<s>[INST] context: A child with a constellation of findings including fever, disabling arthritis, rash, and blindness is most likely suffering from juvenile rheumatoid arthritis (JRA). JRA is characterized by a chronic synovial inflamma­tion of unknown origin; it most commonly affects the knees, but can also manifest in wrists, ankles, and the atlanto-axial joint in the neck. In general, JRA is more common in girls than boys, but this varies with the type of JRA, which can be divided into the following variant subsets: Still disease (20%), polyarticular (40%), and pauciarticular (40%). Still disease most closely resembles an infectious disease, with spiking fever, a centripetal rash, generalized lymphadenopathy, hepatosplenomegaly, transient arthralgias and ar­thritis, and effusions (pericardial and pleural). The polyarticular variant is associated with destructive ar­thritis, particularly if the patient tests positive for the rheumatoid factor. The pauciarticular variant features polyarthritis and inflammation of the anterior uveal tract 10%-50%), which predisposes the patient to visual loss and blindness. In most cases of JRA, with the exception of the polyarticular variant, the rheumatoid factor is negative. Anemia and leukocytosis are noted in acute attacks. Aspirin is the major anti-inflamma­tory agent that is used for treatment. Regarding the other choices in the question:

rheumatic fever features polyarthritis, but it is not destructive
Lyme disease displays many of these findings, but blindness is not a key feature
Henoch-Schoenlein vasculitis has palpable purpura, non-disabling arthritis, but is not associated with blindness
dermatomyositis does not usually involve the joints [/INST] question: A child with a constellation of finding including fever, disabling arthritis, rash, and blindness is MOST likely suffering form | options: A: Rheumatic fever B: Lyme disease C: Juvenile rheumatoid arthritis D: Henoch-Schoenlein vasculitis | answer: C </s>