title: Longitudinally extensive optic neuritis in neuromyelitis optica spectrum disorder.
abstract: BACKGROUND
  Neuomyelitis optica, sarcoid, and multiple sclerosis can all cause optic neuritis. Further means of distinguishing the causes of optic neuritis among these etiologies would be valuable for the clinician.
  
  
  METHODS
  This is a retrospective, cohort study from a single university based hospital and neuro-ophthalmology clinic. Blinded interpretation of orbit MRIs was performed on patients with acute optic neuritis from multiple sclerosis (n=25), sarcoid (n=5) and neuromyelitis optica spectrum disorder (n=6).
  
  
  RESULTS
  A length of >40 mm anterior visual pathway enhancement distinguished neuromyelitis optica spectrum disorder from multiple sclerosis (p=0.0376). No statistically significant differences were found for presence of pain or papillitis, however there was a trend for bilateral involvement and chiasmal involvement in neuromyelitis optica spectrum disorder compared to multiple sclerosis.
  
  
  CONCLUSIONS
  In acute optic neuritis, enhancing anterior visual pathway lesion length >40 mm helps differentiate neuromyelitis optica spectrum disorder from multiple sclerosis. This degree of involvement can be considered longitudinally extensive optic neuritis. Further characterization is necessary as this degree of enhancement occurs in other clinical syndromes besides neuromyelitis optica.
authors.affiliation: Department of Neurology, NorthShore University Health System Glenview, IL 60026, USA. Electronic address: Jpula12004@yahoo.com.
authors.forename: John H
authors.initials: JH
authors.lastname: Pula
authors.affiliation: Department of Neurology, University of Illinois College of Medicine at Peoria, USA.
authors.forename: Jorge C
authors.initials: JC
authors.lastname: Kattah
authors.affiliation: Department of Neurology, University of Illinois College of Medicine at Peoria, USA.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Keung
authors.affiliation: University of Illinois College of Medicine at Peoria, USA.
authors.forename: Huaping
authors.initials: H
authors.lastname: Wang
authors.affiliation: University of Buffalo School of Medicine and Biomedical Sciences, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Daily
mesh_terms: D000470:Alkaloids; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009471:Neuromyelitis Optica / Q000150:complications*; D009902:Optic Neuritis / Q000175:diagnosis* / Q000209:etiology*
chemical_list: D000470:Alkaloids; C110131:Wilcox compound
keywords: Longitudinally extensive; Multiple sclerosis; NMO; NMO spectrum disorder; Neuromyelitis optica; Optic neuritis