Psoriatic Arthritis Emily Chang Morning Report August 14, 2009 August

Definition Inflammatory arthritis associated with psoriasis Usually seronegative for Rheumatoid Factor Classified with HLA-B27-associated spondyloarthropathies

Epidemiology Likely in up to 25-34% of patients with presence of skin disease Overall prevalence 0.04-1.2% M=F although it differs in subsets Peak age of onset between 30-55 years

CASPAR criteria evidence of psoriasis current - 2 history of - 1 family history of - 1 psoriatic nail dystrophy (onycholysis, pitting, hyperkeratosis) negative rheumatoid factor dactylitis, either current or history of radiological evidence of juxta-articular new bone formation CASPAR = Classification of Psoriatic Arthritis based on study of 588 pts with PsA, 536 pts with other inflammatory arthritis Once presence of MSK inflammatory condition is established, if they score three + points, can be classified as PsA with sensitivity 91.4%, specificity of 98.7%.

Subtypes DIP joint pattern oligoarticular (<5 joints) pattern, usually assymetric polyarticular (>=5 joints), symmetric in half arthritis mutilans spondyloarthritis Patterns of involvement may be helpful early in course of disease, but over time the pattern often changes. But it is useful as a predictor of prognosis. Distal and arthritis mutilans are most specific for PsA but not most common. Polyarthritis is most common, followed by oligoarthritis.

Other Rheum Findings enthesitis (inflammation at site of tendon insertion) tenosynovitis (inflammation of tendon and its enveloping sheath) dactylitis or “sausage digit”

Extra-articular findings skin - psoriasis nails - pits and onycholysis pitting edema - often asymmetrical ocular inflammation - conjunctivitis, iritis articular disease can develop before skin changes in ~15% of adults, ~15% concomitantly, ~70% skin first pits = sharply defined depressions in the plate usually occuring in large numbers and involving several nails onycholysis = separation of nail from its bed (sometimes need to distinguish from fungal infection) while skin dz does not necessarily correlate with joint disease, nail involvement does seem to correlate more . nonpitting edema from chronic lymphedema is a rare extra-articular finding

How to diagnose those without skin findings look for distal joint involvement in asymmetric distribution look at the nails look in ears ask about family history dactylitis nail lesions are present in 80-90% of those with PsA, 46% of those with psoriasis uncomplicated by arthritis

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Diagnostic Testing no diagnostic laboratory testing radiologically: erosive changes and new bone formation in distal joints lysis of terminal phalanges fluffy periostitis and new bone formation at sites of enthesitis “pencil in cup” appearance can have elevated ESR and leukocytosis in 1/3 from inflammatory response can see anemia from AoCD RhF positive in 2-10%, ANA low titer in ~1/2, clinically significant titers ~14%, anti-dsDNA 3%, anti-CCP in 8-16%

Differential Reactive (Reiter’s) Arthritis Rheumatoid Arthritis with concomitant psoriasis ankylosing spondylitis gouty arthritis reactive - lack of preceding infectious episode, absence of genitourinary involvement rheumatoid - involvement of DIPs, asymmetry, spondyloarthropathy, dactylitis, skin and nail findings, radiologic ankylosing spondylitis - radiography, more frequent involvement of cervical spine & less of lumbar spine, asymmetric sacroiliitis, skin and nail findings

Treatment NSAIDs if disease is mild. PT, OT, splinting devices If erosive disease, treat aggressively with DMARDs (MTX, Sulfasalazine, CsA). If skin disease is the major issue, should be managed by a dermatologist. Early referral to rheumatology for initiation of DMARDs to prevent progression. Only two RCTs of MTX in PsA and the evidence is not overwhelming in terms of efficacy of MTX. Sulfasalazine involved in 6 RCTs with only modest effect. CsA effective for both skin and joint manifestations, but not well tolerated. Other DMARDs = azathioprine, gold, antimalarials, anti-TNF agents (etanercept, infliximab, adalimumab, golimumab), and newer T-cell directed agents not yet approved for PsA (although approved for psoriasis)

Course and Prognosis 20% of patients have a severe an debilitating form of arthritis originally thought to be more benign course than RhA progression of clinical damage occurs in a majority of patients radiologic changes occur over time despite treatment presence of >=5 swollen joints + high medication level were predictors for progression of clinical damage low ESR protective. HLA B22 protective, but others (HLA-B27, HLA-DR7, HLA-B39, HLA-DQw3 in absence of HLA-DR7) predict progression

References Klippel, John. Primer on the Rheumatic Diseases. Edition 12. Atlanta, GA: Arthritis Foundation; 2001: 584-586. Gladman, Dafna. Psoriatic arthritis. Dermatologic Therapy. Vol 22. 2009, 40-55. www.utdol.com