title: Painful tonic spasm in neuromyelitis optica: incidence, diagnostic utility, and clinical characteristics.
abstract: OBJECTIVE
  To evaluate the diagnostic utility and clinical characteristics of painful tonic spasm (PTS) in neuromyelitis optica (NMO).
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Two referral hospitals.
  
  
  METHODS
  Forty patients who had NMO spectrum disorder with anti-aquaporin 4 autoantibody or met the revised diagnostic criteria for definite NMO; 35 patients with multiple sclerosis; and 41 patients with idiopathic acute transverse myelitis without anti-aquaporin 4 antibody.
  
  
  METHODS
  The incidence and clinical characteristics of PTS in the different groups, diagnostic value of PTS in identifying patients with NMO, and predictors of PTS in NMO.
  
  
  RESULTS
  The incidence of PTS was significantly higher in the patients with NMO (10 patients [25.0%]) than in those with multiple sclerosis (1 patient [2.9%]) or idiopathic acute transverse myelitis without anti-aquaporin 4 antibody (1 patient [2.4%]). Most PTS episodes (in 8 of 10 patients [80.0%]) in the NMO group occurred after a mean interval of 48.13 days from the onset of the first myelitis episode and were not accompanied by another demyelinating episode with its onset. Painful tonic spasm associated with myelitis had a specificity of 98.7% for identifying the NMO group. Myelitis at disease onset was a predictor of PTS in the NMO group (odds ratio = 6.545, presence vs absence).
  
  
  CONCLUSIONS
  Painful tonic spasm is a common symptom in NMO. When associated with myelitis, it is relatively specific to patients with NMO and is most commonly observed during recovery from the first myelitis episode. Patients with NMO presenting with myelitis at disease onset appear to be at higher risk for developing PTS compared with other patients with NMO.
authors.affiliation: Department of Neurology, Seoul National University College of Medicine, Korea.
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Min Jin
authors.initials: MJ
authors.lastname: Go
authors.forename: Jung-Joon
authors.initials: JJ
authors.lastname: Sung
authors.forename: Kyung Seok
authors.initials: KS
authors.lastname: Park
authors.forename: Kwang-Woo
authors.initials: KW
authors.lastname: Lee
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000453:epidemiology*; D010146:Pain / Q000175:diagnosis* / Q000453:epidemiology*; D012189:Retrospective Studies; D013035:Spasm / Q000175:diagnosis* / Q000453:epidemiology*