Narcolepsy as an initial manifestation of neuromyelitis optica with anti-aquaporin-4 antibody

The Pathological Activation of Microglia Is Modulated by Sexually Dimorphic Pathways

Microglia are the primary immunocompetent cells of the central nervous system (CNS). Their ability to survey, assess and respond to perturbations in their local environment is critical in their role of maintaining CNS homeostasis in health and disease. Microglia also have the capability of functioning in a heterogeneous manner depending on the nature of their local cues, as they can become activated on a spectrum from pro-inflammatory neurotoxic responses to anti-inflammatory protective responses. This review seeks to define the developmental and environmental cues that support microglial polarization towards these phenotypes, as well as discuss sexually dimorphic factors that can influence this process. Further, we describe a variety of CNS disorders including autoimmune disease, infection, and cancer that demonstrate disparities in disease severity or diagnosis rates between males and females, and posit that microglial sexual dimorphism underlies these differences. Understanding the mechanism behind differential CNS disease outcomes between men and women is crucial in the development of more effective targeted therapies.

Frequency of diencephalic syndrome in NMOSD

BACKGROUND

Diencephalic region of the brain harbors sites with a considerable amount of aquaporin-4 expression. Neuromyelitis optica spectrum disorder (NMOSD) primarily involves autoimmune processes against this molecule. However, little is known about the frequency of symptoms of diencephalic involvement in NMOSD patients.

OBJECTIVE

To investigate the frequency of symptoms of diencephalic involvement in NMOSD patients and describe the associated characteristics in patients presenting such symptoms.

MATERIALS AND METHODS

This retrospective cohort included 145 NMOSD patients (39 males and 106 females) who visited Isfahan Multiple Sclerosis Center from January 2013 to February 2020 for approximately 61 months. Demographic and clinical information of patients and findings from radiological and serological investigations were retrieved.

RESULTS

The frequency of diencephalic involvement in NMOSD patients was 3.4% (five cases). Diencephalic syndrome-associated symptoms observed in this cohort consisted of narcolepsy (n = 2; 40%), hypotension (n = 1; 20%), amenorrhea (n = 1; 20%), and syndrome of inappropriate antidiuretic hormone secretion (n = 1; 20%). These manifestations responded well to NMOSD-associated treatments, i.e., rituximab and azathioprine.

CONCLUSION

Although rarely manifested through symptoms suggestive of diencephalic involvement, NMOSD should be considered when encountering patients with the diencephalic syndrome to identify the primary cause of these manifestations.

Symptomatic and restorative therapies in neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) are a group of autoimmune inflammatory conditions that primarily target the optic nerves, spinal cord, brainstem, and occasionally the cerebrum. NMOSD is characterized by recurrent attacks of visual, motor, and/or sensory dysfunction that often result in severe neurological deficits. In recent years, there has been a significant progress in relapse treatment and prevention but the residual disability per attack remains high. Although symptomatic and restorative research has been limited in NMOSD, some therapeutic approaches can be inferred from published case series and evidence from multiple sclerosis literature. In this review, we will discuss established and emerging therapeutic options for symptomatic treatment and restoration of function in NMOSD. We highlight NMOSD-specific considerations and identify potential areas for future research. The review covers pharmacologic, non-pharmacologic, and neuromodulatory approaches to neuropathic pain, tonic spasms, muscle tone abnormalities, sphincter dysfunction, motor and visual impairment, fatigue, sleep disorders, and neuropsychological symptoms. In addition, we briefly discuss remyelinating agents and mesenchymal stem cell transplantation in NMOSD.

Neuromyelitis optica, aquaporin-4 antibodies, and neuroendocrine disorders

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that preferentially affects the optic nerve and the spinal cord. In around 80% of NMO patients, autoantibodies binding to aquaporin-4 (AQP4) are detected. AQP4-IgG unifies a spectrum of disorders (NMOSD) that include not only optic neuritis, longitudinally extensive transverse myelitis but also syndromes caused by lesion of the diencephalic region and the circumventricular organs (CVOs). The distinctive immunopathological characteristics of NMOSD lesions, occurring in regions where AQP4 is highly expressed, supports a central role for AQP4-IgG in disease pathogenesis. AQP4 expression is concentrated in CVOs and in the hypothalamus, mainly in the dorsal hypothalamic area, dorsomedial hypothalamic nucleus and suprachiasmatic nucleus. Several neuroendocrine disorders caused by inflammatory lesions involving the diencephalic region have been described in patients with NMOSD, including syndrome of inappropriate antidiuresis, sleep disorders, and other endocrinopathies caused by hypothalamic injury. Focus of this chapter is the involvement of hypothalamus and CVOs in AQP4 autoimmunity.

Sleep disorders as a possible predisposing attack factor in neuromyelitis optica spectrum disorder (NMOSD): A case-control study

BACKGROUND

Sleep disturbances are common in neuromyelitis optica spectrum disorder (NMOSD) and have a great impact on patients' quality of life. According to a report, there is a 64% prevalence of poor sleep quality in NMOSD patients. Therefore, this study was done to evaluate the effect of sleep disturbances on NMOSD acute exacerbations.

MATERIALS AND METHODS

This case-control study was conducted at Sina Hospital in 2019. A total of 60 patients with NMOSD diagnosis were enrolled in the study (30 patients were in the remission phase while 30 patients were hospitalized due to acute attacks). Sleep disorders were evaluated in both groups. Sleep quality was assessed during the last month using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. Data were analyzed by SPSS software version 21.

RESULTS

Among 60 patients who were evaluated in both the control and attack groups, 86.7% were female. The duration of the disease was 68.23 ± 42.89 months in the control group and 69.83 ± 6.90 in the attack group. The mean age of patients was 34.15 years old. Sleep quality was unfavorable in 30% and 56% of patients in control and attack groups, respectively. There were significant differences between the two groups in sleep latency, habitual sleep efficiency, sleep duration, and sleep disturbance.

CONCLUSION

The present study revealed that there was a significant difference in sleep quality between controls and attack patients and could show a direct relationship between sleep disorders and NMOSD attacks.

Hypothalamic lesions in neuromyelitis optica spectrum disorders: exploring a scoring system based on magnetic resonance imaging

PURPOSE

We propose a scoring system for early diagnosis of sleep abnormalities in neuromyelitis optica spectrum disorders (NMOSD) with hypothalamic lesions based on magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We evaluated MRI features of 45 patients with hypothalamic lesions identified from two cohorts. Univariate logistic regression analysis identified factors associated with sleepiness, which were subsequently used to develop a scoring system. Interrater reliability was determined using intraclass correlation coefficient (ICC). Correlations between scores and clinical features were analyzed.

RESULTS

In total, 48.9% of 45 patients with hypothalamic lesions exhibited sleepiness. The number of involved slices, maximum width/length of hypothalamic lesions, and boundaries extending beyond the hypothalamus were associated with sleepiness (all p < 0.05). The sensitivity and specificity of the scoring system were 68.2% and 87.0%, respectively. The ICC values for the maximum width and length measurement of hypothalamic lesions were 0.82 and 0.81, respectively. Daily sleep time and Epworth sleepiness scale scores were positively correlated with MRI-based scores (p < 0.05, 95% confidence interval (CI) 0.69-0.93 and p < 0.05, 95% CI 0.55-0.88, respectively).

CONCLUSION

A scoring system based on MRI features was developed to provide diagnosis of sleepiness in NMOSD with hypothalamic lesions earlier than other measures.

Sleep Disturbances Associated with Neurological Autoimmunity

Associations between sleep disorders and neurological autoimmunity have been notably expanding recently. Potential immune-mediated etiopathogenesis has been proposed for various sleep disorders including narcolepsy, Kleine-Levin syndrome, and Morvan syndrome. Sleep manifestations are also common in various autoimmune neurological syndromes, but may be underestimated as overriding presenting (and potentially dangerous) neurological symptoms often require more urgent attention. Even so, sleep dysfunction has been described with various neural-specific antibody biomarkers, including IgLON5; leucine-rich, glioma-inactivated protein 1 (LGI1); contactin-associated protein 2 (CASPR2); N-methyl-D-aspartate (NMDA)-receptor; Ma2; dipeptidyl-peptidase-like protein-6 (DPPX); alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R); anti-neuronal nuclear antibody type-1 (ANNA-1, i.e., Hu); anti-neuronal nuclear antibody type-2 (ANNA-2, i.e., Ri); gamma-aminobutyric acid (GABA)-B-receptor (GABA-B-R); metabotropic glutamate receptor 5 (mGluR5); and aquaporin-4 (AQP-4). Given potentially distinctive findings, it is possible that sleep testing could potentially provide objective biomarkers (polysomnography, quantitative muscle activity during REM sleep, cerebrospinal fluid hypocretin-1) to support an autoimmune diagnosis, monitor therapeutic response, or disease progression/relapse. However, more comprehensive characterization of sleep manifestations is needed to better understand the underlying sleep disruption with neurological autoimmunity.

Secondary hypersomnia as an initial manifestation of neuromyelitis optica spectrum disorders

The identification of AQP4-IgG, a specific and pathogenic antibody of NMO/SD has led to a broadening of the clinical spectrum of manifestations of NMO/SD including the presence of encephalic symptoms. Lesions are often distributed on peri‑ependymal area and sometimes affected the diencephalon leading to sleep disorders. We report a case of hypersomnia with polysomnographic documentation during the first attack of NMO/SD. Brain MRI revealed bilateral hypothalamic lesions around the third ventricle, whereas optic nerves and spinal cord were intact. The record of the nocturnal video-polysomnography followed by multiple sleep latency tests (MSLT) revealed an abnormal shortened sleep period with a single sleep onset in REM allowing secondary central hypersomnia diagnosis. The recovery of hypersomnia was complete within few months without psychostimulant treatment and the diencephalic lesion disappeared. Thus, diencephalic form of NMO/SD seems to cause narcolepsy or non-narcoleptic central hypersomnia and have a good recovery.

Role of complement and potential of complement inhibitors in myasthenia gravis and neuromyelitis optica spectrum disorders: a brief review

The complement system is a powerful member of the innate immune system. It is highly adept at protecting against pathogens, but exists in a delicate balance between its protective functions and overactivity, which can result in autoimmune disease. A cascade of complement proteins that requires sequential activation, and numerous complement regulators, exists to regulate a proportionate response to pathogens. In spite of these mechanisms there is significant evidence for involvement of the complement system in driving the pathogenesis of variety of diseases including neuromyelitis optica spectrum disorders (NMOSD) and myasthenia gravis (MG). As an amplification cascade, there are an abundance of molecular targets that could be utilized for therapeutic intervention. Clinical trials assessing complement pathway inhibition in both these conditions have recently been completed and include the first randomized placebo-controlled trial in NMOSD showing positive results. This review aims to review and update the reader on the complement system and the evolution of complement-based therapeutics in these two disorders.

A new M23-based ELISA assay for anti-aquaporin 4 autoantibodies: diagnostic accuracy and clinical correlation

Purpose

Although many assays have been developed to detect anti-aquaporin-4 (AQP4) antibodies, most of these assays require sophisticated techniques and are thus only available at specialized laboratories. The aim of this study was to evaluate the analytical and clinical performance of a new commercial enzyme-linked immunosorbent assay (ELISA RSR, AQP4 Ab Version 2) to detect anti-AQP4 antibodies performed on a fully automated system (SkyLAB 752).

Methods

Serum samples from 64 patients with neuromyelitis optica spectrum disorders (NMOSD) (including NMO, longitudinally extensive myelitis-LETM, optical neuritis and myelitis) and 27 controls were tested for anti-AQP4 antibodies. All sera were previously tested using an indirect immunofluorescence (IIF) method on primate tissue, as the reference method. Commercial control sera were used to determine within-run, between-day and within-laboratory precision (CLSI guidelines).

Results

At a cut-off value of 2.1 U/mL as determined by ROC curves, sensitivity and specificity for NMO were 83.3% and 100%, respectively. The ELISA assay provided 100% concordant results with the reference IIF method. The median concentration of anti-AQP4 antibodies was statistically higher in patients with NMO than in patients with LETM (p = 0.0006) or with other NMOSD and in controls (p < 0.0001). At the concentration of 12.4 and 28.1 U/mL, the within-run, between-day and within-laboratory coefficients of variation (CV) were 3.2% and 3%, 7.6% and 7.4%, and 8.2% and 8.0%, respectively.

Conclusions

This new ELISA method performed on a fully automated system, showed high sensitivity and absolute specificity, good CV in precision tests, and provided observer-independent quantitative results.

NEUROMYELITIS OPTICA SPECTRUM DISORDERS: DIAGNOSIS AND TREATMENT, THE EXPERIENCE OF CLINICAL OBSERVATIONS

Neuromyelitis optica spectrum disorder (NMOSD) is an aggregate of inflammatory and autoimmune disorders of the central nervous system characterized by recurrent, disabling clinical course and damages predominantly targeting optic nerves, brain stem and spinal cord. NMOSD is stratified into two types: seropositive for aquaporin-4 antibodies (AQP4-IgG) and seronegative, which is reported in 25 % of cases. This article presents modern conceptualizations of NMOSD and describes authors’ own experience of clinical observation of patients.

Comprehensive review of neuromyelitis optica and clinical characteristics of neuromyelitis optica patients in Puerto Rico

Neuromyelitis optica (NMO) is an immune-mediated inflammatory disorder of the central nervous system. It is characterized by concurrent inflammation and demyelination of the optic nerve (optic neuritis [ON]) and the spinal cord (myelitis). Multiple studies show variations in prevalence, clinical, and demographic features of NMO among different populations. In addition, ethnicity and race are known as important factors on disease phenotype and clinical outcomes. There are little data on information about NMO patients in underserved groups, including Puerto Rico (PR). In this research, we will provide a comprehensive overview of all aspects of NMO, including epidemiology, environmental risk factors, genetic factors, molecular mechanism, symptoms, comorbidities and clinical differentiation, diagnosis, treatment, its management, and prognosis. We will also evaluate the demographic features and clinical phenotype of NMO patients in PR. This will provide a better understanding of NMO and establish a basis of knowledge that can be used to improve care. Furthermore, this type of population-based study can distinguish the clinical features variation among NMO patients and will provide insight into the potential mechanisms that cause these variations.

Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article provides a practical approach for providers caring for patients with neuromyelitis optica (NMO) spectrum disorders. Clinical and imaging features, diagnostic criteria, treatment of acute exacerbations, chronic preventive therapy, and symptom management in NMO spectrum disorders are discussed.

RECENT FINDINGS

The rapid pace of research in NMO spectrum disorders has led to many recent advances. A broader understanding of the clinical spectrum of the disease as well as improvements in anti-aquaporin-4 antibody assays have led to recent revision of the diagnostic criteria. Several recent studies have expanded the knowledge base regarding the efficacy and safety of current therapies for NMO spectrum disorders.

SUMMARY

An NMO spectrum disorder is an inflammatory disorder affecting the central nervous system, previously thought to be closely related to multiple sclerosis but more recently demonstrated to represent a distinct clinical and pathophysiologic entity. As NMO spectrum disorders carry significant morbidity and, at times, mortality, prompt and accurate diagnosis followed by swift initiation of therapy for both treatment of acute exacerbations and prevention of further relapses is critical. This article provides a practical approach to the diagnosis and management of NMO spectrum disorders.

Peduncular Hallucinosis and Autonomic Dysfunction in Anti-Aquaporin-4 Antibody Syndrome

Neuromyelitis optica is a rare, severe inflammatory demyelinating disease of the central nervous system, previously described as affecting only the optic nerve and spinal cord. Since the discovery of a highly specific autoantibody, anti-aquaporin-4, lesions are now recognized outside these regions. We report a man with severe, debilitating symptoms resulting from a symptomatic lesion within the diencephalon, manifesting with abnormal circadian rhythms, autonomic dysfunction, behavioral disturbance, and complex visual hallucinations. The patient reported seeing nonexistent small people and animals, streaks of color across people's faces, movement of objects and facial features, water cascading down walls, bright spots, and writing appearing as hieroglyphics. His centrally driven sick sinus syndrome required insertion of a permanent cardiac pacemaker. We have been able to suppress his disease activity with methotrexate for 30 months. We review the literature on patients with positive anti-aquaporin-4 serology and dysregulation of hypothalamic function, to provide evidence that the clinical manifestations can include complex visual phenomena.

Fatigue in patients with neuromyelitis optica spectrum disorder and its impact on quality of life

Fatigue is a prevalent symptom and major burden in neuroimmunological diseases. In neuromyelitis optica spectrum disorder (NMOSD), a severe autoimmune central nervous system (CNS) inflammatory disease with autoantibodies reactive to aquaporin-4, there are few reports about fatigue and quality of life (QOL). We aimed to evaluate the severity of fatigue and its relationship with QOL in patients with NMOSD. We prospectively studied patients with NMOSD who were in remission and seropositive for anti-aquaporin-4 antibody, and they were divided into 2 groups based on the presence of fatigue assessed using the Functional Assessment of Chronic Illness Therapy-fatigue score. Sleep quality, depression, pain, and QOL were also evaluated. A total of 35 patients were enrolled (mean age, 46.5 ± 14.1 years; female: male = 29:6), and the median Expanded Disability Status Scale (EDSS) score was 2.0 (range, 0 to 8.0). The patients with fatigue (N = 25, 71.4%) had poorer sleep quality and more severe depression than those without fatigue (p = 0.009 and p = 0.001). Both the physical and mental QOL scores were lower in patients with fatigue than in those without fatigue (p = 0.033 and p = 0.004). Multiple linear regression analyses showed that the degree of fatigue with EDSS score and pain were independent predictors of physical aspects of QOL (B = 0.382, p = 0.001), whereas depression was the only predictor of the mental components of QOL (B = -0.845, p = <0.001). Fatigue is a common symptom and an important predictor of QOL in patients with NMOSD.

Common and Rare Manifestations of Neuromyelitis Optica Spectrum Disorder

The discovery of a highly specific biomarker of neuromyelitis optica (NMO)-the anti-aquaporin-4 (AQP4) antibody-has opened new paths to understanding disease pathogenesis and afforded a way to confirm the diagnosis in clinical practice. An important consequence of the discovery is the broadening of the spectrum of syndromes seen in the context of AQP4 autoimmunity. These syndromes have been subsumed under the rubric of NMO spectrum disorder (NMOSD). The current classification recognizes not only optic neuritis and myelitis as core syndromes of NMOSD but also cerebral, diencephalic, brainstem, and area postrema syndromes. These neurologic syndromes are the focus of our review. AQP4 is also expressed in many organs outside of the central nervous system, and this may explain some of the unusual, non-neurologic features that have been occasionally reported in NMOSD. Our review catalogues non-neurologic manifestations seen in NMOSD and concludes with a discussion of frequently associated autoimmune and neoplastic comorbidities of NMOSD.

Autonomic Dysregulation, Cognitive Impairment, and Symptoms of Psychosis as an Unusual Presentation in an Anti-Aquaporin 4-Positive Patient

We present the unusual case of a patient with an aquaporin 4 antibody-seropositive neuromyelitis optica spectrum disorder who presented with autonomic dysregulation, cognitive impairment, and symptoms of psychosis. Only a few previous cases have been described with similar psychiatric symptoms. Brain MRI showed an abnormal hyperintense T2 signal of the hypothalamus and, to a lesser extent, a minor hyperintense signal of the right optic nerve. Her symptoms and MR abnormalities improved after high-dose methylprednisolone.

Brain MRI findings in patients with idiopathic hypersomnia

OBJECTIVE

Proper diagnosis of idiopathic hypersomnia necessitates the exclusion of neurologic or medical causes of sleepiness that better explain the clinical syndrome. However, there are no formal guidelines regarding the use of neuroimaging to identify such secondary causes of symptoms. We sought to characterize brain MRI findings in a series of patients with idiopathic hypersomnia.

METHODS

We reviewed medical records on a consecutive series of 61 patients diagnosed with idiopathic hypersomnia to determine the frequency and results of brain magnetic resonance imaging (MRI).

RESULTS

One-third of patients had undergone brain MRI, with focal neurologic signs or symptoms being the most common indication for neuroimaging. Although seven patients had an identifiable finding on neuroimaging (e.g., chronic microvascular ischemic changes), clinical management was changed as a result of imaging in only three cases. In all three, the imaging finding was predated by clear clinical abnormalities.

CONCLUSIONS

Neuroimaging may be a complementary part of an idiopathic hypersomnia evaluation, but the decision to pursue imaging should be made on a case-by-case basis.

What's new in neuromyelitis optica? A short review for the clinical neurologist

The evolution of neuromyelitis optica spectrum disorder (NMOSD) from a rare, incurable and misunderstood disease with almost universally poor outcomes to its present state in just over a decade is unprecedented in neurology and possibly in medicine. Our knowledge of NMOSD biology has led to the recognition of wider phenotypes, new disease mechanisms, and thus clinical trials of new and effective treatments. This article aims to update readers on the recent developments in NMOSD with particular emphasis on clinical advances, the 2015 diagnostic criteria, biomarkers, imaging, and therapeutic interventions.

Post-Encephalitic Parkinsonism and Sleep Disorder Responsive to Immunological Treatment: A Case Report

We describe a 70-year-old man who, after a viral encephalitis associated with pneumonia, progressively developed a parkinsonism associated with lethargy. Encephalitis manifested with persistent hiccups, seizures and impairment of consciousness. After 2 weeks, the initial neurologic symptoms subsided and the patient progressively developed movement disorders (rigidity and bradykinesia, resistant to L-DOPA), lethargy and behavioral hypersomnia. Magnetic resonance imaging showed thalamic and hippocampal signal abnormalities, immunohistochemistry on a mouse brain substrate revealed serum autoantibodies binding to the brainstem neuropil. Polysomnographic monitoring was consistent with a very severe disruption of sleep: the sleep-wake cycle was fragmented, and the NREM-REM ultradian cycle was irregular. Intravenous immune globulin therapy resulted in the complete reversal of the movement and the sleep disorders. Our observation confirms that parkinsonism and sleep disorders may be consequences of encephalitis, that an immune-mediated pathogenesis is likely, and, consequently, that immunotherapy can be beneficial in these patients. The polysomnographic monitoring suggests that lethargia, rather than a mere hypersomnia, is the result of a combination between sleep disruption and altered motor control.

Autoimmune sleep disorders

A number of autoantibodies, some paraneoplastic, are associated with sleep disorders. Morvan syndrome and limbic encephalitis, associated with voltage-gated potassium channel-complex antibodies, principally against CASPR2 and LGI1, can result in profound insomnia and rapid eye movement sleep behavior disorder (RBD). Patients with aquaporin-4 antibodies and neuromyelitis optica may develop narcolepsy in association with other evidence of hypothalamic dysfunction, sometimes as the initial presentation. Central sleep apnea and central neurogenic hypoventilation are found in patients with anti-N-methyl-d-aspartate receptor antibody encephalitis, and obstructive sleep apnea, stridor, and hypoventilation are prominent features of a novel tauopathy associated with IgLON5 antibodies. In addition, paraneoplastic diseases may involve the hypothalamus and cause sleep disorders, particularly narcolepsy and RBD in those with Ma1 and Ma2 antibodies. Patients with antineuronal nuclear autoantibodies type 2 may develop stridor. Several lines of evidence suggest that narcolepsy is an autoimmune disorder. There is a strong relationship with the human leukocyte antigen (HLA) DQB1*06:02 haplotype and polymorphisms in the T-cell receptor alpha locus and purinergic receptor P2Y11 genes. Patients with recent-onset narcolepsy may have high titers of antistreptococcal or other antibodies, although none has yet been shown to be disease-specific but, supporting an immune basis, recent evidence indicates that narcolepsy in children can be precipitated by one type of vaccination against the 2009-2010 H1N1 influenza pandemic.

What do we know about brain contrast enhancement patterns in neuromyelitis optica?

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that usually presents with acute myelitis and/or optic neuritis. Recently, some brain magnetic resonance imaging findings have been described in NMO that are important in the differential diagnosis. Pencil-thin, leptomeningeal, and cloud-like enhancement may be specific to NMO. These patterns are usually seen during relapses. Recognizing these lesions and enhancement patterns may expedite the diagnosis and allows early effective treatment. The purpose of this article is to review the latest knowledge and to share our experience with the contrast enhancement patterns of NMO brain lesions.

Hypoxemia, Sleep Disturbances, and Depression Correlated with Fatigue in Neuromyelitis Optica Spectrum Disorder

AIMS

Among patients with neuromyelitis optica spectrum disorder (NMOSD), fatigue is commonly complained about and is one of the most debilitating symptoms. This study aimed to investigate the incidence of fatigue and explore impacting factors attributed to fatigue in NMOSD.

METHODS

Thirty-three patients with NMOSD and twenty matched healthy controls were enrolled. A battery of self-reported questionnaires was conducted to assess quality of sleep, daytime sleepiness, fatigue, depression, and level of activity of daily life. The structure of sleep was assessed by polysomnography with blood oxygen saturation monitored by noninvasive pulse oximeter. Brain and spinal cord lesions were evaluated by MRIs.

RESULTS

Fatigue was more severe and more prevalent among the patients with NMOSD compared with controls (fatigue score which ranges from 0 to 11 with higher scores indicating more severe fatigue: 6.4 ± 0.6 vs. 3.8 ± 0.4, P = 0.002; incidence, 64% vs. 35%, P = 0.043), and it was negatively associated with daily activity level (r = 0.455, P = 0.008). The patients with fatigue had higher Pittsburgh Sleep Quality Index score, higher Epworth Sleepiness Scale score, lower blood oxygen state, and higher depression score than patients without fatigue; blood oxygen was especially negatively correlated with fatigue (nadir SpO2 , r = -0.558, P = 0.001; mean SpO2 , r = -0.457, P = 0.007); depression was also positively correlated with fatigue (r = 0.599, P < 0.001).

CONCLUSION

Patients with NMOSD experienced significant fatigue, which had an obvious impact on their daily activity. Fatigue in these patients was related to hypoxemia, sleep disturbances, and depression.

Aquaporin-4 autoimmunity

Neuromyelitis optica (NMO) and a related spectrum of inflammatory CNS disorders are unified by detection of a serum autoantibody specific for the aquaporin-4 (AQP4) water channel, which is abundant in astrocytic foot processes. The classic clinical manifestations of NMO are optic neuritis and longitudinally extensive transverse myelitis. Newly recognized manifestations of AQP4 autoimmunity include lesions of circumventricular organs and skeletal muscle. NMO is commonly relapsing, is frequently accompanied by other autoimmune disorders, and sometimes occurs in a paraneoplastic context. The goals of treatment are to minimize neurologic disability in the acute attack and thereafter to prevent relapses and cumulative disability. The disease specificity of AQP4 immunoglobulin (Ig) G approaches 100% using optimized molecular-based detection assays. Clinical, immunohistopathologic, and in vitro evidence support this antibody being central to NMO pathogenesis. Current animal models yield limited histopathologic characteristics of NMO, with no clinical deficits to date. Recent descriptions of a myelin oligodendrocyte glycoprotein autoantibody in a minority of patients with NMO spectrum phenotype who lack AQP4-IgG predict serologic delineation of additional distinctive disease entities.

Sleep abnormality in neuromyelitis optica spectrum disorder

Objectives:

We investigated the sleep structure of patients with neuromyelitis optica spectrum disorder (NMOSD) and the association of abnormalities with brain lesions.

Methods:

This was a prospective cross-sectional study. Thirty-three patients with NMOSD and 20 matched healthy individuals were enrolled. Demographic and clinical characteristics of patients were collected. Questionnaires were used to assess quality of sleep, daytime sleepiness, fatigue, and depression. Nocturnal polysomnography was performed.

Results:

Compared with healthy controls, patients with NMOSD had decreases in sleep efficiency (7%; p = 0.0341), non-REM sleep N3 (12%; p < 0.0001), and arousal index (6; p = 0.0138). REM sleep increased by 4% (p = 0.0423). There were correlations between arousal index and REM% or Epworth Sleepiness Scale (r = −0.0145; p = 0.0386, respectively). Six patients with NMOSD (18%, 5 without infratentorial lesions and 1 with infratentorial lesions) had a hypopnea index >5, and all of those with sleep apnea had predominantly the peripheral type. The periodic leg movement (PLM) index was higher in patients with NMOSD than in healthy controls (20 vs 2, p = 0.0457). Surprisingly, 77% of the patients with PLM manifested infratentorial lesions.

Conclusions:

Sleep architecture was markedly disrupted in patients with NMOSD. Surveillance of nocturnal symptoms and adequate symptomatic control are expected to improve the quality of life of patients with NMOSD.

Gaze palsy, hypogeusia and a probable association with miscarriage of pregnancy--the expanding clinical spectrum of non-opticospinal neuromyelitis optica spectrum disorders: a case report

BACKGROUND

Neuromyelitis optica is characterised by optic neuritis, longitudinally-extensive transverse myelitis and presence of anti-aquaporin-4 antibodies in the serum. However, non-opticospinal central nervous system manifestations have been increasingly recognised. Awareness of the widening clinical spectrum of neuromyelitis optica (unified within the nosology of 'neuromyelitis optica spectrum disorders') is key to earlier diagnosis and appropriate therapy. We report 2 patients to illustrate the varied clinical manifestations of neuromyelitis optica spectrum disorders while postulating an effect of anti-aquaporin-4 antibodies on the miscarriage of pregnancy. This is the first report of horizontal gaze palsy as a presenting symptom of neuromyelitis optica spectrum disorders.

CASE PRESENTATION

Patient 1: A 17-year-old Sri Lankan female presented with hypersomnolence, lateral gaze palsy and loss of taste of 1 week duration. Two years previously she had presented with intractable hiccups and vomiting followed by a brainstem syndrome. Magnetic resonance imaging showed a lesion in the left cerebellum extending into the pons while lesions in bilateral hypothalami and medulla noted 2 years ago had resolved. Autoimmune, vasculitis and infection screens were negative. Anti-aquaporin-4 antibodies were detected in serum. All her symptoms resolved with immunosuppressive therapy. Patient 2: A 47-Year-old Sri Lankan female presented with persistent vomiting lasting over 3 weeks. Three years previously, at 25-weeks of her 4(th) pregnancy, she had presented with quadriparesis and was found to have a longitudinally extensive transverse myelitis from C2 to T2 vertebral levels, which gradually improved following intravenous steroid therapy. Magnetic resonance imaging showed a hyper-intense lesion in the area postrema and longitudinally extensive atrophy of the cord corresponding to her previous myelitis. Autoimmune, vasculitis and infection screens were negative. Anti-aquaporin-4 antibodies were detected in serum. Her vomiting subsided with immunosuppressive therapy. Her second pregnancy had resulted in a first-trimester miscarriage.

CONCLUSION

The clinical spectrum of neuromyelitis optica spectrum disorders has expanded beyond optic neuritis and myelitis to include non-opticospinal syndromes involving the diencephalon, brainstem and cerebrum. Our report highlights the varied central nervous system manifestations of neuromyelitis optica spectrum disorders and miscarriage of pregnancy possibly related to anti-aquaporin-4 antibodies.

Syndrome of inappropriate antidiuretic hormone secretion in patients with aquaporin-4 antibody

The objective of this study was to analyze the frequency of syndrome of inappropriate antidiuretic hormone secretion (SIADH) in patients with positive aquaporin-4 (AQP4) antibodies and evaluate the relationship between SIADH and hypothalamic lesions in patients with NMO and NMO spectrum disorder (NMOSD). AQP4 antibodies were tested by an indirect immunofluorescence assay employing HEK-293 cells transfected with recombinant human AQP4. Clinical data of patients were analyzed retrospectively. In total, 192 patients with AQP4 antibodies were certified, of which 41 patients (21.4 %) were included in the present study. Six patients (14.6 %, 6/41) met the criteria of SIADH, of which hyponatremia was mild in one patient, and severe in five. Five patients experienced confusion or decreased consciousness. Four patients were diagnosed with NMO and two were diagnosed with recurrent optic neuritis. Magnetic resonance imaging showed 11 of 41 patients (26.8 %) had hypothalamic lesions. All patients with SIADH had hypothalamic abnormalities. Hyponatremia resolved in all patients after intravenous methylprednisolone and intravenous immunoglobulin therapy. SIADH is not rare in patients with NMO/NMOSD, especially in patients with lesions close to the hypothalamus.

[Hypothermia and memory disturbance as initial manifestations associated with lesions of the diencephalon in a patient with anti-aquaporin 4 antibody-associated disorder: a case report]

A 69-year-old woman was admitted due to gradual progression of daytime sleepiness and forgetfulness over a period of approximately 1 month. Bradycardia and hypothermia were observed on admission, and neurological examination revealed memory disturbance, mild dysarthria, and bradykinesia. Fluid-attenuated inversion recovery (FLAIR) images of the brain magnetic resonance imaging (MRI) indicated signal hyperintensity in the region bordering the lateral and third ventricles. Serum anti-aquaporin 4 (AQP4) antibody was detected. The patient had no history or findings of optic neuritis or myelitis, and she was diagnosed as anti-AQP4 antibody-associated disorder. Diencephalon lesion and/or symptoms are rarely observed at the onset of neuromyelitis optica. Differential diagnosis of this disorder is necessary in cases manifesting diencephalon symptoms or involving lesions bordering the third ventricle without evidence of previous optic neuritis or myelitis.

[A 39 years old woman responding to modafinil with bilateral hypothalamic lesion associated with hyperthermia and hypersomnia: a case report]

A 39 years old woman was admitted to our hospital with a status epilepticus, with high fever of 41°C. Magnetic resonance Imaging (MRI) revealed high signal intensities of both sides of thalami and hypothalami in T2 weighted and fluid attenuated inversion recovery (FLAIR) images. A needle biopsy of the thalamic lesion was consistent with neuromyelitis optica spectrum disorder although her serum antibody to aquaporin-4 was negative. The level of orexin in celebrospinal fluid (CSF) was reduced. She presented hypersomnia, which didn't improve even after intravenous methylprednisolone 1 g daily for 3 days. Administration of oral modafinil extended her waking time. There is a number of reports about neuromyelitis optica (NMO) with hypothalamic lesions. We report this case as important suggestion of treatment of these cases.

Conventional and advanced imaging in neuromyelitis optica

Myelitis and optic neuritis are prototypic clinical presentations of both multiple sclerosis and neuromyelitis optica. Once considered a subtype of multiple sclerosis, neuromyelitis optica, is now known to have a discrete pathogenesis in which antibodies to the water channel, aquaporin 4, play a critical role. Timely differentiation of neuromyelitis optica from MS is imperative, determining both prognosis and treatment strategy. Early, aggressive immunosuppression is required to prevent the accrual of severe disability in neuromyelitis optica; conversely, MS-specific therapies may exacerbate the disease. The diagnosis of neuromyelitis optica requires the integration of clinical, MR imaging, and laboratory data, but current criteria are insensitive and exclude patients with limited clinical syndromes. Failure to recognize the expanding spectrum of cerebral MR imaging patterns associated with aquaporin 4 antibody seropositivity adds to diagnostic uncertainty in some patients. We present the state of the art in conventional and nonconventional MR imaging in neuromyelitis optica and review the place of neuroimaging in the diagnosis, management, and research of the condition.

Seronegative Neuromyelitis Optica Spectrum - The challenges on disease definition and pathogenesis

Neuromyelitis optica spectrum disorders (NMOSD) are characterized by severe optic neuritis and/or longitudinally extensive transverse myelitis, and some brain lesions are also unique to NMOSD. Serum autoantibodies against aquaporin-4 (AQP4) are detected in most cases of NMOSD. However, some patients with NMOSD remain seronegative despite repetitive testing during attacks with highly sensitive cell-based assays. The differential diagnosis of NMOSD is not restricted to multiple sclerosis and it includes many diseases that can produce longitudinally extensive myelitis and/or optic neuritis. We review the clinical features, imaging, and laboratory findings that can be helpful on the diagnostic work-up, discuss the differences between AQP4 antibody positive and negative patients with NMOSD, including features of NMOSD with antibodies against myelin oligodendrocyte glycoprotein.

A review of the current literature and a guide to the early diagnosis of autoimmune disorders associated with neuromyelitis optica

Neuromyelitis optica (NMO) is an immune-mediated neurological disorder characterised by recurrent episodes of optic neuritis and longitudinally extensive transverse myelitis. A serum biomarker, aquaporin-4 IgG, the autoantibody against aquaporin-4 water channel, has been specifically associated with NMO and has assisted early recognition and prediction of relapses. Less commonly, a monophasic course, associated with antibodies to myelin oligodendrocyte glycoprotein has been reported. Specific diagnostic criteria have been defined; however, some cases that do not fulfil these criteria (but are nevertheless associated with aquaporin-4 IgG) are classified as NMO spectrum disorder and follow the same relapsing course. An ever-growing list of autoimmune disorders, both organ-specific and non-organ-specific, have been associated in up to 20-30% of patients with NMO. These disorders, which may become symptomatic before or after the development of NMO, are often diagnosed long after the diagnosis of NMO, as symptoms may be wrongly attributed to NMO, its residual effects or medication side effects. In addition, autoantibodies can be found in patients with NMO without coexisting disease (up to 40% in some series) and maybe suggestive of a heightened humoral immune response. We present a comprehensive review of the current literature on autoimmune disorders co-existing with NMO and identified 22 autoimmune conditions (myasthenia gravis, coeliac disease, ulcerative colitis, sclerosing cholangitis, systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid antibody syndrome, Sjogren's syndrome, autoimmune hypothyroidism, immune thrombocytopenic purpura, pernicious anaemia, narcolepsy, pemphigus foliaceus, alopecia areata, psoriasis, scleroderma, dermatitis herpetiformis, polymyositis, chronic inflammatory demyelinating polyneuropathy, paraneoplastic disorders, insulin dependent diabetes mellitus and autoimmune encephalitis).

Neuromyelitis optica IgG stimulates an immunological response in rat astrocyte cultures

Neuromyelitis optica (NMO) is a primary astrocyte disease associated with central nervous system inflammation, demyelination, and tissue injury. Brain lesions are frequently observed in regions enriched in expression of the aquaporin-4 (AQP4) water channel, an antigenic target of the NMO IgG serologic marker. Based on observations of disease reversibility and careful characterization of NMO lesion development, we propose that the NMO IgG may induce a dynamic immunological response in astrocytes. Using primary rat astrocyte-enriched cultures and treatment with NMO patient-derived serum or purified IgG, we observed a robust pattern of gene expression changes consistent with the induction of a reactive and inflammatory phenotype in astrocytes. The reactive astrocyte factor lipocalin-2 and a broad spectrum of chemokines, cytokines, and stress response factors were induced by either NMO patient serum or purified IgG. Treatment with IgG from healthy controls had no effect. The effect is disease-specific, as serum from patients with relapsing-remitting multiple sclerosis, Sjögren's, or systemic lupus erythematosus did not induce a response in the cultures. We hypothesize that binding of the NMO IgG to AQP4 induces a cellular response that results in transcriptional and translational events within the astrocyte that are consistent with a reactive and inflammatory phenotype. Strategies aimed at reducing the inflammatory response of astrocytes may short circuit an amplification loop associated with NMO lesion development.

A guide to facilitate the early treatment of patients with idiopathic demyelinating disease (multiple sclerosis and neuromyelitis optica)

Definite diagnosis of inflammatory demyelinating disease (multiple sclerosis (MS) and neuromyelitis optica (NMO)) may require time, but early treatment offers the opportunity to maximize patient outcomes. The purpose of this report is to provide guidance to facilitate early treatment decisions for patients with inflammatory demyelinating disease, before definitive diagnosis. Neurology experts reviewed the existing literature and clinical evidence. A treatment decision pathway was developed, defining patients for whom first-line MS disease-modifying therapies (a) are unlikely to be effective, (b) may be effective but require careful monitoring and (c) are likely to provide benefit. This algorithm seeks to ensure that patients, particularly those in Asia, receive appropriate treatment early in inflammatory demyelinating disease.

Brain abnormalities in neuromyelitis optica spectrum disorder

Neuromyelitis optica (NMO) is an idiopathic inflammatory syndrome of the central nervous system that is characterized by severe attacks of optic neuritis (ON) and myelitis. Until recently, NMO was considered a disease without brain involvement. However, since the discovery of NMO-IgG/antiaqaporin-4 antibody, the concept of NMO was broadened to NMO spectrum disorder (NMOSD), and brain lesions are commonly recognized. Furthermore, some patients present with brain symptoms as their first manifestation and develop recurrent brain symptoms without ON or myelitis. Brain lesions with characteristic locations and configurations can be helpful in the diagnosis of NMOSD. Due to the growing recognition of brain abnormalities in NMOSD, these have been included in the NMO and NMOSD diagnostic criteria or guidelines. Recent technical developments such as diffusion tensor imaging, MR spectroscopy, and voxel-based morphometry reveal new findings related to brain abnormalities in NMOSD that were not identified using conventional MRI. This paper focuses on the incidence and characteristics of the brain lesions found in NMOSD and the symptoms that they cause. Recent studies using advanced imaging techniques are also introduced.

The expanded spectrum of neuromyelitis optica: evidences for a new definition

Neuromyelitis optica (NMO) has been traditionally described as the association of recurrent or bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM). Identification of aquaporin-4 antibody (AQP4-IgG) has deeply changed the concept of NMO. A spectrum of NMO disorders (NMOSD) has been formulated comprising conditions which include both AQP4-IgG seropositivity and one of the index events of the disease (recurrent or bilateral optic neuritis and LETM). Most NMO patients harbor asymptomatic brain MRI lesions, some of them considered as typical of NMO. Some patients with aquaporin-4 autoimmunity present brainstem, hypothalamic or encephalopathy symptoms either preceding an index event or occurring isolatedly with no evidence of optic nerve or spinal involvement. On the opposite way, other patients have optic neuritis or LETM in association with typical lesions of NMO on brain MRI and yet are AQP4-IgG seronegative. An expanded spectrum of NMO disorders is proposed to include these cases.

A case with anti-galactocerebroside antibody-positive Mycoplasma pneumoniae meningoencephalitis presenting secondary hypersomnia

Galactocerebroside (Gal-C) is a major myelin component in the central nervous system. The anti-Gal-C antibody induced by mycoplasma infection may therefore be involved in the pathogenic mechanisms of mycoplasma-associated encephalitis. Here we report an adult case of mycoplasma encephalitis developing excessive daytime sleepiness. Brain MRI suggested that hypothalamic involvement was compatible with hypersomnia. This finding was corroborated by decreased hypocretin-1 in cerebrospinal fluid (CSF) and the manifestation of diabetes insipidus. Screening for anti-glycolipid antibody profiles showed the selective increase of serum anti-Gal-C antibody. After treatment with minocyclin, the patient's daytime sleepiness was markedly improved and the CSF hypocretin-1 level became almost normal, as well. It is known that CSF hypocretin-1 is decreased in Guillain-Barré syndrome mediated by anti-glycolipid antibody, suggesting a possible mechanistic link between anti-glycolipid antibodies and hypothalamic involvement. The present case further emphasizes the broad spectrum of neurological complications after mycoplasma infection.