title: Neuromyelitis optica spectrum disorder as an initial presentation of primary Sjögren's syndrome.
abstract: OBJECTIVE
  Longitudinal myelitis in patients with Sjögren's syndrome (SS) is a rarely reported occurrence. Here, we present a patient with longitudinal myelitis who was found to have both primary SS and a positive antibody to aquaporin-4 (NMO-IgG). We review the recent literature concerning the overlap between primary SS-associated myelitis and the presence of NMO-IgG, suggestive of a neuromyelitis optica spectrum disorder (NMOSD).
  
  
  METHODS
  A patient with longitudinal myelitis, SS, and a positive NMO-IgG is presented. A review of the relevant English literature based on a PubMed and Embase search is then discussed. The keywords used were Sjögren's syndrome, myelitis (longitudinal and transverse), neuromyelitis optica, and Devic's disease.
  
  
  RESULTS
  Our patient fulfills the criteria for both primary SS and NMOSD. Several small studies have shown that most SS patients with longitudinal myelitis are positive for the antibody to aquaporin-4. Additionally, minor salivary gland biopsies of patients with NMO or NMOSD have evidence of lymphocytic inflammation, suggesting that there may be an overlap in the mechanism of NMOSD and longitudinal myelitis secondary to primary SS. This overlap in mechanism may have important ramifications with regard to prognosis and treatment of SS-related myelitis.
  
  
  CONCLUSIONS
  The presentation of longitudinal myelitis in a patient with SS should be considered a possible NMOSD. Checking for the presence antiaquaporin-4 antibodies provides important prognostic information and may help to guide treatment decisions.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109-5358, USA. mkahlenb@umich.edu
authors.forename: J Michelle
authors.initials: JM
authors.lastname: Kahlenberg
mesh_terms: D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000209:etiology* / Q000276:immunology; D012859:Sjogren's Syndrome / Q000150:complications* / Q000175:diagnosis / Q000276:immunology
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies