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Neuromyelitis optica (NMO; Devic’s disease) is an aggressive inflammatory disorder characterized by recurrent attacks of optic neuritis (ON) and myelitis; the more inclusive term NMO Spectrum Disorders (NMOSD) incorporates pts with partial forms, and with involvement of additional CNS structures (Table 193-1). NMO is more frequent in women than men (>3:1), and typically begins in adulthood but can arise at any age. An important consideration is distinguishing between NMO and multiple sclerosis (MS; Chap. 192). In NMO, attacks of ON can be bilateral and produce severe visual loss (uncommon in MS); myelitis can be severe and transverse (rare in MS) and is typically longitudinally extensive (Fig. 193-1) involving three or more contiguous vertebral segments. Also in contrast to MS, progressive symptoms typically do not occur in NMO.
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