RT Journal Article SR Electronic T1 Response to Early-onset Pamidronate Treatment in Chronic Nonbacterial Osteomyelitis: A Retrospective Single-center Study JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP 1515 OP 1523 DO 10.3899/jrheum.181254 VO 46 IS 11 A1 Caroline Marie Andreasen A1 Anne Grethe Jurik A1 Mia B. Glerup A1 Christian Høst A1 Birgitte T. Mahler A1 Ellen-Margrethe Hauge A1 Troels Herlin YR 2019 UL http://www.jrheum.org/content/46/11/1515.abstract AB Objectives. Chronic nonbacterial osteomyelitis (CNO) is a sterile inflammatory bone disorder with an unpredictable disease course. The objective was to assess clinical and radiological disease activity in children with CNO including response to early-onset pamidronate treatment.Methods. A single-center retrospective study was conducted of children fulfilling the Bristol Criteria for CNO. At the time of diagnosis, whole-body magnetic resonance imaging (WB-MRI) or local MRI was performed to assess radiological disease activity. Children with multifocal or spinal bone inflammation and clinical disease activity not responding to nonsteroidal antiinflammatory drugs were categorized as having extended CNO. Clinical disease activity was assessed annually.Results. Fifty-one children were included. Median followup time was 4 years (interquartile range 3–7). Children categorized with extended CNO (n = 32) were treated in an early-onset 2-year pamidronate regimen. In extended CNO, WB-MRI was performed at time of diagnosis, and at years 1 and 2 in 88%, 84%, and 91% of cases, respectively. During the first year, the total number of radiologically active lesions and number of spinal lesions per patient declined (p = 0.01). Clinically inactive disease was recorded in 12/32 children (38%). However, 8/12 children (67%) experienced clinical relapse. In limited CNO (n = 19), 10/19 children (53%) presented with clinically inactive disease after 1 year and did not experience clinical relapse.Conclusion. Pamidronate might contribute to improvement in clinical and radiological disease activity in extended CNO, especially after 1 year of treatment. However, children with continuously active disease after 2 years of pamidronate treatment were seen.