title: Transient hyperckemia in the setting of neuromyelitis optica (NMO).
abstract: BACKGROUND
  Neuromyelitis optica (NMO) is characterized by inflammatory demyelinating lesions of the spinal cord and optic nerves from an autoimmune response against water channel aquaporin-4 (AQP4). We report 2 patients with transient hyperCKemia associated with NMO suggesting possible skeletal muscle damage.
  
  
  METHODS
  Patient 1 was a 72-year-old man who presented with muscle soreness and elevated serum creatine kinase (CK) preceding an initial attack of NMO. Patient 2 was a 25-year-old woman with an established diagnosis of NMO who presented with diffuse myalgias, proximal upper extremity weakness, and hyperCKemia. Muscle biopsies were obtained for histopathologic evaluation, protein gel electrophoresis, immunofluorescence, and complement staining.
  
  
  RESULTS
  In both patients the muscle showed only mild variation in fiber diameter. There were no inflammatory changes or muscle fiber necrosis, though there was reduced AQP4 expression and deposition of activated complement.
  
  
  CONCLUSIONS
  Complement-mediated sarcolemmal injury may lead to hyperCKemia in NMO.
authors.affiliation: UCSF, Neurology, 505 Parnassus Avenue Box 0114 M-798, San Francisco, California, USA, 94143.
authors.forename: Rabia
authors.initials: R
authors.lastname: Malik
authors.forename: Aaron
authors.initials: A
authors.lastname: Lewis
authors.forename: Bruce A C
authors.initials: BA
authors.lastname: Cree
authors.forename: Julien
authors.initials: J
authors.lastname: Ratelade
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Alan S
authors.initials: AS
authors.lastname: Verkman
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Bollen
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Ralph
mesh_terms: D000368:Aged; D051401:Aquaporin 4 / Q000097:blood; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009471:Neuromyelitis Optica / Q000097:blood* / Q000201:enzymology; D013116:Spinal Cord / Q000473:pathology; D055815:Young Adult
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D003402:Creatine Kinase
keywords: aquaporin 4; creatine kinase; hyperCKemia; immunofluorescence; neuromyelitis optica