A.  The diagnosis of juvenile idiopathic arthritis/juvenile rheumatoid arthritis is a diagnosis of exclusion. There are many causes of joints being swollen such as infection, connective tissue diseases, inflammation of the blood vessels called vasculitis and some times cancers as well. Only one form of childhood arthritis presents with fever: Systemic onset arthritis. Your cousin may have this form of arthritis or indeed other serious disease that can have arthritis. Usually children with juvenile rheumatoid arthritis don’t have severe joint pains. This is a serious concern and he needs to be urgently evaluated by a paediatric rheumatologist as soon as possible.