Understanding EEG indications and reports: a survey of NCHDs.

Since the discovery of EEG almost 150 years ago, it remains a valuable tool in the work-up of suspected epilepsy. However, EEG is not without its limitations and an understanding of the indications and how to interpret the findings are essential to avoid over-reliance on an investigation which can lead to misdiagnosis if inappropriately used. We conducted a survey of NCHDs to assess their level of understanding for EEG. Overall 45% (54/119) do not have a clear understanding of the indications for EEG associated with transient loss of consciousness, 5% (6/119) failed to correctly interpret a report and 6% (7/119) are unclear as to when an EEG should be ordered.

Mortality due to SUDEP and status epilepticus.

Mortality in patients with epilepsy (PWE) is increased compared to the general population. For this reason the National Programme of Epilepsy Care, which was established under the Health Service Executive's National Director for Clinical Strategy and Programmes, identified a reduction in mortality from epilepsy as a key quality metric to monitor the success of the programme. The increased mortality is greatest in the first years after diagnosis where it is predominantly related to the underlying cause but there remains a persistent elevation in mortality rates especially amongst those with longstanding epilepsy. This group of patients is more likely to die from epilepsy, predominantly sudden unexpected death in epilepsy (SUDEP) or status epilepticus (SE). This paper identifies a number of studies on mortality in epilepsy from SE and SUDEP and uses this data to generate an estimate for annual mortality from SUDEP and SE in Ireland. These estimates indicate that mortality in patients with epilepsy due to SUDEP and SE account for between 48 and 162 deaths per year in Ireland and sources of mortality information currently available possibly underestimate the numbers involved especially if deaths due to non-convulsive status are included.

A case of Lambert-Eaton myasthenic syndrome with possible myasthenia gravis.

Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of neuromuscular transmission (NMJ) that shares many clinical features with myasthenia gravis (MG). We report a 73 year-old lady who presented 10 years previously with stiffness of both calves, dry mouth, fatigue, proximal weakness and areflexia in lower limbs. Neurophysiological studies were consistent with LEMS. Her work up for an underlying neoplasm was negative. She recently developed unilateral ptosis and diplopia which dramatically improved with pyridostigmine suggesting concomitant MG.

Intravascular large B-cell lymphoma presenting clinically as rapidly progressive dementia.

BACKGROUND: In patients presenting with rapidly progressive dementia, prion disease may enter the differential diagnosis. The commonest malignancies masquerading as prion disease are primary CNS lymphoma and intravascular large B-cell lymphoma, both rare and difficult to diagnose without brain biopsy. CASE PRESENTATION: This 82-year-old lady with a past history of hypertension, presented with rapidly progressive cognitive impairment and ataxia. The possibility of sCJD was raised. Brain biopsy was carried out. Western blot for prion protein was negative. Brain biopsy showed intravascular large B-cell lymphoma. She died shortly afterwards. CONCLUSION: The clinical presentation of intravascular large B-cell lymphoma is diverse. Patients may present as in this case with dementia, seizures, and myoclonus leading to a clinical diagnosis of sCJD. The diagnosis here was made at biopsy but is made at autopsy in over 50% of cases.

A study of mortality after temporal lobe epilepsy surgery.

OBJECTIVE: To determine early and late mortality in a cohort of 305 consecutive patients who had temporal lobe epilepsy (TLE) surgery over a 20-year period. METHODS: Survival status, cause of death, and postoperative clinical details of those who died were ascertained in a cohort of 305 patients who had TLE surgery. Mortality was related to postoperative seizure status, operative pathology, and side of resection. RESULTS: The survival status of 299 patients was established. Twenty deaths occurred. Mortality was 1 per 136 person-years, with a standardized mortality ratio (SMR) of 4.5 (95% confidence interval [CI], 3.2 to 6.6). Six deaths were sudden and unexpected (SUDEP). The SUDEP rate was 1 per 455 person-years. The overall death and SUDEP rates were lower than those reported for similar patient populations with chronic epilepsy. Mortality in patients who had right-sided resections for mesial temporal sclerosis (MTS) remained considerably elevated with a mortality rate of 1 per 54 person-years, an SMR of 32.0 (95% CI, 24.7 to 40.5), and a SUDEP rate of 1 per 134 person-years. These patients had significantly lower seizure remission rates than left-sided patients, but the excess mortality was not simply explained by those patients whose partial seizures were uninfluenced by surgery. Patients who died had more severe or convulsive seizures despite an overall reduction in seizure frequency. CONCLUSIONS: The present findings confirm previous reports that TLE surgery lowers but does not normalize the overall mortality associated with chronic epilepsy. In patients with right-sided MTS, however, the postoperative mortality has remained similar to other groups with medically intractable seizures.

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.

The incidence of sudden unexpected death in epilepsy (SUDEP) in South Dublin and Wicklow.

Patients with epilepsy have a mortality rate higher than that of the general population. Some of this excess mortality is attributable to sudden unexpected death (SUDEP). We examined the incidence of this phenomenon both retrospectively and prospectively in the population of South Dublin and Wicklow over the period May 1992-1995. Cases were ascertained by examination of post-mortem registers of hospitals serving the area studied. Information on cases was sought from hospital records, general practitioners and families. Fifteen cases (10 male, five female) were identified resulting in an overall incidence rate of SUDEP of 1:680/year for the 3 years of the study. This is the only study of incidence of SUDEP conducted in Ireland and our results are in keeping with incidence rates elsewhere in Europe and the USA.

Case-control study of SUDEP.

OBJECTIVE: To examine the influence of various factors on the risk of sudden unexpected death in epilepsy (SUDEP). METHODS: The authors investigated 154 cases in which a postmortem examination was performed. Each case had four controls with epilepsy from the community, matched for age and geographic location. Backward stepwise conditional logistic regression analysis was performed and odds ratios for risk and protection were determined. RESULTS: The risk of SUDEP was increased with a history of generalized tonic-clonic seizures in the previous 3 months (odds ratio [OR]: 13.8, 95% CI: 6.6 to 29.1). The presence of supervision at night was found to be protective (OR: 0.4, 95% CI: 0.2 to 0.8) when a supervising individual shared the same bedroom or when special precautions such as a listening device were employed (OR: 0.1, 95% CI: 0.0 to 0.3). CONCLUSION: This work lends support to the view that SUDEP is a seizure-related phenomenon and that control of tonic-clonic seizures is important in its prevention. Nocturnal supervision seems to protect against SUDEP.

Cranial and peripheral neuropathy due to Epstein-Barr virus infection.

A case of Epstein-Barr virus infection with neurological complications is described. An 18-year-old man developed cranial neuropathy and peripheral sensorimotor polyneuropathy three weeks after a sore throat. Though severely affected initially, he made a good recovery and no specific therapeutic intervention appears to have influenced his clinical course.

Sudden unexpected death in epilepsy: a series of witnessed deaths.

OBJECTIVES: Sudden unexpected death in epilepsy (SUDEP) represents a significant category of mortality in the population with chronic epilepsy. A consistent feature is that most of these deaths are unwitnessed. The aim was to identify witnessed deaths, examine the circumstances, and relate these findings to the proposed mechanisms for SUDEP. METHODS: During the course of case ascertainment for a control study on SUDEP, witnessed deaths were identified and the circumstances examined in detail. Cases were notified by coroners, neurologists, and bereaved families. The findings were related to the proposed mechanisms for SUDEP which include central and obstructive apnoea and cardiac arrhythmia. RESULTS: One hundred and thirty five SUDEP cases have been identified to date, of which 15 were witnessed deaths. Twelve deaths were associated with convulsive seizures, one collapse occurred 5 minutes after a generalised seizure, another collapse occurred after an aura and one patient died while in a probable post ictal state. Witnesses reported that 12 of the 15 cases experienced respiratory difficulty. CONCLUSIONS: Most sudden epilepsy deaths are unwitnessed. Where witnessed most occur in association with a seizure and respiratory compromise is a prominent feature. Positioning or stimulation of respiration may be important in the prevention of these deaths.

An audit of the perceived efficacy and tolerability of gabapentin therapy in an out-patient cohort with chronic epilepsy.

A retrospective audit of the perceived efficacy and tolerability of adjunctive gabapentin (GBT) therapy in patients with intractable epilepsy was carried out. The case-notes of 263 consecutive patients attending a tertiary referral centre in whom GBT had been added to concomitant anti-epileptic drugs were reviewed. There were 119 males (45%); the median age was 35 years (range 15-81 years) and the median duration of epilepsy was 20 years. The median dose of GBT administered was 1,600 mg (range 300-4,800 mg). Twenty-nine patients (11%) had a reduction in seizure frequency of greater than 50% and 7 (3%) achieved seizure freedom of 6 months' duration at least while taking GBT. Side-effects were reported by 169 patients (61%) and in 40 (15%) an increase in seizure frequency of 50% occurred, this being the commonest reason for GBT withdrawal. The median duration of treatment was 4 months (range 0.03-47 months). Ten patients, in whom GBT therapy had proven ineffective in doses of 900-1,800 mg, were rechallenged with doses of 300-4,800 mg. One individual experienced a 50% reduction in seizure frequency and 1 an increase in seizures of at least 50%. GBT was generally well tolerated at high doses and rechallenge of a small number with GBT in doses up to 4,800 mg did not result in further improvement in seizure frequency in the majority.

Sudden unexpected death in epilepsy.

The majority of persons with epilepsy develop lasting remission from seizures, although mortality is significantly greater than that of the age-matched general population. Of the deaths that are thought to be directly related to seizures, sudden unexpected death in epilepsy is probably the commonest category; more so than status epilepticus or seizure-related accidents. Annual incidence rates vary from 1 in 200 patients with chronic epilepsy to about 1 in 1000 in more population-based studies. Young adults with severe, intractable epilepsy appear to be the most frequently affected group and may have even higher incidence rates. Other risk factors may also be important. An area of great research interest, several pathogenetic mechanisms have been postulated, centering mainly around cardiac rhythm and central hypoventilation. Given the frequent devastation caused by sudden unexpected death in epilepsy, the importance of seizure control is emphasised.

Certification of deaths attributable to epilepsy.

OBJECTIVE: To estimate the number of sudden unexpected epilepsy deaths occurring annually in England and Wales in those 16-50 years of age. METHODS: All 1997 death entries mentioning epilepsy as a cause of death in those 16-50 years were examined and classified as sudden unexpected death in epilepsy (SUDEP), other epilepsy related deaths, or non-epilepsy deaths. RESULTS: 612 death entries were obtained with postmortem examination having been performed in 498 cases. Forty four deaths were certified as being attributable to SUDEP and a further 292 deaths were considered to be probable SUDEP cases. CONCLUSION: It is estimated that between 350 and 400 cases of SUDEP occurred in England and Wales in 1997 in those 16-50 years. SUDEP is the commonest category of epilepsy related death and accurate certification of such deaths is vital for the monitoring of trends in mortality.