Physicians' Perspectives on the Diagnosis and Treatment of Chronic Nonbacterial Osteomyelitis

Chronic Nonbacterial Osteomyelitis in Inflammatory Bowel Disease

Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis (CRMO), is a rare autoinflammatory bone disease primarily affecting children and adolescents. This review presents a comprehensive analysis of the intricate relationship between CNO and inflammatory bowel disease (IBD), shedding light on shared pathophysiological mechanisms and clinical management. A thorough literature review was conducted, encompassing 24 case reports involving 40 patients. The demographic distribution of patients revealed a near-equal gender ratio, with a median age of diagnosis at 12 years. The diagnosis patterns showed a higher proportion of CNO as the initial diagnosis, while Crohn's disease was more prevalent than ulcerative colitis. The time interval between the clinical presentations varied, ranging from simultaneous detection to a substantial 15-year gap. Treatment modalities included nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, aminosalicylates, and biologic agents, such as infliximab, often overlapping in their use and suggesting shared pathophysiological pathways. Both conditions displayed systemic manifestations, and patients often responded well to immunosuppressive medications. The pathophysiology of CNO involves a genetic predisposition, cytokine dysregulation, and osteoclast activation. Dysregulated innate immunity results in immune cell infiltration into bones, causing sterile bone lesions. Notably, emerging evidence hints at a potential link between the microbiome and CNO. In contrast, IBD results from imbalanced mucosal immune responses to the intestinal microbiota. Polymorphisms in the promotor region of IL-10, common cytokines, immune cells, and genetic markers indicate shared immunological and genetic factors between CNO and IBD. Both conditions also involve extraintestinal symptoms. This analysis underscores the need for clinical awareness of the co-occurrence of CNO and IBD, especially among pediatric patients. A deepened understanding of the connections between these seemingly distinct diseases could lead to more effective management and improved patient outcomes.

Feasibility of Conducting Comparative Effectiveness Research and Validation of a Clinical Disease Activity Score for Chronic Nonbacterial Osteomyelitis

OBJECTIVE

Prospective comparative effectiveness research (CER) in chronic nonbacterial osteomyelitis (CNO) is lacking. Our objectives were to (1) determine the use and safety of each consensus treatment plan (CTP) regimen for CNO, (2) assess the feasibility of using the Chronic Nonbacterial Osteomyelitis International Registry (CHOIR) data for CER, and (3) develop and validate a CNO clinical disease activity score (CDAS) using CHOIR.

METHODS

Consenting children or young adults with CNO were enrolled into CHOIR. Demographic, clinical, and imaging data were prospectively collected. The CNO CDAS was developed through a Delphi survey and nominal group technique. External validation surveys were administered to CHOIR participants.

RESULTS

One hundred forty (78.2%) CHOIR participants enrolled between August 2018 and September 2020 received at least 1 CTP regimen. Baseline characteristics from different CTP groups were well matched. Patient pain, patient global assessment, and clinical CNO lesion count were key variables included in the CNO CDAS. The CDAS showed a strong correlation with patient/parent report of difficulty using a limb, back, or jaw and patient/parent report of disease severity, but a weak correlation with patient/parent report of fatigue, sadness, and worry. The change in CDAS was significant in patients reporting disease worsening or improvement (P < 0.001). The CDAS significantly decreased after initiating second-line treatments from median 12.0 (IQR 8.0-15.5) to 5.0 (IQR 3.0-12.0; P = 0.002). Although second-line treatments were well tolerated, psoriasis was the most common adverse event.

CONCLUSION

The CNO CDAS was developed and validated for disease monitoring and assessment of treatment effectiveness. CHOIR provided a comprehensive framework for future CER.

Diagnostic and therapeutic practices in adult chronic nonbacterial osteomyelitis (CNO)

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is a rare, and impactful auto-inflammatory bone disease occurring in children and adults. Clinical care for CNO is challenging, as the condition lacks validated classification criteria and evidence-based therapies. This study aimed to map the current diagnostic and therapeutic practices for CNO in adults, as a first step towards a standardized disease definition and future consensus treatment plans.

METHODS

A primary survey was spread among global rheumatological/bone networks and 57 experts as identified from literature (May 2022), covering terminology, diagnostic tools (clinical, radiological, biochemical) and treatment steps. A secondary survey (sent to primary survey responders in August 2022) further queried key diagnostic features, treatment motivations, disease activity and treatment response monitoring.

RESULTS

36 and 23 physicians completed the primary and secondary survey respectively. Diagnosis was mainly based on individual physician assessment, in which the combination of chronic relapsing-remitting bone pain with radiologically-proven osteitis/osteomyelitis, sclerosis, hyperostosis and increased isotope uptake on bone scintigraphy were reported indicative of CNO. Physicians appeared more likely to refer to the condition as synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome in the presence of joint and skin pathology. MRI was most frequently performed, and the preferred diagnostic test for 47%. X-rays were second-most frequently used, although considered least informative of all available tools. Typical imaging features reported were hyperostosis, osteitis, osteosclerosis, bone marrow edema, while degeneration, soft tissue calcification, and ankylosis were not regarded characteristic. Inflammation markers and bone markers were generally regarded unhelpful for diagnostic and monitoring purposes and physicians infrequently performed bone biopsies. Management strategies diverged, including indications for treatment, response monitoring and declaration of remission. Step-1 treatment consisted of non-steroidal anti-inflammatory drugs/COX-2 inhibitors (83%). Common step 2-3 treatments were pamidronate, methotrexate, and TNF-a-inhibition (anti-TNFα), the latter two regarded especially convenient to co-target extra-skeletal inflammation in SAPHO syndrome. Overall pamidronate and anti-TNFα and were considered the most effective treatments.

CONCLUSIONS

Following from our survey data, adult CNO is a broad and insufficiently characterized disease spectrum, including extra-osseous features. MRI is the favoured imaging diagnostic, and management strategies vary significantly. Overall, pamidronate and anti-TNFα are regarded most successful. The results lay out current practices for adult CNO, which may serve as backbone for a future consensus clinical guideline.

Update on treatment responses and outcome measure development in chronic nonbacterial osteomyelitis (CNO)

PURPOSE OF REVIEW

To review recent trends in treatment and recent progress in developing outcome measures needed for chronic nonbacterial osteomyelitis (CNO) clinical trials.

RECENT FINDINGS

CNO is an autoinflammatory bone disease. In a minority of patients, the disease is genetically driven, and diagnosis can be made by DNA sequencing. However, for nonsyndromic CNO there is no diagnostic test. The number of children with CNO appears to be increasing and damage is common. Increases in CNO diagnosis is due to raised awareness, increased availability of whole-body magnetic resonance imaging and rising incidence. Treatment remains empiric and it is unclear which second line treatment is superior. Tumor necrosis factor inhibitors (TNFi) and bisphosphonates continue to be used as second line agents for nonsteroidal anti-inflammatory drugs (NSAID) refractory CNO; newer immune modulatory medications are used if this fails. Validated classification criteria, clinical outcome measures and imaging scoring standards are needed for successful clinical trials.

SUMMARY

Best treatment for NSAID refractory CNO remains unclear. Classification criteria, clinical outcomes measures and standardized imaging scoring have been developed or are near completion. This will facilitate robust clinical trials in CNO with the goal of having approved medications for this painful disease.

Classification and management strategies for paediatric chronic nonbacterial osteomyelitis and chronic recurrent multifocal osteomyelitis

INTRODUCTION

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disease that most commonly affects children and adolescents causing significant pain and damage to bones. The absence of diagnostic criteria and biomarkers, an incomplete understanding of the molecular pathophysiology, and lack of evidence from randomized and controlled trials make the diagnosis and care challenging.

AREAS COVERED

This review provides an overview of the clinical and epidemiological features of CNO and displays diagnostic challenges and how they can be addressed following strategies used internationally and by the authors. It summarizes the molecular pathophysiology, including pathological activation of the NLRP3 inflammasome and IL-1 secretion, and how these observations can inform future treatment strategies. Finally, it provides a summary of ongoing initiatives aiming at classification criteria (ACR/EULAR) and outcome measures (OMERACT) that will enable the generation of evidence through clinical trials.

EXPERT OPINION

Scientific efforts have linked molecular mechanisms to cytokine dysregulation in CNO, thereby delivering arguments for cytokine blocking strategies. Recent and ongoing collaborative international efforts are providing the basis to move toward clinical trials and target directed treatments for CNO that find approval by regulatory agencies.

Diagnosis and Treatment of Chronic Non-bacterial Osteomyelitis: A Survey on Current Practices Adopted by Pediatric Rheumatologists in Saudi Arabia

INTRODUCTION

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease usually managed by pediatric rheumatologists (PRs). There is a need for a consensus treatment plan to minimize the diversity in clinical practice in the diagnosis and management of CNO. In this study, we explored the practice of PRs in Saudi Arabia on the diagnosis and treatment of patients with CNO.

METHODS

This is a cross-sectional study that was conducted among PRs in Saudi Arabia (May to September 2020). A survey was performed among PRs registered in the Saudi Commission for Health Specialties using an electronic-based questionnaire. The survey consisted of 35 closed-ended questions about the diagnosis and management of CNO patients. We explored the approaches adopted by PRs in diagnosing and monitoring the disease activity, their awareness of clinical possibilities that necessitate ordering bone biopsy, and the treatment choices they considered for CNO patients.

RESULTS

We scrutinized data from a total of 77% (n=41/53) PRs who responded to our survey. Magnetic resonance imaging (MRI) was reported as the most frequently used modality in suspected CNO (82%, n=27/33), followed by plain X-ray (61%) and bone scintigraphy (58%). Magnetic resonance imaging of a symptomatic site is the imaging modality of choice for the diagnosis of CNO (82%), Followed by X-ray (61%) and bone scintigraphy (58%). The reasons for performing bone biopsy were unifocal lesions (82%), unusual sites of presentation (79%), and multifocal lesions (30%). The preferred treatment regimens were bisphosphonates (53%), non-steroidal anti-inflammatory drugs alone (43%), or biologics with bisphosphonates (28%). The reasons to upgrade the treatment in CNO included the development of vertebral lesions (91%), the development of new lesions in MRI (73%), and the elevation of inflammatory markers (55%). The disease activity was assessed by history and physical examination (91%), inflammatory markers (84%), MRI of targeted symptomatic site (66%), and a whole-body MRI (41%).

CONCLUSIONS

The approach to diagnosis and treatment of CNO varies among PRs in Saudi Arabia. Our findings provide a background for the development of a consensus treatment plan for challenging CNO patients.

Neurosurgical management of vertebral lesions in pediatric chronic recurrent multifocal osteomyelitis: patient series

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare pediatric autoinflammatory disorder involving 2 or more inflammatory bone lesions separated in time and space associated with pathological vertebral fractures. There are no current guidelines for the role of pediatric spine surgeons in the management of this condition. The authors demonstrate the importance of close and early involvement of neurosurgeons in caring for patients with CRMO with vertebral involvement.

OBSERVATIONS

Fifty-six pediatric patients with clinical and radiographic evidence of CRMO were identified and clinical, radiographic, laboratory, and histopathological data were reviewed. All were evaluated via Jansson and Bristol CRMO diagnostic criteria. Ten had radiographic evidence of vertebral involvement (17.9%). Nine of these had multifocal disease. Five patients had multiple vertebrae affected. Six patients were evaluated for possible surgical intervention and one required intervention due to vertebra plana leading to a progressive kyphotic deformity and significant spinal canal stenosis.

LESSONS

In conjunction with management by the primary pediatric rheumatology team using nonsteroidal anti-inflammatory drugs, disease-modifying anti-rheumatic drugs, immunotherapies, and bisphosphonates, given the risk of pathological fractures and potential resulting long-term neurological deficits, the authors recommend close monitoring and management by pediatric spine surgeons for any patient with CRMO with vertebral lesions.

Not all benign: disease course, complications, and sequalae of chronic recurrent multifocal osteomyelitis in children

PURPOSE OF REVIEW

Advances in pathogenesis of chronic recurrent multifocal osteomyelitis in children (CRMO) have shaped therapeutic strategies. The use of whole-body MRI (WBMRI) and improved awareness of CRMO has increased rates and timeliness of CRMO diagnoses. In this review, we highlight the findings from recently published CRMO cohorts and describe the course, complications, and long-term sequalae of CRMO. It is important for clinicians to be aware of the potential for long-term sequelae in order to optimize therapy and avoid complications.

RECENT FINDINGS

Despite recent advances in defining disease pathogenesis, children with CRMO continue to suffer from complications and deformities. Involvement of the spine can be asymptomatic and is not as rare as previously suggested. This can result in damaging outcomes, such as vertebral fractures and permanent deformities. A subset of patients has polycyclic disease course and some continue to have active disease for years and well into adulthood, with significant impacts on quality of life.

SUMMARY

These recent findings have considerable implication on clinical practice regarding diagnosis, treatment, and monitoring of the disease. Collectively, they support the need for continued monitoring of the disease and screening using comprehensive imaging, such as WBMRI.

Canakinumab treatment in a young girl with refractory chronic recurrent multifocal osteomyelitis associated with pyoderma gangrenosum

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a bone inflammatory disorder characterized by osteolytic, usually multiple, symmetric lesions. Diagnosis is one of exclusion, and no standardized therapies are available. Presumed deregulation of the interleukin (IL)-1β axis, as observed in 2 monogenic autoinflammatory conditions such as Majeed syndrome (LPIN2 mutations) and deficiency of IL-1 receptor antagonist (IL1RN mutations) with CRMO-like bone involvement, suggests the blockade of IL-1 as potentially useful also in this condition, even if scarce data are available.

CASE PRESENTATION

We report the case of a 13-year-old girl affected by a multidrug-resistant and pyoderma gangrenosum-complicated CRMO treated with canakinumab, a human monoclonal antibody targeting IL-1β.

CONCLUSION

In this young patient pyoderma gangrenosum and CRMO showed a rapid and satisfactory response to canakinumab, although over time a decreased efficacy in controlling bone disease was observed.

Chronic recurrent multifocal osteomyelitis, a rare disease. Case report

Introduction: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory bone disease usually observed in children and adolescents. It is caused by an imbalance between proinflammatory and anti-inflammatory factors. To establish its diagnosis, it is necessary to integrate clinical and laboratory elements that are typically aimed at ruling out other conditions, constituting a diagnosis of exclusion. Treatment is based on non-steroidal anti-inflammatory drugs and other drugs in specific cases. Case presentation: A 16-year-old female patient with a 1-year history of joint pain, especially in the knees, accompanied by signs of local inflammation was admitted to the emergency department of a quaternary care hospital due to a fever >38.5°, odynophagia, asthenia, and adynamia over the last two days. The patient underwent multiple extension studies, including laboratory, imaging and histopathological tests, which ruled out various etiologic causes. She received empirical antibiotic treatment without remission of symptoms, so a diagnosis of CRMO was finally established and outpatient treatment with non-steroidal anti-inflammatory drugs and corticosteroids was indicated, obtaining a favorable response. Conclusions: CRMO should be considered in children and adolescents with bone pain and a poorly defined clinical history with non-specific laboratory, imaging and histopathological findings. To date, little is known about CRMO, so it is necessary to carry out research and expand the knowledge related to this disease.

Early diagnosis and response assessment in chronic recurrent multifocal osteomyelitis: changes in lesion volume and signal intensity assessed by whole-body MRI

Objective:

To assess the effectiveness of whole-body MRI (WB-MRI) in early diagnosis of chronic recurrent multifocal osteomyelitis (CRMO) and the prediction of clinical response through quantitative MRI features.

Methods:

20 children (mean age, 10.3 years; range, 5–14 years) with CRMO underwent WB-MRI and were assessed with a clinical score (Jansson) at baseline (median time after first encounter, 8 months) and follow-up (median time after baseline, 11.5 months). Baseline WB-MRI scans were classified as early (within 6 months after first encounter) and late. Clinical responders and non-responders were compared regarding number and localization of bone lesions, lesion volume and T2 signal intensity (SI) ratio (lesion to muscle).

Results:

Diagnosis of CRMO was made promptly in the early WB-MRI group (n = 10; median, 3 months) compared to the late WB-MRI group (n = 10; 18 months; p = 0.006). Bone lesions were mainly located in the lower extremities (n = 119/223; 53%). No significant difference was detected regarding the number of bone lesions and lesion volume in the subgroups of clinical responders (n = 10) and non-responders (n = 10). Responders showed a higher volume reduction of bone lesions at follow-up compared to non-responders (p = 0.03). Baseline and follow-up SI ratios were lower in responders (5.6 and 5.8 vs 6.1 and 7.2; p = 0.047 and p = 0.005).

Conclusion:

The use of WB-MRI within 6 months of disease suspicion may serve as a benchmark to support early diagnosis of CRMO. T2 SI ratios and the reduction of lesions’ volume correlate with clinical outcome.

Advances in knowledge:

WB-MRI at an early stage of suspected CRMO plays a key role for early diagnosis. This is the first study showing that quantitative MRI features are suitable for response assessment and can be used as prognostic markers for the prediction of clinical response.

Chronic Nonbacterial Osteomyelitis: Insights into Pathogenesis, Assessment, and Treatment

Chronic nonbacterial osteomyelitis, or its most severe form, chronic recurrent multifocal osteomyelitis, is an autoinflammatory bone disease that causes skeletal inflammation characterized by bone pain and swelling that primarily affects children. It is a diagnosis of exclusion and its clinical presentation may mimic underlying infectious processes and malignancy. Clinical suspicion for this diagnosis and timely referral to pediatric rheumatology is crucial to achieve earlier diagnosis, appropriate treatment, and improved quality of life of affected patients and families. This article focuses on recent insights into the pathogenesis of chronic nonbacterial osteomyelitis and outlines recent advances and ongoing research.

Role of Diagnostic Imaging in Chronic Recurrent Multifocal Osteomyelitis (CRMO) in Children: An Observational Study

The aim of this single-center observational study was to analyze the applicability of various imaging studies to the diagnosis and further evaluation of patients with chronic recurrent multifocal osteomyelitis (CRMO). The analysis included the data of 10 patients with CRMO treated between 2016 and 2021. The mean ages of the patients at the first manifestation of CRMO and ultimate diagnosis were 10 years and 7 months and 11 years and 10 months, respectively. Conventional radiography demonstrated focal loss of bone density in only 30% of the patients. Computed tomography showed disseminated foci with non-homogeneous osteolytic/osteosclerotic structure, with a massive loss of cortical layer and strong periosteal reaction. On magnetic resonance imaging (MRI), most patients presented with multifocal hypodense areas on T1-weighted images, with the enhancement of signal on T-weighted and STIR sequences. The duration of follow-up varied between 3 months and 3 years. In 40% of the patients, both clinical symptoms and the abnormalities seen on MRI resolved completely, whereas another 50% showed partial regression of clinical and radiological manifestations. MRI findings, co-existing with characteristic clinical manifestations, play a pivotal role in establishing the ultimate diagnosis of CRMO. MRI can also be used to monitor the outcomes of treatment in CRMO patients.

Imaging in non-bacterial osteomyelitis in children and adolescents: diagnosis, differential diagnosis and follow-up-an educational review based on a literature survey and own clinical experiences

Background

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disorder affecting children and adolescents. Previously classified as a rare disease, recent studies suggest a higher incidence of the disease. CNO may develop into the clinical presentation of chronic recurrent osteomyelitis (CRMO) with high relapse rate and multifocality.

Main body

Diagnosis of CNO/CRMO is often delayed, with implications for disease severity and relapse rate. This can be significantly improved by knowledge of the disease entity and its characteristics. Imaging plays a key role in diagnosis, differential diagnosis and therapy monitoring. Magnetic resonance imaging (MRI) has several advantages compared to other imaging methods and is increasingly applied in clinical studies. Recent studies show that a whole-body (WB) coverage (WB-MRI) without contrast agent administration is a rational approach. This educational review is based on a systematic analysis of international peer-reviewed articles and presents our own clinical experiences. It provides an overview of disease entity, incidence and clinical diagnosis. The role of imaging, especially of whole-body MRI, is discussed in detail. Finally, practical advice for imaging, including flowcharts explaining when and how to apply imaging, is provided.

Conclusion

Knowing the specifics of CNO/CRMO and the importance of MRI/whole-body MRI allows rapid and efficient diagnosis as well as therapy support and helps to avoid irreversible secondary damage.

Chronic Nonbacterial Osteomyelitis in Children

Chronic nonbacterial osteomyelitis (CNO) is an auto-inflammatory bone disorder with a wide spectrum of clinical manifestations, from unifocal to multifocal lesions. When it manifests with multifocal lesions, it is also referred to as chronic recurrent multifocal osteomyelitis (CRMO). CNO/CRMO can affect all age groups, with the pediatric population being the most common. Patients may present with systemic inflammation, but there is no pathognomonic laboratory finding. Magnetic resonance imaging (MRI) is the gold standard radiological tool for diagnosis. In the absence of validated diagnostic criteria, CNO/CRMO remains an exclusion diagnosis. Bone biopsy does not show a specific disease pattern, but it may be necessary in unifocal or atypical cases to differentiate it from malignancy or infection. First-line treatments are non-steroidal anti-inflammatory drugs (NSAIDs), while bisphosphonates or TNF-α blockers can be used in refractory cases. The disease course is unpredictable, and uncontrolled lesions can complicate with bone fractures and deformations, underlying the importance of long-term follow-up in these patients.

Assessing Knowledge and Promoting Awareness of Chronic Recurrent Multifocal Osteomyelitis Among Oral and Maxillofacial Surgeons

PURPOSE

Chronic recurrent multifocal osteomyelitis (CRMO) is underdiagnosed and underreported because of a lack of awareness among providers. While patients with undiagnosed CRMO often present to oral and maxillofacial surgeons (OMSs) with a chief complaint of mandibular pain, to our knowledge, there is no literature regarding how well informed these providers are about this disease. Survey studies and educational efforts have been carried out among other specialists with the aim of raising awareness. The purpose of this study was to document current levels of understanding and determine knowledge gaps among OMSs regarding the diagnostic process for CRMO.

MATERIALS AND METHODS

For this cross-sectional cohort study, the investigators sent an anonymous and electronic survey to OMSs practicing in the United States. Using a clinical vignette, the survey captured respondents' ability to evaluate, diagnosis, and take appropriate next steps for a hypothetical patient with CRMO.

RESULTS

A total of 429 respondents completed the entire survey. The following proportion of respondents correctly answered questions pertaining to information gathering (10.3%), differential diagnosis (9.8%), overall diagnostic workup (76.7%), diagnostic imaging (78.8%), diagnostic laboratory tests (36.8%), biopsy and specimen (0.5%), and final diagnosis and next steps (9.6%).

CONCLUSION

Our findings demonstrate incomplete understanding of this disorder among OMSs and uncover knowledge deficiencies that can lead to misdiagnosis and/or delay in appropriate treatment. To improve patient outcomes, it is paramount to augment educational initiatives among practitioners regarding this disease.

Mandibular involvement in SAPHO syndrome: a retrospective study

BACKGROUND

Mandible osteomyelitis can occur in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, a rare chronic inflammatory disease; however, few studies have explored its characteristics and management.

METHODS

We reviewed the medical records of consecutive SAPHO patients with mandible involvement diagnosed in Peking Union Medical College Hospital from September 2014 to July 2019. Demographic, clinical, laboratory, and imaging data were collected at baseline. Prescription data and follow-up magnetic resonance imaging (MRI) and cone beam computed tomography (CBCT) images were collected from the hospital information system. An electronic questionnaire was distributed to all patients to obtain their latest symptoms.

RESULTS

A total of 26 SAPHO patients with mandibular involvement were involved, all of whom responded to the questionnaire (38.5% male; median age, 28 years; median follow-up duration, 2.1 years). Ten patients (38.5%) had undergone an oral procedure 1 month before the onset of mandibular symptoms. All 14 of the patients who underwent a surgical intervention relapsed within a median duration of 2 months (range 0.25-4.0 months), and 24 patients (92.3%) achieved improvement with conservative treatment. Following bisphosphonate treatment, remission of bone marrow oedema and osteolysis was observed on MRI and CBCT, and 5 patients receiving bisphosphonates with follow-up CBCT after remission did not relapse in 5.4 months (mean 6.0, range 3.2-9.9 months).

CONCLUSION

Mandibular involvement of SAPHO syndrome predominantly occurs in young women. Dental procedures are a possible risk factor. Conservative treatment, especially intravenous bisphosphonates, can lead to oral improvement.

The Many Faces of Pediatric Chronic Recurrent Multifocal Osteomyelitis (CRMO): A Practical Location- and Case-Based Approach to Differentiate CRMO From Its Mimics

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease of childhood and adolescence characterized by episodic bone pain. Diagnosis relies heavily on whole-body MRI and is made by excluding a wide variety of other disorders with overlapping imaging features, depending on location, marrow distribution, and the presence or absence of multifocality. We present an overview of the clinical and imaging features of CRMO and, through various clinical scenarios, provide tips for tailoring the differential diagnosis based on location and distribution of encountered abnormalities. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 3.

Diagnostic and therapeutic difficulties in a patient with chronic recurrent multifocal osteomyelitis coexisting with ulcerative colitis

Chronic non-bacterial osteomyelitis (CNO) is a rare autoinflammatory bone disease, affecting mainly children. CNO includes a broad clinical spectrum of symptoms and signs, from mild, limited in time, unifocal osteitis to severe, chronic, active or recurrent, multifocal osteomyelitis. In 2014 diagnostic criteria for CNO were proposed, the Bristol Criteria for the Diagnosis of Chronic Non-bacterial Osteitis, taking into account the clinical picture – location and number of inflammatory foci, characteristic changes on radiological examination (X-ray) and magnetic resonance imaging (MRI), C-reactive protein (CRP) concentration, and changes in bone biopsy.

The paper presents the case of a four-year-old boy in whom the diagnosis of multifocal osteomyelitis coexisting with ulcerative colitis was established. Attention was paid to the long diagnostic process of the disease, requiring in the first place differentiation with proliferative diseases. The choice of drugs was also a significant problem in the patient described in view of both intolerance of individual preparations and their ineffectiveness.

Disease burden and social impact of pediatric chronic nonbacterial osteomyelitis from the patient and family perspective

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disorder that if left untreated can result in bone destruction and severe continuing pain due to persistent inflammation. The impact this chronic disease has on the daily lives of affected children and their families is not well known. The purpose of this study is to understand the disease burden and socioeconomic and psychological impact of CNO from the patients' and families' perspectives and identify areas of improvement for patient care and reduced disease burden based on patients' and families' responses.

METHODS

Participants were invited through a social media platform group and at clinic visits at Stanford Children's Health. An online survey was administered to patients with a diagnosis of CNO made at < 22 years of age and/or the parent/guardian of a patient with CNO diagnosis made at < 22 years of age.

RESULTS

There was a total of 284 survey participants. The median age at CNO diagnosis was 10 years (range 2-22+). Median time from first CNO symptom to diagnosis was 2 years. Antibiotics were used in 35% of patients prior to CNO diagnosis; of these, 24% received antibiotics for greater than 6 months. Between 25 and 61% reported a negative effect of CNO on relationships, school/work performance, or finances; and 19-50% reported effects on psychosocial well-being. The majority agreed patients' performance with daily tasks and hobbies was challenged by pain, fatigue and physical limitation related to CNO.

CONCLUSIONS

Patients with CNO experienced on average a 2-year delay in diagnosis and receiving effective treatments. At least 25% reported problems with relationships, school, work, finances and well-being due to CNO. Recognition of these challenges emphasizes the need to increase awareness of this disease and address the socioeconomic stressors and mental health issues in order to provide optimal care of children with CNO.

Chronic non bacterial osteitis- a multicentre study

OBJECTIVE

To understand the demographics, clinical features and treatment outcomes of Chronic Non-bacterial Osteitis (CNO) from three tertiary paediatric rheumatology services in the United Kingdom.

METHODS

Children less than 18 years of age diagnosed with CNO between 2001 to 2016 from one tertiary service and between 2001 to 2017 from two tertiary services were included. Clinical notes were reviewed and all pertinent data were collected on a pre-defined proforma. One hundred and thirty one patients were included in the study. The Bristol diagnostic criteria were applied retrospectively.

RESULTS

Retrospective analysis of the data showed that the disease was more common in girls than boys (2.5:1), median age at onset of symptoms was 9.5 years (IQR 8 to 11 years). Bone pain was the predominant symptom in 118/129 (91.4%) followed by swelling in 50/102 (49.01%). Raised inflammatory markers were present in 39.68% of the patients. Whole body Magnetic Resonance Imaging (MRI) was a useful diagnostic tool. Metaphyses of long bones were most often involved and the distal tibial metaphyses 65/131 (49.6%) was the most common site. Non-steroidal anti-inflammatory drugs were used as first line (81.67%) followed by bisphosphonates (61.79%). Treatment was escalated to a TNF blocker when response to bisphosphonates was suboptimal. The disease was in remission in 82.4% of the patients during the last follow up.

CONCLUSION

Our multicentre study describes features and outcomes of CNO in a large number of patients in the United Kingdom.

SIGNIFICANCE AND INNOVATION

Raised inflammatory markers were present in 39.68% of our patients. Whole body MRI is useful for diagnosis and also determining response to treatment. A greater number of lesions were detected on radiological imaging compared to clinical assessment. Metaphyses of long bones were most often involved and the distal tibial metaphyses (49.6%) were the most common site. Non-steroidal anti-inflammatory drugs were used as first line (81.67%) followed by bisphosphonates (61.79%). There was no difference in number of medications used for management in unifocal versus multifocal disease. TNF blockers were used with good effect in our cohort.

Chronic Nonbacterial Osteomyelitis and Chronic Recurrent Multifocal Osteomyelitis in Children

Chronic nonbacterial osteomyelitis (CNO) is an innate immune system disorder that predominantly affects children. It can present as part of a syndrome or in isolation. It presents as bone pain with or without fever or objective swelling at the site. It is difficult to diagnose. Laboratory studies can be normal, whereas a biopsy reveals sterile osteomyelitis. Osteolytic or sclerotic bone changes may be seen on radiographs. However, MRI is more sensitive for detecting CNO and is considered the gold standard for monitoring the disease. Treatment depends on disease severity and includes nonsteroidal antiinflammatory drugs, bisphosphonates, and cytokine inhibitors.

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

OBJECTIVE

To develop standardized treatment regimens for chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis (CRMO), to enable comparative effectiveness treatment studies.

METHODS

Virtual and face-to-face discussions and meetings were held within the CNO/CRMO subgroup of the Childhood Arthritis and Rheumatology Research Alliance (CARRA). A literature search was conducted, and CARRA membership was surveyed to evaluate available treatment data and identify current treatment practices. Nominal group technique was used to achieve consensus on treatment plans for CNO refractory to nonsteroidal antiinflammatory drug (NSAID) monotherapy and/or with active spinal lesions.

RESULTS

Three consensus treatment plans (CTPs) were developed for the first 12 months of therapy for CNO patients refractory to NSAID monotherapy and/or with active spinal lesions. The 3 CTPs are methotrexate or sulfasalazine, tumor necrosis factor inhibitors with optional methotrexate, and bisphosphonates. Short courses of glucocorticoids and continuation of NSAIDs are permitted for all regimens. Consensus was achieved on these CTPs among CARRA members. Consensus was also reached on subject eligibility criteria, initial evaluations that should be conducted prior to the initiation of CTPs, and data items to collect to assess treatment response.

CONCLUSION

Three consensus treatment plans were developed for pediatric patients with CNO refractory to NSAIDs and/or with active spinal lesions. Use of these CTPs will provide additional information on efficacy and will generate meaningful data for comparative effectiveness research in CNO.

Complete resolution and remodeling of chronic recurrent multifocal osteomyelitis on MRI and radiographs

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare condition thought to be under-diagnosed, with a true prevalence of more than the 1 in 10,000 estimated. It is a condition that is classically described as polyostotic with a relapsing and remitting course, preferentially affecting the metaphyses of tubular bones in the pediatric population. Lesions have characteristic appearances of cortical hyperostosis and mixed lytic/sclerotic medullary appearances radiographically, with active osteitis and periostitis best seen with fluid-sensitive sequences on magnetic resonance imaging (MRI). There are reports of lesions resolving on follow-up radiographs and MRI scans, but no supporting images. In particular, although the marrow appearances and degree of osteitis have been shown to improve on MRI, complete resolution and remodeling back to normal has never been demonstrated. We present a case of a lesion that has completely healed and remodeled back to normal appearances on both radiographs and MRI, and consider this the standard for the often loosely used terms "normalization" and "resolution". We discuss the implications of this for our understanding of the natural history of CRMO, and how this adds weight to the condition being significantly under-diagnosed. It provides a "gold standard" to be aimed for when assessing treatments for CRMO, and the optimal outcomes that are possible. It also provides further insight into the potential of pediatric bone to recover and remodel when affected by inflammatory conditions.

Chronic Recurrent Multifocal Osteomyelitis and Related Diseases-Update on Pathogenesis

PURPOSE OF REVIEW

We focus on recent advances in the understanding of the genetic, molecular, immunologic, and environmental factors implicated in the pathogenesis of autoinflammatory bone diseases including the syndromic and non-syndromic forms of chronic recurrent multifocal osteomyelitis (CRMO).

RECENT FINDINGS

Evidence implicating the IL-1 pathway in the pathogenesis of the Mendelian forms of CRMO is growing. LIPIN2 can regulate the NLRP3 inflammasome by affecting P2X7 receptor activation, and intracellular cholesterol can modulate P2X7R currents. Work in a mouse model of CRMO demonstrates that dietary manipulation can alter the microbiome and protect these mice from the development of sterile osteomyelitis in vivo. Although the genetic and immunologic basis of non-syndromic CRMO remains only partially understood, the IL-1 pathway is central to the pathogenesis in the syndromic autoinflammatory bone disorders. Recent work implicates lipids and the microbiome in sterile osteomyelitis.