BackgroundChronic Musculoskeletal Pain (MSP) in children can be due to non-inflammatory conditions, such as the benign joint hypermobility syndrome (BJHS) or idiopathic MSP (IMSP). Aim of the study was to evaluate type and persistence of MSP in a cohort of schoolchildren with MSP followed for 3 years, in order to identify the main risk factors.MethodsHealthy schoolchildren, aged 8–13 years, underwent a general and rheumatologic examination, focusing on presence of chronic MSP, defined as continuous or recurrent pain lasting more than 3 months and heavily interfering with daily life activities, presence of generalized joint hypermobility, the body mass index and the pubertal stage. All symptomatic subjects were re-evaluated 3 years later with the same methods.ResultsSeventy of the 88 symptomatic subjects of the initial cohort of 289 were re-evaluated 3 years later. Of these, 38 (54.3 %) still presented MSP, including 19 with BJHS and 19 with IMSP. Main symptoms were lower limbs arthralgia and myalgia. MSP persisted more in females than in males (p = 0.038) and in pubertal rather than pre-pubertal subjects (p = 0.022); these subjects recovered significantly more both from BJHS (p = 0.004) and IMSP (p = 0.016). Gender did not influence the distribution of MSP according to pubertal stage.ConclusionsFemale gender, BJHS and pubertal stage are important risk factors for persistence of MSP. Further studies are needed to evaluate the natural history of MSP towards adulthood and the role of the pubertal age.

ANA prevalence and titers increase during puberty, especially in females, but have no relationship with chronic noninflammatory MSP. This finding may be related to the complex hormonal changes during the puberty switch period and opens new insights into autoimmunity.

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Background Dry synovitis (DS) is a rare entity as only a few cases have been reported to date. We describe the clinical features, radiological manifestations and course of DS in comparison with rheumatoid factor negative polyarticular juvenile idiopathic arthritis (RFneg-polyJIA). Methods We performed a multicenter retrospective collection of data of DS patients who presented with progressive joint limitations without palpable synovitis, absence of elevated acute phase reactants, negative ANA and RF, and imaging showing joint and/or osteochondral involvement. For comparative purposes, we included a cohort of RF neg-polyJIA patients. Results Twelve DS patients, 8F/4 M, with mean age at onset of 6.1 years, were included. Presenting signs comprised delayed motor development, functional limitations and/or progressive stiffness. Clinical examination showed symmetric polyarticular involvement with variable muscular atrophy. MRI showed mild, diffuse synovial involvement, without effusion. With time, signs of progressive osteochondral damage became evident, despite treatment. All patients were treated with low-dose corticosteroids and methotrexate. Anti-TNF agents were prescribed in five. The response was variable with limited joint mobility in 11/12, and need of joint replacement in 2. In comparison with a cohort of RFneg-polyJIA, DS patients presented higher number of joint involved (p = 0.0001) and contractures (p = 0.0001), less swelling (p = 0.0001) and prolonged diagnostic delay (p = 0.0001). Conclusion DS represents a unique juvenile-onset arthropathy, distinct from polyarticular JIA. Awareness among pediatricians is essential for early recognition and proper treatment. Further studies, including synovial pathology, immunology and genetics may contribute to a better understanding of this rare disorder of childhood.

Background Dry synovitis (DS) is considered to be a rare form of juvenile idiopathic arthritis (JIA), incompletely understood and following a potentially destructive course. Since its first description only a few reports mention this entity within the spectrum of JIA. Objectives To describe the clinical and radiological manifestations and clinical course of DS and to compare it with classic polyarticular RF negative JIA (c-poly JIA). Methods We performed a retrospective study of 10 patients followed in 3 pediatric rheumatology centers who presented with progressive articular limitations without clinical synovitis and radiologic signs of articular damage. This cohort was compared with a cohort of 35 consecutive patients with classical polyarticular RF negative JIA, seen at the Pediatric Rheumatology Unit of Padua in the period January-June 2012. Clinical, laboratory and imaging (X-rays, MRI) data of both groups were reviewed and compared. Treatment was grouped in 4 categories: no treatment, just corticosteroids (CS), Methotrexate (MTX) + CS, Biological agents (BA) + MTX. Outcome measures included growth, remission state as: clinical remission without medication (CR), clinical remission on medication (CRM), progressive arthropathy with mild functional disability (PA), severe arthropathy with ankylosis and irreversible disability (SA). Results The cohort included 4 male and 6 female, mean (range) age at first manifestation and diagnosis were respectively 4.3 yrs (1.3-8.5) and 7.3 yr (2.8-14). Presenting signs included delayed motor development, progressive articular stiffness and contractures. Little or no pain was present. Clinical examination showed a symmetric and polyarticular involvement without clinical signs of synovitis. CRP was normal in all and ESR>20mm/h in 1/10. In 9/10 patients ANA were absent. Radiological imaging showed osteopenia and/or erosions in all patients. MRI revealed synovial thickening in 9/10 patients; bone edema was variably present and bone erosions were demonstrated in 8/10 patients. Treatments comprised NSAIDs (n=8/10), corticosteroids (n=8/10), methotrexate (n=9/10), biological agents (anti-TNF, IL-RA) (n=6/10). The comparison of DS with c-poly JIA showed that the age at disease onset and at diagnosis were comparable in the two groups. Significant differential features of DS resulted: higher diagnostic delay, increased number of joint involved and joint contractures, lack of swelling/tenderness, prevalent upper limbs involvement, lack of acute phase reactants (ESR, CRP) and no ANA detection. X-ray revealed a significant higher prevalence of osteopenia, erosions and bone edema at MRI in DS. At the last evaluation 77% of patients with c-poly JIA were in CR or CRM while 50% of DS had PA. Growth was significantly impaired in DS (p 0.016). Conclusions Dry Synovitis is actually considered as a subtype of polyarticular JIA. Our study clearly shows that it represents a distinct and unique entity characterized by increased number of joint involved and contractures, prevalent upper limb...