title: Undifferentiated arthritis in an early synovitis out-patient clinic.
abstract: OBJECTIVE
  To describe the features of undifferentiated arthritis in an early synovitis out-patient clinic.
  
  
  METHODS
  In a two-year prospective cohort study 320 patients with rheumatic symptoms of less than one year were investigated in an early synovitis out-patient clinic. Besides the clinical parameters, an intensive laboratory program was performed, including routine blood and serum parameters, immunological investigations (CRP, IgG,A,M,C3C4,RF,ANA, DNA, HLA B-27), and a microbiological program to search for reactive arthritis-inducing infections.
  
  
  RESULTS
  217 patients had inflammatory rheumatic diseases, of whom only 100 (46%) could be given a definite diagnosis, whereas 117 (54%) were considered as having undifferentiated arthritis (UA). Patients with UA had a mean age of 41 +/- 15 years, the sex-ratio was 1.8:1.0 (f/m), joint manifestations were oligoarticular in 68%, monarticular in 14%, and polyarticular in 18%. Rheumatoid factor was positive in 17%, HLA-B27 was found in 27%, and 21% of the patients had a history of recent infection. Follow up over 26 (range 4-38) months of 28 (24%) patients with UA revealed complete remission in 15 patients (54%), while 10 patients (36%) had further UA with partial remission, unchanged activity or progressive disease, and only 2 (7%) developed rheumatoid arthritis (RA) and 1 (4%) was diagnosed as having ankylosing spondylitis.
  
  
  CONCLUSIONS
  Most patients with early synovitis followed at our clinic remain unclassified with a good prognosis.
authors.affiliation: Department of Internal Medicine and Dermatology, Medical School Hannover, Germany.
authors.forename: J L
authors.initials: JL
authors.lastname: Hülsemann
authors.forename: H
authors.initials: H
authors.lastname: Zeidler
mesh_terms: D000328:Adult; D000554:Ambulatory Care Facilities; D001168:Arthritis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001424:Bacterial Infections / Q000150:complications; D015331:Cohort Studies; D005260:Female; D015796:HLA-B27 Antigen / Q000032:analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012217:Rheumatoid Factor / Q000032:analysis; D013585:Synovitis
chemical_list: D015796:HLA-B27 Antigen; D012217:Rheumatoid Factor