Psoriatic Arthritis

Question 1

Types of seronegative spondyloarthropathies

Answer 1

-Psoriatic Arthritis
-Axial spondyloarthropathy
=Inflammatory back pain
=Sacroileitis on MRI
-Ankylosing spondylitis
=AxSpA with x-ray change
-Reactive Arthritis
-Enteropathic arthritis

Question 2

Definition and Epidemiology of PsA

Answer 2

-An inflammatory arthritis associated with psoriasis or a family history of psoriasis
=Affects about 20-30% of people with psoriasis
-Peak incidence age 20-50
-Men and women affected equally
-Population prevalence approximately 0.3%
-Associations with metabolic syndrome, obesity and high alcohol intake

Question 3

Pathophysiology of PsA

Answer 3

-Genetic predisposition
=HLA-C region (Class I)
=Multiple other genes
-Environmental trigger
=Microbiome, mechanical factors?
-Increased production of IL-23
-Activation of Th17 cells
-Increased IL-17 and TNF production
-Inflammatory infiltrate of joints and tendons at enthesis

Question 4

Clinical presentation of PsA

Answer 4

-Inflammatory back and joint pain, stiffness, and swelling (soft tissue swelling and tenderness of affected joints on examination)
-Asymmetrical arthritis, monoarticular or oligoarticular
=PIP and DIP joints of hands
=Large joints
=Sacro-ileitis
-Early morning stiffness (typically >30min) and inactivity gelling
-Psoriasis (not always)- skin rash
-Nail pitting and nail dystrophy
-Symptoms of enthesitis
-Uveitis
-Dactylitis (swelling of entire digit)

Question 5

CASPAR Criteria for diagnosis of PsA

Answer 5

Inflammatory arthritis with score of >3 points from any of the following criteria:

–Current psoriasis (2 points)
–History of psoriasis in first or second degree relative (1 point)
–Psoriatic nail dystrophy (1 point)
–Negative for rheumatoid factor (1 point)
–Current dactylitis (1 point)
–Previous dactylitis (1 point)
–Juxta-articular new bone on x-ray (1 point)

Question 6

Physical examination in PsA

Answer 6

-Check hands and feet for dactylitis
-Check for pitting and nail dystrophy
-Check large joints for synovitis
-Check tendon insertions for enthesitis
=Feature of PsA and AxSpA
-Evaluate skin for extent and severity of
Psoriasis
=May influence treatment choice

Question 7

Diagnosis and investigations in PsA

Answer 7

-PsA is a clinical diagnosis based on history and examination
-Raised ESR and CRP
=May be normal in limited disease
-CCP, RF and ANA negative
-Imaging
=Erosive arthritis on x-ray (DIPJ)
=Sacroileitis on x-ray or MRI
=Synovitis, tenosynovitis on MRI or USS

Question 8

Management of PsA

Answer 8

-Immunosuppressive therapy (start with single agent and escalate dose- combination therapy for poor response, progressive peripheral joint disease)
=Methotrexate
=Leflunomide
=Sulfasalazine
=Ciclosporin
-AVOID systemic steroids
=Can cause flare in psoriasis
-NSAID for symptom control with analgesics (limited disease)
-Biologics and tsDMARD for resistant disease

Question 9

Role of Biologics and tsDMARD in PsA

Answer 9

-Indicated for active disease which has responded inadequately to DMARD
=Three or more swollen and tender joints
-Options include:
=Anti-TNF therapy (TNFi)
=Secukinumab, Ixekizumab (IL-17)
=Ustekinumab (IL-12/IL-23), Guselkumab (IL-23)
=Tofacitinib (JAKi)
=Apremilast (PDE4)

Question 10

Non-pharmacological treatment of PsA

Answer 10

-Physiotherapy
=Joint protection
-Occupational therapy
=Aids and devices
-Address comorbidities
=Obesity
=Smoking / alcohol
-Orthopaedic surgery
=Arthroplasty

Question 11

Main differential of PsA

Answer 11

-Osteoarthritis
=There is bony swelling of the DIP and PIP and 1st CMC joints of the hands rather than synovitis
=Morning stiffness is not prominent
=X-rays show OA change and no erosions.