Progressive necrotizing myelopathy: part of the spectrum of neuromyelitis optica?

Acute Ascending Necrotizing Myelitis Following COVID-19 Infection: A Clinicopathological Report

Background and Objectives:

Neurological manifestations of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2, COVID-19) infection are common and varied. The objective of this report is to describe clinicopathological findings of rare acute ascending necrotizing myelitis (ANM) and briefly summarize similar COVID-19-associated longitudinally extended transverse myelitis (LETM) cases.

Methods:

We describe the clinical presentation, disease course, diagnostic workup, therapeutic measures, and pathological findings of ANM associated with COVID-19 infection.

Results:

A 31-year-old previously healthy woman developed a longitudinally extensive lower thoracic myelopathy three weeks after COVID-19 infection. The thoracic spinal cord lesion extended to cervical level in one week and then to the lower medullary level in two more weeks. Thoracic laminectomy at T5 – T6 level and cord biopsy revealed necrobiotic changes without viral particles or microglial nodules. The clinical deficit stabilized following immunomodulatory and eculizumab therapy.

Conclusion:

COVID-19 infection can cause ascending necrotizing myelitis. It adds to the spectrum of reported cases of COVID-19-associated encephalitis and myelitis.

Evidence for and against subclinical disease activity and progressive disease in MOG antibody disease and neuromyelitis optica spectrum disorder

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) and aquaporin-4 IgG seropositive neuromyelitis optica spectrum disorder (AQP4-IgG+ NMOSD) are generally considered to be relapsing disorders, without clinical progression or subclinical disease activity outside of clinical relapses, in contrast to multiple sclerosis (MS). With advances in the diagnosis and treatment of these conditions, prolonged periods of remission without relapses can be achieved, and the question of whether progressive disease courses can occur has re-emerged. In this review, we focus on studies exploring evidence for and against relapse-independent clinical progression and/or subclinical disease activity in patients with MOGAD and AQP4-IgG+ NMOSD.

Primary progression in NMOSD. Does it really exist?

Acute myelitis, in conjunction with a longitudinally extensive MRI pattern, is a core feature of aquaporin 4 IgG-associated neuromyelitis optica spectrum disorders (NMOSD). According to current diagnostic criteria for transverse myelitis and NMOSD, clinical worsening should not exceed 3-4 weeks from attack onset. Recently, we were able to document, through frequent clinical examination and radiological follow-up, the unusual case of an ab initio progressive myelopathy, ultimately attributed to aquaporin-4 autoimmunity. Although this case might merely represent an overlooked cluster of individual clinical attacks, it could, however, draw attention to the controversial concept of disease progression in the context of NMOSD.

Differential diagnosis of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disorder of the central nervous system (CNS) mostly manifesting as optic neuritis and/or myelitis, which are frequently recurrent/bilateral or longitudinally extensive, respectively. As the autoantibody to aquaporin-4 (AQP4-Ab) can mediate the pathogenesis of NMOSD, testing for the AQP4-Ab in serum of patients can play a crucial role in diagnosing NMOSD. Nevertheless, the differential diagnosis of NMOSD in clinical practice is often challenging despite the phenotypical and serological characteristics of the disease because: (1) diverse diseases with autoimmune, vascular, infectious, or neoplastic etiologies can mimic these phenotypes of NMOSD; (2) patients with NMOSD may only have limited clinical manifestations, especially in their early disease stages; (3) test results for AQP4-Ab can be affected by several factors such as assay methods, serologic status, disease stages, or types of treatment; (4) some patients with NMOSD do not have AQP4-Ab; and (5) test results for the AQP4-Ab may not be readily available for the acute management of patients. Despite some similarity in their phenotypes, these NMOSD and NMOSD-mimics are distinct from each other in their pathogenesis, prognosis, and most importantly treatment. Understanding the detailed clinical, serological, radiological, and prognostic differences of these diseases will improve the proper management as well as diagnosis of patients.

Role of low plasma volume treatment on clinical efficacy of plasmapheresis in neuromyelitis optica

BACKGROUND:

Neuromyelitis optica (NMO) is an autoimmune demyelinating disease preferentially targeting the optic nerves and spinal cord. Plasmapheresis (PP) is an effective adjunct therapy in severe NMO attacks. The recommended minimum plasma volume to be treated per session of PP is equivalent to total plasma volume (TPV) of the patient.

AIM:

To study the effect of lower plasma volume treated in patients with NMO on clinical efficacy of plasmapheresis in comparison to minimum recommended volume.

METHODS:

This retrospective study was done on acute NMO patients who were managed with PP at our center. Patients who had 5 sessions of PP, spread over 10 days, were included. Clinical outcome was defined as per predefined criteria.

RESULTS:

24 patients who underwent PP for acute NMO met our inclusion criteria. Females (age; mean (SD) 33.7 (11.2) years) were more common (n = 18). The minimum recommended plasma volume (PV) that was supposed to be treated per patient during entire acute therapeutic period was 195.5 (14.6) mL per kilogram-body-weight (kg-bw). We treated lower plasma volume (mean (SD) 112.7 (17.0) mL per kg-bw); the difference was significant (P < 0.05). The volume treated was same across the gender (P > 0.05). Significant clinical improvement was observed in 79% of patients (n = 19) after 6 months. There were no significant differences in volume of plasma treated, between patients who had moderate and marked improvement; also, who did, and did not have significant clinical improvement (P > 0.05; for both).

CONCLUSIONS:

Plasmapheresis is a safe and efficient add-on therapy in NMO, especially in steroid-resistant cases. Although the volumes of plasma treated during acute plasmapheresis were less than recommended minimum volumes, majority of patients had significant clinical improvement.

Systemic Lupus Erythematosus (SLE) Complicated by Neuromyelitis Optica (NMO - Devic's Disease): Clinic-Pathological Report and Review of the Literature

Neuromyelitis optica (NMO) is usually a relapsing demyelinating disease of the central nervous system associated with optic neuritis, transverse myelitis involving three or more contiguous spinal cord segments, and seropositivity for NMO-IgG antibody. NMO is often mistaken for multiple sclerosis and there are relatively sporadic publications about NMO and overlapping systemic or organ-specific autoimmune diseases, such as systemic lupus erythematosus (SLE). We described a unique case of a 25-year-old Arab young woman who was diagnosed with SLE, depending on clinical, laboratory investigations and after she had fulfilled the diagnostic criteria for SLE and had presented the following findings: constitutional findings (fatigue, fever, and arthralgia); dermatologic finding (photosensitivity and butterfly rash); chronic renal failure (proteinuria up to 400 mg in 24 hours); hematologic and antinuclear antibodies (positivity for antinuclear factor (ANF), anti-double-stranded DNA antibodies, direct Coombs, ANA and anti-DNA, low C4 and C3, aCL by IgG and IgM). Recently, she presented with several episodes of transverse myelitis and optic neuritis. Clinical, radiological, and laboratory findings especially seropositivity for NMO-IgG were compatible with NMO. Accurate diagnosis is critical to facilitate initiation of immunosuppressive therapy for attack prevention. This case illustrates that NMO may be associated with SLE.

Optical coherence tomography helps differentiate neuromyelitis optica and MS optic neuropathies

OBJECTIVE

To evaluate the retinal nerve fiber layer (RNFL) thickness and macular volume in neuromyelitis optica (NMO) spectrum patients using optical coherence tomography (OCT).

BACKGROUND

OCT can quantify damage to retinal ganglion cell axons and can identify abnormalities in multiple sclerosis and optic neuritis (ON) eyes. OCT may also be useful in the evaluation of patients with NMO.

METHODS

OCT and visual function testing were performed in 26 NMO spectrum patients with a history of ON, 17 patients with isolated longitudinally extensive transverse myelitis (LETM) without ON, 378 patients with relapsing-remitting multiple sclerosis (RRMS), and 77 healthy controls at 2 centers.

RESULTS

Substantial RNFL thinning was seen in NMO ON eyes (63.6 microm) relative to both RRMS ON eyes (88.3 microm, p < 0.0001) and control eyes (102.4 microm, p < 0.0001). A first episode of ON was estimated to cause 24 microm more loss of RNFL thickness in NMO than RRMS. Similar results were seen for macular volume. ON also was associated with more severe visual impairment in NMO spectrum patients than in RRMS patients. Eyes in the LETM group and unaffected NMO eyes were not significantly different from controls, though conclusions about these subgroups were limited by small sample sizes.

CONCLUSIONS

Optical coherence tomography (OCT) shows more severe retinal damage after optic neuritis (ON) episodes in neuromyelitis optica (NMO) than in relapsing-remitting multiple sclerosis. Identification of substantial retinal nerve fiber layer loss (>15 microm) after ON in a non-multiple sclerosis patient should prompt consideration of an NMO spectrum condition. OCT may be a useful tool for the evaluation of patients with NMO.

Plasma exchange in severe spinal attacks associated with neuromyelitis optica spectrum disorder

Background

Plasma exchange (PE) is increasingly undertaken in diseases involving humoral factors and is proven to be beneficial in acute demyelinating diseases. Spinal attacks in relapsing neuromyelitis optica (NMO) and in extensive transverse myelitis (ETM) – a truncated form of NMO with spinal involvement – are usually devastating.

Objective

We retrospectively studied the outcome of PE-treated versus steroid-only treated spinal attacks in relapsing NMO and ETM.

Methods

We included 96 severe spinal attacks in 43 Afro-Caribbean patients. PE was given as an add-on therapy in 29 attacks. Expanded disability status score (EDSS) was obtained before attack, during the acute and residual stage. We defined the ΔEDSS as the rise from basal to residual EDSS.

Results

The ΔEDSS was found to be lower in the PE-treated group (1.2 ± 1.6 vs 2.6 ± 2.3; P < 0.01). A low basal impairment is associated with a better outcome. Improvement was obtained in both NMO-IgG negative and positive NMO attacks. Minor adverse events manifested in seven PE sessions (24%).

Conclusion

PE appears to be a safe add-on therapy that may be employed early in severe spinal attacks in the NMO spectrum disorders in order to maximize improvement rate. PE efficiency is independent of NMO-IgG positivity.

The spectrum of neuromyelitis optica

Neuromyelitis optica (also known as Devic's disease) is an idiopathic, severe, demyelinating disease of the central nervous system that preferentially affects the optic nerve and spinal cord. Neuromyelitis optica has a worldwide distribution, poor prognosis, and has long been thought of as a variant of multiple sclerosis; however, clinical, laboratory, immunological, and pathological characteristics that distinguish it from multiple sclerosis are now recognised. The presence of a highly specific serum autoantibody marker (NMO-IgG) further differentiates neuromyelitis optica from multiple sclerosis and has helped to define a neuromyelitis optica spectrum of disorders. NMO-IgG reacts with the water channel aquaporin 4. Data suggest that autoantibodies to aquaporin 4 derived from peripheral B cells cause the activation of complement, inflammatory demyelination, and necrosis that is seen in neuromyelitis optica. The knowledge gained from further assessment of the exact role of NMO-IgG in the pathogenesis of neuromyelitis optica will provide a foundation for rational therapeutic trials for this rapidly disabling disease.