title: Neuromyelitis optica preceded by hyperCKemia episode.
abstract: BACKGROUND
  Neuromyelitis optica (NMO) is a disease of the CNS characterized by severe optic neuritis and longitudinally extended transverse myelitis. Recent studies suggest that anti-aquaporin-4 (AQP4) antibodies, NMO-specific biomarkers, are pathogenic and target AQP4-expressing astrocytes in NMO, although an additional event (T-cell response or infection) should occur for anti-AQP4 antibodies and complements to pass through the blood-brain barrier and cause the CNS lesions. AQP4 is the major water channel in the CNS, but it is also expressed in fast-twitch skeletal muscle fibers. However, muscle diseases have not been described in NMO.
  
  
  METHODS
  We retrospectively examined the serologic database of 733 cases of NMO with anti-AQP4 antibody at the Department of Neurology, Tohoku University School of Medicine. The serum samples were sent to our laboratory for testing anti-AQP4 antibody from around the country during the period from 2006 to 2009.
  
  
  RESULTS
  We found 3 anti-AQP4 antibody-positive female patients (7, 34, and 67 years old) with NMO who had episodes of prominent hyperCKemia (12,520, 19,415, and 59,660 IU/L) with general fatigue some weeks before the onset of optic neuritis. HyperCKemia was transient without any treatment in all patients, but recurred once in one of them.
  
  
  CONCLUSIONS
  These cases suggest that hyperCKemia may be involved in the pathogenesis of neuromyelitis optica (NMO) in a fraction of patients. The causes of transient hyperCKemia are unknown. Further studies are needed to know the frequency of hyperCKemia in NMO and clarify its pathogenic role.
authors.affiliation: Department of Neurology, Tohoku University School of Medicine, Aoba-ku, Sendai 980-8574, Japan. naoki@em.neurol.med.tohoku.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Aoki
authors.forename: T
authors.initials: T
authors.lastname: Misu
authors.forename: S
authors.initials: S
authors.lastname: Konohana
authors.forename: T
authors.initials: T
authors.lastname: Okumura
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: S
authors.initials: S
authors.lastname: Kameya
authors.forename: K
authors.initials: K
authors.lastname: Yamaki
authors.forename: T
authors.initials: T
authors.lastname: Kumagai
authors.forename: K
authors.initials: K
authors.lastname: Fujihara
authors.forename: Y
authors.initials: Y
authors.lastname: Itoyama
mesh_terms: D000328:Adult; D000368:Aged; D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis / Q000097:blood; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002648:Child; D015897:Comorbidity; D003402:Creatine Kinase / Q000032:analysis / Q000097:blood*; D005260:Female; D006801:Humans; D018763:Muscle Fatigue / Q000276:immunology; D018908:Muscle Weakness / Q000097:blood / Q000201:enzymology / Q000453:epidemiology; D018482:Muscle, Skeletal / Q000201:enzymology / Q000276:immunology / Q000503:physiopathology; D009135:Muscular Diseases / Q000097:blood* / Q000201:enzymology / Q000453:epidemiology*; D009471:Neuromyelitis Optica / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D012189:Retrospective Studies; D015854:Up-Regulation / Q000502:physiology
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies; D015415:Biomarkers; D003402:Creatine Kinase