Intractable nausea and vomiting from autoantibodies against a brain water channel

Area postrema syndrome in patients with autoimmune glial fibrillary acidic protein astrocytopathy

Objective

Area postrema syndrome (APS) is a relatively rare symptom of autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A). This study aimed to report the APS in GFAP-immunoglobulin G (GFAP-IgG) positive patients.

Methods

We retrospectively analyzed the clinical data of APS in GFAP-IgG positive patients and reviewed relevant literature. Moreover, we compared these data with APS patients in aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders (AQP4-IgG+ NMOSD).

Results

7 of 75 (9.3%) GFAP-IgG positive patients experienced APS, including 4 females and 3 males. The median age of onset was 42 years (range, 12-71 years). All patients presented with APS as their initial manifestation. Nausea and vomiting were observed in all 7 patients, while hiccups occurred in 5 patients. The median duration of APS episodes was 12 days (range, 6-40 days). None of the patients experienced isolated APS episodes during their illness. AQP4-IgG was positive in 2 patients. 5 patients had dorsal medulla oblongata lesions, while 3 patients showed an "inverted V" sign on axial images. In addition, 5 patients presented with longitudinally extensive linear or patchy lesions in cervical spinal cord extending to area postrema on sagittal images. All APS attacks completely disappeared after immunotherapy. Compared with the APS in AQP4 + NMOSD, APS in A-GFAP-A had a lower proportion of females (33.3% vs. 80%, p = 0.003), more hiccups (81% vs. 50%, p = 0.037), more leptomeningeal enhancement (61.9% vs. 5%, p = 0.000), higher CSF white blood cell count (median 120 vs. 10 cells/mm3, p = 0.000) and protein (median 0.949 vs. 0.407 g/L, p = 0.000). Furthermore, fewer patients with A-GFAP-A received long-term immunotherapy (19% vs. 65%, p = 0.003).

Conclusion

APS often occurs as an initial manifestation of A-GFAP-A. MRI examination and antibody testing should be performed in suspected patients to avoid misdiagnosis.

Occurrence of area postrema syndrome during follow-up: phenotype and influence over NMOSD activity in LATAM in real-world settings

INTRODUCTION

We aimed to assess the frequency, duration, and severity of area postrema syndrome (APS) during follow-up in neuromyelitis optica spectrum disorder (NMOSD) patients, as well as its association with inflammatory activity and prognostic factors of APS severity in a real-world setting.

METHODS

We conducted a retrospective study on a cohort of Latin American (LATAM) NMOSD patients who had experienced APS during their follow-up. Patients from Mexico, Peru, Brazil, Colombia, Panama, Chile and Argentina patients who met 2015 NMOSD criteria were included. We evaluated data on symptom type (nausea, vomiting and/or hiccups), frequency, duration, severity (measured by APS severity scale), association with other NMOSD core relapses, and acute treatments (symptomatic and immunotherapy or plasmapheresis). Logistic regression was conducted to evaluate factors associated with APS severity (vs. mild-moderate).

RESULTS

Out of 631 NMOSD patients, 116 (18.3%) developed APS during their follow-up. The most common APS phenotype was severe. Inflammatory activity (i.e., relapses) significantly decreased after the onset of APS. Half of the patients experienced isolated APS with a median duration of 10 days, and the most frequently used acute treatment was IV steroids. All three symptoms were present in 44.6% of the patients. APS symptoms resolved following immunotherapy. Logistic regression did not identify independent factors associated with the severity of APS.

CONCLUSIONS

Our findings indicate that 18.3% of NMOSD patients developed APS during the follow-up period, with most patients fulfilling criteria for severe APS. The inflammatory activity decreased after the onset of APS compared to the previous year.

Characteristics of recurrence in area postrema-onset NMO spectrum disorder - a retrospective cohort study

BACKGROUND

Neuromyelitis Optica Spectrum Disorder (NMOSD) is an inflammatory autoimmune disease with high risk of recurrence and disability, the treatment goal is a recurrence free state. Area postrema (AP) is one of the most common involved area of NMOSD, which may have a particular significance in the pathogenesis of NMOSD and clinical heterogeneity. Our study is to investigate the clinical and recurrent characteristics AP onset NMOSD patients.

METHODS

A retrospective study was done in a cohort of 166 AQP4-IgG seropositive NMOSD patients which were identified by the 2015 IPND criteria. The patients were divided into AP onset (APO-NMOSD) group and non-AP onset (NAPO-NMOSD) group based on the initial episode location. Clinical features and recurrence differences of two groups were compared.

RESULTS

The APO-NMOSD group and NAPO-NMOSD group had a population ratio of 24:142. APO-NMOSD patients were younger (34.6y VS 42.3y, P = 0.013), had lower EDSS at first episode (0.7 VS 4.2, p = 0.028) and last follow up (1.9 VS 3.3, p = 0.001), more likely to have multi-core lesions at the first attack (33.3% VS 9.2%, P = 0.001). Also, they had a higher annual recurrence rate (0.4 ± 0.28 VS 0.19 ± 0.25, P = 0.012). In natural course NMOSD patients without immunotherapy, APO-NMSOD had a shorter time of first relapse (P < 0.001) and higher annual recurrence rate (0.31 ± 0.22 VS 0.16 ± 0.26, P = 0.038) than NAPO-NMOSD. APO-NMOSD group also have a higher risk of having the first relapsing compared to optic neuritis onset-NMOSD (HR 2.641, 95% CI 1.427-4.887, p = 0.002) and myelitis onset-NMOSD group (HR 3.593, 95% CI 1.736-7.438, p = 0.001). Compared to NAPO-NMOSD, APO-NMOSD has a higher likelihood of brainstem recurrence (28.6% vs. 4.7%, p<0.001) during the first recurrence, while NAPO-NMOSD is more susceptible to optic nerve involvement (10.7% vs. 41.1%, p = 0.01).

CONCLUSION

AQP4-IgG seropositive NMOSD patients with AP onset are youngers and have higher risk of recurrence. Clinicians should pay attention to AP damage in NMOSD, as it indicates a potential risk of recurrence.

TRIAL REGISTRATION

Retrospectively registered.

Paraneoplastic Neuromyelitis Optica Spectrum Disorder: A Rare Case of Advanced Breast Cancer with Intractable Nausea and Vomiting

BACKGROUND Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disease of the central nervous system that includes the triad of transverse myelitis, optic neuritis, and area postrema syndrome (APS), characterized by intractable nausea and vomiting. NMOSD can be part of a paraneoplastic syndrome and is associated with seropositivity to aquaporin-4 (AQP-4). We present a patient with uncontrollable nausea and vomiting who developed herpes zoster and acute myelitis and was finally diagnosed with paraneoplastic NMOSD due to breast cancer. CASE REPORT A 51-year-old woman was hospitalized due to 2 weeks of intractable nausea and vomiting. Although contrast-enhanced thoracoabdominal computed tomography (CT) on day 4 suggested breast cancer in her left breast, the etiology of her symptoms remained unknown. On day 13, she developed herpes zoster, followed by acute myelitis on day 25. Magnetic resonance imaging (MRI) showing longitudinal extensive transverse myelitis and an elevated serum AQP-4 antibody level led to the diagnosis of NMOSD. Brain MRI detected a small lesion in the dorsal medulla oblongata, which explained the preceding APS. After starting intravenous methylprednisolone pulse therapy, her nausea and vomiting rapidly subsided. Breast cancer was resected on day 63, and immunohistochemical staining revealed overexpression of AQP-4 in the tumor cells, suggesting paraneoplastic NMOSD. CONCLUSIONS This report has highlighted the presentation and diagnosis of NMOSD and supports the possibility that this can present as part of a paraneoplastic syndrome. In addition, diagnosis of NMOSD preceded by APS requires meticulous history taking and careful interpretation of MRI in the dorsal medulla oblongata.

Area postrema syndrome: An unusual presentation of neuromyelitis optica spectrum disorder

Isolated area postrema syndrome (APS) is a rare neurological presentation of, neuromyelitis optica spectrums disorder (NMOSD), recognizable by uncontrollable hiccups, nausea, or vomiting. When it occurs as the first presentation of NMOSD, it may present as a diagnostic challenge as the condition may be frequently attributed to gastrointestinal pathology, and the subsequent diagnostic delay may result in debilitating neurological sequelae such as optic neuritis or myelitis. We report such a case of isolated APS in a young woman who presented with a clinical picture of bouts of vomiting and intractable hiccups causing considerable distress and was finally diagnosed to be a case of seronegative NMOSD.

Area Postrema Syndrome in Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy

Background and Objectives

To report the frequency of area postrema syndrome (APS) in glial fibrillary acidic protein-immunoglobulin G (GFAP-IgG)–positive patients and emphasize the importance of APS among the phenotypes in autoimmune GFAP astrocytopathy.

Methods

Eight GFAP-IgG–positive cases with APS were retrospectively identified during 2015–2021. The APS phenotypes were described. A literature review of 8 previously reported cases was also included in analysis.

Results

A total of 8 patients (11%) (1 woman, 7 men; mean age: 52.4 ± 18.4 years) presented with APS in a cohort of 74 GFAP-IgG–positive patients, 3 of whom (4%) had disease onset with APS. All patients had hiccups, and hiccups was the unique symptom of APS in 5 patients. The median time from disease onset to APS occurrence was 2 days (range 0–20), and the mean duration of APS episodes was 23.6 ± 11.4 days. No patient had isolated APS attack. All episodes were completely resolved with a mean duration of 9.3 ± 5.4 days after immunotherapy. APS manifestations of 8 cases in previous studies showed similar features with our cases. In total, coexisting aquaporin-4-IgG was only detected in one of the 16 cases.

Discussion

APS could be an early, but not isolated clinical manifestation of autoimmune GFAP astrocytopathy. Hiccups was the predominant symptom of APS in this disorder. APS attacks of autoimmune GFAP astrocytopathy have good response to immunotherapy.

Dorsal medulla surface texture: Differentiating neuromyelitis optica spectrum disorder from multiple sclerosis

BACKGROUND AND PURPOSE

The timely and accurate diagnosis of neuromyelitis optica spectrum disorder (NMOSD) is essential and exposure to multiple sclerosis (MS) disease-modifying therapies may result in permanent neurological disability.

METHODS

Standardized 3-Tesla 3-dimensional brain MRI studies were retrospectively studied from people with NMOSD, MS, other CNS neurological diseases, and healthy control subjects. Comparisons of surface texture characteristics at the area postrema involving absolute introverted planar triangle counts, representing more complex and concave tissue topography, along with the spatial dissemination pattern of these triangles were performed cross-sectionally and longitudinally. An ideal introverted planar triangle threshold separating groups with NMOSD and MS was accomplished using the highest Youden's J statistic. For the classification of NMOSD, out-of-sample and in-sample measurements of the following were acquired: sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

The study cohort included 60 people with NMOSD, 100 people with MS, 12 with other neurological diseases, and five healthy controls. Significantly higher cross-sectional median introverted triangle counts were observed when the NMOSD (median [interquartile range]: 100 [23.5]) group was compared to MS (65 [20.25]; p < .0001) and other neurological diseases (66 [13.75]; p < .0001). Distinct spatial dissemination patterns of triangles extending craniocaudally at the region of interest within the dorsal medulla was also seen between groups with NMOSD and MS (p < .0001). For the identification of NMOSD, out-of-sample sensitivity (83%), specificity (100%), PPV (100%), and NPV (60%) were achieved.

CONCLUSIONS

Cross-sectional and longitudinal dorsal medulla surface texture differences within selective regions of vulnerability differentiate NMOSD from MS.

Case Report: Interferon-Alpha-Induced Neuromyelitis Optica Spectrum Disorder

Background and Objectives

To describe a new case of neuromyelitis optica spectrum disorder (NMOSD) induced by the administration of interferon-alpha (IFNα) and to raise awareness of this rare drug-induced disease of IFNα treatment.

Methods

A single case study and comprehensive literature review of eight cases.

Results

A 24-year-old man was diagnosed with cerebral venous thrombosis and essential thrombocythemia. He had been undergoing IFNα treatment (IFNα-2b, 3 million IU per day) without any side effects for 18 months, at which point the patient developed persistent hiccups, nausea, urinary retention, and numbness. Spinal magnetic resonance imaging revealed a longitudinal abnormality extending from the medulla to the entire spinal cord. The patient was positive for anti-aquaporin-4 antibody (AQP4-IgG) in both the serum and cerebrospinal fluid (CSF), which confirmed the diagnosis of NMOSD. Thus, recombinant IFNα-2b was suspended immediately. Because his condition did not improve after 6-day treatment of methylprednisolone pulse therapy (1,000 mg for 3 days, then 500 mg for 3 days), intravenous immunoglobulin (0.4 g/kg/day for 5 days) was administered. The patient gradually improved. Low-dose prednisolone and mycophenolate mofetil were subsequently administered as a long-term treatment. The patient was discharged with subtle limb numbness and their expanded disability status score (EDSS) was 1. At the 1-year follow-up, the patient had not relapsed and tested negative for AQP4-IgG. We further identified the eight patients with IFNα-induced NMOSD. The median onset age was 59 years, and the median time of IFNα exposure was 18 months. Optic neuritis was the most common initial symptom (five, 55.6%), followed by myelitis in three patients and area postrema syndrome in one patient. More than half (five, 55.6%) of the patients were monophasic. After IFNα discontinuation and immunotherapy, most (seven, 77.8%) patients remained relapse-free. However, only one patient was free of sequelae.

Conclusion

This study highlights the potential pathogenic risk of NMOSD of IFNα treatment. Given the high disability rates of this rare drug-induced disease, it is crucial to monitor the early manifestations of NMOSD during IFNα treatment.

Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy Associated With Area Postrema Syndrome: A Case Report

Glial fibrillary acidic protein astrocytopathy is an immunotherapy-responsive autoimmune disease of the central nervous system with various clinical manifestations; among these, there are few reports about area postrema syndrome (APS). The authors present the case of a female patient admitted to the hospital with intractable nausea and vomiting as the predominant symptom. The patient's cerebrospinal fluid was tested by cell-based assays (CBA) and found positive for the presence of anti-glial fibrillary acidic protein (GFAP) antibody, in addition, serological testing showed elevated levels of thyroglobulin and thyroperoxidase-specific antibodies. Brain and cervical MRI showed abnormally high signal on the T2 sequence in the dorsal medulla oblongata and right pontine arm. Therefore, the patient was diagnosed with autoimmune GFAP astrocytopathy. The symptoms improved rapidly after treatment with corticosteroids, and no recurrence has been observed thus far. APS may be a relatively rare clinical manifestation of GFAP astrocytopathy. Importantly, such presentation is challenging to correctly diagnose without typical MRI imaging findings. However, the detection of antibodies in the cerebrospinal fluid or serum may be valuable. Systemic and neurological autoimmunity often coexist, comprehensive antibody screening should be conducted.

Area postrema syndrome in neuromyelitis optica spectrum disorder: diagnostic challenges and descriptive patterns

Background

Although area postrema syndrome (APS) is one of the core clinical features of neuromyelitis optic spectrum disorder (NMOSD), it is frequently misdiagnosed as gastrointestinal or systemic disorders. In this study, we describe the diagnostic challenges in NMOSD patients with APS and their characteristic clinical and radiological features. All patients who attended our university hospitals during the period from March 2019 to August 2020 with a diagnosis of NMOSD according to the latest diagnostic criteria were admitted and evaluated clinically, radiologically with gadolinium-enhanced brain and spinal MRI, measures of serum Anti-Aquaporin 4 (Anti-AQP4) and clinical status using the Expanded Disability Status Scale (EDSS) scores. APS was diagnosed if there was a history of intractable nausea, vomiting, or hiccups (INVH) that had lasted longer than 1 week with the exclusion of other etiologies, or less than 48 h if associated with a lesion in the dorsal medulla on MRI scan.

Results

Twenty out of 90 (22.2%) identified patients with a diagnosis of NMOSD had a history of unexplained intractable nausea, vomiting or hiccoughs lasting an average of 20 days. Seventeen patients were anti-Aquaporin 4 seropositive. Seven patients (35%) presented initially with isolated clinical features of APS and were diagnosed only after subsequent relapse. Patients with APS preceding other core clinical presentations (13 cases, 65%) were diagnosed after development of motor manifestations. All patients developed acute myelitis during the course of illness. Brain and spinal MRI scans showed that 13 had a linear lesion in the dorsal tegmentum of the medulla oblongata adjacent to the fourth ventricle. Otherwise, longitudinally extensive transverse myelitis was found in 80%, while 35% showed extension of the cord lesion to the AP.

Conclusions

APS as a core clinical characteristic of NMOSD is not a rare presentation as was previously thought and can occur in both AQP4-seropositive and seronegative 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.

Autoimmune Brainstem Encephalitis: An Illustrative Case and a Review of the Literature

Autoimmune brainstem encephalitis (BSE) is a rare neurological condition with a wide range of underlying etiologies. It can be subdivided into two broad groups: a primary inflammatory disease of the central nervous system (CNS) or a brainstem disorder secondary to systemic diseases where the CNS is only one of many affected organs. Symptoms range from mild to life-threatening manifestations. Most cases respond well to immunotherapy. Therefore, broad and in-depth knowledge of the various inflammatory disorders that target the brainstem is essential for guiding the diagnostic approach and assisting in early initiation of appropriate therapy. We herein report on a case of BSE and provide an overview of the various causes of autoimmune BSE with an emphasis on the clinical manifestations and diagnostic approach.

Area postrema syndrome as initial manifestation in neuromyelitis optica spectrum disorder patients: A retrospective study

BACKGROUND

Area postrema syndrome (APS) is recognized as a core feature in neuromyelitis optica (NMO) diagnosis. Isolated APS can occur at NMO onset and frequently results in a delay of diagnosis, along with devastating secondary neurologic deficits. To date, few studies have characterized APS-onset neuromyelitis optica spectrum disorder (APSO-NMOSD).

OBJECTIVE

We aimed to describe the clinical and radiologic features of patients with APSO-NMOSD who are initially misdiagnosed in a cohort of patients from Zhengzhou, China.

MATERIALS AND METHODS

We identified 15 patients who presented with APS as an initial manifestation, based on the 2015 international consensus diagnostic criteria for NMOSD, and reviewed their demographic, clinical, laboratory, and magnetic resonance imaging (MRI) data.

RESULT

Fifteen patients (3 men, 12 women) aged 14-50 years old were included in our study. All patients presented with APS that included intractable nausea, vomiting, or hiccups (INVH) as the initial manifestation; many experienced a delay in diagnosis. Serum AQP4 was positive in eleven patients and myelin oligodendrocyte glycoprotein (MOG) in one patient. All patients had a linear medullary lesion or a linear medulla-spinal lesion on sagittal MRI. An "inverted V sign" on axial medulla oblongata images, representing a lesion involving the area postrema, was noted in seven patients in this study.

CONCLUSIONS

APS can occur as a sole and initial manifestation of NMOSD, often leading to misdiagnosis in the early process of disease. Identifying patients with an "inverted V" sign and a linear medullary lesion upon MRI examination can help to quickly identify APS patients and avoid further diagnostic delays.

A concise historical perspective of the area postrema structure and function

First described by Retzius at the end of the 19th century, the structure in the posterior medulla oblongata, then named area postrema, underwent an intense investigation into its function in the decades that followed. Findings, mainly in animal studies, have partially elucidated its role as an emetic center in the central nervous system. In the second half of the 20th century, this function was associated with reports of syndromes characterized by uncontrollable nausea and vomiting related to structural damage in the area postrema, mainly in the context of demyelinating diseases. At the beginning of the 21st century, the so-called area postrema syndrome has been consolidated as a diagnostic factor in diseases related to the spectrum of neuromyelitis optica, more than 100 years after its first description.

Neuromyelitis optica spectrum disorders in the Arabian Gulf: challenges and growing experience

Neuromyelitis optica spectrum disorders (NMOSD) have been studied in different ethnic groups, including Asians, African-Americans, and Caucasians. Demonstrating the clinical features among diverse communities is important to understand the variable disease phenotypes, which will lead to further classification and better clinical management. Testing for antibody against aquaporin-4 (AQP4), the most common target antigen in NMOSD, is not available in many countries and tests use different methods, with variable sensitivity. With negative antibody results, the diagnosis of NMOSD becomes challenging and may affect the outcomes of patients with NMOSD. There are no adequate studies that assess NMOSD cohorts in the Arabian Gulf region, despite the increasing number of diagnosed cases. It is worth assessing NMOSD cohorts in the Arabian Gulf population to study the natural history of disease and to establish an epidemiological background for future perspectives. Various challenges to implement such a mission are outlined, including disease rarity, overlapping presenting symptoms and signs, which posed the issue of mimickers in the differential diagnosis, lack of specialized clinics, absence of highly sensitive testing methods for diagnosis, and the indefinite agreement on the negative AQP4 NMOSD criteria. Collaborative efforts started to take a place among many experts in the region to establish a registry of NMOSD patients for better perception of the disease pattern.

Intractable Vomiting and Hiccups: An Atypical Presentation of Neuromyelitis Optica

Neuromyelitis optica is an inflammatory disorder of the central nervous system. It involves the immune-mediated demyelination of predominantly the optic nerves and the spinal cord, which can lead to optic neuritis and transverse myelitis, respectively. Patients usually present with symptoms related to the eyes or the spinal cord, like loss of vision, pain in the eyes, visual field defects or numbness and weakness of limbs. Vomiting and hiccups are common cases encountered in medicine clinics and can sometimes be an atypical presentation of this disorder. Here we present a case of a 33-year-old female who initially presented to our tertiary care centre with repeated episodes of bilious vomiting and intractable hiccups for 10 days. After multiple investigations over a couple of days, the patient was found to be positive for anti-NMO antibodies and displayed neuro-radiological findings on MRI brain and spine, which finally led to the diagnosis of neuromyelitis optica spectrum disorder (NMOSD). Through this case we highlight the importance of suspecting NMO in a patient with complaints of intractable vomiting and hiccups, so that early intervention and treatment can prevent further disabling complications of the disease.

Neurological autoimmune disorders with prominent gastrointestinal manifestations: A review of presentation, evaluation, and treatment

BACKGROUND

The identification of autoantibodies directed against neuronal antigens has led to the recognition of a wide spectrum of neurological autoimmune disorders (NAD). With timely recognition and treatment, many patients with NAD see rapid improvement. Symptoms associated with NAD can be diverse and are determined by the regions of the nervous system affected. In addition to neurological symptoms, a number of these disorders present with prominent gastrointestinal (GI) manifestations such as nausea, diarrhea, weight loss, and gastroparesis prompting an initial evaluation by gastroenterologists.

PURPOSE

This review provides a general overview of autoantibodies within the nervous system, focusing on three scenarios in which nervous system autoimmunity may initially present with gut symptoms. A general approach to evaluation and treatment, including antibody testing, will be reviewed.

Review: Recent advances in the understanding of the pathophysiology of neuromyelitis optica spectrum disorder

Neuromyelitis optica is an autoimmune inflammatory disorder of the central nervous system that preferentially targets the spinal cord and optic nerve. Following the discovery of circulating antibodies against the astrocytic aquaporin 4 (AQP4) water channel protein, recent studies have expanded our knowledge of the unique complexities of the pathogenesis of neuromyelitis optica and its relationship with the immune response. This review describes and summarizes the recent advances in our understanding of the molecular mechanisms underlying neuromyelitis optica disease pathology and examines their potential as therapeutic targets. Additionally, we update the most recent research by proposing major unanswered questions regarding how peripheral AQP4 antibodies are produced and their entry into the central nervous system, the causes of AQP4-IgG-seronegative disease, why peripheral AQP4-expressing organs are spared from damage, and the impact of this disease on pregnancy.

Vomiting in Neuromyelitis Optica: An Atypical Presentation

Neuromyelitis Optica (NMO), also known as Devic's disease, is a demyelinating disorder of the central nervous system (CNS) that majorly involves the optic nerves and the spinal cord. It is an idiopathic and an autoimmune disorder. The patient typically presents with symptoms pertaining to the eye or spinal cord, such as a decrease in visual acuity, visual field defects, pain in the eyes, loss of vision, numbness, and weakness of the limbs with or without bladder dysfunction. Vomiting, however, is an atypical presentation of this disorder. We report here a case of an 18-year-old female who presented to our tertiary care set-up with a one-month history of intractable non-bilious vomiting and dull epigastric pain. After going through several initial investigations and being discharged home, she returned after five days with complaints of intractable vomiting, double vision and inability to stand or walk. Later, the presence of anti-NMO antibodies led to the diagnosis of Neuromyelitis Optica Spectrum Disorder (NMOSD). Through this case, we highlight the importance of considering NMO in a patient presenting with intractable vomiting to enable prompt diagnosis and treatment of the disease, thus preventing further disability.

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.

Area postrema syndrome: A short history of a pearl in demyelinating diseases

In this topical review, we discuss the history of the area postrema syndrome, with special attention given to early studies aimed at identifying the area postrema and its function, possible early cases of the syndrome and its current relevance in neuroimmunology and demyelinating diseases. In 1896, Retzius named a structure in the posterior medulla oblongata as the area postrema. The work of Borison in the middle of the 20th century led to the elucidation of its function as a “vomiting center.” The historical medical literature is filled with excellent examples that could be described as “area postrema syndrome.” While severe and bilateral optic neuritis and transverse myelitis still constitute the classic components of neuromyelitis optica spectrum disorder (NMOSD), intractable vomiting and hiccups due to area postrema involvement is now recognized as essentially pathognomonic, indeed a shiny pearl in neuroimmunology and demyelinating diseases.

Racial differences in neuromyelitis optica spectrum disorder

OBJECTIVE

We aimed to evaluate racial differences in the clinical features of neuromyelitis optica spectrum disorder.

METHODS

This retrospective review included 603 patients (304 Asian, 207 Caucasian, and 92 Afro-American/Afro-European), who were seropositive for anti-aquaporin-4 antibody, from 6 centers in Denmark, Germany, South Korea, United Kingdom, United States, and Thailand.

RESULTS

Median disease duration at last follow-up was 8 years (range 0.3-38.4 years). Asian and Afro-American/Afro-European patients had a younger onset age than Caucasian patients (mean 36, 33, and 44 years, respectively; p < 0.001). During the disease course, Caucasian patients (23%) had a lower incidence of brain/brainstem involvement than Asian (42%) and Afro-American/Afro-European patients (38%) (p < 0.001). Severe attacks (visual acuity ≤0.1 in at least one eye or Expanded Disability Status Scale score ≥6.0 at nadir) at onset occurred more frequently in Afro-American/Afro-European (58%) than in Asian (46%) and Caucasian (38%) patients (p = 0.005). In the multivariable analysis, older age at onset, higher number of attacks before and after immunosuppressive treatment, but not race, were independent predictors of severe motor disabilities at last follow-up.

CONCLUSION

A review of a large international cohort revealed that race affected the clinical phenotype, age at onset, and severity of attacks, but the overall outcome was most dependent on early and effective immunosuppressive treatment.

Area postrema syndrome: Frequency, criteria, and severity in AQP4-IgG-positive NMOSD

Objective

To define the frequency, duration, and severity of intractable nausea, vomiting, or hiccups in aquaporin-4–immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD) and propose diagnostic criteria and a severity scale for area postrema syndrome (APS).

Methods

An International NMOSD database was interrogated for frequency of APS. Patients with AQP4-IgG–positive NMOSD completed an APS symptom questionnaire. Nausea and vomiting severity was derived from the Pregnancy-Unique Quantification of Emesis and Nausea (PUQE) score. The diagnostic criteria, severity scale, and immunotherapy response was applied to a prospective validation cohort of patients from multiple centers.

Results

Analysis of an international database for AQP4-IgG–seropositive NMOSD (n = 430) revealed a high prevalence of isolated APS attacks (onset 7.1%–10.3%; subsequent 9.4%–14.5%) across continents. For 100 patients with 157 episodes of APS, nausea (n = 127, 81%) lasted for a median of 14 days (range 2–365), vomiting (113, 72%) with a median of 5 episodes/d (2–40) lasted 1–20 minutes, and hiccups (102, 65%) lasted a median of 14 days (2–365). Symptoms consistently and completely resolved following immunotherapy. Data were used to propose APS diagnostic criteria and repurpose PUQE score (hiccups severity grade based on symptom duration). The clinical utility was demonstrated in a prospective validation cohort.

Conclusion

Isolated APS attacks are frequently encountered both at onset and during the NMOSD course. The diagnostic criteria proposed here will assist clinicians in recognizing APS. Diagnosis of an APS attack earlier than 48 hours is possible if a dorsal medulla lesion is detected. Accurate diagnosis and evaluation of APS attack severity will assist in outcome measurement in NMOSD clinical trials.

Intractable nausea and vomiting as an uncommon presentation in an anti-aquaporin 4-positive patient

Autoantibodies targeting aquaporin 4 (AQP4) water channels are a sensitive and specific biomarker for neuromyelitis optica spectrum disorder (NMOSD). Presence of AQP4 antibodies distinguishes NMOSD from multiple sclerosis. We present our experience with an anti-AQP4 antibody-positive patient diagnosed with NMOSD who complained of intractable nausea and vomiting, not restricted to optic neuritis or acute myelitis during the first attack. Her symptoms partially resolved after appropriate therapy with intravenous methylprednisolone and oral prednisolone. Through this case, we hope to draw attention to an unusual neurological presentation of NMOSD which should be included in the differential diagnosis of intractable nausea and vomiting.

Gastroparesis as the Sole Presenting Feature of Neuromyelitis Optica

A 33-year-old African-American woman recently diagnosed with severe idiopathic gastroparesis was readmitted for hypoxic respiratory failure secondary to aspiration pneumonia. A fiber-optic endoscopic evaluation of swallow study revealed severe pharyngeal dysphagia. Brain magnetic resonance imaging showed an ill-defined lesion in the posterior aspect of the medulla concerning for a demyelinating process. Serum neuromyelitis optica immunoglobulin G returned positive. Neuromyelitis optica treatment resulted in the patient's clinical improvement. She is currently on a suppressive regimen of intravenous rituximab and is recovering well.

Neuromyelitis Spectrum Disorders

The understanding of neuromyelitis optica spectrum disorder (NMOSD) has evolved substantially since its initial description over a century ago. The discovery in 2004 of a pathogenic autoantibody biomarker targeting aquaporin 4 IgG revolutionized diagnosis and therapeutic development. Although NMOSD resembles multiple sclerosis (MS), differences were identified and articulated in the late 1990s. New diagnostic criteria incorporating the biomarker as well as better understanding of the clinical and radiologic features of NMOSD now permit accurate diagnosis and differentiation from MS. Aquaporin 4 IgG-associated NMOSD is now regarded as an immune astrocytopathy with lytic and nonlytic effects on astrocytes. A second autoantibody, myelin oligodendrocyte glycoprotein IgG, which targets myelin rather than astrocytes, leads to an NMOSD syndrome with clinical and radiologic features that overlap but are distinct from those of aquaporin 4 IgG-associated NMOSD and MS. We review current understanding of the clinical aspects, pathophysiology, and treatment of NMOSD.

Syndrome of inappropriate antidiuretic hormone secretion associated with seronegative neuromyelitis optica spectrum disorder

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a potential cause of hyponatremia of the central nervous system (CNS). Although SIADH has been reported to be associated with many other central nervous disorders, its association with neuromyelitis optica (NMO) or NMO spectrum disorders are rare. NMO is a demyelinating disorder characterized by optic neuritis and transverse myelitis. Aquaporin-4 (AQP4), which is the target antigen for a NMO autoantibody, is the predominant CNS water channel. However, some NMO patients show seronegative AQP4 antibody results. The spectrum of NMO has been changed, and new findings about the disease have been reported. Here, we report a case of seronegative NMO spectrum disorder associated with SIADH.

Different Phenotypes at Onset in Neuromyelitis Optica Spectrum Disorder Patients with Aquaporin-4 Autoimmunity

Background

Although rare, brain abnormalities without optic neuritis (ON) or transverse myelitis (TM) diagnosed with neuromyelitis optica spectrum disorder (NMOSD) have been reported in patients positive for the aquaporin-4 (AQP4) antibody.

Objective

To analyze demographic and clinical differences among NMOSD patients without ON or TM, those with either ON or TM, and patients with simultaneous ON and TM at disease onset.

Methods

In this retrospective study, patients who were positive for the AQP4 antibody, as detected using a cell-based assay, at the Second Affiliated Hospital of Guangzhou Medical University in China were recruited. Demographic and clinical data were obtained from each patient’s medical record.

Results

A total of 292 patients were included in this study and were divided into four subgroups based on their initial manifestations: (i) NMOSD without ON or TM (NMOSD-ON⁻TM⁻, n = 70); (ii) NMOSD with ON (NMOSD-ON⁺, n = 95); (iii) NMOSD with TM (NMOSD-TM⁺, n = 116); and (iv) simultaneous ON and TM [neuromyelitis optica (NMO), n = 11]. We found that age at onset was lower in the NMOSD-ON⁻TM⁻ group than that in the other groups. The interval from the first episode to relapse was shorter in the NMOSD-ON⁻TM⁻ group than that in NMOSD-TM⁺ group. Cerebral spinal fluid white cell counts and protein levels were significantly higher in the NMOSD-ON⁻TM⁻ group than those in the other groups. Lower Expanded Disability Status Scale scores were observed in the NMOSD-ON⁻TM⁻ group. Brain abnormalities, including in area postrema and hemisphere lesions, were more frequent in the NMOSD-ON⁻TM⁻ group. Kaplan–Meier analysis showed that patients in the NMOSD-ON⁻TM⁻ group experienced earlier relapse than those in other groups. Conversion to NMO in the NMOSD-ON⁺ group was greater than that in the other groups. Only 14 patients (4.8%, 14/292) had pure brain abnormalities, of which 12 had disease duration of several more years and 8 (57.1%) experienced relapses.

Conclusion

NMOSD patients with different initial manifestations present with significant differences in clinical features during follow-up. Patients with long-term AQP4 autoimmunity in the brain in the absence of ON or TM are not common.

Clinical analysis of neuromyelitis optica presenting as intractable nausea, vomiting and hiccups

Vomiting and hiccups can be the manifestations of numerous systemic and neurological illnesses. Intractable nausea, vomiting and hiccups (INH) are reported as possible initial manifestations of neuromyelitis optica (NMO), but not correctly identified. Awareness of these atypical presentations is conducive to NMO early diagnosis and proper treatment to prevent further disability. In this paper, 12 NMO were reported, whose intractable vomiting and hiccups were the sole manifestations of the first attack and other attacks involving spinal cord and optic nerves developed later. All the patients were women and serum aquaporin 4 antibody (AQP4-Ab) of 83% patients was positive. MRI of 50% patients showed T2-weighted imaging/fluid attenuated inversion recovery hyperintensity which were longitudinally extensive transverse myelitis or linear signal changes. Sixty-seven percent of patients had medulla lesions, in which dorsomedial and area postrema were involved.

MOG-IgG in NMO and related disorders: a multicenter study of 50 patients. Part 3: Brainstem involvement - frequency, presentation and outcome

Background

Myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) are present in a subset of aquaporin-4 (AQP4)-IgG-negative patients with optic neuritis (ON) and/or myelitis. Little is known so far about brainstem involvement in MOG-IgG-positive patients.

Objective

To investigate the frequency, clinical and paraclinical features, course, outcome, and prognostic implications of brainstem involvement in MOG-IgG-positive ON and/or myelitis.

Methods

Retrospective case study.

Results

Among 50 patients with MOG-IgG-positive ON and/or myelitis, 15 (30 %) with a history of brainstem encephalitis were identified. All were negative for AQP4-IgG. Symptoms included respiratory insufficiency, intractable nausea and vomiting (INV), dysarthria, dysphagia, impaired cough reflex, oculomotor nerve palsy and diplopia, nystagmus, internuclear ophthalmoplegia (INO), facial nerve paresis, trigeminal hypesthesia/dysesthesia, vertigo, hearing loss, balance difficulties, and gait and limb ataxia; brainstem involvement was asymptomatic in three cases. Brainstem inflammation was already present at or very shortly after disease onset in 7/15 (47 %) patients. 16/21 (76.2 %) brainstem attacks were accompanied by acute myelitis and/or ON. Lesions were located in the pons (11/13), medulla oblongata (8/14), mesencephalon (cerebral peduncles; 2/14), and cerebellar peduncles (5/14), were adjacent to the fourth ventricle in 2/12, and periaqueductal in 1/12; some had concomitant diencephalic (2/13) or cerebellar lesions (1/14). MRI or laboratory signs of blood-brain barrier damage were present in 5/12. Cerebrospinal fluid pleocytosis was found in 11/14 cases, with neutrophils in 7/11 (3-34 % of all CSF white blood cells), and oligoclonal bands in 4/14. Attacks were preceded by acute infection or vaccination in 5/15 (33.3 %). A history of teratoma was noted in one case. The disease followed a relapsing course in 13/15 (87 %); the brainstem was involved more than once in 6. Immunosuppression was not always effective in preventing relapses. Interferon-beta was followed by new attacks in two patients. While one patient died from central hypoventilation, partial or complete recovery was achieved in the remainder following treatment with high-dose steroids and/or plasma exchange. Brainstem involvement was associated with a more aggressive general disease course (higher relapse rate, more myelitis attacks, more frequently supratentorial brain lesions, worse EDSS at last follow-up).

Conclusions

Brainstem involvement is present in around one third of MOG-IgG-positive patients with ON and/or myelitis. Clinical manifestations are diverse and may include symptoms typically seen in AQP4-IgG-positive neuromyelitis optica, such as INV and respiratory insufficiency, or in multiple sclerosis, such as INO. As MOG-IgG-positive brainstem encephalitis may take a serious or even fatal course, particular attention should be paid to signs or symptoms of additional brainstem involvement in patients presenting with MOG-IgG-positive ON and/or myelitis.

Epidemiology of aquaporin-4 autoimmunity and neuromyelitis optica spectrum

OBJECTIVE

Neuromyelitis optica (NMO) and its spectrum disorders (NMOSD) are inflammatory demyelinating diseases (IDDs) with a specific biomarker, aquaporin-4-immunoglobulin G (AQP4-IgG). Prior NMO/NMOSD epidemiological studies have been limited by lack of AQP4-IgG seroprevalence assessment, absence of population-based USA studies, and under-representation of blacks. To overcome these limitations, we sought to compare NMO/NMOSD seroepidemiology across 2 ethnically divergent populations.

METHODS

We performed a population-based comparative study of the incidence (2003-2011) and prevalence (on December 31, 2011) of NMO/NMOSD and AQP4-IgG seroincidence and seroprevalence (sera collected in 80-84% of IDD cases) among patients with IDD diagnosis in Olmsted County, Minnesota (82% white [Caucasian]) and Martinique (90% black [Afro-Caribbean]). AQP4-IgG was measured by M1 isoform fluorescence-activated cell-sorting assays.

RESULTS

The age- and sex-adjusted incidence (7.3 vs 0.7/1,000,000 person-years [p < 0.01]) and prevalence (10 vs 3.9/100,000 [p = 0.01]) in Martinique exceeded that in Olmsted County. The AQP4-IgG age- and sex-adjusted seroincidence (6.5 vs 0.7/1,000,000 person-years [p < 0.01]) and seroprevalence (7.9 vs 3.3/100,000 [p = 0.04]) were also higher in Martinique than Olmsted County. The ethnicity-specific prevalence was similar in Martinique and Olmsted County: 11.5 and 13/100,000 in blacks, and 6.1 and 4.0/100,000 in whites, respectively. NMO/NMOSD represented a higher proportion of IDD cases in Martinique than Olmsted County (16% vs 1.4%; p < 0.01). The onset age (median = 35-37 years) and female:male distribution (5-9:1) were similar across both populations; 60% of prevalent cases were either blind in 1 eye, dependent on a gait aid, or both.

INTERPRETATION

This study reports the highest prevalence of NMO/NMOSD in any population (10/100,000 in Martinique), estimates it affects 16,000 to 17,000 in the USA (higher than previous predictions), and demonstrates it disproportionately affects blacks. Ann Neurol 2016;79:775-783.

A diagnostic challenge in a young woman with intractable hiccups and vomiting: a case of neuromyelitis optica

Intractable nausea and vomiting along with hiccups is a commonly encountered problem on any general medicine or gastroenterology service. These symptoms are usually not appreciated as the possible initial manifestation of neuromyelitis optica (NMO). Missing diagnosis at this early stage will lead to a delay in the treatment, and hence, irreversible complications including blindness and paraplegia could occur. We report a case of a 22-year-old young female who presented with intractable hiccups and vomiting. After extensive evaluation, she was found to have NMO which involved the area postrema, the vomiting center of the brain. Early diagnosis from the clinical picture aided by aquaporin-4 serologic testing is extremely important to allow early initiation of immunosuppressive therapy. Immunosuppression gives an opportunity to modify the disease at an earlier stage rather than waiting for evolution of disease to fulfill the diagnostic criteria of NMO.

Neuromyelitis optica spectrum disorder as a paraneoplastic manifestation of lung adenocarcinoma expressing aquaporin-4

Background:

The observations of neuromyelitis optica spectrum disorders (NMOSD) occurring in the setting of cancer suggest that aquaporin-4 (AQP4) autoimmunity may in some cases be paraneoplastic.

Results:

We describe a 72-year-old patient who developed a longitudinally extensive transverse myelitis associated with AQP4 autoantibodies in the setting of a lung adenocarcinoma recurrence. AQP4 expression was demonstrated in tumor cells. IgG in patient’s cerebrospinal fluid bound to tumor cells co-localizing with AQP4 immunoreactivity.

Conclusions and relevance:

This case expands the spectrum of paraneoplastic AQP4 autoimmunity highlighting the importance of considering an oncological screening in patients with late-onset NMOSD.

Changes of CXCL12, CXCL14 and PDGF levels in the brain of patients with idiopathic demyelinating optic neuritis and neuromyelitis optica

The CXC chemokines (CXC-motif ligand 12 and CXC-motif ligand 14) and platelet-derived growth factor are suggested to modulate remyelination in the course of many demyelinating diseases. The present study compared the difference in the brain levels of these chemokines between patients with idiopathic demyelinating optic neuritis (IDON) and neuromyelitis optica (NMO) by measuring their concentrations in the cerebrospinal fluid using an enzyme linked immunosorbent assay. Our data indicate that the prognosis of neuritis depends on the remyelinating process that is impaired due to decreased chemokines. The much lower levels of chemokines would specifically indicate the severe neuritis, such as NMO.

Neuromyelitis optica: clinical features, immunopathogenesis and treatment

The term 'neuromyelitis optica' ('Devic's syndrome', NMO) refers to a syndrome characterized by optic neuritis and myelitis. In recent years, the condition has raised enormous interest among scientists and clinical neurologists, fuelled by the detection of a specific serum immunoglobulin (Ig)G reactivity (NMO-IgG) in up to 80% of patients with NMO. These autoantibodies were later shown to target aquaporin-4 (AQP4), the most abundant water channel in the central nervous system (CNS). Here we give an up-to-date overview of the clinical and paraclinical features, immunopathogenesis and treatment of NMO. We discuss the widening clinical spectrum of AQP4-related autoimmunity, the role of magnetic resonance imaging (MRI) and new diagnostic means such as optical coherence tomography in the diagnosis of NMO, the role of NMO-IgG, T cells and granulocytes in the pathophysiology of NMO, and outline prospects for new and emerging therapies for this rare, but often devastating condition.

Immunopathogenesis of neuromyelitis optica

Neuromyelitis optica (NMO, Devic's syndrome) is a clinical syndrome characterized by optic neuritis and (mostly longitudinally extensive) myelitis. If untreated, NMO usually takes a relapsing course and often results in blindness and tetra- or paraparesis. The discovery of autoantibodies to aquaporin-4, the most abundant water channel in the CNS, in 70-80% of patients with NMO (termed NMO-IgG or AQP4-Ab) and subsequent investigations into the pathogenic impact of this new reactivity have led to the recognition of NMO as an autoimmune condition and as a disease entity in its own right, distinct from classic multiple sclerosis. Here, we comprehensively review the current knowledge on the role of NMO-IgG/AQP4-Ab, B cells, T cells, and the innate immune system in the pathogenesis of NMO.

Brainstem manifestations in neuromyelitis optica: a multicenter study of 258 patients

BACKGROUND

Neuromyelitis optica (NMO) is a severe autoimmune disease of the central nervous system characterized by spinal cord and optic nerve involvement. Brainstem manifestations have recently been described.

OBJECTIVE

To evaluate the time of occurrence, the frequency and the characteristics of brainstem symptoms in a cohort of patients with NMO according to the ethnic background and the serologic status for anti-aquaporin-4 antibodies (AQP4-abs).

METHODS

We performed a multicenter study of 258 patients with NMO according to the 2006 Wingerchuk criteria and we evaluated prospectively the frequency, the date of onset and the duration of various brainstem signs in this population.

RESULTS

Brainstem signs were observed in 81 patients (31.4%). The most frequently observed signs were vomiting (33.1%), hiccups (22.3%), oculomotor dysfunction (19.8%), pruritus (12.4%), followed by hearing loss (2.5%), facial palsy (2.5%), vertigo or vestibular ataxia (1.7%), trigeminal neuralgia (2.5%) and other cranial nerve signs (3.3%). They were inaugural in 44 patients (54.3%). The prevalence was higher in the non-Caucasian population (36.6%) than in the Caucasian population (26%) (p<0.05) and was higher in AQP4-ab-seropositive patients (32.7%) than in seronegative patients (26%) (not significant).

CONCLUSIONS

This study confirms the high frequency of brainstem symptoms in NMO with a majority of vomiting and hiccups. The prevalence of these manifestations was higher in the non Caucasian population.

Distinctive clinical and neuroimaging characteristics of longitudinally extensive transverse myelitis associated with aquaporin-4 autoantibodies

Longitudinally extensive transverse myelitis (LETM) is a characteristic feature of Neuromyelitis Optica (NMO), but it can also occur in several other inflammatory diseases of the central nervous system (CNS). An IgG autoantibody that binds to aquaporin-4 (AQP4), the predominant water channel of the CNS, is a reliable biomarker of the NMO spectrum disorders, and if detected predicts the recurrence of the myelitis. In this study, we compared the clinical and neuroimaging characteristics of AQP4-IgG+ and AQP4-IgG- LETM patients. Thirty-seven first-ever LETM patients were retrospectively evaluated and divided into two groups according to the presence of AQP4 autoantibodies. AQP4-IgG was detected in the serum and in the cerebrospinal fluid of sixteen patients. The female to male ratio was higher in AQP4-IgG+ patients. Intractable nausea and vomiting and paroxysmal tonic spasms often accompanied the LETM in AQP4-IgG+ patients. T2-weighted spinal cord MRI revealed that inflammatory lesions extending into the brainstem and involving the central grey matter occurred more frequently in AQP4-IgG+ LETM patients. Hypointense lesions on T1-weighted spinal cord MRI were detected more frequently in the seropositive group, and their presence correlated with attack severity. In conclusion, this study provides clinical and spinal cord neuroimaging clues that can help distinguishing AQP4-IgG+ LETM patients.