Psoriatic Arthritis (PsA) PDF

19 SY PSORIATIC ARTHRITIS MUHANNA KAZEMPOUR MD Psoriatic arthritis refers to an inflammatory musculoskeletal disease that has both autoimmune and autoinflammatory features characteristically occurring in individuals with psoriasis. EPIDEMIOLOGY Recent data suggest that up to 30% of patients w...

19 SY PSORIATIC ARTHRITIS MUHANNA KAZEMPOUR MD Psoriatic arthritis refers to an inflammatory musculoskeletal disease that has both autoimmune and autoinflammatory features characteristically occurring in individuals with psoriasis. EPIDEMIOLOGY Recent data suggest that up to 30% of patients with psoriasis develop PsA. Longer duration and greater severity of psoriasis increase the likelihood of developing PsA. First-degree relatives of PsA patients have an elevated risk for psoriasis, for PsA, and for other forms of SpA. The frequency in men and women is almost equal. The disease can begin in childhood or late in life but typically begins in the fourth or fifth decade, at an average age of 37 years. HLA-C6 is directly associated with psoriasis. HLA-B27 is associated with psoriatic spondylitis. CLINICAL FEATURES In 70% of cases, psoriasis precedes joint disease. In 15% of cases, the two manifestations appear within 1 year of each other. In about 15% of cases, the arthritis precedes the onset of psoriasis and can present a diagnostic challenge. Spectrum of arthropathy in PsA There are five patterns: (1) arthritis of the DIP joints (2) asymmetric oligoarthritis (3) symmetric polyarthritis similar to RA (4) axial involvement (spine and sacroiliac joints) (5) arthritis mutilans, a highly destructive form of the disease. Nail changes in the fingers or toes occur in most patients with PsA. Accompanying nail changes in the affected digits are almost always present. pustular psoriasis is said to be associated with more severe arthritis. Longitudinal ridging Six patterns of nail involvement are identified: ❑Pitting ❑horizontal ridging ❑onycholysis ❑yellowish discoloration of the nail margins ❑dystrophic hyperkeratosis ❑combinations of these findings. Dactylitis and enthesitis are common in PsA and help to distinguish it from other joint disorders. Shortening of digits because of underlying osteolysis is particularly characteristic of PsA, and there is a much greater tendency than in RA. Rapid ankylosis of one or more proximal interphalangeal (PIP) joints early in the course of disease is not uncommon. Joint involvement tends to follow a “ray” distribution, with all of the joints of one finger involved, while sparing adjacent fingers entirely. arthritis mutilans (telescoping”), Back and neck pain and stiffness are also common in PsA. Arthropathy confined to the DIP joints occurs in ~5% of cases.. Extraarticular manifestations Extraarticular and extradermal manifestations are common. Eye involvement, either conjunctivitis or uveitis, is reported. The prevalences of aortic valve insufficiency and heart block are apparently similar to those in AS. LABORATORY FINDINGS There are no laboratory tests diagnostic of PsA. ESR and CRP are elevated in only 30% of patients. A small percentage of patients may have low titers of RF or ANAs. About 10% of patients have anti-CCP antibodies. Uric acid may be elevated in the presence of extensive psoriasis. HLA-B27 is found in 50–70% of patients with axial disease but in ≤20% of patients with only peripheral joint involvement. RADIOGRAPHIC FINDINGS Peripheral and axial arthritis in PsA show several radiographic features that distinguish them from RA and AS, respectively. Characteristics of peripheral PsA include: ❑DIP involvement, including the classic “pencil-in-cup” deformity ❑marginal erosions with adjacent bony proliferation (“whiskering”) ❑small-joint ankylosis ❑osteolysis of phalangeal and metacarpal bone, with telescoping of digits ❑periostitis and proliferative new bone at sites of enthesitis ❑a “ray” distribution of lesions Characteristics of axial PsA that differ from idiopathic AS include: ❑asymmetric sacroiliitis ❑less facet joint arthritis ❑nonmarginal, bulky, “comma”-shaped syndesmophytes that tend to be fewer, less symmetric, and less delicate than the marginal syndesmophytes of AS ❑fluffy hyperperiostosis on anterior vertebral bodies ❑severe cervical spine involvement, with a tendency to atlantoaxial subluxation but relative sparing of the thoracolumbar spine ❑paravertebral ossification DIAGNOSIS Classification criteria for PsA were published in 2006 (Classification of Psoriatic Arthritis [CASPAR] criteria). The sensitivity and specificity of these criteria exceed 90%. TREATMENT-Psoriatic Arthritis Ideally, coordinated therapy is directed at both the skin and joints in PsA, and biologic agents have dramatically facilitated this goal. This was first observed with anti-TNF agents, with prompt and dramatic resolution of both arthritis and skin lesions. Other treatment include : methotrexate, cyclosporine, leflunomide, monoclonal antibodies to IL-17A(secukinumab and ixekizumab), monoclonal antibody to the shared IL-23/IL-12(ustekinumab), an oral JAK inhibitor (tofacitinib) , an oral phosphodiesterase-4 inhibitor (Apremilast)