RELAPSING INFLAMMATORY OPTICNEURITIS: IS IT NEUROMYELITIS OPTICA?

Abstract

Subacute loss of vision accompanied by pain is most commonly due to some form of inflammatory optic neuropathy (ON), and may be the first symptom of multiple sclerosis (MS). ON may also be due to viral or bacterial infection or systemic diseases. Although ON is frequently limited to a single episode, some patients experience recurrent episodes. The name recently given to these recurrent episodes of inflammatory ON with a negative workup for MS or other causes of ON is relapsing inflammatory ON (RION).1 MRI scans are normal and oligoclonal bands are rarely found in the CSF. Some patients with an initial diagnosis of RION are, after several years of follow-up, diagnosed with neuromyelitis optica (NMO), due to the occurrence of one or more episodes of myelitis.2 Recently, a specific marker of NMO, named NMO antibody, was found.3 There is now evidence to suggest that patients who experience recurrent episodes of myelitis and are positive for NMO antibodies are at a high risk of developing NMO.4 A similar hypothesis could be applied to RION. In the first study on NMO antibodies, a positive result was found in 2 of 8 patients with RION.3 However, the …