Neuromyelitis optica (NMO) was described by Eugène Devic in 1894 and it is known since then as Devic’s NMO (Devic’s disease). It is uncommon heterogeneous inflammatory demyelinating neuro-immunological disease of the central nervous system (CNS) that is characterized by severe attacks of optic neuritis (ON) and transverse myelitis with contiguous spinal cord MRI lesion extending over three or more vertebral segments, and seropositivity for NMO-IgG (anti-aquaporin-4 (anti-AQP4), which has been recently described as a sensitive and specific marker for NMO.1-8

NMO affects both genders with three to nine times more prevalence in women than in men, the age of onset ranges from childhood to late adulthood, with a median of 20 to 50 years among adults and 4.5 years among children.

Cases of NMO have been reported from different parts of the world and different races, although the disease is more prevalent in areas with black, Asian, and Indian populations, in which NMO constitutes from 15% to 57% of demyelinating diseases.

 Controversy about whether NMO is a subtype of multiple sclerosis (MS) or a different disease has persisted for years. However, a series of clinical, radiological, histopathologic, and immunologic studies provide evidence that NMO and NMO disorders are distinct from MS in spite of common pathologic characteristics, like demyelination of CNS.9-10

Clinical Manifestations

Sequential or simultaneous optic neuritis (ON) and transverse myelitis are typical features of NMO. Optic neuritis usually presents with unilateral or, less often, bilateral ocular pain and visual loss.

 Myelitis caused by NMO, often present with complete transverse myelitis with tetraplegia or paraplegia and a well-defined sensory level and sphincter dysfunction, and may be accompanied by pain and paroxysmal tonic spasms of the trunk and the extremities. Prominent dysesthetic, radicular pain, possibly associated with Lhermitte symptoms, is common and may occur in up to 35% of acute severe myelitis attacks in relapsing NMO.11, 12 The lesion may extend toward the brain stem and cause hiccups, intractable nausea, or respiratory  failure.11-13 

Treatment Options

Today, the first-line therapy with Azathioprine or Rituximab for severe disease course of NMO calls for prompt initiation of immunosuppressive treatment once the diagnosis of NMO has been confirmed. IVIg may be used as the first-line therapy for children or for patients with contraindication to immunosuppressive therapies.

Second-line therapy of NMO: In the case of side effects or poor response, treatment can be switched from azathioprine to rituximab or vice versa, or to mycophenolate mofetil, methotrexate, or mitoxantrone.

The third-line therapy for NMO should be applied if disease progression occurs, and if the above treatments fail, the newer agents such as Tocilizumab should be given with combination therapy (combination of steroid plus cyclosporin-A or methotrexate or azathioprine; combination of immu¬nosuppression plus intermittent plasma exchange (PE); or combination of rituximab with methotrexate or intravenous immunoglobulins (IVIg).14

Treatment goes beyond medicine to include occupational therapists, physiotherapists, and social service professionals in cases of complex disability.

Summary

For sufferers of NMO, effective treatments are becoming available. The recognition of a specific marker NMO-IgG has not only facilitated the diagnosis of the condition but also presented a rational approach to the cure of the condition. Not only there are therapies that can decrease the impact of relapsing attacks and prevent attacks, but a therapy may be also possible by reduced-dose myeloablative regimens and hematopoietic cell replacement. Moreover, with reduced-dose myeloablative regimens, the mortality rate is low and approaching 1%.

Prof. Dr. Abdalla Bowirrat is author of the recently published paper Systemic Lupus Erythematosus (SLE) Complicated by Neuromyelitis Optica (NMO – Devic’s Disease): Clinic-Pathological Report and Review of the Literature, available for download now in Clinical Medicine Insights: Case Reports.

References

1. Lennon VA, Wingerchuk DM, Kryzer TJ, et al. A serum autoantibody marker of neuromyelitis optica: distinction from multiple sclerosis. Lancet. 2004;364:2106–12.

2. Wingerchuk DM, Hogancamp WF, O’Brien PC, Weinshenker BG. The clinical course of neuromyelitis optica (Devic’s syndrome). Neurology. 1999;53:1107–14.

3. Kim W, Kim S-H, Huh S-Y, Kim HJ. Brain abnormalities in neuromyelitis optica disorder. Mult Scler Int. 2012;2012:735486.

4. Choi SI, Lee YJ, Kim DW, Yang JY. A case of neuromyelitis optica misdiag¬nosed as cervicogenic headache. Korean J Pain. 2014;27:77–80.

5. Papadopoulos MC, Verkman AS. Aquaporin 4 and neuromyelitis optica. Lancet Neurol. 2012;11:535–44.

6. Trebst C, Jarius S, Berthele A, et al. Neuromyelitis Optica Study Group (NEMOS). Update on the diagnosis and treatment of neuromyelitis optica: recommendations of the neuromyelitis optica Study group (NEMOS). J Neurol. 2014;261:1–16.

7. Jarius S, Wildemann B. The history of neuromyelitis optica. J Neuroinflammation. 2013;10:8.

8. Kimbrough DJ, Fujihara K, Jacob A, et al. Treatment of neuromyelitis optica: review and recommendations. Mult Scler Relat Disord. 2012;1:180–7.

9. Lennon VA, Wingerchuk DM, Kryzer TJ, et al. A serum autoantibody marker of neuromyelitis optica: distinction from multiple sclerosis. Lancet 2004;364: 2106–12.

10. Scolding N. The differential diagnosis of multiple sclerosis. J Neurol Neurosurg Psychiatry. 2001;71:ii9–ii15.

11. Wingerchuk DM, Hogancamp WF, O’Brien PC, et al. The clinical course of neuromyelitis optica (Devic’s syndrome). Neurology. 1999;53:1107–14.

12. Papais-Alvarenga RM, Carellos SC, Alvarenga MP, et al. Clinical course of optic neuritis in patients with relapsing neuromyelitis optica. Arch Ophthalmol. 2008;126:12–6.

13. Misu T, Fujihara K, Nakashima I, et al. Intractable hiccup and nausea with periaqueductal lesions in neuromyelitis optica. Neurology. 2005;65:1479–82.

14. Trebst C, Jarius S, Berthele A, et al. Neuromyelitis Optica Study Group (NEMOS). Update on the diagnosis and treatment of neuromyelitis optica: recommendations of the neuromyelitis optica Study group (NEMOS). J Neurol. 2014;261:1–16.

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