PREDICTION OF DIAGNOSIS IN ACUTE AND SUBACUTE OLIGOARTHRITIS OF UNKNOWN ORIGIN

A total of 146 consecutive patients between 18 and 60 yr of age with o ligoarthritis of unknown origin (less than or equal to 6 active joints , less than or equal to 8 weeks duration) were examined by a variety o f clinical, laboratory and microbiological investigations, and followe d longitudinally for 24 weeks. Reactive arthritis was diagnosed in 46 patients (19 induced by Chlamydia trachomatis, 27 by enterobacteria), 62 had undifferentiated arthritis, eight other inflammatory arthritic diseases, 15 acute sarcoid arthritis and 15 non-inflammatory joint dis eases. Group differences were found for many baseline variables, but w ith considerable overlap between the groups. A set of four clinical an d laboratory variables (elevated CRP, genitourinary symptoms, metatars ophalangeal joint involvement, HLA B27) could predict reactive arthrit is with a sensitivity of 69.2% and a specificity of 93.5%. A wide rang e of clinical and laboratory examinations are required to determine th e final diagnosis in oligoarthritis, but individual and sets of clinic al and laboratory measures may give helpful clues for the correct diag nosis.