Neuromyelitis optica with hypothalamic involvement

A comparative study of hypothalamic involvement in patients with myelin oligodendrocyte glycoprotein antibody-associated disease, neuromyelitis optica spectrum disorder, and multiple sclerosis

BACKGROUND AND PURPOSE

We aimed to characterize hypothalamic involvement in myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and compare it with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS).

METHODS

A retrospective study was performed to identify hypothalamic lesions in patients diagnosed with MOGAD, NMOSD, or MS from January 2013 to May 2020. The demographic, clinical, and radiological features were recorded. Hypothalamic dysfunction and prognosis were assessed through physical examination, biochemical testing, sleep monitoring, and magnetic resonance imaging.

RESULTS

Hypothalamic lesions were observed in seven of 96 patients (7.3%) with MOGAD, 34 of 536 (6.3%) with NMOSD, and 16 of 356 (4.5%) with MS (p = 0.407). The time from disease onset to development of hypothalamic lesions was shortest in MOGAD (12 months). The frequency of bilateral hypothalamic lesions was the lowest in MOGAD (p = 0.008). The rate of hypothalamic dysfunction in MOGAD was 28.6%, which was lower than that in NMOSD (70.6%) but greater than that in MS patients (18.8%; p = 0.095 and p = 0.349, respectively). Hypothalamic dysfunction in MOGAD manifests as hypothalamic-pituitary-adrenal axis dysfunction and hypersomnia. The proportion of complete regression of hypothalamic lesions in MOGAD (100%) was much greater than that in NMOSD (41.7%) and MS patients (18.2%; p = 0.007 and p = 0.001, respectively). An improvement in hypothalamic dysfunction was observed in all MOGAD patients after immunotherapy.

CONCLUSIONS

MOGAD patients have a relatively high incidence of asymptomatic hypothalamic lesions. The overall prognosis of patients with hypothalamic involvement is good in MOGAD, as the lesions completely resolve, and dysfunction improves after immunotherapy.

Neuromyelitis optica spectrum disorder: Exploring the diverse clinical manifestations and the need for further exploration

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder characterized by inflammatory assaults on the central nervous system (CNS), particularly on the optic nerves and spinal cord. In recent years, a wider range of clinical manifestations of this complex disease have been observed, emphasizing the importance of gaining a more profound understanding beyond optic neuritis (ON) and transverse myelitis (TM).

CURRENT KNOWLEDGE

This study explores the many clinical symptoms of NMOSD, including common and uncommon presentations. Distinctive aspects of ON, TM, and diencephalic/brainstem syndromes are examined, highlighting their unique characteristics in contrast to conditions such as multiple sclerosis. We also discuss extra-CNS involvement, such as unusual signs, including muscle involvement, retinal injury, auditory impairment, and rhinological symptoms.

AIMS AND OBJECTIVES

Our study intends to highlight the wide range and complexity of NMOSD presentations, emphasizing the significance of identifying unusual symptoms for precise diagnosis and prompt management. The specific processes that contribute to the varied clinical presentation of NMOSD are not well understood despite existing information. This emphasizes the necessity for more study to clarify the mechanisms that cause different symptoms and discover new treatment targets for this complex autoimmune disorder.

CONCLUSION

It is essential to acknowledge the complex and varied clinical manifestations of NMOSD to enhance diagnosis, treatment, and patient results. By enhancing our comprehension of the fundamental processes and investigating innovative therapeutic approaches, we may aim to enhance the quality of life for persons impacted by this illness.

Treatment of neuromyelitis optica spectrum disorder: revisiting the complement system and other aspects of pathogenesis

Neuromyelitis optica spectrum disorder (NMOSD) represents a rare neuroimmunological disease causing recurrent attacks and accumulation of permanent disability in affected patients. The discovery of the pathogenic IgG‑1 antibody targeting a water channel expressed in astrocytes, aquaporin 4, constitutes a milestone achievement. Subsequently, multiple pathophysiological aspects of this distinct disease entity have been investigated. Demyelinating lesions and axonal damage ensue from autoantibodies targeting an astroglial epitope. This conundrum has been addressed in the current disease model, where activation of the complement system as well as B cells and interleukin 6 (IL-6) emerged as key contributors. It is the aim of this review to address these factors in light of novel treatment compounds which reflect these pathophysiological concepts in aiming for attack prevention, thus reducing disease burden in patients with NMOSD.

Factors associated with the misdiagnosis of neuromyelitis optica spectrum disorder

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune condition that is associated with severe disability. Approximately 40% of individuals are misdiagnosed with multiple sclerosis (MS) or other diseases. We aimed to define factors that influence the misdiagnosis of people with NMOSD and provide strategies for reducing error rates.

METHODS

A retrospective study was performed involving all people with a confirmed diagnosis of NMOSD within a single academic institution. Comprehensive clinical timelines were constructed for each individual that included presenting symptoms, provider type and timing of evaluations, aquaporin 4-IgG (AQP4) results, and MRI scans. Two-sample comparisons of continuous and categorial variables were performed for people accurately diagnosed with NMOSD and those originally misdiagnosed with another medical condition. A subanalysis of only AQP4-IgG positive people was also performed.

RESULTS

The study cohort included 199 people fulfilling International Panel criteria for NMOSD with 71 people (62 female; mean age at first symptom presentation (standard deviation (SD)) = 32.8 years (y) (SD 16.1)) being initially misdiagnosed and 128 people (106 female; 41.14y (SD 15.41)) who were accurately diagnosed. Of the 199 people with NMOSD, 166 had a positive serostatus. Identified factors associated with misdiagnosis, regardless of AQP4-IgG serostatus, were the presence of protracted nausea/vomiting/hiccups without any accompanying neurological symptoms, 23 (32.4%) versus 16 (12.5%) (p = 0.001), a longer median (range) time to see a neuroimmunology specialist 4.2y (0.14-31.8) versus 0.5y (0.0-21.2) (p<0.0001), and a delay in acquiring an MRI study, 4.7y (0.0-27.3) versus 0.3y (0.0-20.2) (p<0.0001). A greater proportion of people misdiagnosed were identified with a negative live-cell based AQP4-IgG serum test result, 13/13 (100%) versus 22/114 (19.3%) (p<0.0001). Additionally, the mean (SD) time between a first negative and successive live-cell based AQP4-IgG positive test result was greater for people misdiagnosed with another condition, 3.9y (SD 5.0) versus 1.5y (SD 2.1) (p = 0.01). Although not significant between groups, a rash was also reported in 63/199 people with NMOSD, with 31/63 having an anti-nuclear antibody titer ≥ 1:160.

CONCLUSION

Defined factors can help guide both generalists and specialists in the pursuit of strategies aimed at efficiently diagnosing those with NMOSD such that effective care can be delivered.

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.

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.

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.

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.

Hypothalamic Gliosis by MRI and Visceral Fat Mass Negatively Correlate with Plasma Testosterone Concentrations in Healthy Men

OBJECTIVE

This study aimed to determine whether a relationship was evident between gliosis in the mediobasal hypothalamus (MBH) and plasma testosterone concentrations in men.

METHODS

A total of 41 adult men (aged 18-50 years) from 23 twin pairs underwent fasting morning blood draw and brain magnetic resonance imaging. T2 relaxation time was used to quantify gliosis in the MBH and control areas in the putamen and amygdala. Plasma concentrations of testosterone and 17β-estradiol were measured by liquid chromatography-tandem mass spectrometry. Body composition including visceral adiposity was measured by dual x-ray absorptiometry.

RESULTS

A negative association was found between MBH T2 relaxation time and plasma concentrations of both free and total testosterone (r = -0.29, P < 0.05 and r = -0.37, P < 0.01, respectively). Visceral adiposity exhibited a negative correlation with plasma total testosterone concentration (r = -0.45, P = 0.001) but a positive correlation with MBH T2 relaxation time (r = 0.24, P = 0.03). The negative correlation between plasma total testosterone and MBH T2 relaxation time remained significant after adjustment for visceral adiposity, age, BMI, and insulin resistance.

CONCLUSIONS

In healthy men across a range of BMIs, MBH gliosis was associated with higher visceral adiposity but lower endogenous testosterone. These findings suggest that MBH gliosis could provide novel mechanistic insights into gonadal dysfunction in men with obesity.

Neuromyelitis optica spectrum disorder and menstruation

BACKGROUND

Gender issues and the female preponderance in neuromyelitis optica spectrum disorder (NMOSD) have been investigated before, yet the interplay between NMOSD and menstrual characteristics has remained unknown. Thus, the aim was to compare menstrual cycle patterns and their symptoms in NMOSD patients and healthy women.

METHODS

This cross-sectional study was conducted during 2015-2016 in Isfahan, Iran, and included female patients aged>14years with a diagnosis of NMOSD and healthy subjects as controls. Data regarding age at menarche, menstrual characteristics, history of premenstrual syndrome (PMS) and possible perimenstrual symptoms were collected. Also, NMOSD patients were asked to report changes in their menstrual cycles after onset of the disorder.

RESULTS

The final study population included 32 NMOSD and 33 healthy controls. These groups did not differ regarding their demographics (P>0.05), and age at menarche in the NMOSD and control groups was 13.31±1.49 years and 13.48±1.44 years, respectively (P=0.637). The controls experienced PMS more frequently (78.8% vs. 40.6% in the NMOSD patients; P=0.03), with no significant differences in other menstrual features between groups (P>0.05). However, changes in menstruation after NMOSD onset were reported by 43.8% of patients, with an increase in menstrual irregularities from 15.6% to 43.7% (P=0.012); other menstrual characteristics did not differ after disease onset (P>0.05).

CONCLUSION

Menstruation do not differ between healthy controls and NMOSD patients before the onset of disease whereas, after its onset, those affected experienced more irregularities in their menstrual cycles. This may be an effect of NMOSD and its underlying disorders on menstruation and suggests that further interventions may be required for affected women.

Hyponatremia in neuromyelitis optica spectrum disorders: Literature review

Hyponatremia is a potentially serious electrolyte abnormality observed in neuromyelitis optica spectrum disorders (NMOSDs), and its most common cause is syndrome of inappropriate antidiuretic hormone secretion (SIADH). Another potential cause of hyponatremia is cerebral salt-wasting syndrome (CSWS), although CSWS has not previously been reported in NMOSDs. Accurate and early differentiation between SIADH and CSWS is difficult. However, the two conditions have important implications for the selection of therapy. Here, we describe two patients with aquaporin-4 antibody (AQP4-Ab)-positive NMOSDs who developed hyponatremia as a result of CSWS and SIADH, respectively. Additionally, we review all previously reported studies of hyponatremia in patients with NMOSDs and propose several potential pathophysiological mechanisms of hyponatremia. In conclusion, NMOSDs accompanied by hyponatremia are not actually rare, but have previously been given little attention. Furthermore, SIADH should not be the only consideration, before the exclusion of rare but significant CSWS.

Symptomatic Narcolepsy as a Presenting Feature of Neuromyelitis Optica

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness. It can be either primary or symptomatic due to other neurologic disorders. Neuromyelitis optica (NMO) is an inflammatory demyelinating disorder in which symptomatic narcolepsy is being described as one of the core clinical features. Here, we report a patient with NMO who presented with narcolepsy. Signal changes on magnetic resonance imaging in hypothalamus and other periventricular regions of high aquaporin-4 expression should prompt considering NMO as diagnosis. Serum anti-aquaporin-4 IgG antibody testing should be done in such cases, and appropriate treatment should be initiated to prevent further neurological worsening and relapses.

The Contribution of Optical Coherence Tomography in Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSD) comprises a group of central nervous system disorders of inflammatory autoimmune origin that mainly affect the optic nerves and the spinal cord and can cause severe visual and general disability. The clinical signs are similar to those of multiple sclerosis (MS), with the result that it is often difficult to differentiate between the two, thus leading to misdiagnosis. As the treatment and prognosis of NMOSD and MS are different, it is important to make an accurate and early diagnosis of NMOSD. Optical coherence tomography (OCT) is a non-invasive technique that enables a quantitative study of the changes that the optic nerve and the macula undergo in several neurodegenerative diseases. Many studies have shown that some of these changes, such as retinal nerve fiber layer thinning or microcystic macular edema, can be related to alterations in the brain due to neurodegenerative disorders. The purpose of this mini-review is to show how OCT can be useful for the diagnosis of NMOSD and follow-up of affected patients, as well as for the differential diagnosis with MS.

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.

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.

Recurrent Longitudinally Extensive Myelitis and Aquaporin-4 Seronegativity - The Expanding Spectrum of Neuromyelitis Optica

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a recently proposed unifying term for Neuromyelitis Optica (NMO), also known as Devic's disease and related syndromes. It is a relapsing inflammatory demyelinating disease that most commonly affects optic nerves and the spinal cord, leading to sudden vision loss or weakness in one or both eyes, and loss of sensation and bladder function. Though inflammation may also involve the brain, the lesions seen in NMO are different from Multiple Sclerosis (MS) which has a similar clinical course. Attacks of NMOSD tend to be more severe and often different in nature from MS. MS and NMOSD are often confused but require a different course of treatment for optimal results. Here, we describe a patient who had clinical features suggestive of NMO but showed seronegativity for anti-aquaporin antibodies, done twice. Initially he was managed on the lines of MS but showed a deteriorating clinical course on initiation of treatment with interferons. Later, his diagnosis was revised to seronegative NMO and he was started on immunosuppressive therapy with azathioprine to which he showed optimal response and achieved disease stabilization.

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.

Lymphomas-Part 2

There are 2 types of central nervous system lymphoma: primary and secondary. Both have variable imaging features making them diagnostic challenges. Furthermore, a patient's immune status significantly alters the imaging findings. Familiarity with typical appearances, variations, and common mimics aids radiologists in appropriately considering lymphoma in the differential diagnosis. Moreover, special types of lymphoma, such as lymphomatosis cerebri, intravascular lymphoma, and lymphomatoid granulomatosis, also are found. This article discusses uncommon types of lymphoma and the differential diagnosis for focal, multifocal, meningeal, and infiltrative lymphomas.

Galactorrhea in a Patient With Aquaporin-4 Antibody-positive Neuromyelitis Optica Spectrum Disorder: A Case Report and Review of the Literature

This is the first report of a case of galactorrhea in a patient with neuromyelitis optica spectrum disorder (NMOSD) diagnosed on the basis of antiaquaporin-4 antibody seropositivity. The hypothalamus is becoming known as an area highly expressing aquaporin-4 and frequently involved in intracranial lesions of patients with neuromyelitis optica (NMO). We reviewed cases of hypothalamic endocrinopathy among patients with NMO, NMOSD, and the Japanese opticospinal form of MS. Among these cases, galactorrhea was the second most common symptom. Signs of hypothalamic endocrinopathies may be obscured by the grave neurological deficits caused by NMO. We recommend paying special attention to hypothalamic endocrinopathies among patients with NMO or NMOSD, irrespective of brain MRI findings.

Recurrent optic neuromyelitis with endocrinopathies: a new syndrome or just a coincidence?

The spectrum of optic neuromyelitis (ONM) ranges from monophasic or recurrent idiopathic forms of the disease, to ONM associated with autoimmune disorders. A distinct form of the disease, called recurrent ONM with endocrinopathies, characterized by spinal cord involvement (cavitations with syringomyeloid sensory disturbance), rapid evolution to blindness and paraplegia, characteristic cerebrospinal fluid (CSF) findings, and association with hypothalamus - pituitary dysfunction, has recently been described. The first case of ONM with endocrinopathies in a female Caucasian from Europe is presented, supporting the existence of this syndrome as a separate entity.

Evaluation of the 2015 diagnostic criteria for neuromyelitis optica spectrum disorder

OBJECTIVE

To evaluate the application of the 2015 International Panel for NMO Diagnosis (IPND) criteria to consecutive cases of neuromyelitis optica spectrum disorder (NMOSD) in a large cohort of individuals with CNS inflammatory diseases.

METHODS

In total, 594 patients with CNS inflammatory diseases were included. Rigorous confirmation of the patients' aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) status throughout the disease duration (mean 9.2 ± 5.7 years) using repeated assays, including ELISA and cell-based assay, was performed.

RESULTS

A total of 252 patients fulfilled the IPND criteria (AQP4-IgG positive: 226 [90%], AQP4-IgG negative: 26 [10%]). Of these, 136 (54%) patients met the 2006 neuromyelitis optica criteria. When we assumed an unknown AQP4-IgG status in the confirmed NMOSD group with AQP4-IgG, 162 of 226 (72%) patients with AQP4-IgG were classified as having NMOSD by the IPND criteria. The majority of patients were diagnosed with NMOSD within 2 years of onset (73%) or after a second attack (72%). Acute myelitis (83%) and optic neuritis (65%) were the most common clinical features throughout the disease duration. Optic neuritis (42%) was the most common initial manifestation, followed by acute myelitis (38%) and area postrema syndrome (14%).

CONCLUSIONS

The IPND criteria well-reflected the broader clinical spectrum of NMOSD and markedly improved the diagnostic yield compared to the previous criteria, even in patients with an unknown AQP4-IgG status.

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.

International consensus diagnostic criteria for neuromyelitis optica spectrum disorders

Neuromyelitis optica (NMO) is an inflammatory CNS syndrome distinct from multiple sclerosis (MS) that is associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Prior NMO diagnostic criteria required optic nerve and spinal cord involvement but more restricted or more extensive CNS involvement may occur. The International Panel for NMO Diagnosis (IPND) was convened to develop revised diagnostic criteria using systematic literature reviews and electronic surveys to facilitate consensus. The new nomenclature defines the unifying term NMO spectrum disorders (NMOSD), which is stratified further by serologic testing (NMOSD with or without AQP4-IgG). The core clinical characteristics required for patients with NMOSD with AQP4-IgG include clinical syndromes or MRI findings related to optic nerve, spinal cord, area postrema, other brainstem, diencephalic, or cerebral presentations. More stringent clinical criteria, with additional neuroimaging findings, are required for diagnosis of NMOSD without AQP4-IgG or when serologic testing is unavailable. The IPND also proposed validation strategies and achieved consensus on pediatric NMOSD diagnosis and the concepts of monophasic NMOSD and opticospinal MS.

The pathology of an autoimmune astrocytopathy: lessons learned from neuromyelitis optica

Neuromyelitis optica (NMO) is a disabling autoimmune astrocytopathy characterized by typically severe and recurrent attacks of optic neuritis and longitudinally extensive myelitis. Until recently, NMO was considered an acute aggressive variant of multiple sclerosis (MS), despite the fact that early studies postulated that NMO and MS may be two distinct diseases with a common clinical picture. With the discovery of a highly specific serum autoantibody (NMO-IgG), Lennon and colleagues provided the first unequivocal evidence distinguishing NMO from MS and other central nervous system (CNS) inflammatory demyelinating disorders. The target antigen of NMO-IgG was confirmed to be aquaporin-4 (AQP4), the most abundant water channel protein in the CNS, mainly expressed on astrocytic foot processes at the blood-brain barrier, subpial and subependymal regions. Pathological studies demonstrated that astrocytes were selectively targeted in NMO as evidenced by the extensive loss of immunoreactivities for the astrocytic proteins, AQP4 and glial fibrillary acidic protein (GFAP), as well as perivascular deposition of immunoglobulins and activation of complement even within lesions with a relative preservation of myelin. In support of these pathological findings, GFAP levels in the cerebrospinal fluid (CSF) during acute NMO exacerbations were found to be remarkably elevated in contrast to MS where CSF-GFAP levels did not substantially differ from controls. Additionally, recent experimental studies showed that AQP4 antibody is pathogenic, resulting in selective astrocyte destruction and dysfunction in vitro, ex vivo and in vivo. These findings strongly suggest that NMO is an autoimmune astrocytopathy where damage to astrocytes exceeds both myelin and neuronal damage. This chapter will review recent neuropathological studies that have provided novel insights into the pathogenic mechanisms, cellular targets, as well as the spectrum of tissue damage in NMO.

[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.

Neuromyelitis optica (Devic's syndrome)

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system that selectively targets the optic nerve and spinal cord, although it may also target certain areas of the brain. The majority of cases are associated with relapses. A specific biomarker, an autoantibody that targets aquaporin-4, is present in the majority of patients and facilitates the diagnosis. Detection of this biomarker in serum has enabled recognition of an expanded spectrum of clinical disorders that previously would not have met diagnostic criteria for NMO. Aquaporin-4 IgG1 autoantibodies are pathogenic and produce lesions of the brain when injected intracerebrally or systemically. The clinical course of NMO is dominated by acute attacks. Progressive worsening of disability, as occurs in prototypic multiple sclerosis, is distinctly unusual. Corticosteroids and plasma exchange are useful for management of acute attacks. Several treatments used to prevent attacks of multiple sclerosis are ineffective in this condition; effective immunotherapies include azathioprine, mycophenolate mofetil and rituximab.

Update on the diagnosis and treatment of neuromyelitis optica: recommendations of the Neuromyelitis Optica Study Group (NEMOS)

Neuromyelitis optica (NMO, Devic’s syndrome), long considered a clinical variant of multiple sclerosis, is now regarded as a distinct disease entity. Major progress has been made in the diagnosis and treatment of NMO since aquaporin-4 antibodies (AQP4-Ab; also termed NMO-IgG) were first described in 2004. In this review, the Neuromyelitis Optica Study Group (NEMOS) summarizes recently obtained knowledge on NMO and highlights new developments in its diagnosis and treatment, based on current guidelines, the published literature and expert discussion at regular NEMOS meetings. Testing of AQP4-Ab is essential and is the most important test in the diagnostic work-up of suspected NMO, and helps to distinguish NMO from other autoimmune diseases. Furthermore, AQP4-Ab testing has expanded our knowledge of the clinical presentation of NMO spectrum disorders (NMOSD). In addition, imaging techniques, particularly magnetic resonance imaging of the brain and spinal cord, are obligatory in the diagnostic workup. It is important to note that brain lesions in NMO and NMOSD are not uncommon, do not rule out the diagnosis, and show characteristic patterns. Other imaging modalities such as optical coherence tomography are proposed as useful tools in the assessment of retinal damage. Therapy of NMO should be initiated early. Azathioprine and rituximab are suggested as first-line treatments, the latter being increasingly regarded as an established therapy with long-term efficacy and an acceptable safety profile in NMO patients. Other immunosuppressive drugs, such as methotrexate, mycophenolate mofetil and mitoxantrone, are recommended as second-line treatments. Promising new therapies are emerging in the form of anti-IL6 receptor, anti-complement or anti-AQP4-Ab biologicals.

Comparison of deep gray matter lesions on magnetic resonance imaging among adults with acute disseminated encephalomyelitis, multiple sclerosis, and neuromyelitis optica

BACKGROUND

Deep gray matter lesions have been reported in patients with acute disseminated encephalomyelitis (ADEM), multiple sclerosis (MS), and neuromyelitis optica (NMO).

OBJECTIVES

The purpose of this study was to compare the features of deep gray matter lesions on magnetic resonance imaging (MRI) among adult patients with ADEM, MS, and NMO.

METHODS

Ninety-five adult patients with ADEM (n=12), MS (n=60), and NMO (n=23) who had deep gray matter lesions on MRI were enrolled. Morphological features of deep gray matter lesions among these patients were assessed.

RESULTS

Putamen involvement was more common in patients with ADEM than in patients with MS and NMO. Differing from children, thalamus involvement might not be helpful in differentiating ADEM from MS in adults. Hypothalamus involvement was more common in patients with NMO than in patients with ADEM and MS. More importantly, bilateral hypothalamus involvement was more helpful in differentiating NMO from MS. The diameter of the thalamus lesions in patients with ADEM was larger than that in patients with NMO.

CONCLUSIONS

Morphological features of deep gray matter lesions vary among adult patients with ADEM, MS, and NMO, and may be helpful in distinguishing these diseases.

Longer T(2) relaxation time is a marker of hypothalamic gliosis in mice with diet-induced obesity

A hallmark of brain injury from infection, vascular, neurodegenerative, and other disorders is the development of gliosis, which can be detected by magnetic resonance imaging (MRI). In rodent models of diet-induced obesity (DIO), high-fat diet (HFD) consumption rapidly induces inflammation and gliosis in energy-regulating regions of the mediobasal hypothalamus (MBH), and recently we reported MRI findings suggestive of MBH gliosis in obese humans. Thus, noninvasive imaging may obviate the need to assess MBH gliosis using histopathological end points, an obvious limitation to human studies. To investigate whether quantitative MRI is a valid tool with which to measure MBH gliosis, we performed analyses, including measurement of T(2) relaxation time from high-field MR brain imaging of mice fed HFD and chow-fed controls. Mean bilateral T(2) relaxation time was prolonged significantly in the MBH, but not in the thalamus or cortex, of HFD-fed mice compared with chow-fed controls. Histological analysis confirmed evidence of increased astrocytosis and microglial accumulation in the MBH of HFD-fed mice compared with controls, and T(2) relaxation times in the right MBH correlated positively with mean intensity of glial fibrillary acidic protein staining (a marker of astrocytes) in HFD-fed animals. Our findings indicate that T(2) relaxation time obtained from high-field MRI is a useful noninvasive measurement of HFD-induced gliosis in the mouse hypothalamus with potential for translation to human studies.

Pathology of demyelinating diseases

There has been significant progress in our understanding of the pathology and pathogenesis of central nervous system inflammatory demyelinating diseases. Neuropathological studies have provided fundamental new insights into the pathogenesis of these disorders and have led to major advances in our understanding of multiple sclerosis (MS) heterogeneity, the substrate of irreversible progressive disability in MS, the relationship between inflammation and neurodegeneration in MS, the neuroimaging correlates of MS lesions, and the pathogenesis of other central nervous system inflammatory disorders, including neuromyelitis optica, acute disseminated encephalomyelitis, and Balo's concentric sclerosis. Herein, we review the pathological features of these central nervous system inflammatory demyelinating disorders and discuss neuropathological studies that have yielded novel insights into potential mechanisms involved in the formation of the demyelinated lesion.

Modifications of longitudinally extensive transverse myelitis and brainstem lesions in the course of neuromyelitis optica (NMO): a population-based, descriptive study

BACKGROUND

Neuromyelitis optica (NMO) includes transverse myelitis, optic neuritis and brain lesions. Recent studies have indicated that the brainstem is an important site of attack in NMO. Longitudinally extensive transverse myelitis (LETM) is an important component of the clinical diagnosis of NMO. The frequency of brainstem and LETM lesions, changes over time of LETM and the clinical consequences in the course of NMO have only been sparsely studied.

METHODS

The study was a population-based retrospective case series with clinical and magnetic resonance imaging (MRI) follow-up of 35 patients with definite NMO and a relapsing-remitting course.

RESULTS

Brainstem lesions were observed in 25 patients, 18 in medulla oblongata (11 in area postrema). Lesions in the pons, mesencephalon and diencephalon occurred in 10, 7 and 7 patients, respectively. Lesions were symptomatic in medulla oblongata and pons, asymptomatic in mesencephalon and diencephalon. Brainstem lesions were observed significantly more often in anti-aquaporin-4 (AQP-4) antibody positive than in seronegative patients (p < 0.002).LETM was demonstrated by MRI of the spinal cord in 30/36 patients, 23/30 of whom had follow-up MRI of the spinal cord. Recurrent LETM was observed in five patients. In nine patients the LETM changed into multiple lesions during remission or treatment. Spinal cord atrophy was observed in 12/23 (52%) patients, correlating to Expanded Disability Status Scale (r = 0.88, p < 0.001).

CONCLUSIONS

NMO patients had frequent occurrence of brainstem lesions and LETM. Brainstem lesions were associated with anti-AQP4 antibody positivity. LETM lesions differentiated over time and the outcome included relapses, fragmentation and atrophy. Correlation was observed between spinal cord atrophy and neurological disability.

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.

Neuromyelitis optica spectrum disorders

Neuromyelitis optica is an uncommon inflammatory demyelinating CNS disorder that is distinct from multiple sclerosis with respect to clinical, laboratory, neuroimaging, and prognostic characteristics. Autoantibodies that target aquaporin-4 are highly specific for neuromyelitis optica and have helped define a spectrum of disease beyond the classic definition of acute transverse myelitis and optic neuritis. Accumulating evidence supports the pathogenic potential that these autoantibodies possess in relation to the unique vasculocentric immunopathology of the disease. Current treatment strategies therefore include the use of corticosteroids and plasmapheresis for acute attacks and general or humoral immunosuppression for attack prevention. Ongoing research will focus on establishing the pathogenic mechanisms of the disease, in part derived from newly reported animal models, and testing-focused treatment strategies that evolve from this knowledge.

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.

Consciousness disturbance and poikilothermia revealing brain involvement in neuromyelitis optica

A 21-year-old woman was admitted due to altered mental status and hypothermia. The patient had a diagnosis of neuromyelitis optica (NMO) for 12 years and she was positive for serum anti-aquaporin 4 antibody. On admission, physical examination revealed coma with decerebration rigidity and poikilothermia. Magnetic resonance images of the brain revealed widespread, gadolinium enhancing lesions in the periventricular areas and the diencephalic structures. Laboratory investigations revealed hyponatremia and hypothyroidism. The patient was treated with high dose steroids. Both symptomatic and asymptomatic brain lesions may develop in patients with NMO. However, poikilothermia has not been reported in patients with NMO before.

Neuromyelitis optica: an antibody-mediated disorder of the central nervous system

Neuromyelitis optica (NMO) is a recurrent inflammatory disease that preferentially targets the optic nerves and spinal cord leading to blindness and paralysis. The hallmarks of NMO include bilateral optic neuritis and longitudinally extensive transverse myelitis. Woman and African Americans are overrepresented in the US patient population. NMO is associated with the NMO-IgG biomarker, which targets the aquaporin-4 water channel on astrocytes. The humoral pathology of NMO lesions include IgG and IgM deposits and infiltration by granulocytes suggesting that the NMO-IgG may be involved in the pathogenesis of disease. This review of the recent NMO literature covers the clinical features, epidemiology, radiology and pathology of disease and includes discussion of the important basic science research work in the field.