TY - JOUR T1 - Response to Early-onset Pamidronate Treatment in Chronic Non-Bacterial Osteomyelitis: A Retrospective Single Center Study JF - The Journal of Rheumatology JO - J Rheumatol DO - 10.3899/jrheum.181254 SP - jrheum.181254 AU - Caroline Marie Andreasen AU - Anne Grethe Jurik AU - Mia Glerup AU - Christian Høs AU - Birgitte Mahler AU - Ellen-Margrethe Hauge AU - Troels Herlin Y1 - 2019/04/15 UR - http://www.jrheum.org/content/early/2019/04/09/jrheum.181254.abstract N2 - Objective Chronic non-bacterial osteomyelitis (CNO) is a sterile inflammatory bone disorder with an unpredictable course of disease. The aim of the present study was to assess clinical and radiological disease activity in children with CNO including response to early-onset pamidronate treatment in CNO. Methods We conducted a single center retrospective study of children fulfilling the Bristol Criteria for CNO. At the time of diagnosis, whole-body MRI (WBMRI) or local MRI was performed to assess radiological disease activity. Children with multifocal or spinal bone inflammation and clinical disease activity not responding to NSAIDs were categorized as having extended CNO. Clinical disease activity was assessed annually. Results Fifty-one children were included. Median follow-up time was 4 [IQR 3-7] years. Children categorized with extended CNO (n=32) were treated in an early onset two-year pamidronate regimen. In extended CNO, WBMRI was performed at time of diagnosis, at year one and two in 88%, 84% and 91% of cases, respectively. During the first year, number of bone lesions per patient and spinal bone lesions declined significantly. After one year of treatment, 12/32 children presented with clinically inactive disease; 8/12 children experienced clinical relapse. In limited CNO (n=19), 10/19 children on medication and 10/17 children off medication presented with clinically inactive disease after two years. Conclusion Pamidronate might contribute to improvement in clinical and radiological disease activity in extended CNO, especially after one year of treatment. However, children with continuously active disease after two years of pamidronate treatment were seen. ER -