Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy with a prevalence between 0.1 and 1% . Psoriasis affects 1-3% of the population, with approximately a third of patients developing PsA . The course of PsA is variable and unpredictable ranging from a mild non-destructive disease to a severe debilitating erosive arthropathy. Erosive and deforming arthritis occurs in 40-60% of PsA patients (followed at hospital clinics), and is progressive from within the first year of diagnosis ,.
PsA can develop at any time including childhood, but for most it appears between the ages of 30 and 50 years. PsA affects men and women equally. PsA is characterized by stiffness, pain, swelling, and tenderness of the joints and surrounding ligaments and tendons (dactylitis and enthesitis). The enthesis is the anatomic location where tendon, ligament, or joint capsule fibers insert into the bone. Enthesitis may occur at any such site, although common locations include the insertion sites of the plantar fascia, the Achilles' tendons, and ligamentous attachments to the ribs, spine, and pelvis. Dactylitis, or "sausage digit," is a combination of enthesitis of the tendons and ligaments and synovitis involving a whole digit. Nail disease is commonly found in patients with PsA especially those with distal interphalangeal (DIP) joint involvement.
Although patients with mild psoriatic arthritis may be treated with nonsteroidal anti-inflammatory drugs and/or intra-articular steroid injections, the use of disease- modifying anti rheumatic drugs, particularly Methotrexate or Sulphasalazine, along with the biologic agents, are considered the standard of care in patients with more significant psoriatic arthritis.
Flares and remissions usually characterize the course of PsA. Left untreated, patients with PsA can have persistent inflammation, progressive joint damage, severe physical limitations, disability, and increased mortality.
The guidelines have been developed to give assistance to the early diagnosis of Psoriatic arthritis and to facilitate early referral to a rheumatologist to alleviate signs and symptoms, inhibit structural damage, and improve quality of life parameters.
1.3 Patient/client group
All Patients with Psoriatic arthritis.
1.4 Exceptions/ contraindications
Patients with Ankylosing Spondylitis (including axial I spinal PsA) and Rheumatoid arthritis (see separate ICID guidance)
2. Clinical Management
2.1 Staff & equipment
Rheumatology has in place all equipment, staff and necessary skills to diagnose and treat PsA. All consultant clinic rooms have ultrasound machines to detect inflammation in joints, tendons and entheseal sites in early PsA. The Rheumatology multidisciplinary team incorporates nurse specialists, occupational therapists, physiotherapists, pharmacists, orthotists and podiatrists.
The classification and diagnosis of PsA is an area of ongoing international discussion. The original classification of PsA proposed by Moll and Wright (Appendix 1) in 1973 is still commonly used considerable.
The recently developed CASPAR (classification criteria for PsA) criteria (Appendix 2 ) classifies PsA as a disease of established inflammatory arthritis (defined by the presence of tender and swollen joints and prolonged morning or immobility-induced stiffness) combined with a total of at least 3 points from the features listed in Appendix 2. these include having clinically observed Psoriasis, a history of Psoriasis or a family history of Psoriasis. These CASPAR criteria have a specificity of 98.7% and sensitivity of 91.4% for diagnosing PsA.
There are two major patterns of arthritis in PsA: peripheral joint disease, which can be polyarticular or pauciarticular, and skeletal or axial disease. Approximately 95% of patients with PsA have involvement of the peripheral joints, predominantly the polyarticular form, whereas a minority have the oligoarticular form. About 5% of patients have exclusively axial involvement, whereas 20% to 50% of patients have involvement of both the spine and the peripheral joints, with peripheral joint involvement being the predominant pattern.
Both MRI and ultrasound (performed in clinic) will detect erosions and synovitis in joints earlier than plain X-Rays.
Who to Refer
The hallmark of PsA is joint, digit (finger or toe) and tendon swelling associated with pain or stiffness. If present, and affecting either one large joint (knee, hip) or three or more small joints, with early morning stiffness lasting more than 30 minutes and pain on squeezing joint then early referral is recommended. It should be noted that a raised CRP or ESR and positive RF are not necessary to make the diagnosis and the clinical signs may be masked by non-steroidal anti-inflammatories or systemic corticosteroids.
All patients with Psoriasis or a family history of Psoriasis and a good history of inflammatory Arthritis (stiffness in any of joints of hands, wrists, feet, elbows, shoulders, hips and knees lasting more than 30 minutes after awakening).
All patients with Psoriasis or family history of Psoriasis presenting with an enthesitis (Plantar fascitis, epicondylitis or Achilles tendonosis)
All patients with a swollen digit (dactylitis).
Patients with Psoriasis or a family history of Psoriasis and either swollen or painful joints (either subjectively form history or objectively from examination).
What investigations should be ordered
C-reactive protein (CRP): THIS IS OFTEN NORMAL IN PsA
Full blood count, Urea and Electrolytes and Liver function tests
X-rays affected joint (s) (often normal in early disease)
Rheumatoid factor (RF) and Anti-cyclic Citrullinated Peptide (CCP) antibodies
(If either positive than diagnosis is Rheumatoid Arthritis rather than PsA)
Anti nuclear antibodies (ANA)
How to Refer
Patients with suspected Psoriatic arthritis can be referred to Rheumatology through choose and book. The Rapid Access Referral for Inflammatory Arthritis form may be used and can be found on ICID.
Management of Patients with PsA
The management of patients with mild, moderate and severe PsA is summarized in Appendix 3. Management is aimed at early and complete remission (no swollen or tendon joints and maintenance of that remission using a combination of simple anti inflammatories (NSAIDs and COXIBs) escalating as required to DMARDs (Methotrexate, Sulphasalazine, Leflunomide and Hydroxychloroquine) and to Biological therapies (TNF alpha inhibitors, Infliximab, Adalimumab and Etanercept) as per NICE guidance. It is important that patients at risk of developing erosive disease are identified early in order to limit future disability and the need for joint replacement.
2.3 Potential complications / Risk Management
2.4 After care
Assessing disease activity: The most widely used method for assessing peripheral joint disease activity in PsA is the American College of Rheumatology (ACR) joint count, which in some studies has been modified for PsA ,.
Assessing Response to therapy: Two main instruments have been used for measuring clinical response in PsA, the PsARC and the ACR20 (including ACR50 and ACR70).
The PsARC is a response criterion adapted from the Veterans Affairs Cooperative Study of sulphasalazine .
Response is defined as improvement in two factors (with at least one being a joint score) with worsening of none of the following four factors:
patient global assessment (on a 0-5 Likert scale)
physician global assessment (as above) (improvement defined as decrease by at least 1 unit; worsening defined as increase by at least 1 unit)
tender joint score
swollen joint score (improvement defined as decrease of at least 30% worsening defined as an increase of at least 30%).
Quality of life: This is obtained by using the SF-36 General Health Survey.
3. Patient Information
Information on what the patient will experience upon arrival in the Rheumatology clinic may be found on the second sheet of the combined inflammatory arthritis referral form. Arthritis Research Campaign (ARC) information leaflets on PsA and the drugs used in PsA are available in paper form in Rheumatology outpatients and online at http://www.arc.org.uk.
Psoriatic Arthritis Alliance (Patient support group which provides information about the condition and campaigns for increased awareness and better treatment). The link address is: http://www.paalliance.org.uk
4.1 Audit Indicators
Audit management of PsA against NICE guidelines
Audit use of biological agents in the treatment of Psoriatic arthritis
4.2 Audit design
4.3 User Involvement
Audit department and Rheumatology Specialist Registrar
5. Evidence Base
5.1 Sources of information
Shbeeb M, Uramoto KM, Gibson LE, O'Fallon WM, Gabriel SE. The epidemiology of psoriatic arthritis in Olmsted County, Minnesota, USA, 1982 1991. J Rheumatol 2000;27:1247-50.
Gladman DD. Psoriatic arthritis. Baillieres Clin RheumatoI1995;9:319-29.
Gladman DD, Stafford-Brady F, Chang CH, Lewandowski K, Russell ML. Longitudinal study of clinical and radiological progression in psoriatic arthritis. J RheumatoI1990;17:809-12.
McHugh NJ, Balakrishnan C, Jones SM. Progression of peripheral joint disease in psoriatic arthritis. Rheumatology 2003;42:778-83.
Moll JM, Wright V. Psoriatic arthritis. Semin Arthritis Rheum 1973;3:55-78.
Taylor W, Gladman D, Mielants H. Classification criteria for psoriatic arthritis: development of new criteria from a large international study. Arthritis Rheum 2006;54:2665-73.
Mease PJ, Goffe BS, Metz J, VanderStoep A, Finck B, Burge DJ. Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial. Lancet 2000;356:385-90
Mease PJ, Kivitz AJ, Burch FX, et al. Etanercept treatment of psoriatic arthritis: Safety, efficacy, and effect on disease progression. Arthritis Rheum 2004;50:226472.
Clegg DO, Reda DJ, Mejias E et al. Comparison of sulfasalazine and placebo in the treatment of psoriatic arthritis. A Department of Veterans Affairs Cooperative Study. Arthritis Rheum 1996;39:2013-20.
NICE Guidance: The summary of the published technology appraisal on Psoriatic arthritis - etanercept and infliximab. The summary of the published technology appraisal on Psoriatic arthritis (moderate to severe) - adalimumab. http://www.nice.org.uk/nicemedia/live/11582/33404/33404.pdf http:/guidance.nice.org.uk/TA125