Background/Purpose: Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis (CRMO), is an autoinflammatory bone disease of unknown cause that can result in persistent bone pain, destruction and pathological fractures. Currently, no guidelines exist in managing patients with CNO. Understanding the practices of pediatric rheumatologists in diagnosing and treating CNO would provide us with important information to refine the diagnostic criteria and guide the development of consensus treatment plans. The objectives of this study were to determine (1) which disease features physicians consider important for ordering a bone biopsy, (2) physicians’ approaches in monitoring disease activity and (3) physicians’ treatment choices.

Methods: After IRB approval, we surveyed members of the Childhood Arthritis and Rheumatology Research Alliance (CARRA) using a web-based questionnaire regarding diagnosis and management of CNO. Data was analyzed using descriptive statistics.

Results: 135 of 369 (38%) members responded to the survey and 124 completed the survey. Thirteen chose an early survey exit point because of lack of experience in managing CNO. 84.2% of responders were pediatric rheumatology attending physicians with 50% of responders having practiced >10 years, and 13.4 % were fellows. The majority of these providers cared for 1-4 patients (70.5%) and diagnosed 0-3 new cases (90.2%) each year. Most providers felt “very or moderately” confident with diagnosing (81.8%) and treating (86.6%) patients with CNO.

Reported bone biopsy frequencies were: never 0%, rarely 11.6%, sometimes 25.6%, often 39.7%, or always 23.1%. The top three reasons for performing a biopsy were constitutional findings (84.8%), unifocal bone lesions (82.6%), and nocturnal bone pain (57.6%). The top three reasons for not performing a biopsy were involvement of typical sites such as the metaphyses of long bones and clavicles (83.5%), presence of multiple bone lesions (79.1%), and presence of conditions known to be associated with CNO, such as psoriasis and inflammatory bowel disease (63.7%). Biopsy sites were usually determined by the orthopedic surgeon or interventional radiologists (67.5%).

Among all imaging modalities, regional MRI and X rays were most commonly used. 36.5% of responders used whole body MRI often or always. 53.3% of responders used imaging regularly to monitor disease activity, 53.1% of which monitored every 6 months and 25% of which obtained imaging every 12 months.

Almost all responders (98.3) routinely prescribed NSAIDs as initial therapy. For patients who failed NSAID treatment, methotrexate (68.6%), TNF inhibitors (66.9%) and bisphosphonates (46.6%) were the next most commonly used treatments. Presence of a spinal lesion increased the use of bisphosphonate treatment.

Conclusion: The diagnostic approach and disease activity monitoring for CNO varied among physicians. NSAIDs remained the first line treatment for CNO. Methotrexate, TNF inhibitors and bisphosphonates were most commonly used after NSAIDs failed. These findings provide important background to move forward with development of consensus treatment plans for CNO.

Funded by NIAMS, Friends of CARRA and the Arthritis Foundation.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/physicians-perspectives-on-the-diagnosis-and-treatment-of-chronic-nonbacterial-osteomyelitis/