musculoskeletal and connective tissue disorders
Reactive Arthritis
Diagnosis of Reactive Arthritis
Typical arthritis Symptoms of antecedent gastrointestinal or genitourinary infection One other extra-articular feature Reactive arthritis should be suspected in patients with acute, asymmetric arthritis affecting the large joints of the lower extremities or toes, particularly if there is tendinitis or a history of an antecedent diarrhea or dysuria. Diagnosis is ultimately clinical and requires the typical peripheral arthritis with symptoms of genitourinary or gastrointestinal infection or one of the other extra-articular features. Because these features may manifest at different times, definitive diagnosis may require several months. Serum and synovial fluid complement levels are high, but these findings are not usually diagnostic and need not be measured. Gonorrhea can closely simulate reactive arthritis. Arthrocentesis may fail to differentiate them, owing to inflammatory characteristics of synovial fluid in both disorders and the difficulty of culturing gonococci from this fluid. Clinical characteristics may help; disseminated gonococcal infection tends to involve upper and lower extremities equally, be more migratory, and not cause back pain, and vesicles tend not to be hyperkeratotic. A positive gonococcal culture from blood or skin lesions helps differentiate the two disorders, but a positive culture from the urethra or cervix, although suggestive, does not. If differentiation is still difficult, a response to Psoriatic Arthritis can simulate reactive arthritis, causing similar skin lesions, 