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PubMed This is a summary of 65 peer-reviewed journal articles Updated
Pediatric Rheumatology · Chronic Nonbacterial Osteomyelitis

Chronic Nonbacterial Osteomyelitis (CNO) / Chronic Recurrent Multifocal Osteomyelitis (CRMO): A Patient Guide

At a Glance

CNO/CRMO is a noninfectious immune-related bone disease in children. Diagnosis requires ruling out infection and bone cancer, while whole-body MRI and tailored treatment help find silent inflammation, protect the skeleton, and monitor remission.

Learning that your child has Chronic Nonbacterial Osteomyelitis (CNO), also known as Chronic Recurrent Multifocal Osteomyelitis (CRMO), often marks the end of a long and confusing search for answers. This rare condition is a sterile, autoinflammatory bone disease, which means the body’s innate immune system mistakenly attacks healthy bone tissue as if it were an infection [1][2]. Primarily affecting children and adolescents, CNO creates areas of painful inflammation without the presence of bacteria, viruses, or fungi [3][4]. It is not contagious, and it is not caused by anything you or your child did.

Because CNO is a “diagnosis of exclusion,” your medical team’s first priority is ruling out look-alike conditions that require very different treatments, such as bacterial infections or bone cancers [5][6]. This process can be stressful, but it is a vital step in ensuring your child receives the correct care. Once other possibilities are cleared, a specialized Whole-Body MRI (WB-MRI) is frequently used as a highly valuable tool for managing the disease [7]. This imaging is essential because CNO is often “multifocal,” meaning it can hide in several bones at once. Children frequently have “silent” lesions—areas of inflammation that show up on a scan even if the child feels no pain in that specific spot [8][9].

Managing CNO is a proactive process designed to protect your child’s skeleton from permanent damage. While treatment often begins with Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), many children require an escalation to more specialized medications, such as biologics or bisphosphonates, to fully control the inflammation [10][11]. This is especially important when the spine is involved, as uncontrolled inflammation in the vertebrae can lead to structural changes over time [12][13]. By following standardized treatment options, doctors can tailor the approach to your child’s unique needs and symptoms.

The journey with CNO requires long-term vigilance and a strong partnership with a pediatric rheumatology team. A key challenge of this condition is that clinical remission—when your child feels great and has no pain—does not always mean the disease is gone [13][14]. Radiological remission, where active inflammation is no longer visible on an MRI, is a common goal for protecting long-term bone health, though doctors understand that residual MRI signal is not always damaging inflammation [13]. While relapses can happen, the combination of modern imaging and targeted therapies allows most children to live active, full lives while keeping the active inflammation under control [15][16].

In this guide

5 chapters

01

Getting Your Bearings: What is CNO/CRMO?

Learn what CNO and CRMO mean, how sterile bone inflammation differs from infection, who is affected, and what associated conditions doctors may check for.

02

The Path to a Diagnosis: Ruling Out the Look-Alikes

Learn how doctors diagnose chronic nonbacterial osteomyelitis in children, use whole-body MRI, decide on biopsy, and rule out infection, cancer, and mimics.

03

Treatment Pathways: Managing Inflammation and Protecting Bone

Learn how CNO/CRMO treatment reduces inflammation, protects the spine, and guides decisions about NSAIDs, steroids, biologics, bisphosphonates, and DMARDs.

04

Long-Term Monitoring: Beyond the Pain

Learn how chronic nonbacterial osteomyelitis follow-up uses MRI to assess remission, detect relapse, and monitor spinal or growth complications in children.

05

Navigating Daily Life: Your Care Team and School Plan

Learn to manage chronic nonbacterial osteomyelitis with a coordinated care team, school accommodations, medication monitoring, and urgent warning signs.

Common questions in this guide

What is the difference between CNO and CRMO?
CNO and CRMO are names used for the same type of sterile, nonbacterial bone inflammation. CRMO often emphasizes inflammation that affects multiple bone sites or returns over time, while CNO is the broader term.
How is CNO diagnosed if it is not an infection?
CNO is diagnosed after doctors carefully rule out conditions that can look similar, especially bacterial bone infection and bone cancer. A whole-body MRI can show inflamed areas in several bones, including lesions that do not cause noticeable pain.
Why does my child need a whole-body MRI for CNO?
CNO can affect more than one bone, and some inflamed areas may be silent, meaning they cause no symptoms. Whole-body MRI helps the medical team find these areas and monitor whether inflammation is still active.
How is CNO treated in children?
Treatment often starts with nonsteroidal anti-inflammatory drugs, also called NSAIDs. If inflammation is not adequately controlled, doctors may consider biologic medicines or bisphosphonates and tailor treatment to the child’s symptoms and affected bones.
Can CNO affect the spine or cause lasting bone problems?
Yes, inflammation in the vertebrae can lead to structural changes if it remains uncontrolled. Regular monitoring and treatment aim to control inflammation and protect the growing skeleton.
Does feeling better mean my child’s CNO is gone?
Not always. A child may have no pain while an MRI still shows active inflammation, so doctors consider both symptoms and imaging when assessing remission and deciding whether treatment should change.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is the most likely long-term outlook for my child's specific case of CNO?
  2. 2.How do you coordinate with the radiologist to ensure they are looking for the 'silent' lesions typical of this condition?
  3. 3.If my child enters clinical remission, how will you decide when it is safe to reduce or stop their medications?
  4. 4.Is our local hospital equipped to perform the specific type of Whole-Body MRI needed for monitoring?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (16)
  1. 1

    Chronic Nonbacterial Osteomyelitis in Children.

    Koryllou A, Mejbri M, Theodoropoulou K, et al.

    Children (Basel, Switzerland) 2021; (8(7)) doi:10.3390/children8070551.

    PMID: 34202154
  2. 2

    Clinical heterogeneity in paediatric patients with chronic nonbacterial osteomyelitis and chronic recurrent multifocal osteomyelitis.

    Shimomura H, Takahashi K, Ueki M, et al.

    Modern rheumatology case reports 2026; (10(2)) doi:10.1093/mrcr/rxag049.

    PMID: 42335002
  3. 3

    CD14+ monocytes contribute to inflammation in chronic nonbacterial osteomyelitis (CNO) through increased NLRP3 inflammasome expression.

    Brandt D, Sohr E, Pablik J, et al.

    Clinical immunology (Orlando, Fla.) 2018; (196()):77-84 doi:10.1016/j.clim.2018.04.011.

    PMID: 29723617
  4. 4

    The multifaceted presentation of chronic recurrent multifocal osteomyelitis: a series of 486 cases from the Eurofever international registry.

    Girschick H, Finetti M, Orlando F, et al.

    Rheumatology (Oxford, England) 2018; (57(7)):1203-1211 doi:10.1093/rheumatology/key058.

    PMID: 29596638
  5. 5

    Diagnosis, treatment and monitoring of chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO) - Evidence, practice and consensus-based recommendations from the German pediatric rheumatology society (GKJR).

    Schnabel A, Reiser C, Beer M, et al.

    Autoimmunity reviews 2026; (25(7)):104075 doi:10.1016/j.autrev.2026.104075.

    PMID: 42155695
  6. 6

    An Update on the Pathogenesis and Treatment of Chronic Recurrent Multifocal Osteomyelitis in Children.

    Taddio A, Zennaro F, Pastore S, Cimaz R

    Paediatric drugs 2017; (19(3)):165-172 doi:10.1007/s40272-017-0226-4.

    PMID: 28401420
  7. 7

    MRI in the Diagnosis and Treatment Response Assessment of Chronic Nonbacterial Osteomyelitis in Children and Adolescents.

    Aydıngöz Ü, Yıldız AE

    Current rheumatology reports 2022; (24(2)):27-39 doi:10.1007/s11926-022-01053-x.

    PMID: 35133566
  8. 8

    Retrospective Review of 80 Patients with Chronic Recurrent Multifocal Osteomyelitis Evaluated by Pediatric Orthopaedic Surgeons.

    Taylor TN, Bridges CS, Ezeokoli EU, et al.

    Journal of the Pediatric Orthopaedic Society of North America 2023; (5(1)):575 doi:10.55275/JPOSNA-2023-575.

    PMID: 40433082
  9. 9

    Chronic nonbacterial osteomyelitis: the role of whole-body MRI.

    Nico MAC, Araújo FF, Guimarães JB, et al.

    Insights into imaging 2022; (13(1)):149 doi:10.1186/s13244-022-01288-3.

    PMID: 36114435
  10. 10

    Consensus Treatment Plans for Chronic Nonbacterial Osteomyelitis Refractory to Nonsteroidal Antiinflammatory Drugs and/or With Active Spinal Lesions.

    Zhao Y, Wu EY, Oliver MS, et al.

    Arthritis care & research 2018; (70(8)):1228-1237 doi:10.1002/acr.23462.

    PMID: 29112802
  11. 11

    Spine Involvement and Vertebral Deformity in Patients Diagnosed with Chronic Recurrent Multifocal Osteomyelitis.

    Rogers ND, Trizno AA, Joyce CD, et al.

    Journal of pediatric orthopedics 2024; (44(9)):561-566 doi:10.1097/BPO.0000000000002743.

    PMID: 38881233
  12. 12

    MRI features of spinal chronic recurrent multifocal osteomyelitis/chronic non-bacterial osteomyelitis in children.

    Guariento A, Sharma P, Andronikou S

    Pediatric radiology 2023; (53(10)):2092-2103 doi:10.1007/s00247-023-05688-5.

    PMID: 37204463
  13. 13

    Whole-body Magnetic Resonance Imaging in Chronic Recurrent Multifocal Osteomyelitis: Clinical Longterm Assessment May Underestimate Activity.

    Voit AM, Arnoldi AP, Douis H, et al.

    The Journal of rheumatology 2015; (42(8)):1455-62 doi:10.3899/jrheum.141026.

    PMID: 25979713
  14. 14

    Image-Based Assessment of Anti-TNF Treatment Outcomes in Pediatric CRMO/CNO: A Single-Center Case Series.

    Houston IG, Heitzmann MD, Robbins RC, et al.

    Children (Basel, Switzerland) 2026; (13(8)) doi:10.3390/children13081041.

    PMID: 42650379
  15. 15

    Response to Early-onset Pamidronate Treatment in Chronic Nonbacterial Osteomyelitis: A Retrospective Single-center Study.

    Andreasen CM, Jurik AG, Glerup MB, et al.

    The Journal of rheumatology 2019; (46(11)):1515-1523 doi:10.3899/jrheum.181254.

    PMID: 30988129
  16. 16

    Aggressive Therapy Reduces Disease Activity without Skeletal Damage Progression in Chronic Nonbacterial Osteomyelitis.

    Zhao Y, Chauvin NA, Jaramillo D, Burnham JM

    The Journal of rheumatology 2015; (42(7)):1245-51 doi:10.3899/jrheum.141138.

    PMID: 25979712

This page is for informational purposes only and does not constitute medical advice. Your child’s pediatric rheumatology team should interpret scans and guide treatment decisions for CNO/CRMO.

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