Tag Archives: CRMO

Chronic Nonbacterial Osteomyelitis Associated with Pediatric Inflammatory Bowel Disease

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M Matar et al. J Pediatr Gastroenterol Nutr. 2026;82:487–494. Chronic nonbacterial osteomyelitis associated with pediatric inflammatory bowel disease: : A multicenter retrospective study from the Paediatric inflammatory bowel disease Porto Group of ESPGHAN

Methods: Retrospective study with 45 pediatric patients with inflammatory bowel disease (n=32 with Crohn’s disease, n=8 with ulcerative colitis, n=5 with IBD-U)

Key findings:

  • CNO presented in 15 patients (33%) within 3 months of IBD diagnosis, and in additional 20 (44%) patients after IBD diagnosis; in 10 (22%) patients CNO preceded the diagnosis of IBD with a median time 46 (25–248) weeks
  • 11 (24%) subjects displayed at least one additional extra-intestinal manifestations, including arthritis (6, 13%), erythema nodosum (4, 9%), sacro-ileitis (2, 4%), psoriasis (1, 2%), and pyoderma gangrenosum (1, 2%).
  • Complications occurred in six patients and included vertebral collapse, bone fracture, and bone deformity. In eight (18%) subjects vertebral collapse was present already at the time of diagnosis.
  • “While in most patients, diagnosis of CNO was associated with either clinical or laboratory indices of active IBD, especially CD, in some cases, the intestinal disease was quiescent.”
  • “All patients achieved remission of CNO at some point during follow-up, which may support the hypothesis that anti-TNF treatment is unlikely to promote CNO development and does not reinforce the theory of a paradoxical effect that has been suggested by Cordesse et al.22“

My take: This is a useful review highlighting the association of CNO with both active disease and quiescent IBD. The authors argue that their data does not support the development of CNO as a paradoxical effect. I disagree with this premise. Many of the extraintestinal manifestations, that anti-TNF agents can treat, rarely can be caused by them. Besides CNO, paradoxical reactions to anti-TNF agents have included the development of rheumatoid arthritis, psoriasis, hidradenitis suppurativa and autoimmune liver disease.

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Chronic Nonbacterial Osteomyelitis (CNO): What a GI Doctor Should Know

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L Lim et al. The Journal of Pediatrics, Volume 283, 114636. Open Access! Chronic Nonbacterial Osteomyelitis: A Noninfectious Autoinflammatory Disorder of Bone

Prior to this review, I was familiar with the term chronic recurrent multifocal osteomyelitis (CRMO) but not CNO. CRMO is a severe form of CNO, usually characterized by symmetrical inflammatory bone lesions (DY Zhao et al. J Transl Autoimmun 2021; 4:100095. Chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO)).

In this useful review, it is noted that IBD was associated with ~9% of cases of chronic nonbacterial osteomyelitis (CNO).

    Key points:

    • “IBD identified before, during, or after CNO diagnosis, has been well-reported as an associated condition.34-37 A review of cases of CNO with IBD showed that the diagnosis of CNO preceded the diagnosis of IBD in over half of the reported cases.38“
    • “Children with CNO frequently experience a high burden of pain and impaired physical function. CNO can cause permanent deformities in any bone, but especially if there is spinal involvement and diagnosis and treatment are delayed”
    • “Bone biopsies should be performed if there is clinical suspicion of infection or malignancy, although tissue usually is not needed for diagnosis unless the clinical presentation is atypical”
    • “MRI is now the standard imaging test that usually starts with targeted examination of the affected area…A whole-body MRI (WB-MRI) should be considered for all patients with CNO at diagnosis when possible, as it may help support a diagnosis of CNO by detecting additional sites of bone inflammation that may be clinically inapparent, particularly vertebral lesions”
    • “Non-steroidal anti-inflammatory drugs (NSAIDs) are usually first-line treatment for children with CNO, except for those with vertebral lesions, who require systemic treatment… over half of children treated with NSAIDs experience a disease flare within the first 2 years,14 requiring either retreatment with NSAIDs or another systemic medication”
    • “In the presence of vertebral CNO lesions, or after failing NSAID monotherapy, three categories of systemic treatments are recommended by the Childhood Arthritis and Rheumatology Research Alliance (CARRA)56: 1) synthetic DMARDs, 2) bisphosphonates, or 3) tumor necrosis factor-inhibitor (TNFi) biologic agents with or without methotrexate (to prevent the development of antibodies to the drug)”
    • “In practice, TNFi tends to be used more if children also have comorbid conditions for which TNFi already is indicated such as inflammatory arthritis and sacroiliitis,7 IBD,4,72 and psoriasis.4,14,24 “

    My take: Being familiar with CNO is important for GI physicians as it can occur (rarely) in our patients with IBD. Another important caveat, which is not discussed in this review, is that CNO can occur paradoxically due to the use of TNFi treatment.

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    The London Eye. This view makes it look a lot like a bicycle wheel.