Still's Disease (cont.)

Still's disease is diagnosed purely on the basis of the typical clinical features of the illness. These features include high intermittent fever, joint inflammation and pain, muscle pain, faint salmon-colored skin rash, swelling of the lymph glands or enlargement of the spleen and liver, and inflammation around the heart (pericarditis) or lungs (pleuritis). Persistent arthritis (arthritis lasting at least six weeks) is required to make a firm diagnosis of Still's disease. Other diseases (especially infections, cancers, and other types of arthritis) are excluded.

Many patients with Still's disease develop markedly elevated white blood cell counts, as if they have a serious infection, but no infection is found. Low red blood counts (anemia) and elevated blood tests that indicate inflammation (such as sedimentation rate, C-reactive protein, and ferritin) are common. However, the classic blood tests for rheumatoid arthritis (rheumatoid factor) and systemic lupus erythematosus (antinuclear antibodies) are usually negative.

Still's disease accounts for 10%-20% of all cases of JIA. It affects about 25,000-50,000 children in the United States. It is rare in adults, a majority of whom are between 20 and 35 years of age at onset of symptoms.

Of all patients with Still's disease, 100% have high intermittent fever, and 100% have joint inflammation and pain, muscle pain with fevers, and develop persistent chronic arthritis. Approximately 95% of Still's disease patients have the faint salmon-colored skin rash, 85% have swelling of the lymph glands or enlargement of the spleen and liver, 85% have a marked increase in the white blood cell count, 60% have inflammation of the lungs (pleuritis) or around the heart (pericarditis), 40% have severe anemia, and 20% have abdominal pain.

Source: MedicineNet.com
http://www.medicinenet.com/stills_disease/article.htm