Juvenile Idiopathic Arthritis (JIA), also sometimes called Juvenile Rheumatoid Arthritis (JRA) or Juvenile Chronic Arthritis (JCC), affects about 1 in 1000 children in the UK. It is a chronic condition that causes joint inflammation, pain, swelling, redness, and stiffness. It may also affect the eyes and internal organs. About one-fifth of those with JIA have an enlarged spleen.
There are three main types of Juvenile Idiopathic Arthritis:
Pauciarticular or Oligoarticular – about 50%. It affects four or less joints and is most common in girls less than 8 years old.
Polyarticular – about 30%. It affects five or more joints, especially in the hands and feet but also other larger joints.
Systemic – about 20%. It affects both joints and internal organs. Children with this type may have frequent fevers and rashes that can come and go rapidly. Also known as Still’s disease.
Each patient’s symptoms will differ and will frequently change over time, with flare-ups and remissions. In a few children the symptoms may be persistent, in a few others they may permanently disappear.
Doctors consider the diagnosis of JIA in patients who have had symptoms for at least 6 weeks. These symptoms may include morning stiffness, limping, reluctance to move an affected joint, joint pain and swelling. Patients with systemic JIA may have intermittent fever, rash, swollen lymph nodes, and in some cases liver, spleen, and (very rarely) lung involvement. Complications of JIA may include eye inflammation and problems related to joint growth. The disease may cause the affected joints to grow either too quickly or too slowly, causing one arm or leg to be shorter or longer than the other. It may also cause uneven growth in the joint itself. General growth may also be affected by JIA.