Arthritis

Abstract

Correct diagnosis of arthritis (Fig. 1) involves consideration of numerous factors, including clinical features [age and sex of the patient, duration of symptoms, clinical appearance of involved joint or joints, presence or absence of associated diseases (e.g., skin disease, uveitis, urethritis)], laboratory values (e.g., markers for inflammation, serum rheumatoid factor, serum uric acid level), and various imaging features. Radiographs represent the mainstay for diagnosis and follow-up of joint damage, although magnetic resonance imaging (MRI) and sonography can be useful evaluation tools, especially in the early stages of disease. Many imaging features have to be systematically assessed to establish a correct diagnosis: (1) the distribution of joint involvement [monoarticular or polyarticular, symmetrical or asymmetrical, proximal or distal, associated axial involvement, associated enthesis (ligament and tendon attachment to bone) involvement]; (2) soft tissue swelling (periarticular, fusiform, nodular); (3) joint space narrowing (uniform, non-uniform, none); (4) bone erosion (marginal, central, periarticular, well-defined, none); (5) bone production (osteophytes, enthesophytes, periosteal new bone); (6) calcification (periarticular, chondrocalcinosis); (7) subchondral cysts; (8) periarticular osteoporosis.