[Methotrexate in juvenile idiopathic arthritis. Adverse effects and associated factors]. / Metotrexato en artritis idiopática juvenil: efectos adversos y factores asociados.

INTRODUCTION: Methotrexate (MTX) is the drug of choice for juvenile idiopathic arthritis. Its clinical efficacy is limited due to the development of adverse effects (AEs). PATIENTS AND METHODS: A retrospective observational study was conducted on the AEs associated with MTX therapy in children diagnosed with juvenile idiopathic arthritis followed-up in a tertiary hospital between 2008 and 2016. RESULTS: The study included a total of 107 patients, of whom 71 (66.3%) were girls (66.3%). The median age at diagnosis was 6.4 years (IQR 3.1-12.4), with a median follow-up of 45.7 months (IQR 28.8-92.4). There were 48 patients (44.9%) with oligoarthritis, and 26 children (24.3%) with rheumatoid-factor negative polyarthritis. Of these, 52/107 (48.6%) developed AEs, with the most frequent being gastrointestinal symptoms (35.6%) and behavioural problems (35.6%). An age older than 6 years at the beginning of therapy increased the risk of developing AEs, both in the univariate (OR=3.5; 95% CI: 1.5-7.3) and multivariate (12% increase per year) analyses. The doses used, administration route, or International League of Associations for Rheumatology (ILAR) classification, were not associated with the development of AEs. Twenty children required a dosage or route of administration modification, which resolved the AE in 11 (55%) cases. MTX was interrupted due to the development of AEs in 37/107 patients (34.6%), mainly due to increased plasma transaminases (n=14, 37.8%), gastrointestinal symptoms (n=9, 24.3%) and behavioural problems (n=6, 16.3%). CONCLUSIONS: MTX is the therapy of choice for patients with juvenile idiopathic arthritis, but 50% of the children develop some form of AE. Although the AEs are not severe, they lead to interruption of therapy in 35% of the children.

[Characteristics of synovial fluid in patients with juvenile idiopathic arthritis]. / Características del líquido sinovial en pacientes con artritis idiopática juvenil.

INTRODUCTION: Synovial fluid (SF) analysis is an important tool for the diagnosis of patients with juvenile idiopathic arthritis (JIA). PATIENTS AND METHODS: A retrospective analysis was carried out of cytological features of SF samples obtained from patients with JIA during the period 2008-2016. RESULTS: A total of 102 SF samples from 59 patients were analysed. JIA was more common in females (66%). The most frequent form was persistent oligoarticular JIA (52.5%). The median age at onset was 5 years (IQR 2.4-11.8). SF usually showed an inflammatory pattern (median white blood cells count 11,757/mm3; IQR 4,543-18,800), with a predominance of polymorphonuclear (PMN) cells (61%; IQR 30-75). Eight patients (14%) had white blood cells counts of less than 2,000 cells/mm3, with predominance of mononuclear cells (80%), whereas 3 patients (5%) had white blood cells counts higher than 50,000 cells/mm3, with a predominance of PMN cells (90%). Synovial white blood cells count did not show significant differences among the different forms of JIA. The median synovial white blood cells count in ANA-positive patients was 20% lower than in ANA-negative (9,340 vs. 11,600/mm3; P=.23). The proportion of PMN increased with increasing levels of ESR (P<.001) and/or CRP (P=.03). No significant correlation was found between JADAS-10 and synovial white blood cells count (P=.4). SF obtained from different joints in simultaneous arthrocentesis showed a significant correlation P=.001). CONCLUSION: SF from JIA patients usually had inflammatory characteristics, although 19% of the patients showed white blood cells counts below 2,000cells/mm3 or higher than 50,000cells/mm3. SF cell count was non-significantly lower in ANA-positive patients, and the proportion of PMN increased with increasing levels of ESR/CRP.

[Non-bacterial chronic osteomyelitis: Experience in a tertiary hospital]. / Osteomielitis crónica no bacteriana: experiencia en un hospital terciario.

INTRODUCTION: Non-bacterial chronic osteomyelitis (NBCO) is an autoinflammatory disease that presents with recurrent bouts of bone inflammation in the absence of microbiological isolation. It is a diagnosis of exclusion. Its treatment was classically based on the use of non-steroidal anti-inflammatory drugs (NSAIDs) and corticosteroids, although nowadays bisphosphonates or anti-tumour necrosis factor-α (anti-TNF) drugs are frequently used with good results. The objective of the study is to describe our experience in the diagnosis and treatment of patients with NBCO. PATIENTS AND METHODS: Retrospective chart review of patients with NBCO followed up in a tertiary centre between 2008 and 2015. RESULTS: A total of 7 patients with NBCO were recorded. Four were female and the median age was 10 years (IQR 2). The most common complaint was pain that interfered with sleep in 5 of the patients. Six patients had multifocal lesions at diagnosis. Bone biopsy demonstrated neutrophilic or lymphocytic infiltration and sclerosis in 6 patients. Four patients received antibiotics and NSAIDs without clinical response. Five received a short course of prednisone with an adequate control of symptoms, but only one of them maintained remission after corticosteroid suspension. Five patients received bisphosphonates with disease remission in 3 of them. The other 2 showed an inadequate response to pamidronate and were started on anti-TNF therapy (etanercept, infliximab or adalimumab), remaining asymptomatic at present. CONCLUSIONS: Our series, although limited, confirms the effectiveness and safety of bisphosphonate and anti-TNF therapy for children with NBCO.