Psoriatic arthritis

Psoriatic arthritis is the inflammatory condition of the joints associated with psoriasis. For the diagnosis of psoriatic arthritis, it is a necessary prerequisite to be seronegative (i.e. that patients do not have rheumatoid factor or other auto-antibodies) and that no data is suggestive of rheumatoid arthritis.

The prevalence of psoriasis is approximately 1 to 3%. Of this population, between 5 to 10% suffer arthritis.). It is unclear why there is an association between arthritis and psoriasis. However, we know the importance played by cytokines, particularly the tumor necrosis factor.

Based on the manifestations of the disease, the following patterns are considered:
Asymmetric oligoarticular forms up to 50% of cases. It mainly affects proximal and distal joints (fingers). It is considered that a maximum of 5 affected joints are needed for a diagnostic criterion. Usually have a preference for the lower extremities; Similar to seronegative rheumatoid arthritis (no rheumatoid factor) with a more benign prognosis and more durable remissions. It is a symmetrical polyarthritis, with possible involvement of the spine;
Distal form: almost path gnomonic (exclusive) of psoriasis, but very rare. Almost always associated with psoriasis of the nails; Peripherally, with or without sacroiliitis spondylitis; Sacroiliitis or ankylosing spondylitis: with or without peripheral joint disease.

The diagnosis is mainly clinical, because analytics are non specific and alter only in severe cases. Synovial fluid analysis, although it is inflammatory, is also non specific.
Radiology is normal, at least until the process is well advanced, which is when signs like the following occur:

There may be a characteristic sign, called a ‘pencil in cup’ in the distal interphalangeal joints (distal narrowing and widening proximal); Bony ankylosis, especially in the fingers; Juxtaarticular Osteoporosis is less obvious than in rheumatoid arthritis. The condition of the spine is more common than in other pathologies, but differs in that it is asymmetric.

And sometimes syndesmophytes appear, but it also differs from other types of arthritis and usually involves only 2 or 3 vertebrae, beginning at the cervical region where it is not progressive.

The treatment of skin lesions is the same as any psoriasis. For joint symptoms are recommended. General measures such as physiotherapy and postural YEAR, which aims to: Encourage the extensor muscles of the back; Maintain the functionality of the large joints, most important for everyday life; Sleep on hard mattress with thin or no pillow can be helpful.

The so-called disease-modifying drugs (DMARDs) such as methotrexate and salazoprina are indicated in ankylosing spondylitis, especially if peripheral. It could be tested with retinoids and cyclosporin A, and anti-TNF biologic therapy (abciximab). Biological therapy involves the use of inhibitors of tumor necrosis factor (TNF).

TNF is a cytokine involved in the natural inflammatory and normal immune responses. It has been shown that the first fully human monoclonal antibody produced by recombinant DNA technology enables the reduction of signs and symptoms of active arthritis in patients with psoriatic arthritis, whether given as monotherapy or in combination with ARME agents.

Adalimumab binds specifically to TNF (tumor necrosis factor alpha) but not to lymphotoxin (TNF-beta) and neutralizes the biological function of this by blocking its interaction with the p55 and p75 for TNF in the cell surface.