1. Psoriatic Arthritis
Emily Chang
Morning Report
August 14, 2009
August

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

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

4. 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%.

5. 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.

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

7. 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

8. 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

9. Images

10. 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%

11. 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

12. 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)

13. 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

14. References
Klippel, John. Primer on the Rheumatic Diseases. Edition 12. Atlanta, GA: Arthritis Foundation; 2001:
Gladman, Dafna. Psoriatic arthritis. Dermatologic Therapy. Vol ,