Acute febrile juvenile rheumatoid arthritis (JRA) of adult onset is often 
diagnosed by ruling out other problems. The classification of JRA is primarily 
based on the distinct type of onset, of which there are usually three: (1) acute 
febrile or Still's type, (2) polyarticular, and (3) monoarticular pauciarticular 
arthritis. Fever of unknown cause is frequently the initial symptom. This type 
of arthritis may be characterized by any or all of the following: unexplained 
high fever, rash, weight loss, lymphadenopathy, splenomegaly, pericarditis, 
pleurisy, pneumonitis, abdominal pain, myalgias, arthralgias, arthritis, sore 
throat, leukocytosis, anemia, circulating immune complexes, liver test 
abnormalities, and carpal-metacarpal and tarsal-metatarsal fusion. Patients 
often respond dramatically to anti-inflammatory agents. Corticosteroids, gold 
salts, penicillamine, and cytotoxic drugs have been effective for certain 
patients. The prognosis of the disease has been generally favorable. Although 
symptoms may recur, remission can be prolonged.