Psoriasis and Psoriatic Arthritis Flashcards
Characteristic patterns of PsA
- Joint pattern (Moll and Wright Criteria)
95% have peripheral joint disease (synovitis, tenosynovitis, dactylitis, enthesitis)
A. Asymmetric oligoarticular disease
- DIPJ, PIPJ, MCPJ, MTPJ, knees, hips, ankle
B. Symmetrical polyarthritis (rheumatoid like)
- MCPJ, PIPJ, fusion of wrists
C. Predominant DIPJ with nail changes
D. Arthritis mutilans - DIPJ, PIPJ telescoping, osteolysis
5% have axial spinal involvement
E. Asymmetric axial involvement
- Sacroiliac, vertebral, jug-handle syndesmophytes
(P/S: other seronegative arthritis are symmetric)
- Psoriasis
- Erythematous plaques with silvery white scales over extensors
- Koebner phenomenon at site of trauma
- Inverse psoriasis (over flexors and intertriginous areas - axillae, inguinal folds, intra-mammary creases, minimal scaling) - Extra-articular features
A. Nail changes - pitting, onycholysis, oil spot sign, hyperkeratosis, nail crumbling, transverse ridge
B. Conjunctivitis, acute iritis (bilateral)
C. Oral ulcers
D. Urethritis
E. Colitis
F. Aortic insufficiency and regurgitation (dilatation of aortic arch base)
G. Apical lung fibrosis
H. Gout
What is enthesitis?
What is dactylitis?
Enthesitis
Inflammation of site of insertion of ligaments, tendon, joint capsule or fascia to bone
Commonest sites: Archilles tendonitis, plantar fasciitis
Dactylitis
Sausage like swelling of finger or toe due to inflammation of tendon sheath and soft tissues
Other causes include: TB, syphilis, sarcoidosis, sickle cell disease, or gout (fusiform swelling)
Epidemiology of psoriasis and PsA
Prevalence of psoriasis 2-3%
Race: White 2x more
Sex: Men = women
Peak incidence 4th decade of life
Inflammatory arthritis accompanying psoriasis 7-42%
Genetic and environmental predisposition in PsA
Genetics
1. HLA-Cw8 - severe, early onset psoriasis
2. HLA-B38 and B-39 - PsA
3. HLA-B27 - sacroilitis and spondylitis, juvenile PsA
Environment
1. Trauma to joint (deep Koebner phenomenon) in 25% patients prior to onset of PsA
2. Subclinical trauma to DIPJ
3. Streptococcus pharyngitis predispose to guttate psoriasis
4. Obesity
Psoriasis and PsA
Psoriasis precedes PsA by 8-10 years in 70% patients
PsA precedes psoriasis in 10-15% patients (especially in childhood)
Simultaneous PsA and psoriasis in 15% patients
Classification Criteria for PsA
Classification of PsA Criteria (CASPAR)
1. Evidence of psoriasis
- Current - 2 points; past or family hx - 1 point
2. Psoriatic nail dystrophy - 1 point
3. Negative RF - 1 point
4. Dactylitis - 1 point
5. Radiographic evidence of juxta-articular new bone formation - 1 point
Others: Moll and Wright Criteria
(See characteristic patterns of PsA)
If psoriasis is not obvious, where to examine?
* To write better cards*
umbilicus, scalp, perineum, and behind ears.
Acute severe psoriasis or PsA
- Consider HIV
How would you differentiate PsA from other polyarticular arthritis (RA)?
- Asymmetric, oligoarticular
- Negative rheumatoid factor
- Significant nail pitting or dystrophy
- DIPJ involvement without OA
- Sausage digits (dactylitis) - synovitis and flexor tenosynovitis
- Enthesitis of Archilles and plantar fascia
- Family history of psoriasis or PsA
- Radiographic evidence of:
- Sacroilitis, paravertebral ossification, syndesmophytes
- Erosive arthritis with no periarticular osteopenia - Synovial biopsy - increased vascularity, macrophages, lymphocytes, neutrophils
Investigations in diagnosing PsA
Laboratory
1. Negative RF and ACCP
(2% low positive RF, 8% low positive ACCP, thus to differentiate via clinical features of DIPJ, dactylitis)
2. ANA positive in 10%
3. Raised ESR, CRP with disease activity
4. Anaemia
5. Hyperuricaemia
6. Synovial fluid analysis - neutrophilic predominant
7. HLA-B27 positive in 25%
Imaging
1. XR of joints
- Asymmetric distribution; involvement of DIP joints
- Eccentric erosions, periostitis, and bony ankylosis, with relative absence of periarticular osteopenia
- Whittling of the phalanges, pencil-in-cup deformity, osteolysis of bones (arthritis mutilans), and erosion of the
terminal tufts (acroosteolysis)
- Polyarticular unidigit—MCP, PIP, DIP of same finger involved
- Erosions at entheseal sites
- Asymmetric sacroiliac and spondylitic changes
- Musculoskeletal ultrasound or MRI
- Enthesitis and dactylitis
Management of PsA
- General measures - education, multidisciplinary team, PT, OT
- NSAIDs and intraarticular steroid injection
- DMARDs
- MTX and leflunomid
- Anti-TNFa - etanercept, infliximab, adalimumab
- Ustekinumab (Stelara) - IL-12 and IL-23
- Seccukinumab, ixekizumab - IL-17
- Apremilast - PDE4i
- Abatacept - CD80 and CD-87
- Tofacitinib - JAKi
Prognosis of PsA
20% develop class III or IV functional impairment with disability
Worse prognosis in:
1. Younger age of onset
2. Female sex
3. Acute onset of arthritis
4. Polyarticular disease
5. High ESR/CRP
What are the adverse effects of anti-TNFa therapy?
What are the contraindications?
Adverse effects
1. Serious infections (tuberculosis) - 3.6%
2. Haematological malignancy - 1.9%
3. Nausea
4. Hypersensitivity
5. Worsening heart failure
6. Anaemia, leukopenia, thrombocytopenia, aplastic anaemia
Contraindications
1. Pregnancy and breastfeeding
2. Active bacterial infection
3. Active or latent TB - at least 2 months anti-PTB before commencement, isoniazid 6 months alongside therapy
4. Septic arthritis
5. Congestive heart failure
6. Demyelinating disease
