Erosive arthritis (differential)
Erosive arthritis has a broad differential:
- erosive osteoarthritis
- clinically an acute inflammatory attacks (swelling, erythema, pain) in postmenopausal woman
- typically the interphalangeal joints, 1carpometacarpal joint , but not the metacarpophalangeal (MCP) joints and large joints
- classic central erosions (gull-wing appearance); possible ankylosis
- rheumatoid arthritis
- sometimes rheumatoid factor (RF) positive
- usually proximal, bilateral and symmetric involvement: metacarpophalangeal joints, proximal interphalangeal joints, and carpal bones; involves the hands before the feet
- erosions in "bare area", frequently in metacarpophalangeal joints
- periarticular osteopenia and later osteoporosis (both unlike psoriatic arthritis), uniform joint space, subchondral cyst formation, and subluxations; no new bone formation unlike psoriatic arthritis and reactive arthritis
- psoriatic arthritis
- commonly involves the hands and there is an interphalangeal predominant distribution in psoriatic arthritis vs. metacarpophalangeal joint predominance in rheumatoid arthritis (RA)
- new bone formation key, not a feature of RA
- affects the synovio-entheseal complex, explaining enthesis, adjacent joint capsule synovitis, and periarticular inflammation
- erosions; classic: "pencil in cup"; osteoporosis is not a feature in psoriatic arthritis
- reactive arthritis (Reiter syndrome)
- predilection for the lower limb
- symmetrical involvement of the proximal interphalangeal joints, metacarpophalangeal joints, and carpal bones.
- osteopenia and then osteoporosis, uniform joint space loss, subchondral cyst formation, subluxations, marginal erosions but no bone formation
- ankylosing spondylitis
- gout
- erosions with overhanging edges (rat bite)
- tophi, most commonly involving the 1metatarsophalangeal joint, known as podagra
- hydroxyapatite crystal deposition disease (HADD)
- amyloidosis
- multicentric reticulohistiocytosis
- infectious arthritis
- scleroderma
- pressure erosion (PVNS and synovial osteochondromatosis)
- articular defects simulating erosions in CPPD, osteonecrosis, osteochondritis dissecans, and osteochondral fractures
- septic arthritis
- single joint
- neuropathic (Charcot) arthropathy