A longitudinal MRI and TSPO PET-based investigation of brain region-specific neuroprotection by diazepam versus midazolam following organophosphate-induced seizures

Acute poisoning with organophosphorus cholinesterase inhibitors (OPs), such as OP nerve agents and pesticides, can cause life threatening cholinergic crisis and status epilepticus (SE). Survivors often experience significant morbidity, including brain injury, acquired epilepsy, and cognitive deficits. Current medical countermeasures for acute OP poisoning include a benzodiazepine to mitigate seizures. Diazepam was long the benzodiazepine included in autoinjectors used to treat OP-induced seizures, but it is now being replaced in many guidelines by midazolam, which terminates seizures more quickly, particularly when administered intramuscularly. While a direct correlation between seizure duration and the extent of brain injury has been widely reported, there are limited data comparing the neuroprotective efficacy of diazepam versus midazolam following acute OP intoxication. To address this data gap, we used non-invasive imaging techniques to longitudinally quantify neuropathology in a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) with and without post-exposure intervention with diazepam or midazolam. Magnetic resonance imaging (MRI) was used to monitor neuropathology and brain atrophy, while positron emission tomography (PET) with a radiotracer targeting translocator protein (TSPO) was utilized to assess neuroinflammation. Animals were scanned at 3, 7, 28, 65, 91, and 168 days post-DFP and imaging metrics were quantitated for the hippocampus, amygdala, piriform cortex, thalamus, cerebral cortex and lateral ventricles. In the DFP-intoxicated rat, neuroinflammation persisted for the duration of the study coincident with progressive atrophy and ongoing tissue remodeling. Benzodiazepines attenuated neuropathology in a region-dependent manner, but neither benzodiazepine was effective in attenuating long-term neuroinflammation as detected by TSPO PET. Diffusion MRI and TSPO PET metrics were highly correlated with seizure severity, and early MRI and PET metrics were positively correlated with long-term brain atrophy. Collectively, these results suggest that anti-seizure therapy alone is insufficient to prevent long-lasting neuroinflammation and tissue remodeling.

Pragmatic computerised perfusion diagnostics for non-convulsive status epilepticus: a prospective observational study

BACKGROUND

Non-convulsive status epilepticus (NCSE) is a time-dependent neurological disorder often misdiagnosed in the emergency setting. Electroencephalography (EEG) is often not available on a 24/7 basis, and Salzburg criteria may at times miss the diagnosis. Here, we tested the accuracy of hyperperfusion on CT perfusion imaging (CTP) in the identification of NCSE against Salzburg criteria, to define its potential role in a pragmatic diagnostic workflow.

METHODS

We enrolled consecutive patients with suspected acute seizure or seizure disorder undergoing brain imaging with CTP and EEG from January 2021 to March 2023. EEG recordings, Salzburg criteria and CTP hyperperfusion were rated and adjudicated by two independent experts blinded to patient status. A reference standard including all clinical, lab, imaging, EEG and therapeutic data was used to adjudicate NCSE diagnosis. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values (NPV) were calculated for CTP hyperperfusion and Salzburg criteria versus NCSE adjudicated according to reference standard.

RESULTS

Seventy-seven patients were enrolled. Among 21 NCSE cases, 17 were adjudicated according to Salzburg criteria (81%) and 4 received NCSE diagnosis according to reference standard. Agreement between EEG and CTP emerged in 16/21 NCSE cases, reaching sublobar level in 37.5% of cases. Receiver operator curve analysis suggested good accuracy for CTP hyperperfusion for the diagnosis of NCSE (AUROC 0.79, 95% CI 0.69 to 0.89). CTP hyperperfusion had a high NPV for NCSE (NPV 0.97, 95% CI 0.86 to 1).

CONCLUSION

CTP hyperperfusion may be implemented in the emergency fast-track to rule out NCSE, given very high NPV. Further validation studies are needed to evaluate CTP application in real-world setting for NCSE codes.

Time to FIRE NORSE: A single acronym for a heterogeneous presentation. Further information from a case series and discussion of the literature

PURPOSE

New-Onset Refractory Status Epilepticus (NORSE) is a rare and severe form of refractory status epilepticus without an apparent underlying cause at presentation or prior history of epilepsy. We aimed to describe the clinical features, etiology, treatment, and outcomes of NORSE in adults in a quaternary-level hospital in Saudi Arabia.

METHODOLOGY

In this retrospective cohort study, inclusion criteria involved patients over 14 years old who met the 2018 consensus definition for NORSE. Patients were identified using a combination of medical record admission labels 'status epilepticus' and 'encephalitis', and continuous EEG reports documenting status epilepticus. Demographic, clinical, and radiological data were collected and then analyzed for factors correlated with specific etiologies, better functional outcomes, and future diagnosis of epilepsy.

RESULTS

We found 24 patients presenting with NORSE between 2010 and 2021. Fever/infectious symptoms were the most common prodrome. Elevated inflammatory serum and cerebrospinal fluid markers in most patients. Brain MRI revealed T2/FLAIR hyperintensity patterns, predominantly affecting limbic and perisylvian structures. The etiology of NORSE varied, with immune-related causes being the most common. Long-term outcomes were poor, with a high mortality rate and most survivors developing drug-resistant epilepsy.

CONCLUSION

This study provides valuable insights into NORSE's clinical characteristics, highlighting the heterogeneity of this condition. The poor outcome is likely related to the progressive nature of the underlying disease, where refractory seizures are a clinical symptom. Thus, we propose to focus future research on the etiology rather than the NORSE acronym.

Assessment of a one-week ketogenic diet on brain glycolytic metabolism and on the status epilepticus stage of a lithium-pilocarpine rat model

The ketogenic diet (KD) has been shown to be effective in refractory epilepsy after long-term administration. However, its interference with short-term brain metabolism and its involvement in the early process leading to epilepsy remain poorly understood. This study aimed to assess the effect of a short-term ketogenic diet on cerebral glucose metabolic changes, before and after status epilepticus (SE) in rats, by using [18F]-FDG PET. Thirty-nine rats were subjected to a one-week KD (KD-rats, n = 24) or to a standard diet (SD-rats, n = 15) before the induction of a status epilepticus (SE) by lithium-pilocarpine administrations. Brain [18F]-FDG PET scans were performed before and 4 h after this induction. Morphological MRIs were acquired and used to spatially normalize the PET images which were then analyzed voxel-wisely using a statistical parametric-based method. Twenty-six rats were analyzed (KD-rats, n = 15; SD-rats, n = 11). The 7 days of the KD were associated with significant increases in the plasma β-hydroxybutyrate level, but with an unchanged glycemia. The PET images, recorded after the KD and before SE induction, showed an increased metabolism within sites involved in the appetitive behaviors: hypothalamic areas and periaqueductal gray, whereas no area of decreased metabolism was observed. At the 4th hour following the SE induction, large metabolism increases were observed in the KD- and SD-rats in areas known to be involved in the epileptogenesis process late-i.e., the hippocampus, parahippocampic, thalamic and hypothalamic areas, the periaqueductal gray, and the limbic structures (and in the motor cortex for the KD-rats only). However, no statistically significant difference was observed when comparing SD and KD groups at the 4th hour following the SE induction. A one-week ketogenic diet does not prevent the status epilepticus (SE) and associated metabolic brain abnormalities in the lithium-pilocarpine rat model. Further explorations are needed to determine whether a significant prevention could be achieved by more prolonged ketogenic diets and by testing this diet in less severe experimental models, and moreover, to analyze the diet effects on the later and chronic stages leading to epileptogenesis.

Status epilepticus in BRAF-related cardio-facio-cutaneous syndrome: Focus on neuroimaging clues to physiopathology

OBJECTIVE

Cardio-facio-cutaneous syndrome (CFC) is a genetic disorder due to variants affecting genes coding key proteins of the Ras/MAPK signaling pathway. Among the different features of CFC, neurological involvement, including cerebral malformations and epilepsy, represents a common and clinically relevant aspect. Status epilepticus (SE) is a recurrent feature, especially in a specific subgroup of CFC patients with developmental and epileptic encephalopathy (DEE) and history of severe pharmacoresistant epilepsy. Here we dissect the features of SE in CFC patients with a particular focus on longitudinal magnetic resonance imaging (MRI) findings to identify clinical-radiological patterns and discuss the underlying physiopathology.

METHODS

We retrospectively analyzed clinical, electroencephalogram (EEG), and MRI data collected in a single center from a cohort of 23 patients with CFC carrying pathogenic BRAF variants who experienced SE during a 5-year period.

RESULTS

Seven episodes of SE were documented in 5 CFC patients who underwent EEG and MRI at baseline. MRI was performed during SE/within 72 hours from SE termination in 5/7 events. Acute/early post-ictal MRI findings showed heterogenous abnormalities: restricted diffusion in 2/7, focal area of pcASL perfusion change in 2/7, focal cortical T2/FLAIR hyperintensity in 2/7. Follow-up images were available for 4/7 SE. No acute changes were detected in 2/7 (MRI performed 4 days after SE termination).

SIGNIFICANCE

Acute focal neuroimaging changes concomitant with ictal EEG focus were present in 5/7 episodes, though with different findings. The heterogeneous patterns suggest different contributing factors, possibly including the presence of focal cortical malformations and autoinflammation. When cytotoxic edema is revealed by MRI, it can be followed by permanent structural damage, as already observed in other genetic conditions. A better understanding of the physiopathology will provide access to targeted treatments allowing to prevent long-term adverse neurological outcome.

PLAIN LANGUAGE SUMMARY

Cardio-facio-cutaneous syndrome is a genetic disorder that often causes prolonged seizures known as status epilepticus. This study has a focus on electroclinical and neuroimaging patterns in patients with cardio-facio-cutaneous syndrome. During these status epilepticus episodes, we found different abnormal brain imaging patterns in patients, indicating various causes like brain malformations and inflammation. Understanding these patterns could help doctors find specific treatments, protecting cardio-facio-cutaneous syndrome patients from long-term brain damage.

Neuroimaging correlation with EEG in status epilepticus

PURPOSE

This study was to correlate EEG patterns with peri‑ictal perfusion CT abnormality (PCA) or peri‑ictal MR abnormality (PMA) in patients with status epilepticus (SE).

METHODS

This is a retrospective study done with SE patients from January 2016 to December 2021. We defined the PCA as single or multi-territorial cortical and/or thalamic hyper-perfusion. The PMA was defined as increased signal intensity in multiple brain regions including the cortex and subcortical regions. EEG patterns were categorized into electrographic seizure (ESz)/electroclinical seizure (ECSz), ictal-interictal continuum (IIC), and lateralized periodic discharges (LPDs) per the American Clinical Neurophysiology Society's guideline. We analyzed the association between the patterns of EEG and the presence of PCA or PMA.

RESULTS

Among 73 patients, 26 % (19/73) showed PCA and 25 % (18/73) demonstrated PMA. The patterns of EEG were as follows; ESz/ECSz in 25 % (18/73), IIC in 34 % (25/73), and LPD in 12 % (9/73). There was a significant correlation between the patterns of EEG and the presence of PMA, but not PCA. 48 % (12/25) had both PMA and PCA whereas 52 % (13/25) showed either PMA (6/25) or PCA (7/25).

CONCLUSION

Although PCA did not reveal an electro-radiographical correlation, PMA was strongly linked to ESz, ECSz, IIC, and LPD.

Sex-based structural and functional MRI outcomes in the rat brain after soman (GD) exposure-induced status epilepticus

OBJECTIVE

Exposure to the nerve agent, soman (GD), induces status epilepticus (SE), epileptogenesis, and even death. Although rodent models studying the pathophysiological mechanisms show females to be more reactive to soman, no tangible sex differences in brains postexposure have been reported. In this study, we used multimodal imaging using MRI in adult rats to determine potential sex-based biomarkers of soman effects.

METHODS

Male and female Sprague Dawley rats were challenged with 1.2 × LD50 soman followed by medical countermeasures. Ten weeks later, the brains were analyzed via structural and functional MRI.

RESULTS

Despite no significant sex differences in the initial SE severity after soman exposure, long-term MRI-based structural and functional differences were evident in the brains of both sexes. While T2 MRI showed lesser soman-induced neurodegeneration, large areas of T1 enhancements occurred in females than in males, indicating a distinct pathophysiology unrelated to neurodegeneration. fMRI-based resting-state functional connectivity (RSFC), indicated greater reductions in soman-exposed females than in males, associating with the T1 enhancements (unrelated to neurodegeneration) rather than T2-hyperintensity or T1-hypointensity (representing neurodegeneration). The wider T1 enhancements associating with the decreased spontaneous neuronal activity in multiple resting-state networks in soman-exposed females than males suggest that neural changes unrelated to cellular atrophy impinge on brain function postexposure. Taken together with lower spontaneous neural activity in soman-exposed females, the results indicate some form of neuroprotective state that was not present in males.

SIGNIFICANCE

The results indicate that endpoints other than neurodegeneration may need to be considered to translate sex-based nerve agent effects in humans.

PET Imaging and Neurohistochemistry Reveal that Curcumin Attenuates Brain Hypometabolism and Hippocampal Damage Induced by Status Epilepticus in Rats

Numerous preclinical studies provide evidence that curcumin, a polyphenolic phytochemical extracted from Curcuma longa (turmeric) has neuroprotective, anti-inflammatory and antioxidant properties against various neurological disorders. Curcumin neuroprotective effects have been reported in different animal models of epilepsy, but its potential effect attenuating brain glucose hypometabolism, considered as an early marker of epileptogenesis that occurs during the silent period following status epilepticus (SE), still has not been addressed. To this end, we used the lithium-pilocarpine rat model to induce SE. Curcumin was administered orally (300 mg/kg/day, for 17 days). Brain glucose metabolism was evaluated in vivo by 2-deoxy-2-[¹⁸F]Fluoro-D-Glucose ([¹⁸F]FDG) positron emission tomography (PET). In addition, hippocampal integrity, neurodegeneration, microglia-mediated neuroinflammation, and reactive astrogliosis were evaluated as markers of brain damage. SE resulted in brain glucose hypometabolism accompanied by body weight (BW) loss, hippocampal neuronal damage, and neuroinflammation. Curcumin did not reduce the latency time to the SE onset, nor the mortality rate associated with SE. Nevertheless, it reduced the number of seizures, and in the surviving rats, curcumin protected BW and attenuated the short-term glucose brain hypometabolism as well as the signs of neuronal damage and neuroinflammation induced by the SE. Overall, our results support the potential adaptogen-like effects of curcumin attenuating key features of SE-induced brain damage.

Increased uptake of the P2X7 receptor radiotracer 18 F-JNJ-64413739 in the brain and peripheral organs according to the severity of status epilepticus in male mice

OBJECTIVE

The P2X7 receptor (P2X7R) is an important contributor to neuroinflammation, responding to extracellularly released adenosine triphosphate. Expression of the P2X7R is increased in the brain in experimental and human epilepsy, and genetic or pharmacologic targeting of the receptor can reduce seizure frequency and severity in preclinical models. Experimentally induced seizures also increase levels of the P2X7R in blood. Here, we tested ¹⁸ F-JNJ-64413739, a positron emission tomography (PET) P2X7R antagonist, as a potential noninvasive biomarker of seizure-damage and epileptogenesis.

METHODS

Status epilepticus was induced via an intra-amygdala microinjection of kainic acid. Static PET studies (30 min duration, initiated 30 min after tracer administration) were conducted 48 h after status epilepticus via an intravenous injection of ¹⁸ F-JNJ-64413739. PET images were coregistered with a brain magnetic resonance imaging atlas, tracer uptake was determined in the different brain regions and peripheral organs, and values were correlated to seizure severity during status epilepticus. ¹⁸ F-JNJ-64413739 was also applied to ex vivo human brain slices obtained following surgical resection for intractable temporal lobe epilepsy.

RESULTS

P2X7R radiotracer uptake correlated strongly with seizure severity during status epilepticus in brain structures including the cerebellum and ipsi- and contralateral cortex, hippocampus, striatum, and thalamus. In addition, a correlation between radiotracer uptake and seizure severity was also evident in peripheral organs such as the heart and the liver. Finally, P2X7R radiotracer uptake was found elevated in brain sections from patients with temporal lobe epilepsy when compared to control.

SIGNIFICANCE

Taken together, our data suggest that P2X7R-based PET imaging may help to identify seizure-induced neuropathology and temporal lobe epilepsy patients with increased P2X7R levels possibly benefitting from P2X7R-based treatments.

The vasodilator naftidrofuryl attenuates short-term brain glucose hypometabolism in the lithium-pilocarpine rat model of status epilepticus without providing neuroprotection

Status epilepticus (SE) triggered by lithium-pilocarpine is a model of epileptogenesis widely used in rats, reproducing many of the pathological features of human temporal lobe epilepsy (TLE). After the SE, a silent period takes place that precedes the occurrence of recurrent spontaneous seizures. This latent stage is characterized by brain glucose hypometabolism and intense neuronal damage, especially at the hippocampus. Importantly, interictal hypometabolism in humans is a predictive marker of epileptogenesis, being correlated to the extent and severity of neuronal damage. Among the potential mechanisms underpinning glucose metabolism impairment and the subsequent brain damage, a reduction of cerebral blood flow has been proposed. Accordingly, our goal was to evaluate the potential beneficial effects of naftidrofuryl (25 mg/kg i.p., twice after the insult), a vasodilator drug currently used for circulatory insufficiency-related pathologies. Thus, we measured the effects of naftidrofuryl on the short-term brain hypometabolism and hippocampal damage induced by SE in rats. 2-deoxy-2-[¹⁸F]fluoro-D-glucose ([¹⁸F]FDG) positron emission tomography (PET) neuroimaging along with various neurohistochemical assays aimed to assess brain damage were performed. SE led to both severe glucose hypometabolism in key epilepsy-related areas and hippocampal neuronal damage. Although naftidrofuryl showed no anticonvulsant properties, it ameliorated the short-term brain hypometabolism induced by pilocarpine. Strikingly, the latter was neither accompanied by neuroprotective nor by anti-inflammatory effects. We suggest that naftidrofuryl, by acutely enhancing brain blood flow around the time of SE improves the brain metabolic state but this effect is not enough to protect from the damage induced by SE.

[Not Available]

New onset of seizures in children presenting with status epilepticus (SE) are rarely caused by intracranial aneurysms and haemorrhage, and the diagnosis is therefore challenging. This case report presents a ten-year-old healthy girl presenting with SE preceded by headache for two weeks. A CT-scan showed a subarachnoidal haemorrhage from a cerebral aneurysm. Intracranial pathology should be considered a differential diagnosis when receiving a child with new onset of seizures and SE. Early neuroimaging should be performed for correct treatment to be initiated without delay.

Child Neurology: Hemiconvulsion-Hemiplegia-Epilepsy Syndrome in the Setting of COVID-19 Infection and Multisystem Inflammatory Syndrome

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare pediatric epilepsy syndrome characterized by prolonged focal febrile convulsive status epilepticus with unilateral hemispheric cerebral edema, followed by the subsequent development of hemiplegia, global atrophy of the affected hemisphere, and epilepsy. The pathophysiology of HHE syndrome remains poorly understood though is clearly multifactorial. Factors thus far implicated are hyperthermia, proinflammatory state, and cytotoxic edema from prolonged ictal activity. Prognosis is variable, from the resolution of hemiplegia and seizures to permanent hemiparesis and refractory epilepsy. We describe a 2-year-old boy who presented with superrefractory focal status epilepticus in the setting of acute coronavirus infectious disease-2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C). He had right-sided hemiplegia on neurologic examination, and an MRI examination of the brain showed left cerebral hemispheric edema consistent with HHE syndrome. Our case represents the first report in the literature on HHE syndrome in the setting of acute COVID-19 and MIS-C.

Isolated aphasic status epilepticus: CT perfusion, SPECT and EEG reveal neurovascular coupling and support the differential diagnosis

Objective Among the clinical manifestations of stroke mimics, isolated aphasia is one of the most challenging due to its aetiopathogenic diagnosis. This short communication describes a specific perfusion and brain oscillatory pattern in a challenging case of prolonged isolated aphasia caused by status epilepticus, jointly investigated by computed tomography (CT) perfusion, single-photon emission computerized tomography (SPECT)/CT and EEG qualitative and quantitative analysis. Methods We discuss the different patterns of perfusion neuroimaging and EEG between SE and ischaemic stroke or postictal (Todd's)-related isolated aphasia, and propose these differences as a basis to support the differential diagnosis. Results The pattern associated with SE was characterized by focal hyperperfusion on CT perfusion maps (the left mean transit time was shorter with >10% asymmetry, and left cerebral blood volume and cerebral blood flow increased or slightly altered, relative to the contralateral side) and SPECT (focal left temporal hyperperfusion), without any early ischaemic signs on non-enhanced CT, while the EEG showed a predominant left hemispheric slow delta power. The aforementioned perfusion pattern contrasts with postictal epileptic Todd's phenomenon, which is characterized by hypoperfusion on CT perfusion (the mean transit time is prolonged and cerebral blood volume and cerebral blood flow are reduced, compared to the contralateral hemisphere) and SPECT (focal hypoperfusion), not restricted to the specific vascular territories. Significance CT perfusion patterns may add valuable information to support the differential diagnosis of status epilepticus, rather than acute ischaemic stroke or postictal Todd's phenomenon, in cases with challenging symptoms of prolonged isolated aphasia.

99mTc-HMPAO SPECT imaging reveals brain hypoperfusion during status epilepticus

Status epilepticus (SE) is a clinical emergency with high mortality. SE can trigger neuronal death or injury and alteration of neuronal networks resulting in long-term cognitive decline or epilepsy. Among the multiple factors contributing to this damage, imbalance between oxygen and glucose requirements and brain perfusion during SE has been proposed. Herein, we aimed to quantify by neuroimaging the spatiotemporal course of brain perfusion during and after lithium-pilocarpine-induced SE in rats. To this purpose, animals underwent ^99mTc-HMPAO SPECT imaging at different time points during and after SE using a small animal SPECT/CT system. ^99mTc-HMPAO regional uptake was normalized to the injected dose. In addition, voxel-based statistical parametric mapping was performed. SPECT imaging showed an increase of cortical perfusion before clinical seizure activity onset followed by regional hypo-perfusion starting with the first convulsive seizure and during SE. Twenty-four hours after SE, brain ^99mTc-HMPAO uptake was widely decreased. Finally, chronic epileptic animals showed regionally decreased perfusion affecting hippocampus and cortical sub-regions. Despite elevated energy and oxygen requirements, brain hypo-perfusion is present during SE. Our results suggest that insufficient compensation of required blood flow might contribute to neuronal damage and neuroinflammation, and ultimately to chronic epilepsy generated by SE.

New-onset refractory status epilepticus: A retrospective cohort study

PURPOSE

To describe the clinical, laboratory, neuroimaging, electroencephalographic features, etiology, treatment, as well as short-term and long-term outcomes of adults with new-onset refractory status epilepticus (NORSE).

METHOD

A retrospective, single institution cohort study (2010-2018) of consecutive adult patients with NORSE.

RESULTS

Among 20 patients with NORSE, nine (45 %) had prodromal febrile illness, 12 (60 %) had evidence of inflammation on CSF profile. Six patients (30 %) met criteria for definite autoimmune encephalitis (AE) while 8 patients (40 %) had probable AE. Eleven out of 13 (85 %) patients had an abnormal FDG-PET scan with the most common finding being regional hypermetabolism. Fourteen patients (70 %) received immunotherapy and ten (50 %) received the ketogenic diet (KD). Fifteen patients (75 %) progressed to super-refractory status epilepticus (SRSE) and seven patients (35 %) died in the hospital or within six months of discharge. Among the surviving patients, eight (40 %) had a good outcome (i.e., modified Rankin Scale score 0-2); 12 (80 %) received a diagnosis of epilepsy of which nine (75 %) developed drug-resistant epilepsy.

CONCLUSIONS

New-onset refractory status epilepticus is a syndrome associated with multiple complications, high mortality, and subsequent intractable epilepsy. There are multiple causes, some of which are autoimmune encephalitides; however, in this series the majority of patients had no clear etiology identified after extensive evaluation. Prospective studies are needed to determine optimal evaluation and treatment.

[Difficulties in distinguishing abnormal intensities associated with convulsion from tumor on MRI: a case report]

A 48-year-old man was admitted to our department with generalized convulsive seizures followed by recurrent partial clonic convulsions in the left face and arm. Convulsions stopped temporarily after administration of diazepam, fosphenytoin, and levetiracetam. However, frequent partial seizures occurred repeatedly and general anesthesia was required to control seizures. Diffusion-weighted and T₂-weighted images revealed a high-intensity lesion in the right frontal lobe. A tumor-like area in the white matter showed high intensity on T₂-weighted images with ring enhancement on gadolinium-enhanced T₁-weighted images. An area of frontal cortex near the tumor was also enhanced. Brain surgery was performed for the purposes of diagnosis, seizure control and tumor resection. Histological findings demonstrated oligodendroglioma in the ring-enhancing area, but not in the frontal cortex. This fact indicated that contrast enhancement of the frontal cortex was caused by status epilepticus. It is important to recognize that status epilepticus could cause contrast enhancement on magnetic resonance imaging.

Status Epilepticus, Refractory Status Epilepticus, and Super-refractory Status Epilepticus

PURPOSE OF REVIEW

Status epilepticus, refractory status epilepticus, and super-refractory status epilepticus can be life-threatening conditions. This article presents an overview of the three conditions and discusses their management and outcomes.

RECENT FINDINGS

Status epilepticus was previously defined as lasting for 30 minutes or longer but now is more often defined as lasting 5 minutes or longer. A variety of potential causes exist for status epilepticus, refractory status epilepticus, and super-refractory status epilepticus, but all three ultimately involve changes at the cellular and molecular level. Management of patients with status epilepticus generally requires several studies, with EEG of utmost importance given the pathophysiologic changes that can occur during the course of status epilepticus. Status epilepticus is treated with benzodiazepines as first-line antiepileptic drugs, followed by phenytoin, valproic acid, or levetiracetam. If status epilepticus does not resolve, these are followed by an IV anesthetic and then alternative therapies based on limited data/evidence, such as repetitive transcranial magnetic stimulation, therapeutic hypothermia, immunomodulatory agents, and the ketogenic diet. Scores have been developed to help predict the outcome of status epilepticus. Neurologic injury and outcome seem to worsen as the duration of status epilepticus increases, with outcomes generally worse in super-refractory status epilepticus compared to status epilepticus and sometimes also to refractory status epilepticus.

SUMMARY

Status epilepticus can be a life-threatening condition associated with multiple complications, including death, and can progress to refractory status epilepticus and super-refractory status epilepticus. More studies are needed to delineate the best management of these three entities.

FDG-PET and MRI in the Evolution of New-Onset Refractory Status Epilepticus

BACKGROUND AND PURPOSE

New-onset refractory status epilepticus is a clinical condition characterized by acute and prolonged pharmacoresistant seizures without a pre-existing relevant neurologic disorder, prior epilepsy, or clear structural, toxic, or metabolic cause. New-onset refractory status epilepticus is often associated with antineuronal antibodies and may respond to early immunosuppressive therapy, reflecting an inflammatory element of the condition. FDG-PET is a useful diagnostic tool in inflammatory and noninflammatory encephalitis. We report here FDG-PET findings in new-onset refractory status epilepticus and their correlation to disease activity, other imaging findings, and outcomes.

MATERIALS AND METHODS

Twelve patients who met the criteria for new-onset refractory status epilepticus and who had FDG-PET and MR imaging scans and electroencephalography at a single academic medical center between 2008 and 2017 were retrospectively identified. Images were independently reviewed by 2 radiologists specialized in nuclear imaging. Clinical characteristics and outcome measures were collected through chart review.

RESULTS

Twelve patients underwent 21 FDG-PET scans and 50 MR imaging scans. Nine (75%) patients were positive for autoantibodies. All patients had identifiable abnormalities on the initial FDG-PET in the form of hypermetabolism (83%) and/or hypometabolism (42%). Eight (67%) had medial temporal involvement. All patients (n = 3) with N-methyl-D-aspartic acid receptor antibodies had profound bilateral occipital hypometabolism. Initial MR imaging findings were normal in 6 (50%) patients. Most patients had some degree of persistent hyper- (73%) or hypometabolism (45%) after immunosuppressive therapy. FDG-PET hypometabolism was predictive of poor outcome (mRS 4-6) at hospital discharge (P = .028).

CONCLUSIONS

Both FDG-PET hypometabolism and hypermetabolism are seen in the setting of new-onset refractory status epilepticus and may represent markers of disease activity.

Recurrent hepatic failure and status epilepticus: an uncommon presentation of hyperargininemia

Argininemia is a rare hereditary disease due to a deficiency of hepatic arginase, which is the last enzyme of the urea cycle and hydrolyzes arginine to ornithine and urea. Herein we report a patient with arginase I (ARG1) deficiency who presented with recurrent nonconvulsive status epilepticus and liver failure. A novel homozygous frameshift mutation c.703_707delGGACTinsAGACTGGACC (p.G235Rfs*20) was detected.

A magnetic resonance imaging study of early brain injury in a rat model of acute DFP intoxication

Current treatments for seizures induced by organophosphates do not protect sufficiently against progressive neurodegeneration or delayed cognitive impairment. Developing more effective therapeutic approaches has been challenging because the pathogenesis of these delayed consequences is poorly defined. Using magnetic resonance imaging (MRI), we previously reported brain lesions that persist for months in a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP). However, the early spatiotemporal progression of these lesions remains unknown. To address this data gap, we used in vivo MRI to longitudinally monitor brain lesions during the first 3 d following acute DFP intoxication. Adult male Sprague Dawley rats acutely intoxicated with DFP (4mg/kg, sc) were MR imaged at 6, 12, 18, 24, 48, 72h post-DFP, and their brains then taken for correlative histology to assess neurodegeneration using FluoroJade C (FJC) staining. Acute DFP intoxication elicited moderate-to-severe seizure activity. T2-weighted (T2w) anatomic imaging revealed prominent lesions within the thalamus, piriform cortex, cerebral cortex, hippocampus, corpus striatum, and substantia nigra that corresponded to neurodegeneration, evident as bands of FJC positive cells. Semi-quantitative assessment of lesion severity demonstrated significant regional variation in the onset and progression of injury, and suggested that lesion severity may be modulated by isoflurane anesthesia. These results imply that the timing of therapeutic intervention for attenuating brain injury following OP intoxication may be regionally dependent, and that longitudinal assessment of OP-induced damage by MRI may be a powerful tool for assessing therapeutic response.

Status epilepticus in pregnancy: Etiology, management, and clinical outcomes

BACKGROUND

Status epilepticus (SE) in pregnancy carries significant risk to both mother and fetus. There is limited literature available on SE occurring in pregnancy world-over, with majority being from obstetric centers.

METHODS

All women who developed SE related to pregnancy (gestation, labor, or puerperium) between January 2000 and December 2016 were included in the study. Data were collected from our SE registry, maintained, and archived in the institute. The variables influencing the maternal and fetal outcome were compared using Student's t-test for continuous variables and Fisher's exact test for discrete variables.

RESULTS

During the 16-year study period, a total of 348 SE events were recorded in 294 patients. Among these, there were 138 women, of which 17 had SE related to pregnancy. The etiology of SE was remote symptomatic in two and acute symptomatic in 15 patients. The various causes detected after initial evaluation for acute symptomatic SE were eclampsia (n=4), posterior reversible encephalopathy syndrome due to various causes other than eclampsia (n=6), cortical venous thrombosis (n=3), subarachnoid hemorrhage (n=1), and NMDA receptor antibody-mediated encephalitis (n=1).13 of 17 women with SE (76%) had good outcome. Majority of the fetuses had good outcomes, i.e., Category 1 (n=9, 57%). Duration of intensive care unit stay (p=0.029) and Status Epilepticus Severity Score (p=0.0324) at admission, were found to be significantly associated with poor outcomes.

CONCLUSION

In any patient presenting with SE occurring in pregnancy, though eclampsia is presumed to be the most common overall cause; it is relevant to consider other etiologies such as posterior reversible encephalopathy syndrome, cortical venous thrombosis, and autoimmune encephalitis especially in cases presenting with refractory SE. Posterior reversible encephalopathy may occur in pregnancy due to diverse etiologies other than eclampsia.

Surgical outcome in adolescents with mesial temporal sclerosis: Is it different?

There are extensive studies evaluating mesial temporal sclerosis (MTS) in adults and limited studies in children, with adolescents being included within both patient populations. Our aim was to evaluate predictors of surgical outcome solely in adolescent patients with MRI- and pathology -proven MTS. The Yale Epilepsy Surgery Database was reviewed from 1987 to 2012 for adolescent patients with confirmed MTS on MRI and pathology who underwent temporal lobectomy and had greater than two-year postsurgical follow-up. Clinical and electrographic data were reviewed. Eighteen patients were identified. Eleven patients (61%) were seizure-free. All seven patients (39%) who were not seizure-free free were found to have lateralized ictal onset within one hemisphere involving two or more lobes on scalp EEG (p<0.001). Of the 7 patients who were not seizure-free, 4 had a history of status epilepticus (compared to 1/11 seizure-free patients; p=0.047), and 4 had lateralized hypometabolism involving two or more lobes within a hemisphere seen on PET (compared to 0/8 seizure-free patients; p=0.002). A novel finding in our study was that lateralized (rather than localized) ictal onset on scalp EEG, lateralized hypometabolism on PET, and history of status epilepticus were risk factors for not attaining seizure freedom in adolescents with MTS who underwent temporal lobectomy.

Generalized Status Epilepticus in a Patient with Acute-onset Type 1 Diabetes Mellitus Associated with Severe Kidney Dysfunction: A Case Report and Literature Review

A 65-year-old Japanese man with advanced chronic kidney disease (CKD) developed acute-onset type 1 diabetes mellitus (T1D) that was associated with severe acute kidney injury and was manifested by generalized tonic-clonic status epilepticus. His seizures resolved without recurrence after correcting the diabetic ketoacidosis. Although hyperglycemia is an important cause of acute symptomatic seizure (ASS), patients with ketotic hyperglycemia develop ASS less frequently. In this T1D case with CKD, severe hyperglycemia in conjunction with other metabolic insults, such as uremia, hyponatremia, and hypocalcemia, probably provoked his seizure despite the severe ketonemia.

Status epilepticus following local anesthesia in a previously healthy adult

BACKGROUND

Local anesthesia could result in lethal complications if injected in highly vascularized area. Dentist should take care to avoid such complications.

CASE PRESENTATION

We present a case of 15 year old girl with a coma following convulsive status epilepticus which developed after inferior alveolar nerve blockade by a dentist. The patient was admitted to the intensive care unit ICU and recovered within several days.

CONCLUSION

This case is reported to tell both of dentists and medical staff that although it is uncommon, such complications of local anesthesia should be in mind to be avoided and managed promptly if happened.

Crossed Cerebellar Diaschisis in Status Epilepticus

Crossed cerebellar diaschisis (CCD) is an interesting phenomenon which classically refers to the depressed blood flow and metabolism affecting one cerebellar hemisphere after a contralateral hemispheric infarction. However, CCD can also be caused by a prolonged seizure. We herein report a case of CCD due to status epilepticus in a patient who showed unique magnetic resonance imaging findings.

[Hemiconvulsion-hemiplegia-epilepsy syndrome]

Hemiconvulsion-hemiplegia-epilepsy syndrome is a rare consequence of a status epilepticus in the course of a febrile illness in children under the age of four years. Various degrees of hemiplegia and within a variable interval, subsequent epilepsia follows. Neuroimaging show unilateral cytotoxic oedema at the initial convulsive state, followed by severe chronic atrophy of the affected hemisphere. The aetiology remains unclear. Several mechanisms may contribute to this condition. To improve the outcome, further studies are needed and early diagnosis is essential.

[Hemiconvulsion-hemiplegia-epilepsy syndrome in a girl with adrenogenital syndrome]

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a very rare condition caused by a fever-associated status epilepticus causing various degrees of hemiplegia and secondary epilepsy affecting children under the age of four. The aetiology is not fully understood. We report a case of a two-year-old girl with adrenogenital syndrome presenting with HHE syndrome in the course of a bacterial septicaemia.

Transient bradycardia induced by thiopentone sodium: a unique challenge in the management of refractory status epilepticus

Thiopentone sodium is one of the important drugs in the armamentarium for terminating refractory status epilepticus, a neurological emergency. We report a case of thiopentone-related bradycardia during the management of the new onset refractory status epilepticus in a young man, which was circumvented by prophylactic insertion of temporary pacemaker while thiopentone infusion was continued. A systematic approach was employed to manage the status epilepticus, including infusion of thiamine and glucose followed by antiepileptic drugs. The patient was ventilated and infused with lorazepam, phenytoin, sodium valproate, levetiracetam and midazolam followed by thiopentone sodium. With the introduction of thiopentone the seizures could be controlled but the patient developed severe bradycardia and junctional rhythm. The bradycardia disappeared when thiopentone was withdrawn and reappeared when the drug was reintroduced. Propofol infusion was tried with no respite in seizures. Later thiopentone sodium was reintroduced after inserting temporary cardiac pacemaker. Seizure was controlled and patient was weaned off the ventilator.

Ictal cerebral positron emission tomography (PET) in focal status epilepticus

The diagnosis of focal status epilepticus (SE) can be challenging, particularly when clinical manifestations leave doubts about its nature, and electroencephalography (EEG) is not conclusive. This work addresses the utility of ictal (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) in focal SE, which was performed in eight patients in whom SE was finally diagnosed. Clinical, MRI and EEG data were reviewed. (18)F-FDG-PET proved useful: (1) to establish the diagnosis of focal SE, when clinical elements were equivocal or the EEG did not show clear-cut epileptiform abnormalities; (2) to delineate the epileptogenic area in view of possible resective surgery; and (3) when clinical features, MRI and EEG were incongruent regarding the origin of SE. We suggest that ictal (18)F-FDG-PET may represent a valuable diagnostic tool in selected patients with focal SE or frequent focal seizures.

(R)-[11C]verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

BACKGROUND

Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate.

METHODS

(R)-[11C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[11C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[11C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM).

RESULTS

All data analysis approaches indicated only modest differences in brain distribution of (R)-[11C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats.

CONCLUSIONS

P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.

Status epilepticus revealing syphilitic meningoencephalitis

The incidence of seizures in neurosyphilis ranges from 14 to 60%, however, neurosyphillis presenting with status epilepticus (SE) is rare. We report the case of a 49 year old man with no history of epilepsy and with a 9-year history of untreated syphilitic chancre. He presented in October 2005 with four stereotyped epileptic seizures lasting less than 2 minutes followed by a prolonged seizure lasting 20 minutes without recovery of consciousness. He regained consciousness after admission in intensive care unit for SE management. Brain CT scan showed disappearance of cortical sulci with collapse of ventricles. Ophthalmological examination revealed papillary hyperemia. Interictal EEG showed bi-frontal bi- and triphasic spikes. Syphilitic serology in blood then in cerebrospinal fluid (CSF) confirmed the diagnosis of neurosyphilis. The clinical course was favorable after early administration of penicillin and carbamazepine with total remission of seizures. We underline the rarity of neurosyphilis vasculitis as possible etiology of SE and underline the crucial value of syphilitic serology in blood then in CSF, especially within any atypical presentation of encephalitis, meningoencephalitis; or encephalitis and vasculitis. We highlight the very good prognosis if treated precociously.

[Non-convulsive status epilepticus secondary to subarachnoid haemorrhage as the presenting symptom of a cerebral amyloid angiopathy]

INTRODUCTION

Cerebral amyloid angiopathy is a frequent cause of haemorrhagic cerebrovascular disease in persons over the age of 65 and, sometimes, the initial symptoms can be epilepsy-like.

CASE REPORT

A 62-year-old female with no relevant past history who was admitted to hospital due to non-convulsive status epilepticus, auditory hallucinations and ideomotor apraxia; an electroencephalogram performed on the patient revealed periodic lateralised epileptiform discharges in the right parietooccipital region. Susceptibility-weighted magnetic resonance imaging showed a sub-acute focal subarachnoid haemorrhage in the right parietotemporal region and cortico-subcortical microbleeding in different stages of the progression of the disease that were compatible with cerebral amyloid angiopathy. A critical simple single-photon emission tomography scan was performed and findings revealed an area of hyperperfusion in the same region. Antiepileptic treatment was established with clinical, neurophysiological and scintigraphic resolution.

CONCLUSIONS

The article reports a case with non-convulsive status epilepticus as the initial symptom of cerebral amyloid angiopathy. It also highlights the usefulness of sequences of susceptibility-weighted magnetic resonance imaging and the physiopathogenesis of periodic lateralised epileptiform discharges as an element of epileptic activity is discussed.

[Differential diagnosis of status epilepticus]

The diagnosis of status epilepticus can be retained, wrongly, in several circumstances. Nonepileptic pseudoseizures from a psychiatric origin and some movement disorders can mimic convulsive status epilepticus. Encephalopathy of various causes (post-anoxic, metabolic, toxic, Creutzfeldt-Jakob disease) can be wrongly taken for non-convulsive status epilepticus, mainly due to inadequate interpretation of the electroencephalogram (EEG). In these encephalopathies, the existence of (non-epileptic) myoclonus and the abolition of the EEG abnormalities with the use of a benzodiazepine (without correction of the clinical symptoms) are additional confounding factors, leading to false diagnosis. Nevertheless, in general, the diagnosis of status epilepticus can be confirmed or rejected base on a combined analysis of the clinical data and the EEG.

Short-term plasticity of central benzodiazepine receptors in status epilepticus: case report

(123)I-iomazenil SPECT is of value in determining an epileptogenic focus, however, transient uptake change has been rarely reported in epileptic disorders. A 78-year-old woman diagnosed as status epilepticus (SE) showed transient reduction in (123)I-iomazenil uptake within the epileptic foci on SPECT images during a couple of weeks. It suggests a seizure-related 'short-term' plasticity in the central benzodiazepine receptors and dynamic change in the regulatory mechanisms of inhibitory neurotransmitter system within the epileptic foci in patients with SE.

Efficacy of Surgical Treatment of De Novo, Adult-Onset, Cryptogenic, Refractory Focal Status Epilepticus

BACKGROUND

There have been few published reports of successful surgical treatment of focal status epilepticus. Surgical intervention is considered a last resort after medical strategies have been exhausted.

OBJECTIVE

To report a case of an adult who was initially seen with de novo, medically refractory, cryptogenic focal status epilepticus and underwent resection of an electrographically defined portion of the left middle frontal gyrus with multiple subpial transections of the adjacent cortex resulting in termination of the electroclinical seizure activity.

DESIGN

Report of a case of successful surgical treatment of cryptogenic focal status epilepticus.

INTERVENTION

After an initial 35 days of oral antiepileptic drug therapy and subsequent 16 days of continuous electroencephalography-guided intravenous antiepileptic drug therapy in an intensive care unit setting, and after extensive preoperative and intraoperative characterization of the epileptogenic zone, a tailored resection of the left middle frontal gyrus with multiple subpial transections of the surrounding cortex was performed.

RESULTS

The restricted surgical resection and multiple subpial transections terminated the seizure activity. Neuropathological examination of the resected tissue revealed moderate inflammatory changes and a few abnormally located neurons without any definitive evidence of dysplasia, which was suspected preoperatively.

CONCLUSIONS

We suggest that focal cortical resection may be an appropriate intervention in medically refractory focal status epilepticus even when an overt structural etiology is not evident preoperatively and should be considered as an option at the onset of intractability.

Low frequency electrical stimulation through subdural electrodes in a case of refractory status epilepticus

OBJECTIVE

We delivered low frequency stimulation through subdural electrodes to suppress seizures in a case of refractory status epilepticus (RSE).

METHODS

A 26-year-old female developed RSE after several days of febrile illness. Seizure control required continuous infusion of two anesthetics plus high doses of 2-4 enteral antiepileptic drugs. After 3 months of RSE, subdural strips were placed to determine surgical candidacy. Five independent ictal onset zones were identified. Because she was a poor candidate for epilepsy surgery and had a poor prognosis, the implanted subdural electrodes were used to administer 0.5 Hz stimulations to the ictal onset zones in 30 min trains daily for 7 consecutive days in an attempt to suppress seizures.

RESULTS

After 1 day of stimulation, one anesthetic agent was successfully discontinued. Seizures only returned by the 4th day when the second anesthetic had been reduced by 60%. Upon returning, seizures arose from only one of the 5 original ictal onset zones. Unfortunately, RSE persisted, and she eventually died.

CONCLUSIONS

In this case of RSE, low frequency stimulation through subdural electrodes transiently suppressed seizures from all but one ictal onset zone and allowed significant reduction in seizure medication.

SIGNIFICANCE

Low frequency cortical stimulation may be useful in suppressing seizures.

H2(15)O or 13NH3 PET and electromagnetic tomography (LORETA) during partial status epilepticus

The authors evaluated the feasibility and source localization utility of H2(15)O or 13NH3 PET and low-resolution electromagnetic tomography (LORETA) in three patients with partial status epilepticus (SE). Results were correlated with findings from intraoperative electrocorticographic recordings and surgical outcomes. PET studies of cerebral blood flow and noninvasive source modeling with LORETA using statistical nonparametric mapping provided useful information for localizing the ictal activity in patients with partial SE.