Psoriatic arthritis

Question 1

ILAR criteria

Answer 1

Arthritis plus psoriasis or arthritis plus at least 2 of the following

• Dactylitis
• Nail pits or onycholysis
• Fam history of psoriasis in a first degree relative

Question 2

ILAR exclusion

Answer 2

1. Arthritis in an HLA b27 positive male beginning after the sixth birthday
2. AS, ERA, sacroilitis with IBD, reactive arthritis or acute anterior uveitis or a history of one of these disorders in a first degree relative
3. The presence of IgM RF on at least two occasions at least 3 months apart
4. Arthritis fulfilling two or greater JIA categories

Question 3

Describe the synovial pathology

Answer 3

Synovial lining is less villous than in adult RA but with distinct tortuous bushy superficial blood vessels

• Microvascular pattern resembles that of a psoriatic plaque
• Infiltrating neutrophils are more prevalent
• Majority of lymphocytes are T cells that express memory CD45RO, with CD4 helper cells predominating over CD8 cells

Question 4

HLA B27 in PsA

Answer 4

Associated with a shorter interval from onset of psoriasis to development of arthritis

Question 5

HLA B*0801

Answer 5

Associated with asymmetrical sacroilitis yet more severe synovial pathology, enthesitis, and dactylics

Question 6

PsJIA has been linked with these SNPs

Answer 6

Autoinflammatory diseases (MEFV, NLRP3, NOD2 and PSTP1P1

Question 7

Difference between children with psJIA and those with psoriasis without arthritis

Answer 7

Prevalence of nail changes, much higher in PsA

Question 8

Which immune axis is important in PsA?

Answer 8

IL-12/23–> TH17

Question 9

Difference between Sacroilitis in PsA and JAS

Answer 9

asymmetrical in pSA