursts. Animal studies have demonstrated the occurrence of central apnoea and also support the theory of acute fatal cardiac failure. Possible association with the daily level of geomagnetic activity is reported. The precise reason for a particular seizure being fatal in an otherwise healthy individual is as yet undetermined.

Sudden unexpected death in epilepsy (SUDEP): a clinical perspective and a search for risk factors

OBJECTIVES

To examine the risk factors and their relative importance and possible role in sudden unexpected death in epilepsy (SUDEP).

METHODS

The study was conducted as a retrospective analysis of deaths in an outpatient population of a tertiary referral centre, based on clinical and pathological data.

RESULTS

Of a total of 140 deaths, 61 (44%) had not been to postmortem and were excluded, 37 (26%) had a verified cause of death and formed the non-SUDEP group, and 42 (30%) were classified as SUDEP. In the SUDEP group there was pulmonary oedema in 62%, signs of preceding seizures in 67%, no visible seizures in three of six observed deaths. A high seizure frequency prevailed in SUDEP as well as non-SUDEP. Sixty per cent of deaths were sleep related. Various other circumstances were temporally associated with death. The prone position at death was seen in 71% of the SUDEP patients; possible interpretations are discussed. Supposedly subtherapeutic serum concentrations of one or more antiepileptic drugs were found in 57% of those with reported serum concentrations. Alcohol was not a factor in the material, whereas hyponatraemia was seen in two cases.

CONCLUSIONS

Most cases of SUDEP are preceded by seizures; their presence, frequency, type, aetiology, tractability, and the use of antiepileptic drugs are factors in the demise. No common risk factor, present in all cases of SUDEP, could be found, suggesting the probability of multiple mechanisms behind SUDEP.

Comparison between premortem and postmortem serum concentrations of phenobarbital, phenytoin, carbamazepine and its 10,11-epoxide metabolite in institutionalized patients with epilepsy

The last premortem serum concentrations of phenobarbital (PB), phenytoin (PHT), carbamazepine (CBZ) and its CBZ-10,11-epoxide metabolite (CE) were compared with the corresponding postmortem serum concentrations in 16 adult patients of an epilepsy centre. Based on complete postmortem examinations, 12 individuals showed a known cause of death (KCD) and four patients succumbed from sudden unexplained death (SUD). The last premortem and the postmortem serum levels of PB (r = 0.991), PHT (r = 0.986), CBZ (r = 0.985) and CE (r = 0.936) were highly correlated. However, the regression analysis indicated that, except for CE, the premortem concentrations were significantly higher than the postmortem concentrations, i.e. 65% for PB, 34% for PHT, and 16% for CBZ. Varying time lapses (4-62 h) between death and serum sampling during autopsy did not significantly influence the ratio of premortem to postmortem serum levels for PB, PHT, CBZ, and CE (p > 0.1). Furthermore we found no significant differences between the premortem and the postmortem serum concentration ratios CE/CBZ. Considering the above variables, the data of SUD and KCD patients were comparable. Postmortem decrease in anticonvulsant serum concentrations, especially for PB and PHT, should be considered in order to avoid misinterpretation in respect to so-called 'subtherapeutic' serum levels and noncompliance in context with SUD or fatal intoxication.