Acute DWI Reductions In Patients After Single Epileptic Seizures - More Common Than Assumed

Background: Changes of cerebral diffusivity detected by magnetic resonance imaging (MRI) have been reported in epilepsy. Diffusion weighted imaging (DWI) detects changes in the distribution of water molecules by measuring the apparent diffusion coefficient (ADC) and is mainly used in the diagnosis of ischemic stroke. DWI changes in epilepsy were reported in status epilepticus (SE) or series of seizures. It remains unclear whether this phenomenon also occurs after single seizures. Accordingly, possible pathomechanisms have only been discussed on the presumed basis of ongoing epileptic brain activity.Methods: In this retrospective study, we systematically analyzed DWI alterations related to epileptic seizures in 454 patients who received MRI scanning within the first 24 h after seizure onset.Results: DWI restrictions not classified as ischemic stroke were observed in 18 patients (4%). We found DWI restrictions in 19% of patients with SE/seizure series and in 3% of patients after single focal and 2.5% after single generalized seizures. 17 patients with DWI alterations were diagnosed with a structural epilepsy. DWI signal decreased in the majority of patients within the first days and could not be detected in follow-up imaging >3 months. In all patients except one, DWI alterations were detected in the same hemisphere as the lesion. In the case of seizure series or SE, DWI restrictions mostly presented with a typical “garland-like” pattern alongside the cortical band or on the border of a defined lesion, while in isolated seizures, the restrictions were often rather subtle and small.Discussion: We show that DWI restrictions can be observed in patients after single epileptic seizures. As the vast majority of these patients was diagnosed with an epilepsy due to structural cerebral pathology, DWI restriction may reflect a higher vulnerability in these regions. This might also explain the fact that diffusivity changes were observed after single focal seizures as well as after multiple seizures or SE. The occurence itself on one side as well as the spatial pattern of this phenomenon on the other may thus not only be related to the duration of ictal activity, but to structural pathology

Clinical characteristics and postoperative seizure outcome in patients with mild malformation of cortical development and oligodendroglial hyperplasia

Abstract Objective We describe for the first time clinical characteristics in a series of 20 pre‐surgically investigated patients with mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE) who were operated on in our epilepsy center. We aimed to better diagnose this entity and help surgical planning. Methods Data on 20 patients with histologically confirmed MOGHE were retrospectively evaluated as to age at epilepsy onset and operation, seizure semiology, magnetic resonance imaging (MRI) localization, electroencephalography (EEG) patterns, extent of the operative resection, and postoperative seizure outcome. Results Epilepsy began mainly in early childhood; however, symptoms did not manifest until adolescence or adulthood in 30% of patients. All patients had pathologic MRI findings. In 45% of patients the lesion was initially overlooked. Most commonly, the lesion was seen in the frontal lobe. Seizure semiology was characterized as follows: (1) epileptic spasms at epilepsy onset were common and (2) nocturnal hyperkinetic seizures during the course of the disease were rare. EEG always showed frequent interictal epileptic discharges. Two peculiar patterns were observed: (1) during sleep stage I‐II, sub‐continuous repetitive (0.5–1.5/s) unilateral plump spike/polyspike slow waves were seen and (2) during wakefulness, unilateral paroxysms of 2–2.5/s spike‐wave complexes occurred. In total, 60% of patients were seizure‐free 1 year postoperatively. Postoperative seizure outcome was positively correlated with the extent of resection, age at epilepsy onset, and age at operation. Postoperative long‐term outcomes remained stable in patients undergoing larger operations. Significance MRI, EEG, and semiology already contribute to the diagnosis of probable MOGHE preoperatively. Because postoperative seizure outcomes depend on the extent of the resection, prior knowledge of a probable MOGHE helps to plan the resection and balance the risks and benefits of such an intervention. In patients undergoing larger operations, epilepsy surgery achieved good postoperative results; the first long‐term outcome data were stable in these patients

Corpus callosotomy in Lennox Gastaut syndrome

Fauser S, Bien C, Rada A. Corpus callosotomy in Lennox Gastaut syndrome. Zeitschrift für Epileptologie . 2022.Corpus callosotomy is a palliative therapy option in patients with drop attacks or therapy-resistant bilateral tonic-clonic seizures (BTCS), particularly in Lennox Gastaut syndrome (LGS), if curative epilepsy surgery is not possible. This is the case in bilateral or multifocal lesions, pathologies near to eloquent areas or in non-lesional epilepsies. Before performing corpus callosotomy, a bilateral Wada test ensures that expressive and receptive language functions are located in the same hemisphere and that this hemisphere also drives the dominant hand. Otherwise, the patient is in danger of callosotomy-related antagonisms, disturbances of speech and severe apraxia. In contrast to curative epilepsy surgery, patients do not become seizure-free. Moreover, a corpus callosotomy bears more perioperative complications than usual epilepsy surgery (e.g. lesions because of pressure on structures lateral to the corpus callosum or venous infarction). Postoperatively, an acute disconnection syndrome in terms of listlessness regularly occurs which normally resolves within a short time. The outcome for tonic and atonic drop attacks and BTCS is favorable: According to the literature, > 80% of patients have a distinct reduction in seizure frequency for these seizure types and in approximately half of the patients these target seizures even disappear. Thus, corpus callosotomy, although infrequently performed, is a treatment option for patients with particularly dangerous and otherwise untreatable seizures

Rasmussen encephalitis: Predisposing factors and their potential role in unilaterality

Fauser S, Elger CE, Wörmann F, Bien C. Rasmussen encephalitis: Predisposing factors and their potential role in unilaterality. Epilepsia. 2021.OBJECTIVE: Rasmussen encephalitis (RE) is a progressive and destructive inflammatory disease of one hemisphere. Its cause is unknown. We investigated comorbidity and laterality factors that might predispose to RE.; METHODS: We retrospectively compared the histories of 160 RE patients to those with genetic generalized epilepsy (n=154) and those with focal cortical dysplasia Type II (FCD II; n=148).; RESULTS: The median/mean age at symptom onset in RE was 7/10years (range = 1-53years), and 58.1% of the patients were female. The female sex predominated in RE patients, with age > 7years at disease manifestation. The left hemisphere was affected in 65.6%. Perinatal complications (preterm birth, twin pregnancies, early acquired brain lesions) were more frequent in RE than in control patients. Ipsilateral facial autoimmune conditions (scleroderma en coup de sabre, uveitis, or chorioretinitis) were only observed in RE patients (6.9%). Onset of RE was more frequently associated with fever than that of FCD II. In 33.1% of RE patients, ≥1 potential risk factor was found. Interestingly, 11.9% of patients had one-sided early brain lesions or facial autoimmune lesions ipsilateral to subsequent RE; none had such a lesion contralaterally.; SIGNIFICANCE: Perinatal complications and facial autoimmune conditions may act as predisposing factors for RE. Fever might trigger RE manifestation. Further genetic or infectious contributors may be identified in the future. Single or combined hits may be required to elicit or facilitate the start of the disease. Ipsilateral early comorbid lesions or facial autoimmune processes might in part explain the enigmatic unilaterality of RE. © 2021 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy

In-vivo and ex-vivo characterization of laser-induced choroidal neovascularization variability in mice

Background Retinal argon laser coagulation is an established procedure for induction of choroidal neovascularization (CNV) in rodents. This study aimed to evaluate the in-vivo and ex-vivo morphology and variability of laser-induced CNV spots over time. Methods Female C57/Bl/6 mice, 3-6 months of age, were treated with five spots of retinal argon laser coagulation per eye (150 mW, 100 ms, 50 mu m). In-vivo fluorescein angiography (FA) and standard high-resolution spectral-domain optical coherence tomography (SD-OCT) were performed on day (d) 0, d1, d4, d7, d14 and d21. Ex-vivo histology, CD31 immunostaining, flatmount and confocal microscopy were also conducted. CNV size in the retinal and choroidal focus, CNV morphology, central retinal thickness (CRT) and FA CNV activity grading were assessed in-vivo at all times and compared to the ex-vivo assessments. Results SD-OCT revealed sub-retinal and intra-retinal fluid, and permitted evaluation of longitudinal morphologic changes of the induced CNV. Laser spot area in FA and CRT in SD-OCT did not differ in longitudinal evaluation. CNV could not be consistently outlined on SD-OCT images, and CNV volume as assessed on SD-OCT did not change over time. Significant CNV activity changes were only found in FA CNV activity grading, peaking on d4 and decreasing by d7. Conclusions Non-invasive SD-OCT provides additional morphological information on laser-induced CNV. However, reliable evaluation of CNV requires FA. Spontaneous regression of CNV activity within 14 days after induction has to be taken into account when utilizing this model for testing the efficacies of potential future treatments

Clinical characteristics and postoperative seizure outcome in patients with mild malformation of cortical development and oligodendroglial hyperplasia

Gaballa A, Woermann FG, Cloppenborg T, et al. Clinical characteristics and postoperative seizure outcome in patients with mild malformation of cortical development and oligodendroglial hyperplasia. Epilepsia. 2021.OBJECTIVE: We describe for the first time clinical characteristics in a series of 20 pre-surgically investigated patients with mild malformation of cortical development with oligodendroglial hyperplasia (MOGHE) who were operated on in our epilepsy center. We aimed to better diagnose this entity and help surgical planning.; METHODS: Data on 20 patients with histologically confirmed MOGHE were retrospectively evaluated as to age at epilepsy onset and operation, seizure semiology, magnetic resonance imaging (MRI) localization, electroencephalography (EEG) patterns, extent of the operative resection, and postoperative seizure outcome.; RESULTS: Epilepsy began mainly in early childhood; however, symptoms did not manifest until adolescence or adulthood in 30% of patients. All patients had pathologic MRI findings. In 45% of patients the lesion was initially overlooked. Most commonly, the lesion was seen in the frontal lobe. Seizure semiology was characterized as follows: (1) epileptic spasms at epilepsy onset were common and (2) nocturnal hyperkinetic seizures during the course of the disease were rare. EEG always showed frequent interictal epileptic discharges. Two peculiar patterns were observed: (1) during sleep stage I-II, sub-continuous repetitive (0.5-1.5/s) unilateral plump spike/polyspike slow waves were seen and (2) during wakefulness, unilateral paroxysms of 2-2.5/s spike-wave complexes occurred. In total, 60% of patients were seizure-free 1year postoperatively. Postoperative seizure outcome was positively correlated with the extent of resection, age at epilepsy onset, and age at operation. Postoperative long-term outcomes remained stable in patients undergoing larger operations.; SIGNIFICANCE: MRI, EEG, and semiology already contribute to the diagnosis of probable MOGHE preoperatively. Because postoperative seizure outcomes depend on the extent of the resection, prior knowledge of a probable MOGHE helps to plan the resection and balance the risks and benefits of such an intervention. In patients undergoing larger operations, epilepsy surgery achieved good postoperative results; the first long-term outcome data were stable in these patients. © 2021 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy