Juvenile idiopathic arthritis

Case history

A 3-year-old girl presents with stiffness and limp of several weeks' duration. The onset was insidious and her parents do not recall any specific injury or prior infections. Her parents mention that one of her knees is swollen and cannot be straightened, although it is not especially painful. Her symptoms are particularly bad in the mornings when she wakes, but her gait improves as the day goes on. She has not had any fevers, rashes, or other constitutional symptoms.

Other presentations

Oligoarticular JIA describes arthritis in four or fewer joints and typically affects young children (often younger than 6 years of age and female). It most often affects the large joints such as the knee, ankle, wrist, and/or elbow joints. It can be associated with uveitis, which affects up to 20% of young people with this type of JIA.

Rheumatoid factor (RF)-negative polyarticular JIA typically affects young girls and usually presents with symmetrical stiffness, swelling, and pain in several joints, often involving small joints of the hands and feet.

RF-positive polyarticular JIA typically affects older girls and usually presents with symmetrical symptoms affecting several joints, often involving the small joints of the hands and wrists.

Systemic-onset juvenile idiopathic arthritis may present with arthritis in one or more joints in addition to daily high spiking fevers, and evanescent, truncal, salmon-colored, macular rashes. Arthritis does not need to be present initially for diagnosis.

Enthesitis-related JIA typically (but not exclusively) affects boys over the age of 6 years and usually presents with asymmetrical arthritis, enthesitis, and sacro-iliac joint involvement.

Psoriatic JIA usually presents with arthritis and definite histories or family histories of psoriasis (in first-degree relative), nail changes, and/or dactylitis; psoriatic rash may/may not be present.

Undifferentiated JIA may present with features of more than one subtype.