Saturday, 26 November 2011

Optic Neuritis: Testing for Neuromyelitis optica

Bojić et al. Role of NMO-Ig in Distinguishing the type of Optic Neuritis. Optom Vis Sci. 2011 Nov 17. [Epub ahead of print]

PURPOSE: To emphasize the importance of neuromyelitis optica (NMO)-immunoglobulin G (IgG) antibodies testing in patients with typical optic neuritis (ON) refractory to steroid treatment.

METHODS: Two patients were evaluated with ON refractory to steroid therapy and poor visual acuity; they were tested for NMO-IgG antibodies.

RESULTS: Brain magnetic resonance imaging was normal in both patients. The serum and cerebrospinal fluid were positive for NMO-IgG antibodies. Magnetic resonance imaging of the cervical and thoracic spine revealed lesions longer than three vertebral segments (3 back bones) and the diagnosis of NMO was confirmed. Treatment with plasma exchange and immunosuppressive therapy resulted in marked improvement of visual acuity. This improvement was sustained.

Spinal cord lesion in NMO

CONCLUSIONS.: The testing for NMO-IgG antibodies is important for distinguishing ON in NMO from multiple sclerosis in cases of ON refractory to steroid treatment. These cases suggest that testing for NMO-IgG antibodies should be performed in comparative trials on a larger series.

Although this study examines too few MSers this is a useful point to consider. Optic-spinal MS (affects the optic nerve and spinal cord with little involvement in the brain): this is a relatively rare form of MS that is most common in Asia and Japan. The majority of these cases now have a specific antibody (NMO-Ig) that can be detected in their blood that labels them as having a disease that we call neuromyelitis optica or NMO. This is an autoimmune disease targeting astrocytes – star-shaped glial cells in the brain and spinal cord. Anti-aquaporin-4 antibodies (NMO-Ig), which are directed against this astrocytic water channel, are involved in the disease pathogenesis and used as diagnostic markers.

3 comments:

  1. So are MS and NMO completely different diseases or part of the same family?

    Thanks

    ReplyDelete
  2. Re: "So are MS and NMO completely different diseases or part of the same family?"

    Two different diseases. Remember we classify diseases as clinicopathological correlates. Both the clinical and pathological features of NMO and MS differ; therefore they are different diseases. In addition, their response to treatments also differs; IFNbeta makes NMO worse and MS better - more support for them different entities.

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  3. Is it just coincidence that the lesion is right on the curve of the spine?

    ReplyDelete

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