Characteristics and outcomes of patients with seizures according to the time of onset in relation to stroke

BACKGROUND/AIM

Although most late-onset seizures (LS) appear within 2 years after stroke, some of them occur later and their characteristics are unknown. The aim of this study was to compare the characteristics of patients with very-late-onset seizures (VLS) to those with early-onset seizures (ES) and those with LS.

PATIENTS

The study group consisted of 204 patients with stroke-related seizures (29 ES, 128 LS and 47 VLS).

RESULTS

Intracranial haemorrhage was a more frequent cause of ES than of LS and no cause at all of VLS. On the other hand, 25% of the VLS were related to lacunar strokes. Status epilepticus occurred in 20.7% of the ES, in 11.7% of the LS and in 2.1% of the VLS patients. Seizure recurrences were 13.8% in the ES, 54.7% in the LS and 34.0% in the VLS group. Neurological impairment, at stroke onset, and the degree of disability were more severe in patients with ES compared to those with LS and were very mild in the VLS group. The EEG findings as a whole did not show significant differences between the three groups, although a normal EEG was more frequent in the VLS group.

CONCLUSION

VLS occur in patients with minor ischaemic strokes with good recovery and benign disease course.

Magnetic Resonance Imaging after Seizures in Patients with an Ischemic Stroke

BACKGROUND

Seizures related to ischemic strokes are harmful. Their pathogenesis is not very well understood. The present study investigates whether diffusion-weighted imaging (DWI) can detect if those seizures are due to recurrent infarction or responsible for secondary ischemic changes.

PATIENTS AND METHODS

DWI was obtained within 8 days in 60 patients with seizures (7 early and 53 late onset) related to an ischemic stroke.

RESULTS

In 30 patients, positive DWI with decreased apparent diffusion coefficient was found. In 11 patients with late-onset seizures, the DWI showed a positive rim, surrounding the old infarct, while in 12 patients a large positive zone corresponding to a new infarct was observed. All 7 patients with early-onset seizures had positive DWI corresponding to the establishing infarct. A large positive zone on DWI was mainly observed in cardioembolic stroke.

CONCLUSIONS

The positive rim around the old infarct can be considered as cytotoxic edema. Recurrent acute infarction, mainly of cardioembolic origin, seems to be a significant cause of so-called late-onset seizures, making the subdivision into early- and late-onset seizures arbitrary.

Computed tomographic changes of the brain and clinical outcome of patients with seizures and epilepsy after an ischaemic hemispheric stroke

It is not well established whether seizures and epilepsy after an ischaemic stroke increase the disability of patients. Seventy-two patients with delayed seizures after a hemispheric infarct (37 with a single seizure and 35 with epilepsy) were included in the study. The modified Rankin scale was used to compare disability of the patients at 1 month after stroke and at 2 weeks after single or the last seizure, in case of epilepsy. The size of the X-ray hypoattenuation zone was compared on computed tomographic (CT) scans, performed in the weeks after the stroke and 1 week after single or repeated seizures. Lesion size was determined by superimposing the CT slices on digital cerebral vascular maps, on which the contours of the infarct area were delineated. The extent of the infarcts was expressed as the percentage fraction of the total surface area of the cerebral hemisphere. Groups with a single seizure and with epilepsy were mutually compared. Infarcts predominated in the parieto-temporal cortical regions. In the overall group the median Rankin score worsened significantly after seizures. The average size of the X-ray hypoattenuation zone was also significantly increased on the CT scans after the seizures, compared with those after stroke, without clear evidence of recent infarction. Mutual comparison of patients with a single seizure episode and of those with epilepsy showed only a trend of more severe disability and of increase in lesion size in the post-stroke epilepsy group. Delayed seizures and epilepsy after ischaemic stroke are accompanied by an increase in lesion size on CT and by worsening of the disability of the patients. This study does not allow to determine whether this is due to stroke recurrence or due to additional damage as a result of the seizures themselves.

Role of CT Angiography in Thrombolysis Decision-Making for Patients With Presumed Seizure at Stroke Onset

BACKGROUND AND PURPOSE

The presence of seizure at stroke onset is a contraindication for intravenous tissue plasminogen activator treatment. A significant proportion of these patients' deficits are not attributable to Todd's paralysis and could be attributable to reversible ischemia. Currently there are no established methods of differentiating Todd's paralysis from ischemic stroke/early seizure. We sought to determine whether computed tomographic angiography (CTA) can be helpful in differentiating the 2.

METHODS

Three hundred and twenty six patients underwent noncontrast CT and CTA for acute stroke at our institution over 3 years (June 2002 to April 2005). Of them, 116 had disabling deficits and presented within 3 hours. We reviewed the clinical data, noncontrast CT, CTA, electroencephalogram and outcome of these patients and identified those who presented with presumed seizure activity at stroke onset (seizure or altered consciousness at stroke onset).

RESULTS

Nine (7.7%) patients had a concern of seizure at stroke onset. Median age 73 years (range, 31 to 85 years), median National Institutes of Health Stroke Scale (NIHSS) score 12 (range, 5 to 29). CTA showed proximal middle cerebral artery occlusion in 2 and distal middle cerebral artery occlusion in 3 patients. All 5 of these patients had evidence of infarction on follow-up (stroke+early seizure group-intracranial occlusion present). Three of these patients received intravenous tissue plasminogen activator because they were deemed to have "ischemic tissue at risk". Four patients had normal CT and CTA studies and recovered completely in 24 hours (Todd's paralysis only group-intracranial occlusion negative).

CONCLUSIONS

Seizure at stroke onset was relatively uncommon in a consecutive cohort of acute stroke patients. CTA was a useful modality in differentiating Todd's paralysis from early seizure and ischemia by detection of intracranial occlusion and may contribute to decision-making for thrombolysis.

Vascular cognitive impairment in patients with late-onset seizures after an ischemic stroke

BACKGROUND

Cognitive impairment and seizures are both common conditions in patients with cerebrovascular disease.

PURPOSE

The present study investigates whether the occurrence of late-onset seizures, following an ischemic stroke, contributes to vascular cognitive impairment.

PATIENTS AND METHODS

The mean Mini-Mental State Examination (MMSE) and the median modified Rankin (mR) scores were compared between 125 patients who developed late-onset seizures (66 with a single seizure and 59 with repeated seizures or epilepsy) following an ischemic stroke and 125 patients who did not during, at least, a 2-year follow-up.

RESULTS

There were no differences in age, gender, etiology and degree of neurological impairment on admission for their stroke between the groups with and without seizures. Although the mean MMSE score was similar between both groups the median mR score was significantly higher in the seizure patients. Comparing the patients with a single seizure to the non-seizure ones showed the same results. On the other hand, comparison of the patients with epilepsy to the non-seizure group revealed, in addition to the higher median mR score, a significantly lower mean MMSE score in the former group.

CONCLUSION

Repeated seizures following an ischemic stroke promote vascular cognitive impairment.

Clinical predictors of late-onset seizures and epilepsy in patients with cerebrovascular disease

BACKGROUND

Seizures and epilepsy are harmful and worsen the disability of stroke patients. There are currently no good clinical predictors of late-onset seizures and epilepsy in patients with cerebrovascular disease (CVD).

PATIENTS AND METHODS

110 patients with delayed seizures after an ischaemic or a haemorrhagic stroke, a transient ischaemic attack or a subarachnoid haemorrhage (60 with a single seizure and 50 with epilepsy) and 366 without seizures were included in this retrospective study. The clinical syndrome, the stroke aetiology and the vascular risk factors were compared. The groups with a single seizure and with epilepsy were also analysed separately.

RESULTS

There were no differences in age, gender, aetiology and vascular risk factors between the groups with and without seizures. When comparing the incidence of the clinical syndromes, ischaemic partial anterior circulation syndrome (PACS) was significantly more and transient ischaemic attack less frequent in the group with seizures compared to the control group. The severity of the neurological impairment on admission and the degree of disability on discharge after a PACS was similar in those who developed late-onset seizures compared with those who did not. Also on the Cox proportional hazards analysis, PACS appeared to be the only clinical risk factor for development of seizures and epilepsy in patients with CVD. No differences were observed in clinical predictors between patients with a single seizure and those with epilepsy.

CONCLUSION

PACS is the only independent predictor for the occurrence of late-onset seizures in patients with CVD.

Cobalt-55 positron emission tomography in late-onset epileptic seizures after thrombo-embolic middle cerebral artery infarction

The pathogenesis of late-onset epileptic seizures after thrombo-embolic cerebral infarction is poorly understood. Our previous positron emission tomographic (PET) studies with 15O have demonstrated that post-apoplectic epilepsy is associated with more severe brain ischemia, but we were unable to determine if this was the cause or the consequence of the seizures. Using cobalt-55 (55Co) as PET tracer we can now distinguish recurrent, recent infarction in patients with a previous old infarct in the same vascular territory. In seven out of twelve patients with post-apoplectic seizures an increased uptake of 55Co was observed in the border area and in two of them also within the old infarct core. In the control group, composed of eight seizure-free patients with also an old infarct involving the cortical territory of the middle cerebral artery, no increase in 55Co uptake was observed on PET examination. The present study indicates that in a significant number of patients late-onset epilepsy is the clinical expression of recurrent strokes, occurring in the same vascular territory.

Crossed cerebellar diaschisis after middle cerebral artery infarction

It is unclear whether crossed cerebellar diaschisis (CCD) is merely an epiphenomenon, as its clinical significance remains uncertain. We retrospectively analysed the positron emission tomographic (PET) findings in 28 patients with a chronic, stable middle cerebral artery (MCA) infarct and in 22 controls, using the steady state technique and 15O. Also, the Orgogozo scores on admission and at the time of the PET examination were compared in the patients with MCA infarction. Based on the asymmetry index and the 95% confidence limits for regional cerebellar blood flow (rCBF) and oxygen consumption (rCMRO2) in the control group, the stroke patients were subdivided in a group with (n = 8) and a group without (n = 20) CCD. The CCD group had lower values of rCMRO2 in the infarct and border areas compared to those of the non-CCD patients. The infarct location within the MCA territory was similar but the size was somewhat larger in the CCC group. The degree of neurological improvement was better in the non-CCD group. Although persistence of CCD has no real clinical significance it appears to be correlated to more severe and widespread ischaemia in the affected MCA territory and to the lack of significant clinical improvement.

Ipsilateral thalamic diaschisis after middle cerebral artery infarction

The significance of ipsilateral thalamic diaschisis (ITD) among patients with chronic, stable middle cerebral artery (MCA) infarcts was investigated. Twenty eight subjects with chronic MCA infarction and twenty two normal controls were studied with positron emission tomography (PET), using the steady state technique with 15O. Stroke patients were subdivided into a group with ITD (n = 12) and a group without ITD (n = 16). Patients with ITD had greater decreases of regional blood flow (rCBF) and oxygen consumption (rCMRO2) in the infarcted MCA territory, compared to MCA infarction without ITD. The neurological deficits at the time of PET scanning were similar between both groups. Extent of infarction by CT brain scan appeared more predominant in peri-insular regions of patients with ITD, while in non diaschisis patients infarcts were more widely distributed throughout the MCA territories. Occurrence of ITD and of crossed cerebellar diaschisis (CCD) did not correlate. Occurrence of ITD seems to be linked to diffuse reductions of blood flow and oxygen metabolism in cortical territories of the MCA. Mechanisms of ITD were different from those of CCD.