Arthritis

Arthritis (plural: arthritides) refers to inflammation of the joints, caused by a broad range of etiologies.

Terminology

Arthropathy is a broader term referring to any disease of the joint, whereas arthritis is a type of arthropathy specifically referring to inflammation of the joint.

Pathology

Etiology 

Degenerative

• osteoarthritis: primary or secondary

  • erosive osteoarthritis

  • post-traumatic osteoarthritis

• neuropathic (Charcot) arthropathy: including diabetic arthropathy

• haemophilic arthropathy

Inflammatory

• rheumatoid arthritis

• seronegative spondyloarthritis

  • ankylosing spondylitis

  • psoriatic arthritis

  • reactive arthritis

  • enteropathic arthritis

  • undifferentiated spondyloarthritis

• juvenile idiopathic arthritis (Still disease)

• adult-onset Still disease

• Behçet disease

• relapsing polychondritis

• multicentric reticulohistiocytosis

Infectious

• septic arthritis

  • tuberculous arthritis

  • Whipple disease

  • Lyme disease

• viral arthritis

  • parvovirus B19 arthritis

  • chikungunya fever

• fungal arthritis

Depositional

• crystal arthropathy

  • gout

  • pseudogout (calcium pyrophosphate dihydrate deposition (CPPD) disease)

  • hydroxyapatite deposition disease (HADD): including Milwaukee shoulder

• hemochromatosis

• Wilson disease

• ochronosis

• sarcoidosis

• amyloidosis

Collagen vascular disease

• systemic lupus erythematosus (SLE)

• Jaccoud arthropathy

• scleroderma

• polymyositis/dermatomyositis

• mixed connective tissue disease

Neoplastic

• diffuse tenosynovial giant cell tumor

• synovial chondromatosis

Classification

Arthritis can also be classified in a number of various ways, including by:

• onset: acute vs chronic

• number: monoarticular (1 joint) vs oligoarticular (2-4 joints) vs polyarticular (≥5 joints)

• distribution: axial vs peripheral

• symmetry: symmetric vs asymmetric

• character: fixed vs migratory

• erosions: erosive vs non-erosive

Radiographic features

Each type of arthritis typically shares one or more of the following imaging features:

• soft tissue swelling

• subluxation/dislocation

• demineralization

• calcification

• joint space narrowing

• erosions

• bone production

See also

• synovitis