Electrographic patterns in patients with posterior reversible encephalopathy syndrome and seizures

Clinical and neuroradiographic features of fentanyl inhalation-induced leukoencephalopathy

A man in his late 40s with no known past medical history was unresponsive for an unknown period of time. Crushed pills and white residue were found on a nearby table. On presentation he was obtunded and unresponsive to verbal commands but withdrawing to painful stimuli. The initial urine drug screen was negative, but a urine fentanyl screen was subsequently positive with a level of 137.3 ng/mL. MRI of the brain showed reduced diffusivity and fluid attenuated inversion recovery (FLAIR) hyperintensity symmetrically in the bilateral supratentorial white matter, cerebellum and globus pallidus. Alternative diagnoses such as infection were considered, but ultimately the history and workup led to a diagnosis of fentanyl-induced leukoencephalopathy. Three days after admission the patient became able to track, respond to voice and follow basic one-step commands. The patient does not recall the mechanism of inhalation. While there are case reports of heroin-induced leukoencephalopathy following inhaled heroin use and many routes of fentanyl, this is the first reported case of a similar phenomenon due to fentanyl inhalation.

Hippocampal injections of soluble amyloid-beta oligomers alter electroencephalographic activity during wake and slow-wave sleep in rats

BACKGROUND

Soluble amyloid-beta oligomers (Aβo) begin to accumulate in the human brain one to two decades before a clinical diagnosis of Alzheimer's disease (AD). The literature supports that soluble Aβo are implicated in synapse and neuronal losses in the brain regions such as the hippocampus. This region importantly contributes to explicit memory, the first type of memory affected in AD. During AD preclinical and prodromal stages, people are also experiencing wake/sleep alterations such as insomnia (e.g., difficulty initiating sleep, decreased sleep duration), excessive daytime sleepiness, and sleep schedule modifications. In addition, changes in electroencephalographic (EEG) activity during wake and sleep have been reported in AD patients and animal models. However, the specific contribution of Aβo to wake/sleep alterations is poorly understood and was investigated in the present study.

METHODS

Chronic hippocampal injections of soluble Aβo were conducted in male rats and combined with EEG recording to determine the progressive impact of Aβ pathology specifically on wake/sleep architecture and EEG activity. Bilateral injections were conducted for 6 consecutive days, and EEG acquisition was done before, during, and after Aβo injections. Immunohistochemistry was used to assess neuron numbers in the hippocampal dentate gyrus (DG).

RESULTS

Aβo injections did not affect the time spent in wakefulness, slow wave sleep (SWS), and paradoxical sleep but altered EEG activity during wake and SWS. More precisely, Aβo increased slow-wave activity (SWA; 0.5-5 Hz) and low-beta activity (16-20 Hz) during wake and decreased theta (5-9 Hz) and alpha (9-12 Hz) activities during SWS. Moreover, the theta activity/SWA ratio during wake and SWS was decreased by Aβo. These effects were significant only after 6 days of Aβo injections and were found with alterations in neuron counts in the DG.

CONCLUSIONS

We found multiple modifications of the wake and SWS EEG following Aβo delivery to the hippocampus. These findings expose a specific EEG signature of Aβ pathology and can serve the development of non-invasive and cost-effective markers for the early diagnosis of AD or other amyloid-related diseases.

Factors associated with acute symptomatic seizure occurrence among patients with posterior reversible encephalopathy syndrome

OBJECTIVES

We aimed to define the factors associated with acute symptomatic seizure occurrence in posterior reversible encephalopathy syndrome (PRES) in the Thai-Asian population.

MATERIALS AND METHODS

We conducted a retrospective cohort study enrolling patients with PRES admitted to the hospital between 2006 and 2019. In addition to seizure characteristics, baseline characteristics, clinical presentations, precipitating factors, neuroimaging characteristics, hospital complications, and hospital outcomes were compared between the seizure and non-seizure groups. Factors with p-value <0.05 in the univariate analysis were entered into the first model of multivariate logistic regression analysis to determine the factors associated with seizure occurrence if the p-value <0.05. The interaction of associated factors was also analyzed in the final multiple logistic regression analysis model.

RESULTS

Acute symptomatic seizure, which is mainly based on the clinical documentation without electroencephalography, occurred in 50.0% of 136 patients with PRES. Of these, early seizures within 14 days of PRES occurred in 98.5% which mostly developed at presentation (82.4%) with a single seizure attack (55.9%). Convulsive seizures (77.9%) were the most common seizure semiology. The seizure group was significantly younger (median [interquartile range: IQR] 36.00 years old (21.75-48.50) vs 46.50 years old (31.25-61.00), p = 0.003). In univariate analysis, the seizure group had a higher prevalence of consciousness impairment (61.76% vs 26.47%, p < 0.001), Glasgow coma scale (GCS) score of 0-13 (42.46% vs 13.23%, p < 0.001), preeclampsia (20.58% vs 4.41%, p = 0.004), autoimmune disease (17.65% vs 5.88%, p = 0.033), and frontal lesions (25.00% vs 11.76%, p = 0.046) than those in the non-seizure group. In contrast, the seizure group had a lower prevalence of headache (27.94% vs 61.76%, p < 0.001). In the final multivariate logistic regression analysis which included the interaction terms, the acute symptomatic seizure occurrence directly associated with preeclampsia (adjusted odds ratio (aOR) 6.426, 95% confidence interval (CI) 1.450-27.031, p = 0.016) and autoimmune disease (aOR 4.962, 95% CI 1.283-18.642, p = 0.025), while headache showed a reverse association (aOR 0.310, 95% CI = 0.158-0.721, p = 0.008).

CONCLUSIONS

Acute symptomatic seizure occurred in a half of patients with PRES in this cohort. Preeclampsia and autoimmune disease were directly associated with seizure occurrence, while headache showed a reverse association.

Different Clinicoradiological Characteristics of Posterior Reversible Encephalopathy Syndrome in Pediatric Oncology and Post-Bone Marrow Transplantation Cases: A Retrospective Study

Posterior reversible encephalopathy syndrome (PRES) is receiving increasing recognition in pediatrics. However, comparisons between PRES in pediatric oncology and post-bone marrow transplantation (BMT) are lacking. Therefore, we aimed to describe the risk factors and clinical and radiological features of PRES and investigate the differences between PRES in pediatric oncology and post-BMT. The PRES data of 13 patients from our center were combined with those of 217 cases from the PubMed, Scopus, and Web of Science databases. The patients were divided into either an oncology or a post-BMT group. We included 230 patients in the analysis, 26.1% of whom belonged to the post-BMT group. Oncology patients developed PRES at a younger age (p = 0.010) and were more likely to develop encephalopathy (p = 0.004). Systemic hypertension (S-HTN) preceding PRES occurred in 43.5% (66/154) of patients. Post-BMT patients were more likely to have S-HTN (p = 0.003). Cyclosporine levels were detected in 37 patients; 40.5% had supra-therapeutic levels. The radiological findings were atypical in 74.3% of patients, and delayed repeated imaging increased the occurrence of resolution (p = 0.004). Sixteen (7%) patients developed PRES recurrence after a median of 8 weeks, with the between-group difference being non-significant. Oncology patients were more likely to develop chronic epilepsy, while BMT patients were more likely to develop rare neurologic abnormalities (p < 0.001). In conclusion, atypical clinical presentation and imaging findings should not hinder the diagnosis of PRES. S-HTN is a risk factor, particularly in post-BMT patients. Supra-therapeutic levels of cyclosporine and previous exposure to immunosuppression did not increase the risk of recurrence.

Posterior Reversible Encephalopathy in Sepsis-Associated Encephalopathy: Experience from a Single Center

BACKGROUND

Sepsis-associated encephalopathy (SAE) is frequently encountered in sepsis and is often accompanied by neuroimaging findings indicating ischemia, hemorrhage, and edema. Posterior reversible encephalopathy syndrome (PRES) has been vastly underrecognized in previously reported cohorts of patients with sepsis and SAE. Our aim was to determine the prevalence and distinguishing clinical, neuroimaging, and electroencephalography features of PRES in SAE.

METHODS

In this prospective observational study, patients with radiologically identified PRES were selected from a consecutively enrolled cohort of 156 patients with SAE and assessed for neurological outcome using the extended Glasgow Outcome Scale for 12 months. Patients with SAE and PRES and other types of brain lesions were compared in terms of clinical and diagnostic workup features.

RESULTS

Fourteen of 156 patients (8.9%) were determined to be radiologically compatible with PRES, whereas 48 patients displayed other types of acute brain lesions. Patients with PRES often showed lesions in atypical regions, including frontal lobes, the corpus callosum, and the basal ganglia. Source of infection was mostly gram-negative bacteria originating from pneumonia or intraabdominal infections. Patients with PRES were not different from other patients with SAE with brain lesions in terms of features of sepsis and neurological outcome. However, patients with PRES showed increased prevalence of seizures and intraabdominal source of infection.

CONCLUSIONS

PRES is highly prevalent in SAE, often encompasses unusual brain regions, and usually presents with generalized seizures. Patients with SAE and PRES do not appear to have distinguishing clinical and diagnostic workup features. However, generalized seizures may serve as warning signs for presence of PRES in patients with SAE.

EEG Delta/Theta Ratio and Microstate Analysis Originating Novel Biomarkers for Malnutrition-Inflammation Complex Syndrome in ESRD Patients

The Malnutrition-Inflammation Score (MIS) was initially proposed to evaluate malnutrition-inflammation complex syndrome (MICS) in end-stage renal disease (ESRD) patients. Although MICS should be routinely evaluated to reduce the hospitalization and mortality rate of ESRD patients, the inconvenience of the MIS might limit its use. Cerebral complications in ESRD, possibly induced by MICS, were previously assessed by using spectral electroencephalography (EEG) via the delta/theta ratio and microstate analysis. Correspondingly, EEG could be used to directly assess MICS in ESRD patients, but the relationships among MICS and these EEG features remain inconclusive. Thus, we aimed to investigate the delta/theta ratio and microstates in ESRD patients with high and low risks of MICS. We also attempted to identify the correlation among the MIS, delta/theta ratio, and microstate parameters, which might clarify their relationships. To achieve these objectives, a total of forty-six ESRD subjects were willingly recruited. We collected their blood samples, MIS, and EEGs after receiving written informed consent. Sixteen women and seven men were allocated to low risk group (MIS ≤ 5, age 57.57 ± 14.88 years). Additionally, high risk group contains 15 women and 8 men (MIS > 5, age 59.13 ± 11.77 years). Here, we discovered that delta/theta ratio (p < 0.041) and most microstate parameters (p < 0.001) were significantly different between subject groups. We also found that the delta/theta ratio was not correlated with MIS but was strongly with the average microstate duration (ρ = 0.708, p < 0.001); hence, we suggested that the average microstate duration might serve as an alternative encephalopathy biomarker. Coincidentally, we noticed positive correlations for most parameters of microstates A and B (0.54 ≤ ρ ≤ 0.68, p < 0.001) and stronger negative correlations for all microstate C parameters (−0.75 ≤ ρ ≤ −0.61, p < 0.001). These findings unveiled a novel EEG biomarker, the MIC index, that could efficiently distinguish ESRD patients at high and low risk of MICS when utilized as a feature in a binary logistic regression model (accuracy of train-test split validation = 1.00). We expected that the average microstate duration and MIC index might potentially contribute to monitor ESRD patients in the future.

The Sensitivity of Scalp EEG at Detecting Seizures-A Simultaneous Scalp and Stereo EEG Study

PURPOSE

Compare the detection rate of seizures on scalp EEG with simultaneous intracranial stereo EEG (SEEG) recordings.

METHODS

Twenty-seven drug-resistant epilepsy patients undergoing SEEG with simultaneous scalp EEG as part of their surgical work-up were included. A total of 172 seizures were captured.

RESULTS

Of the 172 seizures detected on SEEG, 100 demonstrated scalp ictal patterns. Focal aware and subclinical seizures were less likely to be seen on scalp, with 33% of each observed when compared with focal impaired aware (97%) and focal to bilateral tonic-clonic seizures (100%) (P < 0.001). Of the 72 seizures without ictal scalp correlate, 32 demonstrated an abnormality during the SEEG seizure that was identical to an interictal abnormality. Seizures from patients with MRI lesions were statistically less likely to be seen on scalp than seizures from nonlesional patients (P = 0.0162). Stereo EEG seizures not seen on scalp were shorter in duration (49 seconds) compared with SEEG seizures seen on scalp (108.6 seconds) (P < 0.001).

CONCLUSIONS

Scalp EEG is not a sensitive tool for the detection of focal aware and subclinical seizures but is highly sensitive for the detection of focal impaired aware and focal to bilateral tonic-clonic seizures. Longer duration of seizure and seizures from patients without MRI lesions were more likely to be apparent on scalp. Abnormalities seen interictally may at times represent an underlying seizure. The cognitive, affective, and behavioral long-term effects of ongoing difficult-to-detect seizures are not known.

Posterior reversible encephalopathy syndrome with a special focus on seizures

Posterior reversible encephalopathy syndrome (PRES) is a neurological disorder characterized by headache, seizures, confusion and visual disturbances, as well as potentially reversible neuroimaging findings in most patients after proper treatment. Seizures is one of the most common clinical presentations of PRES. This review summarizes the potential pathophysiology and clinical features of PRES, as well as a multimodal approach to imaging and also briefly discusses the phenomenon of seizures in paediatric population.

Prevalence of leukoencephalopathy and its potential cognitive sequelae in cancer patients

Due to the rising use of chemotherapy treatment in cancer patients and growing survival rates, therapy-induced neurotoxic side effects are increasingly reported. Given the ambiguity about the prevalence and severity of leukoencephalopathy, one of such toxic side effects, in non-central nervous system (CNS) cancer patients, we performed a systematic literature search using the PubMed/Medline database to summarize existing literature regarding leukoencephalopathy epidemiology in non-CNS cancer patients and its potential cognitive sequelae. The search was based on the following terms: ('MRI' OR 'T2-weighted MRI' OR 'FLAIR') AND ('cancer' OR 'tumour' OR 'leukaemia' OR 'neoplasms') AND ('chemotherapy' OR 'radiotherapy') AND ('posterior reversible encephalopathy' OR 'leukoencephalopathy' OR 'cerebral ischaemia' OR 'stroke'). Thirty-two studies discussing the occurrence of leukoencephalopathy in cancer patients were included, of which the majority investigated Acute Lymphoblastic Leukaemia (ALL) patients (n = 22).Regularly scanned ALL patients showed a prevalence of leukoencephalopathy between 17 - 87%, and 15 - 83% of patients presented with leukoencephalopathy when only scanned after a CNS event. When diagnosed with posterior reversible encephalopathy syndrome, 100% of patients showed leukoencephalopathy because its diagnosis is based in part on observable lesions. An increased prevalence was observed in ALL patients treated with higher doses of methotrexate (5 g/m² MTX, 42 - 87%) when compared to lower doses (< 5 g/m², 32 - 67%). By contrast, in breast cancer patients, white matter lesions were mainly detected in case of neurological symptoms, but not (yet) clearly associated with chemotherapy administration. However, chemotherapy treatment was associated with more infratentorial microbleeds in breast cancer patients . Up to 50% of other (neurologically asymptomatic) solid tumour patients presented white matter lesions, even years after treatment. When cognitive data were investigated, lesioned patients showed lower scores on neurocognitive tests in 50% of studies, years after ending therapy.In conclusion, leukoencephalopathy is well-documented for ALL patients (with a focus on methotrexate), but there is a lack of knowledge for other intravenous chemotherapeutics, other oncological populations, wider age ranges and possible risk factors (e.g. history of CNS event). Furthermore, the long-term neuropsychological impact and potential risk for neurodegenerative processes due to leukoencephalopathy remains inconclusive. Hence, large international databanks, epidemiological and prospective case-control studies are necessary to stratify risk groups for CNS-related side effects.

Full Recovery From Cocaine-Induced Toxic Leukoencephalopathy: Emphasizing the Role of Neuroinflammation and Brain Edema

Toxic leukoencephalopathy (TL) is characterized by white matter disease on magnetic resonance imaging (MRI) and evidence of exposure to a neurotoxic agent. We describe a case of cocaine-induced TL in which extensive white matter disease did not preclude full recovery. A 57-year-old man with substance abuse disorder presented with a 5-day history of strange behavior. On admission, he was alert but had difficulty concentrating, psychomotor retardation, and diffuse hyperreflexia. Brain MRI revealed confluent subcortical white matter hyperintensities with restricted diffusion in some but not in other areas. Electroencephalography (EEG) showed mild diffuse slowing. Blood tests were normal except for mild hyperammonemia. Urine screen was positive for cocaine and benzodiazepine but quantitative analysis was significant only for cocaine. Prednisone 60-mg qd was initiated on day 4, tapered over a 5-day period, and discontinued on day 9. He was discharged after 3 weeks. Cognitive function returned to normal 2 weeks after discharge. Five months later, neurologic exam and EEG were normal and MRI showed near-100% resolution of white matter lesions. TL has been attributed to white matter ischemia/hypoxia resulting in demyelination/axonal injury. The clinical, EEG, and MRI findings and time course of recovery of our patient suggest that cocaine-induced inflammation/edema resulted in TL but not in ischemic/hypoxic injury. While inflammation/edema may have regressed when cocaine was discontinued, we cannot exclude a role for prednisone in protecting the patient from the ischemic/hypoxic sequelae of inflammation/edema. MRI is indispensable for diagnosing TL but EEG may provide additional useful diagnostic and prognostic information.

Posterior Reversible Encephalopathy Syndrome: Clinical Features and Outcome

Background: Posterior reversible encephalopathy syndrome (PRES) is an acute neurotoxic syndrome that is characterized by a spectrum neurological and radiological feature from various risk factors. Common neurological symptoms includes headache, impairment in level of consciousness, seizures, visual disturbances, and focal neurological deficits. Common triggering factors include blood pressure fluctuations, renal failure, eclampsia, exposure to immunosuppressive or cytotoxic agents and autoimmune disorders. The classic radiographic findings include bilateral subcortical vasogenic edema predominantly affecting the parieto-occipital regions but atypical features include involvement of other regions, cortical involvement, restricted diffusion, hemorrhage, contrast enhancement. This review is aimed to summarize the updated knowledge on the typical and atypical clinical and imaging features, prognostic markers and identify gaps in literature for future research.

Methods: Systematic literature review using PUBMED search from 1990 to 2019 was performed using terms PRES was performed.

Results: While clinical and radiographic reversibility is common, long-standing morbidity and mortality can occur in severe forms. In patients with malignant forms of PRES, aggressive care has markedly reduced mortality and improved functional outcomes. Although seizures were common, epilepsy is rare. Various factors that have been associated with poor outcome include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control the causative factor, elevated C reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging.

Conclusion: Large prospective studies that accurately predict factors that are associated with poor outcomes, determine the pathophysiology, and targeted therapy are required.

Clinical Correlates of Periodic Discharges and Nonconvulsive Seizures in Posterior Reversible Encephalopathy Syndrome (PRES)

IMPORTANCE

The pathophysiological mechanisms of Posterior Reversible Encephalopathy Syndrome (PRES) and related seizures remain poorly understood. The prevalence and clinical significance of nonconvulsive seizures (NCSz) and related epileptiform patterns during continuous electroencephalography monitoring (CEEG) in PRES have not been well described.

OBJECTIVE

To report the prevalence, characteristics and risk factors for NCSz and related highly epileptiform patterns in patients with PRES, and to determine their relation to imaging abnormalities and outcome.

DESIGN, SETTING AND PARTICIPANTS

From a prospective CEEG database, we retrospectively identified patients with PRES and reviewed their medical charts. Based on CEEG findings, we designed a retrospective cohort study comparing two groups defined based on the presence or the absence of NCSz and/or periodic discharges (PDs).

MAIN OUTCOMES AND MEASURES

The prevalence and risk factors for PDs and NCSz, description of EEG and magnetic resonance imaging (MRI) abnormalities and functional outcome as measured by the Glasgow Outcome Scale (GOS) at hospital discharge.

RESULTS

Among 37 eligible patients, 23 (62%) had PDs or NCSz. The presence of NCSz was associated with the presence of PDs (15/22 vs. 1/15; p = 0.0002). NCSz and PDs were usually either lateralized or bilateral independent and predominated in the posterior regions. No clinical features were associated with the occurrence of PDs or NCSz. Cortical restricted diffusion on MRI was more frequent in the PDs/NCSz group (17/23 vs. 1/14; p < 0.001). PDs/NCSz were associated with worse outcome, with 3 deaths vs. 0 in the no PDs/NCSz group and fewer cases with low disability (4 vs. 9 cases with GOS = 5, p < 0.04).

CONCLUSIONS AND RELEVANCE

Our results reveal a high prevalence of NCSz and PDs in critically ill patients with PRES and an association with restricted diffusion and worse outcome, whether treating or preventing these EEG findings can improve outcome requires further research.

EEG Findings in Posterior Reversible Encephalopathy Syndrome

Introduction. Posterior reversible encephalopathy syndrome (PRES) is a relatively common cause of encephalopathy in the hospital setting, and the EEG findings have not been well described. The purpose of this study was to review the EEG findings in a series of patients with PRES. Methods. We retrospectively reviewed our electronic medical record database to identify patients who received a diagnosis of PRES at Tampa General Hospital from January 2016 to October 2017. The diagnosis of PRES was suspected on clinical presentation and confirmed by magnetic resonance imaging. We selected patients with PRES who had received at least 1 EEG. EEGs were interpreted by 2 board-certified electroencephalographers. Results. From January 2016 to October 2017, 19 patients were diagnosed with PRES at Tampa General Hospital. Of those, 10 received at least 1 EEG. Four patients were male, 6 were female. The ages ranged from 21 to 87 (mean was 47). The patients had the following clinical presentations: 5 with encephalopathy, 8 with seizures, 2 with vision changes, and 3 with headache (some patients had more than 1 symptom). EEGs findings were as follows: 3 were normal; 3 showed intermittent generalized slowing; 2 showed continuous generalized slowing; 3 showed background slowing; 1 showed background suppression; 1 showed generalized rhythmic delta activity (GRDA); 1 showed GRDA, plus spike/sharp-wave discharges; 1 showed generalized periodic discharges. The etiologies were as follows: 9 from hypertension, 1 secondary to eclampsia, 3 due to posttransplant immunosuppression, and 1 patient was undergoing chemotherapy (some were multifactorial). Conclusion. EEG findings in PRES are diverse, with no specific or even predominant pattern, based on this small sample size.

Prognostic factors and seizure outcome in posterior reversible encephalopathy syndrome (PRES) in children with hematological malignancies and bone marrow failure: A retrospective monocentric study

PURPOSE

The aim of this study was to evaluate seizure outcome in children with hematological malignancies and PRES and to identify prognostic factors that could help manage the syndrome.

METHOD

We retrospectively reviewed the report data of 21 patients diagnosed with hematological malignancy or aplastic anemia and PRES between 2008 and 2018. Basic demographic data, oncology treatment, presymptomatic hypertension before PRES manifestation, neurological status, seizure type, and EEG and MRI findings at PRES onset and at the one-year follow-up visit were studied. Patients who developed remote symptomatic seizures or epilepsy were identified.

RESULTS

We included 21 children (11 females and 10 males) in the study. Sixteen patients (76.2%) were diagnosed with ALL and the rest individually with AML, CML, T-lymphoma, Burkitt lymphoma, and severe aplastic anemia. Presymptomatic hypertension (PSH) was evaluated in 19 patients and was present in 18 (94.7%). The duration was 9 h and more in 16 patients (88.8%); the severity was grade II in 12 patients (66.7%). Seizures as the initial symptom of PRES were present in 17 patients (80.9%). Four patients (19.0%) were assessed with remote symptomatic seizures. Two of them (9.5%) had ongoing seizures at the one-year follow-up visit and were diagnosed with epilepsy. The presence of gliosis on follow-up MRI indicated worse outcome with development of epilepsy (without statistical significance).

CONCLUSIONS

PRES syndrome has an overall good prognosis and the evolution to epilepsy is rare. The severity and duration of PSH or seizure severity and EEG findings at PRES onsetwere not associated with worse neurological outcomes in this study.

Dysfunction of 67-kDa Laminin Receptor Disrupts BBB Integrity via Impaired Dystrophin/AQP4 Complex and p38 MAPK/VEGF Activation Following Status Epilepticus

Status epilepticus (SE, a prolonged seizure activity) impairs brain-blood barrier (BBB) integrity, which results in secondary complications following SE. The non-integrin 67-kDa laminin receptor (67-kDa LR) plays a role in cell adherence to laminin (a major glycoprotein component in basement membrane), and participates laminin-mediated signaling pathways including p38 mitogen-activated protein kinase (p38 MAPK). Thus, we investigated the role of 67-kDa LR in SE-induced vasogenic edema formation in the rat piriform cortex (PC). SE diminished 67-kDa LR expression, but increased laminin expression, in endothelial cells accompanied by the reduced SMI-71 (a rat BBB barrier marker) expression. Astroglial 67-kDa LR expression was also reduced in the PC due to massive astroglial loss. 67-kDa LR neutralization led to serum extravasation in the PC concomitant with the reduced SMI-71 expression. 67-kDa LR neutralization also decreased expressions of dystrophin and aquaporin-4 (AQP4). In addition, it increased p38 MAPK phosphorylation and expressions of vascular endothelial growth factor (VEGF), laminin and endothelial nitric oxide synthase (eNOS), which were abrogated by SB202190, a p38 MAPK inhibitor. Therefore, our findings indicate that 67-kDa LR dysfunction may disrupt dystrophin-AQP4 complex, which would evoke vasogenic edema formation and subsequent laminin over-expression via activating p38 MAPK/VEGF axis.

Lateralized Periodic Discharges: A Literature Review

The purpose of this article is to provide a comprehensive review of the literature about a particular EEG pattern, lateralized periodic discharges (LPDs), or periodic lateralized epileptiform discharges (PLEDs). The review will discuss the history and terminology of LPDs and provide a detailed summary of the etiologies, pathophysiology, clinical symptoms, and imaging studies related to LPDs. Current controversies about the association of LPDs with seizures and their management will be reviewed. Finally, some unanswered questions and suggestions for future research on LPDs will be discussed.