Prolonged refractory status epilepticus with early and persistent restricted hippocampal signal MRI abnormality

LGI1 antibody-associated encephalitis without evidence of inflammation in CSF and brain MRI

OBJECTIVE

This study aimed to explore the frequency and distinct characteristics of adult patients with LGI1 antibody-associated encephalitis in the absence of inflammatory abnormalities in both routine CSF analysis and brain MRI.

METHODS

We conducted a retrospective study of adult patients with antibodies targeting LGI1 and then screened patients with no evidence of inflammation in brain MRI and normal results in routine CSF analysis, including white blood cell count, protein concentration, IgG, and oligoclonal bands.

RESULTS

Among 80 patients with LGI1 antibody-associated encephalitis in our center, 31 (38.8%) fulfilled the screening criteria. For these patients, the onset age was 57.0 ± 14.7 years, and 19 (61.3%) were female. Viral prodrome occurred in 5 patients (16.1%). Faciobrachial dystonic seizures (FBDS) were the most predominant symptom (38.7%), followed by seizure onset (22.6%) and memory deficits (19.4%). The sensitivity of antibody detection in serum was higher than CSF (96.8% vs. 48.4%, p < 0.001). Most patients (30/31, 96.8%) benefited from the first-line immunotherapy, and 23 patients (74.2%) achieved complete recovery, yet 3 patients (9.7%) had clinical relapses in 2-year follow-up after discharge. The patients had a higher prevalence of females (61.9% vs. 26.7%, p = 0.003) and were more frequently associated with FBDS during the disease course (38.7% vs. 10.2%, p = 0.004). However, there was no difference in treatment outcomes and recurrence ratio between the two groups (p = 0.144 and p = 0.515). Moreover, we divided all 80 patients into four groups according to antibody titer levels in serum and CSF at the time of diagnosis, respectively. WBC and protein concentrations in CSF showed no difference among the four groups.

CONCLUSIONS

The absence of evidence of inflammation in routine CSF analysis and brain MRI did not rule out anti-LGI1 associated encephalitis. FBDS and the subacute onset of cognitive dysfunction should push forward with autoantibody testing for patients even without inflammatory abnormalities. The routine inflammatory indicators in CSF seemed to be unrelated to antibody titer levels.

Seizure-induced reversible MRI abnormalities in status epilepticus: A systematic review

In the context of status epilepticus (SE), seizure-induced reversible MRI abnormalities (SRMA) can be difficult to differentiate from epileptogenic pathologies. To identify patterns and characteristics of SRMA, we conducted a systematic review in accordance with the Preferred Items Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included publications describing patients (a) presenting with status epilepticus, (b) exhibiting seizure-induced MRI abnormalities, (c) who demonstrated complete resolution of MRI abnormality at follow-up, and (d) who had availability of descriptive MRI results. A total of 49 cases from 19 publications fulfilled our eligibility criteria. Signal abnormalities were most frequently reported on T2-weighted sequences followed by diffusion-weighted and fluid-attenuated inversion recovery imaging. Both unilateral and bilateral SRMA were reported. Unilateral EEG abnormalities were often associated with ipsilateral SRMA. The signal changes appeared during the ictus itself in some subjects whilst the median time to SRMA appearance and resolution were 24 h and 96.5 days, respectively. Based on the distribution of reversible signal alterations, we identified five 'composite patterns': (1) predominant cortical (with or without subcortical, leptomeningeal or thalamic involvement), (2) hippocampal (with or without cortical, subcortical, leptomeningeal, or thalamic involvement), (3) claustrum, (4) predominant subcortical, and (5) splenium involvement. Amongst treatment-responsive SE patients, the cortical pattern was the most prevalent whereas hippocampal involvement was most frequently reported in refractory SE. Cortical atrophy, hippocampal sclerosis, and cortical laminar necrosis were common long-term sequelae after the resolution of SRMA. In this review, we highlight many limitations of the literature and discuss future directions for research.

Ketogenic Diet Therapies for Seizures and Status Epilepticus

Ketogenic diet therapies are high-fat, low-carbohydrate diets designed to mimic a fasting state. Although initially developed nearly one century ago for seizure management, most clinical trials for the management of drug-resistant epilepsy in children as well as adults have been conducted over the last 3 decades. Moreover, ketogenic diets offer promising new adjunctive strategies in the critical care setting for the resolution of acute status epilepticus when traditional antiseizure drugs and anesthetic agents fail. Here, we review the history of ketogenic diet development, the clinical evidence supporting its use for the treatment of drug-resistant epilepsy in children and adults, and the early evidence supporting ketogenic diet feasibility, safety, and potential efficacy in the management of status epilepticus.

Therapeutic Options for Patients with Refractory Status Epilepticus in Palliative Settings or with a Limitation of Life-Sustaining Therapies: A Systematic Review

BACKGROUND

Refractory status epilepticus (RSE) represents a serious medical condition requiring early and targeted therapy. Given the increasing number of elderly or multimorbid patients with a limitation of life-sustaining therapy (LOT) or within a palliative care setting (PCS), guidelines-oriented therapy escalation options for RSE have to be omitted frequently.

OBJECTIVES

This systematic review sought to summarize the evidence for fourth-line antiseizure drugs (ASDs) and other minimally or non-invasive therapeutic options beyond guideline recommendations in patients with RSE to elaborate on possible treatment options for patients undergoing LOT or in a PCS.

METHODS

A systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, focusing on fourth-line ASDs or other minimally or non-invasive therapeutic options was performed in February and June 2020 using the MEDLINE, EMBASE and Cochrane databases. The search terminology was constructed using the name of the specific ASD or therapy option and the term 'status epilepticus' with the use of Boolean operators, e.g. "(brivaracetam) AND (status epilepticus)". The respective Medical Subject Headings (MeSH) and Emtree terms were used, if available.

RESULTS

There is currently no level 1, grade A evidence for the use of ASDs in RSE. The best evidence was found for the use of lacosamide and topiramate (level 3, grade C), followed by brivaracetam, perampanel (each level 4, grade D) and stiripentol, oxcarbazepine and zonisamide (each level 5, grade D). Regarding non-medicinal options, there is little evidence for the use of the ketogenic diet (level 4, grade D) and magnesium sulfate (level 5, grade D) in RSE. The broad use of immunomodulatory or immunosuppressive treatment options in the absence of a presumed autoimmune etiology cannot be recommended; however, if an autoimmune etiology is assumed, steroid pulse, intravenous immunoglobulins and plasma exchange/plasmapheresis should be considered (level 4, grade D). Even if several studies suggested that the use of neurosteroids (level 5, grade D) is beneficial in RSE, the current data situation indicates that there is formal evidence against it.

CONCLUSIONS

RSE in patients undergoing LOT or in a PCS represents a challenge for modern clinicians and epileptologists. The evidence for the use of ASDs in RSE beyond that in current guidelines is low, but several effective and well-tolerated options are available that should be considered in this patient population. More so than in any other population, advance care planning, advance directives, and medical ethical aspects have to be considered carefully before and during therapy.

Clinically based score predicting cryptogenic NORSE at the early stage of status epilepticus

Objective

To determine whether a clinically based score predicts cryptogenic new-onset refractory status epilepticus (C-NORSE) at the early stage of status epilepticus (SE) with prominent motor symptoms (SE-M) of unclear etiology.

Methods

The score (range 0–6) included 6 clinical features: highly refractoriness to antiseizure drugs, previously healthy individual, presence of prodromal fever, absence of prodromal psychobehavioral or memory alterations, absence of dyskinesias, and symmetric brain MRI abnormalities (the first 2 mandatory). We retrospectively assessed the usefulness of a high scale score (≥5) in predicting C-NORSE in 83 patients with SE-M of unclear etiology, who underwent testing for neuronal surface antibodies (NS-Abs) between January 2007, and December 2019.

Results

Thirty-one (37.3%) patients had a high score. Patients with a high score had more frequent prodromal fever (28/31 vs 24/52), mechanical ventilatory support (31/31 vs 36/52), and symmetric MRI abnormalities (26/31 vs 12/52), had less frequent involuntary movements (2/31 vs 30/52), and had absent prodromal psychobehavioral alterations (0/31 vs 27/52), CSF oligoclonal band detection (0/27 vs 11/38), tumor association (0/31 vs 13/52), or NS-Abs (0/31 vs 29/52) than those with a low score (<5). Thirty-three patients (median age, 27 years; 18 [54.5%] female) were finally regarded as C-NORSE. The sensitivity and specificity of a high score for predicting C-NORSE were 93.9% (95% CI 0.87–0.94) and 100% (95% CI 0.95–1.00), respectively.

Conclusions

Patients with a high score in the indicated scale are more likely to have C-NORSE, making it a useful diagnostic tool at the early stage of SE-M before antibody test results become available.

The timelines of MRI findings related to outcomes in adult patients with new-onset refractory status epilepticus

OBJECTIVE

To identify the timelines of magnetic resonance imaging (MRI) abnormalities and their relationships with the clinical outcomes of patients with new-onset refractory status epilepticus (NORSE).

METHODS

This retrospective observational study enrolled patients with NORSE who were admitted from March 2008 to July 2018. MRI abnormalities were analyzed visually with the readers blinded to the clinical characteristics of the patients. Poor functional outcome was defined as a Glasgow Outcome Scale score ≤ 3 at discharge. Subsequent pharmacoresistant epilepsy was defined as seizures not controlled by two or more anti-seizure medications 6 months after discharge.

RESULTS

Among 39 patients with NORSE, 32 (82.1%) exhibited an MRI abnormality. The most common abnormalities were persisting mesial temporal lobe signal abnormality (51.3%); initial diffuse leptomeningeal enhancement within 16 days from seizure onset (15/35, 42.9%); and hippocampal atrophy, which started to appear 26 days after seizure onset (15/26, 57.7%). Only three patients had claustrum abnormalities. Patients with insular involvement had longer treatment delay than those without (24.0 vs 5.5 hours, respectively, P = .02). Duration of status epilepticus (SE) tended to have a linear association with hippocampal atrophy (P = .055). Patients with diffuse leptomeningeal enhancement were more likely to have a poor functional outcome and to develop subsequent pharmacoresistant epilepsy than those without this finding (93.3% vs 15.0%, P < .001; 75.0% vs 22.2%, P = .004, respectively); the results were significant even after adjusting for age, sex, and duration of SE. Hippocampal atrophy and diffuse cortical atrophy were also significantly associated with poor functional outcomes (P = .001 and P = .002, respectively), and patients with these conditions were more likely to develop subsequent pharmacoresistant epilepsy than those without these conditions, after adjusting for age and sex (P = .035 and P = .048, respectively), but not after adjusting for duration of SE.

SIGNIFICANCE

Initial diffuse leptomeningeal enhancement and later hippocampal atrophy were associated with a poor functional outcome and subsequent pharmacoresistant epilepsy.

Application of ketogenic diets for pediatric neurocritical care

In this review, we summarize the general mechanisms of the ketogenic diet, and the application of a ketogenic diet in pediatric intensive care units for the neurological disorders of children and young infants. A ketogenic diet is a high-fat, low-carbohydrate, adequate-protein diet. It can alter the primary cerebral energy metabolism from glucose to ketone bodies, which involves multiple mechanisms of antiepileptic action, antiepileptogenic properties, neuro-protection, antioxidant and anti-inflammatory effects, and it is potentially a disease-modifying intervention. Although a ketogenic diet is typically used for the chronic stage of pharmacoresistant of epilepsy, recent studies have shown its efficacy in patients with the acute stage of refractory/super-refractory status epilepticus. The application of a ketogenic diet in pediatric intensive care units is a challenge because of the critical status of the patients, who are often in a coma or have a nothing by mouth order. Moreover, a ketogenic diet needs to be started early and sometimes through parenteral administration in patients with critical conditions such as refractory status epilepticus or febrile infection-related epilepsy syndrome. Animal models and some case reports have shown that the neuro-protective effects of a ketogenic diet can be extended to other emergent neurological diseases, such as traumatic brain injury and ischemic stroke.

Pediatric refractory and super-refractory status epilepticus

PURPOSE

To summarize the available evidence related to pediatric refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE), with emphasis on epidemiology, etiologies, therapeutic approaches, and clinical outcomes.

METHODS

Narrative review of the medical literature using MEDLINE database.

RESULTS

RSE is defined as status epilepticus (SE) that fails to respond to adequately used first- and second-line antiepileptic drugs. SRSE occurs when SE persist for 24 h or more after administration of anesthesia, or recurs after its withdrawal. RSE and SRSE represent complex neurological emergencies associated with long-term neurological dysfunction and high mortality. Challenges in management arise as the underlying etiology is not always promptly recognized and therapeutic options become limited with prolonged seizures. Treatment decisions mainly rely on case series or experts' opinions. The comparative effectiveness of different treatment strategies has not been evaluated in large prospective series or randomized clinical trials. Continuous infusion of anesthetic agents is the most common treatment for RSE and SRSE, although many questions on optimal dosing and rate of administration remain unanswered. The use of non-pharmacological therapies is documented in case series or reports with low level of evidence. In addition to neurological complications resulting from prolonged seizures, children with RSE/SRSE often develop systemic complications associated with polypharmacy and prolonged hospital stay.

CONCLUSION

RSE and SRSE are neurological emergencies with limited therapeutic options. Multi-national collaborative efforts are desirable to evaluate the safety and efficacy of current RSE/SRSE therapies, and potentially impact patients' outcomes.

Cryptogenic NORSE: Its distinctive clinical features and response to immunotherapy

Objective:

To report the distinctive clinical features of cryptogenic new-onset refractory status epilepticus (C-NORSE) and the C-NORSE score based on initial clinical assessments.

Methods:

A retrospective study was conducted for 136 patients with clinically suspected autoimmune encephalitis who underwent testing for autoantibodies to neuronal surface antigens between January 1, 2007, and August 31, 2016. Eleven patients with C-NORSE were identified. Their clinical features were compared with those of 32 patients with anti-NMDA receptor encephalitis (NMDARE).

Results:

The clinical outcome of 11 patients (median age, 27 years; 7 [64%] women) with C-NORSE was evaluated after a median follow-up of 11 months (range, 6–111 months). Status epilepticus was frequently preceded by fever (10/11 [91%]). Brain MRIs showed symmetric T2/fluid-attenuated inversion recovery hyperintensities (8/11 [73%]) and brain atrophy (9/11 [82%]). Only 2 of the 10 treated patients responded to the first-line immunotherapy, and 4 of the 5 patients treated with IV cyclophosphamide responded to the therapy. The long-term outcome was poor in 8 patients (73%). Compared with 32 patients with NMDARE (median age, 27 years; 24 [75%] women), those with C-NORSE had more frequent prodromal fever, status epilepticus, ventilatory support, and symmetric brain MRI abnormalities, had less frequent involuntary movements, absent psychobehavioral symptoms, CSF oligoclonal bands, or tumor association, and had a worse outcome. The C-NORSE score was higher in patients with C-NORSE than those with NMDARE.

Conclusions:

Patients with C-NORSE have a spectrum of clinical-immunological features different from those with NMDARE. The C-NORSE score may be useful for discrimination between them. Some patients could respond to immunotherapy.

Plasmapheresis for refractory status epilepticus Part II: A scoping systematic review of the pediatric literature

BACKGROUND

Our goal was to perform a scoping systematic review of the literature on the use of plasmapheresis or plasma exchange (PE) for refractory status epilepticus (RSE) in children.

METHODS

Articles from MEDLINE, BIOSIS, EMBASE, Global Health, Healthstar, Scopus, Cochrane Library, the International Clinical Trials Registry Platform, clinicaltrials.gov (inception to May 2016), reference lists of relevant articles, and gray literature were searched. The strength of evidence was adjudicated using both the Oxford and GRADE methodology by two independent reviewers.

RESULTS

Twenty-two original articles were identified, with 37 pediatric patients. The mean age of the patients was 8.3 years (age median: 8.5, range: 0.6 years-17 years). Seizure response to PE therapy occurred in 9 of the 37 patients (24.3%) included in the review, with 7 patients (18.9%) displaying resolution of seizures and 2 patients (5.4%) displaying a partial reduction in seizure volume. Twenty-eight of the 37 patients (75.7%) had no response to PE therapy. No adverse events were recorded.

CONCLUSIONS

Oxford level 4, GRADE D evidence exists to suggest little to no benefit of PE in pediatric RSE. Routine application of PE for pediatric RSE cannot be recommended at this time.

From intravenous to enteral ketogenic diet in PICU: A potential treatment strategy for refractory status epilepticus

BACKGROUND

Ketogenic diet (KD) has been used to treat refractory status epilepticus (RSE). KD is a high-fat, restricted-carbohydrate regimen that may be administered with different fat to protein and carbohydrate ratios (3:1 and 4:1 fat to protein and carbohydrate ratios). Other ketogenic regimens have a lower fat and higher protein and carbohydrate ratio to improve taste and thus compliance to treatment. We describe a case of RSE treated with intravenous KD in the Pediatric Intensive Care Unit (PICU).

CASE REPORT

An 8-year-old boy was referred to the PICU because of continuous tonic-clonic and myoclonic generalized seizures despite several antiepileptic treatments. After admission he was intubated and treated with intravenous thiopental followed by ketamine. Seizures continued with frequent myoclonic jerks localized on the face and upper arms. EEG showed seizure activity with spikes on rhythmic continuous waves. Thus we decided to begin KD. The concomitant ileus contraindicated KD by the enteral route and we therefore began IV KD. The ketogenic regimen consisted of conventional intravenous fat emulsion, plus dextrose and amino-acid hyperalimentation in a 2:1 then 3:1 fat to protein and carbohydrate ratio. Exclusive IV ketogenic treatment, well tolerated, was maintained for 3 days; peristalsis then reappeared so KD was continued by the enteral route at 3:1 ratio. Finally, after 8 days and no seizure improvement, KD was deemed unsuccessful and was discontinued.

CONCLUSIONS

Our experience indicates that IV KD may be considered as a temporary "bridge" towards enteral KD in patients with partial or total intestinal failure who need to start KD. It allows a prompt initiation of KD, when indicated for the treatment of severe diseases such as RSE.

Epilepsy in multiple sclerosis: The role of temporal lobe damage

Background:

Although temporal lobe pathology may explain some of the symptoms of multiple sclerosis (MS), its role in the pathogenesis of seizures has not been clarified yet.

Objectives:

To investigate the role of temporal lobe damage in MS patients suffering from epilepsy, by the application of advanced multimodal 3T magnetic resonance imaging (MRI) analysis.

Methods:

A total of 23 relapsing remitting MS patients who had epileptic seizures (RRMS/E) and 23 disease duration matched RRMS patients without any history of seizures were enrolled. Each patient underwent advanced 3T MRI protocol specifically conceived to evaluate grey matter (GM) damage. This includes grey matter lesions (GMLs) identification, evaluation of regional cortical thickness and indices derived from the Neurite Orientation Dispersion and Density Imaging model.

Results:

Regional analysis revealed that in RRMS/E, the regions most affected by GMLs were the hippocampus (14.2%), the lateral temporal lobe (13.5%), the cingulate (10.0%) and the insula (8.4%). Cortical thinning and alteration of diffusion metrics were observed in several regions of temporal lobe, in insular cortex and in cingulate gyrus of RRMS/E compared to RRMS ( p< 0.05 for all comparisons).

Conclusions:

Compared to RRMS, RRMS/E showed more severe damage of temporal lobe, which exceeds what would be expected on the basis of the global GM damage observed.

A clinical approach to diagnosis of autoimmune encephalitis

Encephalitis is a severe inflammatory disorder of the brain with many possible causes and a complex differential diagnosis. Advances in autoimmune encephalitis research in the past 10 years have led to the identification of new syndromes and biomarkers that have transformed the diagnostic approach to these disorders. However, existing criteria for autoimmune encephalitis are too reliant on antibody testing and response to immunotherapy, which might delay the diagnosis. We reviewed the literature and gathered the experience of a team of experts with the aims of developing a practical, syndrome-based diagnostic approach to autoimmune encephalitis and providing guidelines to navigate through the differential diagnosis. Because autoantibody test results and response to therapy are not available at disease onset, we based the initial diagnostic approach on neurological assessment and conventional tests that are accessible to most clinicians. Through logical differential diagnosis, levels of evidence for autoimmune encephalitis (possible, probable, or definite) are achieved, which can lead to prompt immunotherapy.

Rapid onset of hippocampal atrophy in febrile-infection related epilepsy syndrome (FIRES)

Febrile infection-related epilepsy syndrome (FIRES) is a catastrophic and usually refractory epilepsy syndrome that occurs after a febrile illness in previously normal children. The pathogenesis of the syndrome is unknown, and the diagnosis is typically made by exclusion after an exhaustive negative workup for central nervous system infections and autoimmune or metabolic disorders. Magnetic resonance imaging of patients with this condition has previously shown hippocampal abnormalities, typically found several months or longer after initial seizures. We report a previously healthy 5-year-old child who developed hippocampal atrophy by day 37 of his illness. The development of early hippocampal atrophy in this epileptic encephalopathy may provide insight into pathogenesis and highlights the need for aggressive and effective interventions early in the disease process.

Hyperpyrexia resulting in encephalopathy in a 14-month-old patient with cblC disease

Cobalamin C (cblC) defect, the most common inborn error of cobalamin metabolism, is a multisystem disorder usually presenting with progressive neurological, haematological and ophthalmological signs. We report on a cblC patient diagnosed in the newborn age who developed nearly normal during the first year of life. During an upper respiratory tract infection with severe hyperpyrexia at the age of 14months he developed an acute encephalopathic crisis resulting in severe mental retardation and marked internal and external cerebral atrophy. Hyperacute encephalopathic crises have not been observed so far in patients with cblC defect. It remains unclear, if this association is incidental or if the underlying metabolic defect may have predisposed the brain tissue to hyperpyrexia-induced damage.

Prolonged high-dose isoflurane for refractory status epilepticus: is it safe?

Isoflurane is an alternative treatment for refractory status epilepticus. Little is known regarding human toxicities caused by isoflurane. We present 2 patients with prolonged refractory status epilepticus treated with high concentrations of isoflurane who developed signal abnormalities on magnetic resonance imaging. Patient 1 was treated with isoflurane for 85 days with 1975.2% concentration-hours. Patient 2 was treated with isoflurane for 34 days with 1382.4% concentration-hours. Serial brain magnetic resonance images in both showed progressive T2 signal hyperintensity involving thalamus and cerebellum, which improved after discontinuation of isoflurane. These cases suggest that isoflurane may be neurotoxic when used in high doses for long time periods.

Less common etiologies of status epilepticus

Status epilepticus is treated as a neurologic emergency and only later are the potential etiologies assessed. While sometimes the cause for status epilepticus is apparent (e.g., antiepileptic drug withdrawal), all too often it is not identified, even after extensive diagnostic testing has been performed. With emphasis on the less-common etiologies, this review will cover various probable and known causes of status epilepticus among adults, children, and those patients with refractory epilepsy.

Periictal magnetic resonance imaging in status epilepticus

PURPOSE

To determine the changes of magnetic resonance imaging (MRI) during the periictal phase in status epilepticus (SE).

PATIENTS AND METHODS

We identified 15 patients diagnosed of status epilepticus with corresponding MRI changes, including 11 patients with generalized convulsive status epilepticus (GCSE), 2 with complex partial status epilepticus (CPSE), and 2 with simple partial status epilepticus (SPSE). All MRI changes, corresponding electroencephalogram, and prognosis were evaluated.

RESULTS

Regional cortical lesions were observed on MRI, including restricted diffusion in diffusion-weighted images (DWIs) (11 out of 15) and hyperintense signal change in fluid-attenuated inversion recovery (FLAIR) images (12 out of 15) with hypervascularity and parenchymal swelling. The remote lesions included crossed cerebellar diaschisis (3 patients), ipsilateral thalamic lesion (4 patients), and basal ganglia lesions (3 patients). Although the periictal MRI changes were usually reversible, irreversible changes were also found, especially in GCSE, such as focal brain atrophy, cortical laminar necrosis, and mesial temporal sclerosis. GCSE patients with periodic epileptic form discharges had higher possibilities of widespread MRI abnormalities and poor prognosis in the future.

CONCLUSIONS

In this study, DWIs and FLAIR images were proved useful in determining the extent and severity of early neuronal damage caused by epileptic discharges in SE patients. Seizure-induced long-term injuries were also observed in the follow-up MRI.