The role of anti-aquaporin 4 antibody in the conversion of acute brainstem syndrome to neuromyelitis optica

NMOSD and MOGAD: an evolving disease spectrum

Neuromyelitis optica (NMO) spectrum disorder (NMOSD) is a relapsing inflammatory disease of the CNS, characterized by the presence of serum aquaporin 4 (AQP4) autoantibodies (AQP4-IgGs) and core clinical manifestations such as optic neuritis, myelitis, and brain or brainstem syndromes. Some people exhibit clinical characteristics of NMOSD but test negative for AQP4-IgG, and a subset of these individuals are now recognized to have serum autoantibodies against myelin oligodendrocyte glycoprotein (MOG) - a condition termed MOG antibody-associated disease (MOGAD). Therefore, the concept of NMOSD is changing, with a disease spectrum emerging that includes AQP4-IgG-seropositive NMOSD, MOGAD and double-seronegative NMOSD. MOGAD shares features with NMOSD, including optic neuritis and myelitis, but has distinct pathophysiology, clinical profiles, neuroimaging findings (including acute disseminated encephalomyelitis and/or cortical encephalitis) and biomarkers. AQP4-IgG-seronegative NMOSD seems to be a heterogeneous condition and requires further study. MOGAD can manifest as either a monophasic or a relapsing disease, whereas NMOSD is usually relapsing. This Review summarizes the history and current concepts of NMOSD and MOGAD, comparing epidemiology, clinical features, neuroimaging, pathology and immunology. In addition, we discuss new monoclonal antibody therapies for AQP4-IgG-seropositive NMOSD that target complement, B cells or IL-6 receptors, which might be applied to MOGAD in the near future.

Neuromyelitis optica spectrum disorder with acute brainstem manifestations as initial symptoms

Objective

To explore the clinical features and prognosis of patients with neuromyelitis optica spectrum disorder (NMOSD) initially presenting with acute brainstem symptoms.

Methods

The clinical data of NMOSD patients admitted to two medical centers were collected. The clinical characteristics, laboratory data, neuroimaging features and prognoses of patients with NMOSD with acute brainstem manifestations as initial symptoms (NMOSD-BSMIS) were analyzed. The clinical features and prognosis of patients with NMOSD-BSMIS and patients with NMOSD with other manifestations as initial symptoms (NMOSD-OMIS) were compared.

Results

Fifty-two patients (18.37 %, 52/283) initially presented with acute brainstem symptoms. Intractable nausea, vomiting or hiccups, diplopia, vertigo, headache, and facial hypoesthesia were the initial symptoms in most of the patients. The percentage of patients who were positive for serum aquaporin 4 (AQP4)-IgG antibodies was 81.63 % (40/49). MRI revealed that the lesions were usually located in the postrema, dorsal medulla oblongata, pons and other areas around the fourth ventricle. The early-stage misdiagnosis rate was 46.15 %. Compared with those in the non-misdiagnosed group, the age of onset of patients in the NMOSD-BSMIS group was older, and the proportion of patients admitted to the neurology department as the first department was lower in the misdiagnosed group. The annual relapse rate of patients who underwent NMOSD-BSMIS was significantly greater than that of patients who underwent NMOSD-OMIS (P < 0.01).

Conclusions

NMOSD patients can initially present with different brainstem symptoms. The early misdiagnosis rate of NMOSD-BSMIS is high. Moreover, if patients are older or initially admitted to nonneurological departments, they are more likely to be misdiagnosed. Moreover, the annual recurrence rate of NMOSD-BSMIS is greater in the early stage.

Clinical Characteristics and Outcomes of Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder With Brainstem Lesions as Heralding Prodrome

Objective

The present study sought to differentiate multiple sclerosis and neuromyelitis optica spectrum disorder patients at their first attack by describing and distinguishing their clinical features, radiographic characteristics, and immunologic characteristics of serum and cerebrospinal fluid.

Methods

We retrospectively studied 58 patients with multiple sclerosis (MS) and 52 patients with neuromyelitis optica spectrum disorder (NMOSD) by referencing brainstem lesions as the prodromal events. Their demographics and presentation at the time of the first attack was evaluated including their gender, age, clinical features of the first attack, the expanded disability status scale (EDSS), brainstem lesion(s) by head MRI, and immunological indices of serum and cerebrospinal fluid.

Results

The NMOSD group had more female patients (4.8 vs. 1.9, p &lt; 0.05), and was older than the MS group (37.81 ± 16.60 vs. 27.57 ± 11.17, p &lt;0.001). NMOSD patients also had a significantly higher association with autoimmune diseases or positive autoimmune antibodies (p &lt; 0.01). There was no significant difference in the EDSS scores between the two groups (p = 0.420). Central hiccups, vomiting, and pyramidal tract signs were more common in the NMOSD group than the MS group (p &lt; 0.001, p &lt; 0.001, p &lt; 0.01), while eye movement abnormalities were more common with MS (p &lt; 0.01). There were no significant differences in other clinical manifestations such as vertigo, diplopia, limb weakness, numbness, and eating difficulty. MS patients were more likely to have midbrain and pons imaging lesions (p &lt; 0.001, p &lt; 0.001), while NMOSD patients had more lesions in the medulla oblongata (p &lt; 0.001). The lesions in the MS group were mostly located in the periphery, while those in the NMOSD group were centrally located (p &lt; 0.001, p &lt; 0.001). Patchy lesions were more common in MS patients (p &lt; 0.001), while large lesions were more common in the NMOSD group (p &lt; 0.001). Finally, serum AQP4 Ab was found only in the NMOSD group (p &lt; 0.001).

Conclusion

Patients with MS and NMOSD have differentiating clinical manifestations at the time of their first brainstem lesions which include central hiccups, vomiting, pyramidal tract signs, and abnormal eye movements. Additionally, distinct imaging manifestations such as lesion location(s) and morphology may also aid in the development of pathognomonic criteria leading to timely initial diagnosis of MS and NMOSD.

Clinically Isolated Brainstem Progressive Multifocal Leukoencephalopathy: Diagnostic Challenges

Patient: Female, 47-year-old

Final Diagnosis: Brainstem progressive multifocal leukoencephalopathy

Symptoms: Dizziness • intermittent slurred speech • right-sided facial droop and numbness

Medication: —

Clinical Procedure: Lumbar puncture

Specialty: Neurology

[Neuromyelitis Optica Spectrum Disorders - Present Insights and Recent Developments]

The achievements of the last 15 years have essentially shaped the diagnostic methods and therapy of Neuromyelitis optica spectrum disorders (NMOSD): from discovery of aquaporin 4 antibodies and further development of diagnostic criteria the path has led to the approval of eculizumab and satralizumab as first disease modifying treatments in Europe. This article should give an overview on the present insights and future treatment options.

Isolated opsoclonus heralding neuromyelitis optica spectrum disorder

Opsoclonus is an ocular motility disorder characterized by spontaneous, arrhythmic conjugate saccades of varying amplitude occurring in all directions of gaze without normal intersaccadic interval. Etiological spectrum of opsoclonus encompasses paraneoplastic and neoplastic conditions, infectious and para-infectious encephalitis, autoimmune, metabolic and toxic encephalopathies, drugs, motor neuron diseases, multiple sclerosis and rarely neuromyelitis optica spectrum disorder (NMOSD). Opsoclonus has never been reported as a presenting manifestation heralding NMOSD. We herein report a previously healthy 37-year-old Asian Indian woman who presented with oscillopsia and opsoclonus, followed, 12 h later, by right-sided hemiparesis, right-sided appendicular ataxia, and left-sided lower motor neuron type facial palsy and dysarthria. Brain magnetic resonance imaging revealed hyperintense lesions in brainstem and thalamus in T2-weighted and fluid attenuated inversion recovery-weighted images, quite suggestive of NMOSD. Serum and cerebrospinal fluid samples were positive for anti-aquaporin-4 antibodies, which clinched the diagnosis of seropositive NMOSD. After completion of a course of intravenous methylprednisolone 1 g/day for 5 days, her opsoclonus disappeared completely. There was significant improvement in her speech and weakness within the first week of therapy and no objective deficit after day 20 of admission. After one-and-a-half-year follow-up, the patient was maintaining well on rituximab as secondary prophylaxis without any further attack. Our case highlights that isolated opsoclonus can be the presenting feature of NMOSD.

Area Postrema: Fetal Maturation, Tumors, Vomiting Center, Growth, Role in Neuromyelitis Optica

INTRODUCTION

The area postrema in the caudal fourth ventricular floor is highly vascular without blood-brain or blood-cerebrospinal fluid barrier. In addition to its function as vomiting center, several others are part of the circumventricular organs for vasomotor/angiotensin II regulation, role in neuromyelitis optica related to aquaporin-4, and somatic growth and appetite regulation. Functions are immature at birth. The purpose was to demonstrate neuronal, synaptic, glial, or ependymal maturation in the area postrema of normal fetuses. We describe three area postrema tumors.

METHODS

Sections of caudal fourth ventricle of 12 normal human fetal brains at autopsy aged six to 40 weeks and three infants aged three to 18 months were examined. Immunocytochemical neuronal and glial markers were applied to paraffin sections. Two infants with area postrema tumors and another with neurocutaneous melanocytosis and pernicious vomiting also studied.

RESULTS

Area postrema neurons exhibited cytologic maturity and synaptic circuitry by 14 weeks'. Astrocytes coexpressed vimentin, glial fibrillary acidic protein, and S-100β protein. The ependyma is thin over area postrema, with fetal ependymocytic basal processes. A glial layer separates area postrema from medullary tegmentum. Melanocytes infiltrated area postrema in the toddler with pernicious vomiting; two children had primary area postrema pilocytic astrocytomas.

CONCLUSIONS

Although area postrema is cytologically mature by 14 weeks, growth increases and functions mature during postnatal months. We recommend neuroimaging for patients with unexplained vomiting and that area postrema neuropathology includes synaptophysin and microtubule-associated protein-2 in patients with suspected dysfunction.

Neuromyelitis optica: an elusive cause of dysphagia

Neuromyelitis optica spectrum disorder (NMOSD) is a rare neurological condition infrequently associated with dysphagia on initial presentation. We describe the case of a 54-year-old woman who presented multiple times to healthcare professionals with severe vomiting, followed by sudden profound dysphagia. Her diagnosis was elusive, initially attributed to achalasia cardia and subsequently to stroke. A dorsal medullary lesion was revealed on MRI of the brain, which involved and extended beyond the area postrema. The patient required percutaneous gastrostomy, and repeated aspiration pneumonia complicated her clinical course. After aquaporin-4 antibodies returned positive, a diagnosis of NMOSD was made and she improved with immunosuppression. We discuss the process of lesion localisation and aetiology determination, as well as the difficulties that this case presented. Our hope is that this report will facilitate earlier diagnosis in similar cases in the future.

Eye movement abnormalities in AQP4-IgG positive neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorder (NMOSD) has been recognized as a disease characterized by severe visual afferent impairment. Abnormal eye movements, as the other important neuro-ophthalmic manifestation of NMOSD, were commonly overlooked. The aim of our study was to describe the ocular motor manifestations of AQP4-IgG positive NMOSD patients, and explore the value of eye movement abnormalities in the evaluation of the disabled disease.

METHODS

Systemic clinical bedside ocular motor examinations and quantitative horizontal saccadic eye movement assessments were performed in 90 patients with AQP4-IgG positive NMOSD. General disability was evaluated by expanded disability status scale (EDSS). Vision-specific functional status was evaluated by the National Eye Institute-Visual Function Questionnaire (NEI-VFQ 25) and the 10-item neuro-ophthalmic supplement. Brain magnetic resonance imaging (MRI) was acquired in all patients.

RESULTS

In clinical examination, eye movement abnormalities were found in 38% of NMOSD patients. Abnormalities in the quantitative saccadic test were found in 67% of NMOSD patients, including 48% of patients with clinically normal eye movements. EDSS scores in patients with clinical eye movement abnormality were significantly higher (P<0.001) than those with a normal examination. The 10-item neuro-ophthalmic supplement score was significantly associated with quantitative saccadic eye movement abnormalities (P=0.031).

CONCLUSIONS

Eye movement abnormalities were common in AQP4-IgG positive NMOSD patients, and were associated with general disability and specific visual handicap. The systemic clinical eye movement examination combined with the quantitative saccade test was easy to perform, and could provide additional useful information in evaluating NMOSD.

Pattern Recognition of the Multiple Sclerosis Syndrome

During recent decades, the autoimmune disease neuromyelitis optica spectrum disorder (NMOSD), once broadly classified under the umbrella of multiple sclerosis (MS), has been extended to include autoimmune inflammatory conditions of the central nervous system (CNS), which are now diagnosable with serum serological tests. These antibody-mediated inflammatory diseases of the CNS share a clinical presentation to MS. A number of practical learning points emerge in this review, which is geared toward the pattern recognition of optic neuritis, transverse myelitis, brainstem/cerebellar and hemispheric tumefactive demyelinating lesion (TDL)-associated MS, aquaporin-4-antibody and myelin oligodendrocyte glycoprotein (MOG)-antibody NMOSD, overlap syndrome, and some yet-to-be-defined/classified demyelinating disease, all unspecifically labeled under MS syndrome. The goal of this review is to increase clinicians’ awareness of the clinical nuances of the autoimmune conditions for MS and NMSOD, and to highlight highly suggestive patterns of clinical, paraclinical or imaging presentations in order to improve differentiation. With overlay in clinical manifestations between MS and NMOSD, magnetic resonance imaging (MRI) of the brain, orbits and spinal cord, serology, and most importantly, high index of suspicion based on pattern recognition, will help lead to the final diagnosis.