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Psoriatic Arthritis
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The Case: A 44-year-old man presents with a 2-month history of a painful, swollen left finger and a swollen right toe. On physical examination, the left third interphalangeal joint is swollen and tender to palpation and movement. The right third toe has fusiform swelling and is also tender to palpation with impaired range of motion. The nails show pitting and onycholysis (Figure 1).
Key Supporting Information
Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are the two most common forms of chronic inflammatory arthritis. Ankylosing spondylitis (AS) and psoriatic arthritis (PsA) are among the prototypical SpA. Symptoms overlap during the early stages of all three diseases. However, in the absence of effective treatment, a divergent disease course manifests that includes profound peripheral joint and axial skeletal deformities. Although elevated levels of tumor necrosis factor alpha (TNF-a) are common to these diseases, important cellular and genetic differences define their classification and are the basis upon which diagnostic and treatment decisions are made. Early diagnosis and aggressive treatment can improve health outcomes.
Images: Codario RA
Despite progress in understanding the pathophysiology of inflammatory rheumatic diseases, RA, PsA, and AS remain suboptimally diagnosed and managed. It has been reported that 1.5 million adults had RA in the United States (US) in 2007, and the age-adjusted prevalence of SpA by the European Spondyloarthropathy Study Group (ESSG) criteria was 2.7 million people. Symptoms of inflammatory rheumatic diseases overlap in the early stages; however, clinical manifestations become divergent as the disease progresses, with RA characterized by symmetric polyarthritis, PsA by psoriatic skin involvement, and AS with axial involvement. In these disease states, there are profound joint deformities, extra-articular manifestations, functional limitations and a poor impact on quality of life. Specific pathophysiologic differences have been used to develop classification and diagnostic criteria, including the presence of rheumatoid factor in RA and its general absence in SpA, the association of RA with MHC class II molecule HLA-DR4, and SpA with MHC class I molecule HLA-B27. The safety and efficacy of anti-TNF agents in halting disease progression have been demonstrated, and these remain the only biologics that are effective in PsA and AS.
Unlike the unified, validated classification criteria established for RA that can be readily applied in the clinical setting, multiple classification criteria have been developed for PsA (including the Moll and Wright criteria, Bennett’s criteria, and Vasey and Espinoza criteria) and AS (including the modied New York criteria, the Amor criteria, and the ESSG criteria) during the past decade. However, these criteria lacked empirical validation and applicability in the clinical setting, resulting in variation in patients’ diagnoses and confusion among physicians. In recognition of these challenges, the Classification Criteria for Psoriatic Arthritis (CASPAR) was developed for the diagnosis of PsA, and has been further validated by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA). Similarly, the Assessment of Spondyloarthritis International Society (ASAS) criteria for axial SpA is the latest validated criteria for AS. However, the ASAS recommends modification of the criteria to meet the realities of clinical practice in each country and, as such, the U.S. modifications of the ASAS guidelines should be considered for daily practice.
Despite validated classification criteria and diagnostic and assessment tools for RA, PsA and AS, patients with inflammatory rheumatoid disease continue to be suboptimally assessed in clinical practice. Ankylosing spondylitis is often misdiagnosed as “just back pain” or undifferentiated arthritis, taking up to 11 years to diagnose, and subjective assessment continues to be applied to PsA, resulting in up to a 14-year lag from symptom presentation to diagnosis.
Psoriatic arthritis can affect approximately 30% of patients with psoriasis, which is characterized by enthesitis, dactylitis, tenosynovitis, asymmetric oligoarthritis, spondylitis and arthritis of the distal interphalangeal joints (DIPs). Approximately 15% of patients who present with psoriatic arthritis have undiagnosed psoriasis. The nails may show characteristic pitting or onycholysis. Joint pattern of involvement in patients with PsA can involve not only the DIPs, but also symmetric polyarthritis, asymmetric oligoarthritis, arthritis mutilans and spondylitis. Erosive changes of psoriatic arthritis can be associated with the “pencil in cup” deformities of the DIPs of the thumb and middle fingers (Figure 2).
Adherence to medication is essential for optimal disease management. Yet, a Kaiser Permanente Southern California health plan reported adherence rate for first-time etanercept users (n=1,290) was 69% at 1 year, 59% at 2 years and 53% at 3 years. The rates for the adalimumab users (n=382) were 63%, 52% and 46%, respectively. In a 2010 U.S. Medicaid study, 33% of the 1,359 etanercept-treated patients demonstrated greater than 80% adherence to treatment. Poor medication adherence results in poor patient outcomes.
Learning Objectives
Upon successful completion of this educational activity, participants should be better able to evaluate patients for the presence of psoriatic arthritis.
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Overview
Author(s)/Faculty: Ronald A. Codario, MD, FACP, FNLA, RPVI, CCMEP
Source: Healio Rheumatology Education Lab
Type: Monograph
Articles/Items: 7
Release Date: 6/15/2015
Expiration Date: 6/15/2016
Credit Type: CME
Number of Credits: 1
Cost: Free
Provider: Vindico Medical Education
CME Information
Provider Statement: This continuing medical education activity is provided by Vidico Medical Education
Support Statement: No commercial support for this activity.
Target Audience: This activity is designed for this activity is rheumatologists and other health care professionals involved in the treatment of patients with rheumatological disorders.