Juvenile Idiopathic Arthritis
JIA is a chronic (long lasting) inflammatory disorder of the body joints affecting about one in every thousand children and adolescents under 16 years of age.
Joints can become painful and swollen for a number of reasons and in most cases it is possible to quickly identify a cause. This may be injury, infection in the joint or surrounding area or it may be a reaction to some other infection such as a streptococcal throat infection or gastroenteritis.
If there is no obvious cause and the condition persists then JIA must be considered as a cause. There is no diagnostic test for JIA. It is diagnosed based on the history of the patient and a clinical assessment. Tests may be carried out in order to exclude other conditions as the cause of the symptoms or to gather more information about the type or severity of JIA.
In JIA no trigger is identified but the inflammation persists beyond 6 weeks. The child may complain of pain in the affected joint ⁄ joints, which become stiff on waking up in the morning and after periods of inactivity. The joints are often swollen and warmer than the surrounding area.
JIA is split into different types depending on the number of joints affected, the way it initially presents itself and the results of some specific tests. These groups are explained in the linked articles as are two potential complications, Uveitis and MAS.
One of these types, Systemic Onset JIA can be difficult to diagnose initially as it usually starts with a fever and rash resembling a viral infection. The arthritis, usually involving small and large joints, may not develop for several weeks or even occasionally many months.
Inflammation of the internal lining of the eye is called Uveitis and is a potentially serious complication of JIA. Regular eye screening is essential to detect its presence at an early stage, as patients remain symptom free until the eye suffers significant and sometimes irreversible damage.