What should you know about limbic encephalitis?

Clinical characteristics, treatments, outcome, and prognostic factors of severe autoimmune encephalitis in the intensive care unit: Standard treatment and the value of additional plasma cell-depleting escalation therapies for treatment-refractory patients

BACKGROUND AND PURPOSE

To investigate severe autoimmune encephalitis (AE) in the intensive care unit (ICU) with regard to standard treatment in responsive patients and additional escalation therapies for treatment-refractory cases.

METHODS

This retrospective, single-center study analyzed medical records of ICU-dependent AE patients for clinical characteristics, treatments, prognostic factors, and neurological outcome as quantified by modified Rankin Scale (mRS) and Clinical Assessment Scale for Autoimmune Encephalitis (CASE).

RESULTS

From 40 enrolled patients (median age = 52 years; range = 16-89 years) with AE mediated by neuronal surface antibodies (nsAb; 90%) and AE with onconeuronal antibodies (10%), 98% received first-line therapy. Of those, 62% obtained additional second-line therapy, and 33% received escalation therapy with bortezomib and/or daratumumab. Good neurological outcome, defined as mRS = 0-2, was observed in 47% of AE with nsAb (CASE = 5), 77% of anti-N-methyl D-aspartate receptor encephalitis patients (CASE = 1), whereas AE patients with onconeuronal antibodies had the poorest outcome (mRS = 6, 100%). Treatment-refractory AE patients with nsAb requiring escalation therapy achieved similarly good recovery (mRS = 0-2, 39%, CASE = 3) as patients improving without (mRS = 0-2, 54%, CASE = 4), although they presented a higher disease severity at disease maximum (mRS = 5 100% versus 68%, CASE = 24 versus 17; p = 0.0036), had longer ICU stays (97 versus 23 days; p = 0.0002), and a higher survival propability during follow-up (p = 0.0203). Prognostic factors for good recovery were younger age (p = 0.025) and lack of preexisting comorbidities (p = 0.011).

CONCLUSIONS

Our findings suggest that treatment-refractory AE patients with nsAb in the ICU can reach similarly good outcomes after plasma cell-depleting escalation therapy as patients already responding to standard first- and/or second-line therapies.

Refractory and Super-refractory Status Epilepticus

Context

Refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) are neurological emergencies with considerable mortality and morbidity. In this paper, we provide an overview of causes, evaluation, treatment, and consequences of RSE and SRSE, reflecting the lack of high-quality evidence to inform therapeutic approach.

Sources

This is a narrative review based on personal practice and experience. Nevertheless, we searched MEDLINE (using PubMed and OvidSP vendors) and Cochrane central register of controlled trials, using appropriate keywords to incorporate recent evidence.

Results

Refractory status epilepticus is commonly defined as an acute convulsive seizure that fails to respond to two or more anti-seizure medications including at least one nonbenzodiazepine drug. Super-refractory status epilepticus is a status epilepticus that continues for ≥24 hours despite anesthetic treatment, or recurs on an attempted wean of the anesthetic regimen. Both can occur in patients known to have epilepsy or de novo, with increasing recognition of autoimmune and genetic causes. Electroencephalography monitoring is essential to monitor treatment response in refractory/super-refractory status epilepticus, and to diagnose non-convulsive status epilepticus. The mainstay of treatment for these disorders includes anesthetic infusions, primarily midazolam, ketamine, and pentobarbital. Dietary, immunological, and surgical treatments are viable in selected patients. Management is challenging due to multiple acute complications and long-term adverse consequences.

Conclusions

We have provided a synopsis of best practices for diagnosis and management of refractory/superrefractory status epilepticus and highlighted the lack of sufficient high-quality evidence to drive decision making, ending with a brief foray into avenues for future research.

Clinical Characteristics and Treatment Outcomes of De Novo Nonconvulsive Status Epilepticus: A Retrospective Study

Background and Purpose

Nonconvulsive status epilepticus (NCSE) is challenging to diagnose. This study aimed to describe and classify the clinical features and electroencephalography (EEG) findings of patients with de novo NCSE and to correlate them with clinical outcomes.

Methods

We retrospectively reviewed the medical and EEG records of patients admitted to our institution with altered mentation and EEG abnormalities from January 1, 2013 to December 31, 2018. We evaluated premorbid modified Rankin Scale (mRS) scores, underlying disorders, precipitating factors, clinical manifestations, laboratory tests, and outcomes after a 3-month follow-up. Patients who met the Salzburg Consensus Criteria for NCSE were categorized into good-outcome and poor-outcome groups. A good outcome was defined as 1) clinical and electrographic seizures ceasing after treatment, and 2) an mRS score of ≤2 or remaining unchanged during the 3-month follow-up. A poor outcome was defined as 1) death, 2) seizures continuing despite treatment, or 3) a follow-up mRS score of ≥3 in a patient with a premorbid mRS score of ≤2, or a follow-up mRS score that increased in a patient with a premorbid mRS score of ≥3.

Results

The 48 included patients comprised 37 categorized into the good-outcome group and 11 into the poor-outcome group. The presence of acute metabolic disturbances was significantly correlated with poor outcome (p=0.036), while the other analyzed variables were not significantly correlated with outcomes.

Conclusions

Acute metabolic disturbances in NCSE are associated with poor outcomes. Adequate treatment of underlying reversible disorders alongside controlling seizures is critical for patients with NCSE.

Atypical presentation of an elderly male with autoimmune encephalitis: anti-LG1 limbic encephalitis

Introduction

We present a case of an elderly male with anti-LG1 limbic encephalitis involving hypothalamus presenting with acute changes in mental status and persistent hyperthermia.

Case report

A 74-year-old male presented to the hospital with fever and chills. He had also been evaluated by his PCP for changes in his mental status, trouble remembering things, and following directions while driving. A lumbar puncture was performed, and empiric meningitis coverage was initiated. His LP results were not suggestive for any infectious process. An MRI showed bilateral hippocampal edema. As an infectious workup was non-revealing and other causes were ruled out, with the concern for paraneoplastic or autoimmune encephalitis, patient was started on high dose steroids and plasma exchange while results of antibodies for autoimmune and paraneoplastic encephalitis were awaited. After plasmapheresis and a course of steroids, the patient’s mental status began to slowly improve. He was discharged from the hospital and on subsequent neurology office visit, his serum autoimmune encephalitis panel returned positive for anti-LGI 1 antibodies. Further management consisted of outpatient rituximab infusion.

Discussion

Diagnosis of limbic encephalitis can be challenging and can present with symptoms of limbic dysfunction. A modest index of suspicion of limbic encephalitis should be kept in adults with altered mental changes. Early recognition and initiation of therapy can be crucial in the management of patients with autoimmune encephalitis and can prevent permanent cognitive impairment and damage.

The autoantibody-mediated encephalitides: from clinical observations to molecular pathogenesis

The autoimmune encephalitis (AE) syndromes have been characterised by the detection of autoantibodies in serum and/or cerebrospinal fluid which target the extracellular domains of specific neuroglial antigens. The clinical syndromes have phenotypes which are often highly characteristic of their associated antigen-specific autoantibody. For example, the constellation of psychiatric features and the multi-faceted movement disorder observed in patients with NMDAR antibodies are highly distinctive, as are the faciobrachial dystonic seizures observed in close association with LGI1 antibodies. These typically tight correlations may be conferred by the presence of autoantibodies which can directly access and modulate their antigens in vivo. AE remains an under-recognised clinical syndrome but one where early and accurate detection is critical as prompt initiation of immunotherapy is closely associated with improved outcomes. In this review of a rapidly emerging field, we outline molecular observations with translational value. We focus on contemporary methodologies of autoantibody detection, the evolution and distinctive nature of the clinical phenotypes, generalisable therapeutic paradigms, and finally discuss the likely mechanisms of autoimmunity in these patients which may inform future precision therapies.

A 9-year neuropsychological report of a patient with LGI1-associated limbic encephalitis

Introduction: Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (LGI1-LE) is an autoimmune disorder associated with antibodies to voltage-gated potassium channels (VGKC). It is a non-paraneoplastic and partially reversible encephalitis that can be diagnosed via serological testing. Untreated LGI1-LE can be associated with neurocognitive as well as neuropsychiatric sequelae. Here we report the neuropsychological and clinical profile of a patient with LGI1-LE following three different treatment approaches: plasmapheresis (PA), intravenous immunoglobulin (IVIG), and corticosteroids (CO). Method: We investigated our patient with 10 neuropsychological evaluations obtained over a 9-year follow-up period. Multiple MRI scans, EEG recordings, neurological examinations, and serum tests were also obtained. Results: The neurocognitive profile of our patient was characterized by long-term memory impairment (verbal and visual-spatial), and deficits in aspects of executive functioning and language. Neuropsychiatric symptoms of depression and anxiety were noted intermittently. Conclusions: Non-specific treatment prior to diagnosis had marginal effects on neurocognitive profile, neuropsychiatric symptoms, or control of epileptic seizure. In contrast, specific treatments for LGI1-LE following diagnosis resulted in neurocognitive improvement and epileptic control. Among the three treatments, IVIG and CO had the most beneficial impact on neurocognitive status, likely due to the continuity of administration.

The clinical features, underlying immunology, and treatment of autoantibody-mediated movement disorders

An increasing number of movement disorders are associated with autoantibodies. Many of these autoantibodies target the extracellular domain of neuronal surface proteins and associate with highly specific phenotypes, suggesting they have pathogenic potential. Below, we describe the phenotypes associated with some of these commoner autoantibody‐mediated movement disorders, and outline increasingly well‐established mechanisms of autoantibody pathogenicity which include antigen downregulation and complement fixation. Despite these advances, and the increasingly robust evidence for improved clinical outcomes with early escalation of immunotherapies, the underlying cellular immunology of these conditions has received little attention. Therefore, here, we outline the likely roles of T cells and B cells in the generation of autoantibodies, and reflect on how these may guide both current immunotherapy regimes and our future understanding of precision medicine in the field. In addition, we summarise potential mechanisms by which these peripherally‐driven immune responses may reach the central nervous system. We integrate this with the immunologically‐relevant clinical observations of preceding infections, tumours and human leucocyte antigen‐associations to provide an overview of the therapeutically‐relevant underlying adaptive immunology in the autoantibody‐mediated movement disorders. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Diagnosing and treating depression in epilepsy

At least one third of patients with active epilepsy suffer from significant impairment of their emotional well-being. A targeted examination for possible depression (irrespective of any social, financial or personal burdens) can identify patients who may benefit from medical attention and therapeutic support. Reliable screening instruments such as the Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) are suitable for the timely identification of patients needing help. Neurologists should be capable of managing mild to moderate comorbid depression but referral to mental health specialists is mandatory in severe and difficult-to-treat depression, or if the patient is acutely suicidal. In terms of the therapeutic approach, it is essential first to optimize seizure control and minimize unwanted antiepileptic drug-related side effects. Psychotherapy for depression in epilepsy (including online self-treatment programs) is underutilized although it has proven effective in ten well-controlled trials. In contrast, the effectiveness of antidepressant drugs for depression in epilepsy is unknown. However, if modern antidepressants are used (e.g. SSRI, SNRI, NaSSA), concerns about an aggravation of seizures and or problematic interactions with antiepileptic drugs seem unwarranted. Epilepsy-related stress ("burden of epilepsy") explains depression in many patients but acute and temporary seizure-related states of depression or suicidality have also been reported. Limbic encephalitits may cause isolated mood alteration without any recognizable psychoetiological background indicating a possible role of neuroinflammation. This review will argue that, overall, a bio-psycho-social model best captures the currently available evidence relating to the etiology and treatment of depression as a comorbidity of epilepsy.

Anti-leucine-rich glioma-inactivated 1 limbic encephalitis: A case report and literature review

This study describes the case of a 41-year-old woman admitted for anterograde memory loss, right facial grimacing and right arm posturing that had begun 1 month previously. Cranial magnetic resonance-diffusion weighted imaging and -fluid-attenuated inversion recovery imaging revealed a hyperintense signal in the left hippocampus and right basal ganglia, but no contrast enhancement. An electroencephalogram revealed rhythmic sharp and slow waves and rhythmic θ build-ups in the left temporal area. Single-photon emission computed tomography showed increased regional blood flow perfusion in the left cerebral frontal lobe and the right basal ganglia. The cerebrospinal fluid was normal, with the exception of the presence of leucine-rich glioma-inactivated 1 (LGI1) antibodies, and LGI1 antibodies were also found in the blood serum. The presence of the antibodies, the faciobrachial dystonic seizures (FBDSs) and the memory loss indicated limbic encephalitis. After 3 months of immunotherapy, the patient was free from epileptic seizures and had undergone a partial memory restoration. FBDSs alone justify the immediate initiation of immunotherapy, even prior to laboratory confirmation of the disease, as early treatment limits the duration of the illness.

Autoimmune limbic encephalitis: A manifestation of systemic lupus erythematosus in the central nervous system

Autoimmune limbic encephalitis (ALE) associated with systemic lupus erythematosus (SLE) is a rare entity with few reports in the literature to date. In general, ALE associated with SLE has a satisfactory response to immunosuppressive treatment (RIT), but the pathogenesis of this association is poorly understood and may include an autoimmunity component. We report a case study describing the diagnosis and management of limbic encephalitis in a patient with active Systemic Lupus Erythematosus disease (SLE) and past medical history of cancer (endometrial adenocarcinoma in 2004 and papillary urothelial carcinoma in 2011 with curative treatment), followed over a one-year period. We discuss the possible association between limbic encephalitis and all past neoplastic and immune-mediated conditions of this patient. In this particularly case, autoimmunity was the most relevant factor associated with limbic encephalitis given negative neoplastic screening. Moreover, a good response was observed to immunotherapy, not seen with paraneoplastic limbic encephalitis, which is associated with poor response. In this case, the association of ALE with SLE is possible, since laboratory testing disclosed lupic activity and the patient had involvement of other systems (such as hematologic) during the period. However, the presence of other surface membrane antibodies are possible in the search for alternative etiologies.

Neuropsychiatric and seizure outcomes in nonparaneoplastic autoimmune limbic encephalitis

INTRODUCTION

Autoimmune limbic encephalitis is an inflammatory condition often associated with an underlying neoplasm. However, a subset of patients does not have an underlying tumor and have a nonparaneoplastic form of this condition. The focus in the literature has been on the acute phase of this illness, but long-term follow-up is lacking.

METHODS

A retrospective chart review, over a period of 15 years, of patients carrying a diagnosis of encephalitis was performed. Inclusion criteria included a clinical presentation consistent with limbic encephalitis (subacute behavioral change, seizures, or anterograde memory decline) and an identifiable autoantibody, inflammatory CSF (>5 white blood cells/mm(3)), or limbic hyperintensities on MRI. Readmission rates and long-term psychiatric, psychosocial, and seizure outcomes were evaluated.

RESULTS

A total of 16 patients were identified. Clinical presentation included new-onset seizures in 14 (88%), behavioral changes in 7 (44%), and memory decline in 5 (31%). Four (25%) patients presented with status epilepticus. Five patients had antibodies against NMDAR (N-methyl-D-aspartate receptor) and four against VGKC (voltage gated potassium channel) complex. An inflammatory CSF was noted in 7 (44%) and MRI changes in 9 (56%). Four were readmitted during the follow-up period. Around half the patients continued to have medically drug/treatment-refractory seizures, while 7 (44%) had a new psychiatric diagnosis (mood disorder, anxiety disorder, or impulse control disorder). The majority of the patients continued to reside at home, while 43% of previously employed patients lost employment.

CONCLUSION

Nonparaneoplastic autoimmune limbic encephalitis is a neuropsychiatric condition presenting with a combination of seizures (sometimes status epilepticus), behavioral changes, and memory decline. After the acute phase, patients are at risk of readmissions, medically refractory seizures, chronic mood and anxiety disorders, and loss of employment.

Cell-surface central nervous system autoantibodies: clinical relevance and emerging paradigms

The recent discovery of several potentially pathogenic autoantibodies has helped identify patients with clinically distinctive central nervous system diseases that appear to benefit from immunotherapy. The associated autoantibodies are directed against the extracellular domains of cell-surface-expressed neuronal or glial proteins such as LGI1, N-methyl-D-aspartate receptor, and aquaporin-4. The original descriptions of the associated clinical syndromes were phenotypically well circumscribed. However, as availability of antibody testing has increased, the range of associated patient phenotypes and demographics has expanded. This in turn has led to the recognition of more immunotherapy-responsive syndromes in patients presenting with cognitive and behavioral problems, seizures, movement disorders, psychiatric features, and demyelinating disease. Although antibody detection remains diagnostically important, clinical recognition of these distinctive syndromes should ensure early and appropriate immunotherapy administration. We review the emerging paradigm of cell-surface-directed antibody-mediated neurological diseases, describe how the associated disease spectrums have broadened since the original descriptions, discuss some of the methodological issues regarding techniques for antibody detection and emphasize considerations surrounding immunotherapy administration. As these disorders continue to reach mainstream neurology and even psychiatry, more cell-surface-directed antibodies will be discovered, and their possible relevance to other more common disease presentations should become more clearly defined.

Anti-LGI1 Limbic Encephalitis Presented with Atypical Manifestations

Anti-leucine-rich glioma inactivated-1 (LGI1) limbic encephalitis (LE) is a rare neurological disorder that has a subacute course of progressive encephalopathy and fasciobrachial dystonic seizures. We report a patient with anti-LGI1 LE that presented with atypical manifestations that complicated the diagnosis. A 62-year-old woman presented with a chronic course of memory disturbance and a subsequent relapse with an altered mental status after 10 months. The patient reported frequent chest pain of squeezing and dull nature, typically lasting 10-30 seconds. The chest pain was related to partial seizures, which were confirmed by video-EEG monitoring. Anti-LGI1 antibody was identified in serum and CSF. The patient's symptoms improved by immune modulation treatment. Patients with anti-LGI1 LE can experience atypical partial seizures, and a chronic relapsing course. Clinical suspicions and video-EEG monitoring are helpful for the early diagnosis and effective immune modulation.

Limbic encephalitis in a child: an atypical presentation

BACKGROUND

Limbic encephalitis is a rare disorder with a generally subacute onset evolving over days to weeks. Patients present with a variable combination of memory loss, seizures, and psychiatric disturbance, and it is not rare for patients to be initially misdiagnosed.

PATIENT

We describe a previously healthy 12-year-old boy who developed his first seizures at 8 years of age. He had a total of eight prolonged focal seizures, each followed by a month of behavioral changes and short-term memory loss. There was no family history of seizures or other neurological disorders, and he had an otherwise unremarkable neonatal and medical history.

RESULTS

Magnetic resonance imaging during each episode of seizures showed alternating unilateral brain hemispheric involvement consistent with limbic encephalitis that was followed by resolution for a total of six times. Despite a negative laboratory evaluation for a large panel of paraneoplastic antibodies, the clinical scenario and exclusion of other possible disorders made recurrent limbic encephalitis the most likely diagnosis.

CONCLUSION

Limbic encephalitis is a rare disorder that is diagnosed primarily on the basis of clinical criteria and is often associated with the presence of a paraneoplastic antibody. However, lack of a positive paraneoplastic antibody in a patient with a triad of seizure, behavioral changes, and short-term memory loss does not exclude the diagnosis. The unique presentation in a seronegative patient may indicate an unrecognized antibody.

[Therapeutic options for autoimmune encephalomyelitis]

Autoantibodies to neuronal tissue are becoming increasingly more important in the evaluation and classification of several neurological diseases, e.g. neuromyelitis optica, paraneoplastic syndromes of the central nervous system (CNS), stiff person syndrome or autoimmune epilepsy. As these disorders are rare, no evidence-based recommendations for therapy are available. Currently, immunomodulating or immunosuppressive drugs are administered in most cases. In paraneoplastic syndromes treatment of the underlying cancer is of considerable importance. This overview summarizes current experiences and recommendations in the treatment of autoimmune neurological disorders.