title: Recent-onset childhood arthritis--association with Streptococcus pyogenes in a population-based study.
abstract: OBJECTIVE
  To assess the frequency of Streptococcus pyogenes in children with early arthritis, compare the characteristics in patients with post-streptococcal ReA (PSReA) with those in patients with other types of arthritis, and describe the occurrence of carditis in PSRA.
  
  
  METHODS
  In a population-based Norwegian study, the physicians were asked to refer all children with suspected arthritis. The arthritis patients were followed up at 6 weeks, 6 months and 18 months. The presence of S. pyogenes was based on throat smear or antibodies. Echocardiography was performed in the patients with ARF or PSRA.
  
  
  RESULTS
  Thirty-two (18%) of the 173 children with arthritis tested positive for S. pyogenes. The percentage of positive tests rose steadily with age and peaked at ages 8-11 (35%). Six weeks after admission arthritis was present in 33% of the PSRA patients, which was less frequent than in the juvenile idiopathic arthritis (JIA) patients (P < 0.001), but more frequent than in the transient arthritis patients (P = 0.012). Hip arthritis was more frequent and knee/ankle arthritis, ANA and HLA-B27 were less frequent in PSRA than in JIA (P < 0.001, P = 0.009 and P = 0.029, respectively). The PSRA patients were older than those with transient arthritis (P = 0.007). One child with ARF had carditis.
  
  
  CONCLUSIONS
  Streptococcus pyogenes was present in 18% of children with arthritis. The patient characteristics, clinical presentation and early disease course in PSRA was different from that of JIA and transient arthritis.
authors.affiliation: Department of Rheumatology, Rikshospitalet Medical Centre N-0027, Oslo, Norway. oystein.riise@rikshospitalet.no
authors.forename: Ø R
authors.initials: ØR
authors.lastname: Riise
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.forename: M
authors.initials: M
authors.lastname: Cvancarova
authors.forename: K S
authors.initials: KS
authors.lastname: Handeland
authors.forename: K-O
authors.initials: KO
authors.lastname: Wathne
authors.forename: B
authors.initials: B
authors.lastname: Nakstad
authors.forename: P
authors.initials: P
authors.lastname: Gaustad
authors.forename: B
authors.initials: B
authors.lastname: Flatø
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D000367:Age Factors; D001168:Arthritis / Q000175:diagnosis / Q000453:epidemiology; D001171:Arthritis, Juvenile / Q000175:diagnosis / Q000453:epidemiology; D016918:Arthritis, Reactive / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D009205:Myocarditis / Q000382:microbiology; D009664:Norway / Q000453:epidemiology; D010614:Pharynx / Q000382:microbiology; D000091402:Prohibitins; D013290:Streptococcal Infections / Q000175:diagnosis / Q000453:epidemiology*; D013297:Streptococcus pyogenes / Q000302:isolation & purification*