Spondylarthrite ankylosante et autres spondylarthropathies

Spondylarthropathies (SpAs) refer to a group of inflammatory arthrites that are characterized by their association with HLA B27 and the development of sacroiliitis and enthesitis. SpAs comprise five subtypes: rheumatoid spondylitis, reactive arthritis, psoriatic arthritis, inflammatory bowel disease associated with arthritis/spondylitis and undifferentiated SpA. The prevalence of the whole group of SpAs has been recently estimated between 0.2 and 0.5 % of the general population. Onset is typically in the third and fourth decades of life. Frequently, spontaneous remission can be observed during the course of this disease that can also result in severe disability and loss of quality of life. The main clinical manifestations of enthesitis include inflammatory back pain, sacroiliitis - axial involvement- and also involve symphysis pubis, insertion of the Achilles tendons, plantar fascia and costochondral joints. Although SpA is traditionally considered a disease of the axial skeleton, arthritis of the appendicular skeleton is also common. In case of a patient with inflammatory low back pain and/or enthesitis, clinical examination must screen for personal or family history of SpAs, psoriasis, acne, inflammatory bowel disease, genital infection, uveitis. Serum acute phase reactant increase and antibodies can be absent in SpAs. Even if SpAs are strongly associated with HLA B27, phenotyping is useful only for recent onset diseases and undifferentiated SpA, because almost 10% of the general population has at least a B27 allele. Characteristic structural damages become apparent lately, confirming the diagnosis. Non-steroidal anti-inflammatory drugs (NSAIDs), exercise and physiotherapy are considered the cornerstone of the treatment for patients with SpAs. Pain killers can be associated. Disease modifying antirheumatic drugs (DMARDs) are considered second line treatment but conclusive evidence for the efficacy of these drugs with respect to spinal manifestations is still lacking.