Comparing neuromyelitis optica and multiple sclerosis severity: is there a difference?

Comparando a neuromielite óptica e a esclerose múltipla quanto à gravidade: há diferença?

The discovery of the antibody to aquaporin 4, named IgG-NMO, permitted the differential diagnosis between multiple sclerosis (MS) and neuromyelitis optica (NMO). It renewed the researchers' interest on the study of NMO, specially because this disease shares many clinical and radiologic aspects with MS¹.

The positivity for IgG-NMO antibody, by itself, justified admitting NMO as a nosologic entity different from MS, but aroused challenges. As these two diseases integrated during a long time the same nosologic complex, their distinction demanded the identification of other differential parameters related to clinical evolution, treatment and prognostic².

Within the differences between NMO and MS, the researches pointed out greater prevalence of NMO in non-caucasian populations, older age of onset although it may occur in extreme ages, as well as a rare primary or secondary progression².

As to radiologic findings, compared to MS, NMO presents fewer alterations in grey matter, which may suggest less severity³. Nevertheless, the optical coherence tomography shows more severe alterations in NMO than in MS, because a thinner retinian cells layer indicates widespread axonal injury²,⁴.

With respect to cerebrospinal fluid, the oligoclonal bands are less frequent in NMO and are associated to greater number of cells and neurofilaments⁵.

Disability of NMO patients is usually more severe than in MS, due to relapses' severity followed by less recovery⁴,⁶.

Within this publication, Bichuetti et al.⁷ add an interesting approach to all these evidences by comparing clinic evolution of NMO patients to those of MS. Their contribution to the study of this disease consists on the presentation of other differential aspects.

By analyzing expanded disability status scale evolution, annualized rate relapses and progression index, the authors concluded that NMO is more severe than MS, and emphasize early diagnosis and therapeutic management.

The fundamental aspect of this study compared to international researches was the possibility to analyze clinic evolution of those patients in a single center, which assured greater accuracy to data.

Nevertheless, one must wait until these findings can be proved by other studies, so they can integrate the evidences presented since the IgG-NMO discovery, in 2004.

References

• ¹
  Jarius S, Wildemann B. The history of neuromyelitis optica. J Neuroinflammation 2013;10:8.
• ²
  Sellner J, Boggild M, Clanet M, et al. EFNS guidelines on diagnosis and management of neuromyelitis optica. Eur J Neurol 2010;17:1019-1032.
• ³
  Duan Y, Liu Y, Liang P, et al. Comparison of grey matter atrophy between patients with neuromyelitis optica and multiple sclerosis: a voxelbased morphometry study. Eur J Radiol 2012;81:110-114.
• ⁴
  Jacob A, McKeon A, Nakashima I, et al. Current concept of neuromyelitis optica (NMO) and NMO spectrum disorders. J Neurol Neurosurg Psychiatry 2012 [Epub ahead of print].
• ⁵
  Cabezas IL, Llano MC, Rol GP. Neuromielitis óptica. Principales diferencias con la esclerosis múltiple. An Med Interna (Madrid) 2008;25:294-296.
• ⁶
  Jarius S, Ruprecht K, Wildemann B, et al. Contrasting disease patterns in seropositive and seronegative neuromyelitis optica: A multicentre study of 175 patients. J Neuroinflammation 2012;9:14.
• ⁷
  Bichuetti DB, Oliveira EML, Souza NA, Tindoré M, Gabbai AA. Patients with neuromyelitis optica have a more severe disease than patients with relapsing-remitting multiple sclerosis, including higher risk of dying of a demyelinating disease. Arq Neuropsiquiatr 2013;71:275-279.

Publication Dates

• Publication in this collection
  May 2013

History

• Received
  11 Mar 2013
• Accepted
  18 Mar 2013