Poststroke epilepsy in the Copenhagen stroke study: incidence and predictors

Poststroke epilepsy: occurrence, predictors and treatment

Although a well-known clinical phenomenon, there still remain some questions regarding the definitions, pathophysiology and epidemiology of early and late poststroke seizures and of poststroke epilepsy. Poststroke seizures and epilepsy constitute important complications in patients surviving a stroke. Several studies of the prevalence and possible predictors of poststroke seizures and epilepsy have been undertaken during the past few decades. Unfortunately, these studies have not consistently used the established definitions. There are only few studies concerning treatment of poststroke epilepsy in the elderly, especially regarding the effect of the newer antiepileptic drugs. The aim of this article is to give an overview of the latest studies of poststroke seizures, with special emphasis on poststroke epilepsy, by presenting data on occurrence, predictors and treatment. The results from the recent studies on both poststroke seizures (early and late) and poststroke epilepsy are quite consistent. Poststroke epilepsy appears to occur in 2-4% of patients. The most convincing predictors of late poststroke seizures and epilepsy and treatment options are discussed in this review.

Acute seizures predict epilepsy after childhood stroke

OBJECTIVE

To determine incidence rates and predictors of epilepsy after childhood stroke and compare these to published estimates of 3 to 5% cumulative epilepsy incidence by 5 years poststroke in adults.

METHODS

In a retrospective population-based study of children with stroke (29 days-19 years) in an integrated health care system (1993-2007), poststroke seizures were identified through electronic searches and confirmed by chart review. Stroke and seizure characteristics were abstracted from medical records. Survival analysis was used to determine rates and predictors of remote seizures and active epilepsy (anticonvulsant treatment for remote seizure within prior 6 months) at last follow-up.

RESULTS

From a population of 2.5 million children, we identified 305 stroke cases. Over a median follow-up of 4.1 years (interquartile range = 1.8-6.8), 49 children had a first unprovoked remote seizure. The average annual incidence rate of first remote seizure was 4.4% (95% confidence interval [CI] = 3.3-5.8) with a cumulative risk of 16% (95% CI = 12-21) at 5 years and 33% (95% CI = 23-46) at 10 years poststroke. The cumulative risk of active epilepsy was 13% (95% CI = 9-18) at 5 years and 30% (95% CI = 20-44) at 10 years. Acute seizures at the time of stroke predicted development of active epilepsy (hazard ratio = 4.2, 95% CI = 2.2-8.1). At last follow-up, ⅓ of the children with active epilepsy had a recent breakthrough seizure despite anticonvulsant usage.

INTERPRETATION

Unlike adults, children are uniquely vulnerable to epilepsy after stroke. Children with acute seizures at the time of stroke are at particularly high risk.

Incidence and predictors of post-stroke epilepsy

BACKGROUND AND AIMS

Stroke is the leading cause of seizures and epilepsy in the elderly. The aim of this study was to assess the incidence of post-stroke epilepsy (PSE) based on the revised epilepsy definition of the International League Against Epilepsy (ILAE) in a population-based study and to describe possible predictors.

METHODS

Data from the prospective population-based Erlangen Stroke Project (ESPro) were collected to describe the frequency of PSE. Patients were followed up 3, 12, and 24 months after stroke. Stroke was diagnosed according to the WHO and PSE according to the new ILAE criteria. Multivariable analysis was performed to identify predictors of PSE including age, sex, stroke type, stroke severity, and comorbidities.

RESULTS

From 1998 to 2006, 1815 patients with first-ever stroke were included (55.7% women; mean age 72.7 years, SD 13). Patients with known (n = 52) or unknown (n = 331) prior-to-stroke epilepsy or no available information on post-stroke seizures (n = 412) were excluded. From the remaining 1020 patients, 84 (8.2%) developed PSE within 2 years after stroke. Univariate analysis demonstrated stroke severity (P < 0.001) and hypertension (P < 0.05) as predictors for PSE. In multivariable analysis, stroke severity remained the only independent predictor (P = 0.002).

CONCLUSIONS

Based on the revised ILAE definition of epilepsy, the incidence of PSE was high in the ESPro. The only independent predictor for PSE was stroke severity.

[Epilepsy in the elderly]

BACKGROUND

Diagnostic work-up and treatment of patients who have developed epilepsy after the age of 65 can both be difficult. Epilepsy is one of the most common neurological conditions in the elderly, and the incidence of de novo geriatric epilepsy is rising. The aim of this review is to provide guidance on the management of epilepsy in this patient group.

METHOD

The review is based on a discretionary selection of original articles and reviews found in PubMed using the search term combination 'epilepsy' and 'elderly', and the authors' personal experience.

RESULTS

The seizures, which are most commonly of the focal type, are not infrequently overlooked or misdiagnosed. Cerebrovascular disease is the underlying cause of about half of the cases. When selecting an anticonvulsant, it is important to take age-related physiological changes and comorbidities into consideration. Because elderly patients have a narrower therapeutic window than younger persons and greater susceptibility to cognitive and other side effects, a low starting dose and slower dose titration are particularly important.

INTERPRETATION

The results of studies of young epilepsy patients cannot be extrapolated to apply to elderly patients. More studies directly targeting this patient population are therefore needed. As a general rule, we do not recommend starting on enzyme-inducing drugs such as phenytoin, phenobarbital and carbamazepine, partly because of their high interaction potential.

Post-stroke epilepsy in young adults: a long-term follow-up study

BACKGROUND

Little is known about the incidence and risk of seizures after stroke in young adults. Especially in the young seizures might dramatically influence prognosis and quality of life. We therefore investigated the long-term incidence and risk of post-stroke epilepsy in young adults with a transient ischemic attack (TIA), ischemic stroke (IS) or intracerebral hemorrhage (ICH).

METHODS AND FINDINGS

We performed a prospective cohort study among 697 consecutive patients with a first-ever TIA, IS or ICH, aged 18-50 years, admitted to our hospital between 1-1-1980 till 1-11-2010. The occurrence of epilepsy was assessed by standardized questionnaires and verified by a neurologist. Cumulative risks were estimated with Kaplan-Meier analysis. Cox proportional hazard models were used to calculate relative risks. After mean follow-up of 9.1 years (SD 8.2), 79 (11.3%) patients developed post-stroke epilepsy and 39 patients (5.6%) developed epilepsy with recurrent seizures. Patients with an initial late seizure more often developed recurrent seizures than patients with an initial early seizure. Cumulative risk of epilepsy was 31%, 16% and 5% for patients with an ICH, IS and TIA respectively (Logrank test ICH and IS versus TIA p<0.001). Cumulative risk of epilepsy with recurrent seizures was 23%, 8% and 4% respectively (Logrank ICH versus IS p = 0.05, ICH versus TIA p<0.001, IS versus TIA p = 0.01). In addition a high NIHSS was a significant predictor of both epilepsy and epilepsy with recurrent seizures (HR 1.07, 95% CI 1.03-1.11 and 1.08, 95% CI 1.02-1.14).

CONCLUSIONS

Post-stroke epilepsy is much more common than previously thought. Especially patients with an ICH and a high NIHSS are at high risk. This calls upon the question whether a subgroup could be identified which benefits from the use of prophylactic antiepileptic medication. Future studies should be executed to investigate risk factors and the effect of post-stroke epilepsy on quality of life.

Subacute seizure incidence in thrombolysis-treated ischemic stroke patients

BACKGROUND

To assess the incidence of seizures in acute ischemic stroke patients treated with chemical (tPA) thrombolysis.

METHODS

Retrospective study including all thrombolysis patients treated in Calgary between January 1, 2001, and October 31, 2006. Descriptive statistics and age/sex-adjusted P values were calculated.

RESULTS

Of 400 eligible patients (median age 74.0 years, range: 24-77), 16 (4%) developed post-stroke seizures: 10 (62.5%) within one week (early) and 6 (37.5%) after 1 week but within the hospital stay (late). Single-vessel anterior circulation involvement (93.8% vs. 87%, P = 0.34) and hemorrhage (37.5% vs. 20%, P = 0.15) were more common in those with compared to without seizures but did not reach statistical significance. Atrial fibrillation was more common in those with (56.3%) than without (36.1%) seizures (P = 0.04). Death during admission was more likely (P = 0.03) in those who sustained seizures (37.5%) compared to those without seizures (17.6%).

CONCLUSIONS

In this cohort of tPA-treated patients, post-stroke seizures were associated with atrial fibrillation and early mortality.

Acute seizures in acute ischemic stroke: does thrombolysis have a role to play?

Seizures appear at stroke presentation, during the acute phase or as a late complication of stroke. Thrombolysis has not been investigated as a risk factor despite its potential neurotoxic effect. We try to identify risk factors for seizures during the acute phase of ischemic stroke in a cohort including thrombolysed patients. We undertook a case-control study at a single stroke center using data from Acute Stroke Registry and Analyse of Lausanne (ASTRAL). Patients with seizure occurring during the first 7 days following stroke were retrospectively identified. Bi-variable and multivariable statistical analyses were applied to compare cases and randomly selected controls. We identified 28 patients experiencing from seizures in 2,327 acute ischemic strokes (1.2 %). All seizures occurred during the first 72 h. Cortical involvement, thrombolysis with rt-PA, arterial recanalization, and higher initial NIHSS were statistically associated with seizures in univariated analysis. Backward linear regression identified cortical involvement (OR 7.53, 95 % CI 1.6-35.2, p < 0.01) and thrombolysis (OR 4.6, 95 % CI 1.6-13.4, p = 0.01) as being independently associated with seizure occurrence. Overall, 3-month outcome measured by the modified Rankin scale (mRS) was comparable in both groups. In the subgroup of thrombolysed patients, outcome was significantly worse at 3 months in the seizure group with 9/12 (75 %) patients with mRS ≥ 3, compared to 6/18 (33.3 %) in the seizure-free group (p = 0.03). Acute seizures in acute ischemic stroke were relatively infrequent. Cortical involvement and thrombolysis with rt-PA are the principal risk factors. Seizures have a potential negative influence on clinical outcome in thrombolysed patients.

Adverse effect of early epileptic seizures in patients receiving endovascular therapy for acute stroke

BACKGROUND AND PURPOSE

The aim of this study was to analyze epileptic seizures and their impact on outcome in patients with stroke treated with endovascular therapy.

METHODS

From December 1992 to December 2010 we managed 805 patients with stroke with endovascular therapy. Epileptic seizures, bleeding complications, and 3-month outcomes were recorded prospectively. Outcomes of patients with early seizures (within 24 hours of stroke onset) and patients with late seizures (>24 hours after stroke) were compared with outcomes of seizure-free patients using uni- and multivariable statistics.

RESULTS

Forty-four of 805 patients (5.5%) had seizures between stroke onset and 3-month follow-up, 26 patients early and 18 late. Outcome of patients with late seizures and seizure-free patients was similar (P=0.144 and 0.807). Patients with early seizures had higher baseline National Institutes of Health Stroke Scale (P=0.023) and were younger (P=0.021) than seizure-free patients. Their mortality rate was 50% compared with 22.3% of the seizure free-patients (P=0.003), and less patients reached a favorable outcome (modified Rankin Scale 0-2): 15.4% and 46.8%, respectively (P=0.001). Early seizures independently predicted an unfavorable outcome (P=0.014; OR, 4.749; 95% CI, 0.376-3.914) and increased mortality (P=0.001; OR, 5.861; 95% CI, 0.770-2.947) in multiregression analysis. Patients with early seizures had a 1.6-fold higher risk for unfavorable outcome and a 2.2-fold higher risk for death compared with seizure-free patients.

CONCLUSIONS

Seizures within 24 hours of stroke onset were associated with worse outcome in patients with stroke undergoing endovascular therapy. Our findings confirm a need for trials for prophylactic anticonvulsive treatment in patients receiving endovascular therapy for acute stroke.

Prior hospitalization for stroke, diabetes, myocardial infarction, and subsequent risk of unprovoked seizures

PURPOSE

To study diabetes, acute myocardial infarction, and stroke as risk factors for unprovoked seizures in a population-based cohort with incident cases of epilepsy.

METHODS

In this nested case-control study, the cases were 933 patients with newly diagnosed unprovoked seizures from the Stockholm Incidence Registry of Epilepsy. Controls, in total 6,039--matched for gender, year of diagnosis, and catchment area--were randomly selected from the register of the Stockholm County population. A history of diabetes, myocardial infarction, and stroke preceding the date of onset of seizure was determined by search of the Swedish Hospital Discharge Registry. Odds ratios (ORs) were calculated to assess the risk of developing unprovoked seizures after hospital admission for any of these diagnoses.

RESULTS

The age-adjusted OR (95% confidence interval, 95% CI) for unprovoked seizures after a discharge diagnosis of diabetes was 1.9 (95% CI 1.4-2.8) and after acute myocardial infarction 1.7 (95% CI 1.0-2.9). The OR was 9.4 (95% CI 6.7-13.1) after cerebral infarction, 7.2 (95% CI 3.9-13.6) after intracerebral hemorrhage, 7.2 (95% CI 2.9-18.1) after subarachnoid hemorrhage, and 3.2 (95% CI 1.9-5.5) after transient ischemic attack. The population attributable risk percent (PAR%) was <2% for each of the diagnoses except for cerebral infarction, for which the PAR% was 9%. Taken together the studied diagnoses accounted for 15% of the incident cases of unprovoked seizures.

DISCUSSION

As previously known, the risk for unprovoked seizures and epilepsy after a cerebral infarction was highest the first year after the infarction. This risk remained substantial >7 years after a diagnosis of cerebral infarction.

Stroke rehabilitation: strategies to enhance motor recovery

Recent evidence indicates that the brain can remodel after stroke, primarily through synaptogenesis. Task-specific and repetitive exercise appear to be key factors in promoting synaptogenesis and are central elements in rehabilitation of motor weakness following stroke. Expert medical management ensures a patient is well enough to participate in rehabilitation with minimal distractions due to pain or depression. Contraint-induced motor therapy and body-weight-supported ambulation are forms of exercise that "force use" of an impaired upper extremity. Technologies now in common use include robotics, functional electrical stimulation, and, to a lesser degree, transcranial magnetic stimulation and virtual reality. The data on pharmacological interventions are mixed but encouraging; it is hoped such treatments will directly stimulate brain tissue to recovery. Mitigation of factors preventing movement, such as spasticity, might also play a role. Research evaluating these motor recovery strategies finds them generally good at the movement level but somewhat less robust when looking at functional performance. It remains unclear whether inconsistent evidence for functional improvement is a matter of poor treatment efficacy or insensitive outcome measures.

[Seizures and epilepsies after stroke]

Epilepsies after stroke represent 20% of all adult-onset epilepsies and exhibit special characteristics with respect to diagnosis, treatment, and prognosis. Patients are frequently amnestic for their seizures the signs of which can be very subtle. Postictal pareses and confusional states can last for days, which further complicate diagnosis. Single seizures after stroke were reported in 2% to 10% of cases, and community-based studies found epilepsies in 3% to 4% of stroke patients. Analyses of subgroups identified epilepsy risks of 3% after ischemic infarction, 6% to 10% after intracerebral hemorrhage, and 9% after subarachnoid hemorrhage. Status epilepticus developed in less than 1% of stroke patients. Besides etiology, further risk factors for epilepsy comprise: remote seizures (latency >2 weeks, risk of recurrence >50%) more than early seizures (latency <2 weeks, risk of recurrence <50%), extent of stroke, cortical involvement, and degree of neurological deficit. The first appearance of seizures in patients older than 60 years represents a risk factor for future stroke with a hazard ratio of 2.89.There is currently no sufficient evidence for starting AED treatment before seizures occur. The benefit is still unclear of starting AED after a single early post-stroke seizure. Most authors recommend AED treatment after the second seizure but also after a first remote seizure because of the high risk of seizure recurrence in these situations. Possible pharmacokinetic interactions should be considered when choosing AED. Especially the first-generation AED carry the potential to interact with comedication, which is usually seen in stroke patients receiving substances such warfarin and salicylates. Only very few studies investigate specific AED exclusively in stroke patients. Lamotrigine and gabapentin have been successfully tested in these patients.