Abstract
INTRODUCTION: Neuromyelitis optica (NMO) is a severe demyelinating syndrome characterized by optic neuritis (ON) and acute myelitis. The NMO spectrum is actually recognized to typically evolve as a relapsing disorder that also includes patients with atypical unilateral ON and those with index events of ON and myelitis occurring weeks or even years apart (Jarius/Wildemann 2013). NMO was previously assumed to be a variant of multiple sclerosis (MS), but the discovery of aquaporin-4 antibodies in patients with neuromyelitis optica has led to this view being revised (Mandler 2006, Barnett/Sutton 2012, Wingerchuk et al. 2007). The cause of the condition is still unknown, but it has been shown that the antibodies bind selectively to a water channel expressed mainly on astrocytes at the blood-brain-barrier, which has an important role in the regulation of brain volume and ion homeostasis. However, there are some patients with NMO that are antibodies negative. The diagnosis is made on the basis of case history, clinical examination, magnetic resonance imaging (MRI) of the brain and spinal cord, analysis of cerebrospinal fluid (CSF), visual evoked potentials and a blood test with analysis of aquaporin-4 antibodies (Barnett/Sutton 2012, Wingerchuk et al. 2007, Thornton et al. 2011). This suggests that periodical revisions of established concepts and diagnostic criteria are necessary. PURPOSE: The authors describe an extremely rare case of neuromyelitis optica and the aim of this paper is to call attention for the cases of NMO whith NMO-IgG negative. METHODS: The selected method is a case report. RESULTS: To date the patient showed partial recovery of left eye acuity and improvement of muscle strength of upper and lower limbs and does not show recurrence of the disease. CONCLUSION: NMO has a distinct clinical, imaging and immunopathological features sufficient to distinguish it from MS. This distinction is essential, because the treatment and the prognosis is different.