For diseases caused by calcium pyrophosphate deposition (CPPD), validated classification criteria were previously lacking. In this article the recently developed and validated classification criteria are translated, explained, and assessed. In recent years a multinational research group developed classification criteria for CPPD disease with the support by the European Alliance of Associations for Rheumatology (EULAR) and the American College of Rheumatology (ACR), following an established method. The developed criteria were finally validated in an independent cohort. The translation and annotation of the new first classification criteria were carried out in an iterative procedure in consensus with the authors. The presence of a crowned dens syndrome or calcium pyrophosphate crystals in the synovial fluid in patients with pain, swelling or sensitivity of the joints (entry criterion) is sufficient for the classification as CPPD disease, where the symptoms cannot be completely explained by another rheumatic disease (exclusion criterion). If these symptoms are not present, a count of more than 56 points based on weighted criteria comprised of clinical features and the results of laboratory and imaging investigations can be included for classification as a CPPD disease. These criteria had a sensitivity of 92.2% and a specificity of 87.9% in the derivation cohorts (190 CPPD cases and 148 mimics), whereas the sensitivity was 99.2% and the specificity 92.5% in the validation cohorts (251 CPPD cases and 162 mimics). The ACR/EULAR classification criteria 2023 of a CPPD disease will facilitate clinical research in this field. The use in the clinical routine will show how practical the criteria are.

Polymyalgia rheumatica is the second most frequent inflammatory rheumatic disease in people aged over 50years, after rheumatoid arthritis. It is characterized by pain and morning stiffness in the region of the shoulders, hip girdle and neck. It can be associated with giant cell arteritis (CGA). Treatment with glucocorticoids is indispensable. The duration of treatment varies and often exceeds 1year. The additive administration of methotrexate is an option for saving glucocorticoids. The biologicals tocilizumab or secukinumab are very promising alternatives. The course of treatment should be closely monitored for inflammation parameters, glucocorticoid side effects, pain, visual acuity, depression, activities of daily living and especially related to functions of the upper extremities. The geriatric assessment plays an important role in the management of this condition.

The aims of the PROKIND protocols are improvement and harmonization of the diagnostics, monitoring, treatment decision and prognosis. This article reports the results of a prospective treat-to-target observational study of patients with polyarticular juvenile idiopathic arthritis (JIA) during the first year of treatment. Disease activity was assessed with the 10-joint juvenile arthritis disease activity score (JADAS-10), functional limitation with the childhood health assessment questionnaire disability index (CHAQ-DI) and with information on overall well-being, on pain, on fatigue and on global estimation of disease activity. Overall, 129 patients with polyarticular JIA (rheumatoid factor, RF, positive (+) polyarthritis n = 22, RF negative (-) polyarthritis n = 133 from 23pediatric rheumatology institutions in Germany and Austria were recruited. Patients with initial treatment with methotrexate formed cohort1, patients with additional repeated intravenous corticosteroid pulse therapy formed cohort2 and patients with concomitant intra-articular corticosteroid administration in at least 5joints formed cohort3. The mean JADAS10 showed adecrease in disease activity from 16.4 ± 6.1 to 2.8 ± 3.6 and the decrease in the CHAQ-DI from 1.0 ± 0.8 to 0.3 ± 0.5 showed the improvement in functional capacity. Similarly, improvements in quality of life, pain and fatigue were demonstrable. A JADAS inactive disease was achieved by 18.1% at month3, 47.7% at month6 and66.7% at month12. In cohort 1 a JADAS remission was achieved by 72.4%, by 50% in cohort 2 and by 69.2% in cohort 3. An escalation to treatment with biologics was necessary in 38% of patients in cohort 1, 60% in cohort 2 and 46% in cohort 3. Using atreat-to-target approach a dramatic improvement in disease activity, functional capacity and quality of life in polyarticular JIA could be achieved. Even after 12months an inactive disease was achieved in the majority of cases.

Juvenile dermatomyositis (JDM) is by far the most frequent inflammatory myopathy in childhood and adolescence. It is clinically characterized by inflammatory changes of the skin and muscles but as amultisystemic disease can also affect the skeletal system, the gastrointestinal tract, lungs and heart. Intrinsic (multigenetic risk) and extrinsic factors (triggers) are involved in the pathogenesis resulting in endothelial damage, involvement of fascies, activation of the interferon system and autoimmune reactions including formation of myositis-specific autoantibodies (MSA). In contrast to dermatomyositis in adults, in children and adolescents there are no associations with malignant diseases. The variable expression, the rarity of the disease and the risk of long-term damage and complications necessitate pediatric rheumatological experience in the diagnostics and treatment. Recently, new approaches in drug treatment have substantially improved the outcome and prognosis but amultidisciplinary treatment (including physicians, physiotherapists, psychologists, social workers) is mandatory, especially in the first phases of the disease. Particularly important is aprofessionally correct treatment of the functional sequelae, which are aparticular focus of this article.

The ability to visualize the nerves of the lower extremities differs from that of the upper extremities in sonography because the soft tissue cover is significantly larger in some cases. Landmarks are also defined for the lower extremities, which enable precise visualization of the nerves. Nerves and muscles are to be understood as afunctional unit. In addition to the clarification of nerve compression syndromes, polyneuropathies and nerve tumors, sonography is also used to visualize muscle atrophy.