[JUVENILE SPONDYLOARTHRITIS]

Juvenile spondyloartrhritis is a group of multifactorial diseases in which a disturbed interplay occurs between the immune system and environmental factors on a predisposing genetic background, which leads to inflammation and structural damage of the target tissue. First symptoms of jSpA rarely involve the spine, while asymmetrical oligoarthritis of lower extremities, dactylitis, and peripheral enthesitis are much more common. There are many classification criteria for jSpA, but the majority of pediatric rheumatologists currently use the International League Against Rheumatism (ILAR) criteria according to which most patients with jSpA are classified into the enthesitis-related arthritis group of juvenile idiopathic arthritis. To meet these criteria, a patient should have arthritis and/or enthesitis, with two or more symptoms such as sacroiliac joint tenderness and/or inflammatory back pain, HLAB27 genotype, HLA B27 genotype-associated disease in a first- or second-degree relative, uveitis, and male sex with eight or more years of age. Therefore, diagnosis is most oft en made only based on clinical examination and medical history. Anti- nuclear antibodies (ANA), rheumatoid factor (RF), and HLA testing with B27, B7, and DR4 alleles are preferred. Since subclinical gut inflammation is present in many patients, it is recommended to check fecal calprotectin levels. In patients with signs of peripheral enthesitis it is warranted to perform power Doppler musculoskeletal ultrasound (PDUS), and in patients with signs of axial involvement radiographic and contrast-enhanced magnetic resonance imaging. Most patients are treated with nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy, while in refractory cases with peripheral disease synthetic disease- modifying antirheumatic drugs (DMARDs), such as sulfasalazine, are used. In patients with axial involvement, biological DMARDs such as adalimumab, infliximab, and etanercept are obligatory. Although a number of studies gave us a good insight into the disease pathogenesis, the response to treatment and prognosis are still difficult to predict.