Clinical features of the inflammatory peripheral arthritis associated with idiopathic IBD
- Type I (arthritis often parallels IBD activity) occurs in 4% to 6% of patients with IBD. It affects both males and females equally. Children are affected as often as adults.
- The arthritis is typically acute (80%) in onset and asymmetric (80%). It usually involves fewer than five joints (i.e., oligoarticular), especially the knees or ankles.
- It occurs prior to (30% of cases) or early in the course of the bowel disease and is strongly associated (80%) with flares of IBD and other extraarticular manifestations (erythema nodosum, uveitis).
- Synovial fluid analysis reveals an inflammatory fluid with up to 50,000 white blood cells (WBC)/mm 3 (predominantly neutrophils) and negative findings on crystal examination and cultures.
- There is an increased prevalence of human leukocyte antigen (HLA)-B27, HLA-B35, and HLA-DRB1*0103 in this type of arthritis.
- Most arthritic episodes are self-limited (80% within 3 months) and do not result in radiographic changes or deformities.
- Type 2 (arthritis independent of IBD activity) is less common, occurring in 3% to 4% of IBD cases.
- The arthritis tends to be symmetric (80%), polyarticular (metacarpophalangeal joints, knees, and ankles more than other joints), runs a course independent of the activity of IBD, and does not coincide with extraarticular manifestations (except uveitis).
- Active synovitis persists for months (90% of cases) and episodes of exacerbations and remissions may continue for years.
- Because of its chronicity, this type of arthritis can cause erosions and deformities.
- There is an association of this arthritis with HLA-B44 but not with HLA-B27 .
