A large national cohort of French patients with chronic recurrent multifocal osteitis

Update on the genetics of nonbacterial osteomyelitis in humans

PURPOSE OF REVIEW

To summarize the current advances in our understanding or the genetic basis of nonbacterial osteomyelitis.

RECENT FINDINGS

Chronic recurrent multifocal osteomyelitis (CRMO) is a complex genetic disorder. Past discoveries identified several single gene defects (LPIN2, Pstpip2 and IL1RN) that cause IL-1-mediated sterile multifocal osteomyelitis. Recently Lorden et al.'s studies show that LIPIN2 deficiency can activate the NLRP3 inflammasome through alterations in the function of P2X7 receptor providing evidence that Majeed syndrome is an NLRP3 inflammasomopathy. New gene discoveries include the identification of FBLIM1 as a CRMO susceptibility gene. Mutations in FBLIM1 were found in a consanguineous family with CRMO. Fblim1 is one of the most significantly differentially expressed gene in bone from chronic multifocal osteomyelitis (cmo) mice, plays a role in IL-10-driven anti-inflammatory responses, and is involved in the physiology of bone remodeling. Lastly, new data on the putative CRMO susceptibility locus on chromosome 18 is presented here. Using Sanger sequencing, rather than microsatellite analysis, the DS18S60 susceptibility region could not be replicated in a larger cohort.

SUMMARY

CRMO occurs in humans, nonhuman primates, dogs and mice. There is a genetic component to disease but the genetic basis has only been identified for a small percentage of all cases.

Efficacy of pamidronate in children with chronic non-bacterial osteitis using whole body MRI as a marker of disease activity

BACKGROUND

To study the response to pamidronate using whole body magnetic resonance imaging (WB-MRI) in children with chronic non-bacterial osteitis (CNO) in a tertiary health centre.

METHODS

The medical records of children under the age of sixteen with a diagnosis of chronic non-bacterial osteitis between 2005 and 2018 were reviewed. All those who were treated with pamidronate were included and relevant data was collected. Response to therapy was determined based on the status of lesions on WB- MRI.

RESULTS

Forty six patients were included in the study. Pre- and post-treatment WB-MRI was available in forty patients. Cumulative lesions pre-treatment were 150 and reduced to 45 (30%) post-treatment. Seventeen patients (42.5%) had a good response with complete resolution of all lesions and nine patients (22.5%) worsened during or following treatment with pamidronate. Vertebral disease had a good response and 82.3% of the lesions resolved completely.

CONCLUSION

Our study describes the experience with pamidronate in a tertiary health centre using WB-MRI as a marker of disease activity. Pamidronate was well tolerated in our cohort and treatment response was fairly good.

SIGNIFICANCE AND INNOVATION

1. Bisphosphonates can be used in the treatment of CNO when response to NSAIDs is suboptimal. 2. In the presence of spinal or mandibular lesions bisphosphonates were used as first line. 3. Treatment was escalated to a TNF blocker when response to bisphosphonates was suboptimal.

Clinical characteristics and treatment of clavicular osteomyelitis: a systematic review with pooled analysis of 294 reported cases

BACKGROUND

It is usually difficult to diagnose clavicular osteomyelitis (OM), and treatment is delayed because of its rarity. This study aimed to summarize clinical characteristics and treatment of this disease.

METHODS

We searched the PubMed and Embase databases to identify English studies that reported on clavicular OM from January 1980 through December 2016. Effective data were pooled for analysis.

RESULTS

In total, 111 studies comprising 294 cases (bacterial OM, 146; nonbacterial OM, 148) were included, with a sex ratio of 1.89:1 indicating female predilection. Overall, the median age at diagnosis was 16 years. The acute to chronic phase ratio was 0.30, with a median symptom duration of 4 months. The most frequently reported symptom was pain (192 cases), followed by swelling (151 cases) and fever (52 cases). Altogether, 86.94% cases of single-site involvement were reported, with the medial side being the most common site (69.95%). The erythrocyte sedimentation rate achieved the highest positive rate (74.44%) before treatment. The total positive rate of culture for bacterial OM was 81.82%, with Staphylococcus aureus being the most frequently detected pathogen (44.70%). The average cure rate was 83.52%, with no significant difference between surgical (89.70%) and nonsurgical (79.63%) cases (P = .079).

CONCLUSIONS

Clavicular OM, predominant in female patients and young people, usually occurred at a chronic stage. Pain was the most frequent symptom, with the medial side being the most involved site. The erythrocyte sedimentation rate may be a helpful indicator for diagnosis. Regardless of surgery or nonsurgery, most patients achieved a favorable prognosis.

Idiopathic CRMO and MEFV Gene Variant Alleles: Is There Any Relationship?

Background and Objective

CRMO is an inflammatory disease of bone that occurs more often in children. The clinical manifestations are intermittent fever, pain, and bone lesions, especially in long bones. Although there is an idiopathic type of disease, it is usually associated with some autoimmune disorders. This study evaluates MEFV gene mutations as background pathology of idiopathic CRMO.

Methods

Blood samples of patients, who diagnosed as childhood idiopathic CRMO by imaging and pathologic study from June 2011 until September 2018, have been screened for the 12 common pathogenic variants of MEFV gene mutations.

Result

Nine patients enrolled in this study, and eight of them were male. The most common involvement locations were tibia and femur, and the least ones were zygoma, calcaneus, and radius. The mean duration of the involvement was 1.3 years. Six patients had only 1 involved location, 2 patients showed two sites of involvement, and one patient had three affected areas. There were two positive MEFV gene mutations (22%), as E148Q/wt and K695R/wt both in the heterozygote form. There was no meaningful relationship between MEFV gene mutations and the age of onset, gender, and location of involvement. Patients with positive mutation had more involved sites and long duration of involvement significantly.

Conclusion

There is no significant immunopathogenic relationship between the common MEFV gene variant alleles and CRMO disease.

Chronic Non-bacterial Osteomyelitis: A Review

Chronic non-bacterial osteomyelitis (CNO) is a rare auto-inflammatory bone disorder, with a prevalence of around one in a million patients. In the more severe form, it is referred to as chronic recurrent multifocal osteomyelitis (CRMO). We present the current knowledge on epidemiology, pathophysiology as well as diagnostic options and treatment regimens. CNO/CRMO most commonly affects children and lesions are often seen in the metaphyseal plates of the long bones, but cases have been described affecting all age groups as well as lesions in almost every bone. It is, therefore, a disease that clinicians can encounter in many different settings. Diagnosis is mainly a matter of exclusion from differential diagnoses such as bacterial osteomyelitis and cancer. Magnetic resonance imaging is the best radiological method for diagnosis coupled with a low-grade inflammation and a history of recurring episodes. Treatment is based on case reports and consists of alleviating symptoms with non-steroidal anti-inflammatory drugs since the disease is often self-limiting. Recently, more active treatments using either bisphosphonates or biological treatment are becoming more common, to prevent long term bone damage. In general, due to its rarity, much remains unclear regarding CNO/CRMO. We review the known literature on CNO/CRMO and propose areas of interest as well as possible ways to make current diagnostic criteria more detailed. We also find unifocal cases of the jaw to be a possible sub-type that may need its own set of criteria.

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

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.

The Dilemma of Chronic Recurrent Multifocal Osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare idiopathic inflammatory disease that affects mainly children and young adults, resulting in significant morbidity especially if not diagnosed early. The clinical signs and symptoms are nonspecific, with a consequential delay in diagnosis. Radiological and histopathological criteria are important for its definition. Two cases of CRMO are reported, highlighting the diagnostic challenge and demonstrating the importance of timely investigations.

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.

Comparison of different treatment approaches of pediatric chronic non-bacterial osteomyelitis

Chronic non-bacterial osteomyelitis (CNO) is a chronic inflammatory bone disease which usually manifests in children and adolescents. There are a few data about pathogenesis and treatment. The aim of the study to compare the efficacy of different treatment approaches in pediatric CNO cohort patient. Fifty two children (25 boys and 27 girls) with CNO with average age at the onset of the disease 8.4 years (5.4; 11.0), number of foci - 3.0 (2.0; 6.0, incl. multifocal cases in 80.8%). Non-steroid anti-inflammatory drugs (NSAID) was the first-line treatment for non-vertebral cases, as well as pamidronate (PAM) for vertebral involvement. Second-line treatment includes sulfasalazine (SSZ), methotrexate (MTX), PAM and tumor necrosis factor-α inhibitors (TNFα-inh). We evaluated the dynamics of pain, patient's and physician's (MDVAS) assessment with visual-analog scale (VAS) and ability to each medication to achieve remission of CNO activity. According to the NSAID, MTX, SSZ, PAM and TNFα-inh groups the following data were registered: patient's VAS: - 14.2% (p = 0.05), - 50.0% (p = 0.04), - 23.1 (p = 0.89), - 83.3% (p = 0.0001), - 73.6% (p = 0.0007); painVAS: - 21.9% (p = 0.01), - 18.6% (p = 0.13), + 36.4 (p = 0.89), - 79.7% (p = 0.00016), - 74.1%, (p = 0.0015); MDVAS: - 13.8% (p = 0.13); - 56.4% (p = 0.09), + 30.8% (p = 0.89), - 74.7%, (p = 0.0001), - 82.1 (p = 0.0015) respectively. The ability of each treatment strategy to achieve the CNO remission was 52.6%, 44.4%, 57,1%, 88.8% and 73.3%, respectively (log-rank test, p = 0.001). The efficacy of treatment approaches for CNO depended on the severity of the disease. NSAID, methotrexate, and sulfasalazine were effective in forms without spine involvement, but pamidronate and TNF-a inhibitors were useful in vertebral forms of CNO. Pamidronate and TNF-a inhibitors more extensively suppressed CNO activity. The randomized controlled trials for assessment of the efficacy and safety of these medications is mandatory to confirm these results.

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.

Unusual case of chronic recurrent multifocal osteomyelitis

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare auto-inflammatory bone disorder that primarily affects young girls, with a mean age of 10 years at onset. Generally, it is a self-limited disease. However, recent data indicate that more than 50% of patients have a chronic persistent disease and about 20% a recurring course of this condition. Also, there are more cases reported with associated auto-inflammatory and autoimmune diseases. In this case report, we present a rare case of sporadic CRMO in which the patient eventually developed C-ANCA (cytoplasmic anti-neutrophil cytoplasmic antibodies)-associated renal vasculitis and hyperparathyroidism.

CASE PRESENTATION

A 14 year old female patient was brought to the emergency department with a sudden onset of left leg pain and oedema. After physical evaluation and initial investigation, she was diagnosed with femoral and pelvic deep vein thrombosis. While searching for possible thrombosis causes, osteomyelitis of the left leg was identified. Additional CT and MRI scans hinted at the CRMO diagnosis. Due to the multifocal lesions of CRMO, endocrinological evaluation of calcium metabolism was done. The results showed signs of hyperparathyroidism with severe hypocalcaemia. Moreover, when kidney damage occurred and progressed, a kidney biopsy was performed, revealing a C-ANCA associated renal vasculitis. Treatment was started with cyclophosphamide and prednisolone according to the renal vasculitis management protocol. Severe metabolic disturbances and hyperparathyroidism were treated with alfacalcidol, calcium and magnesium supplements. Secondary glomerulonephritis (GN) associated hypertension was treated with ACE (angiotenzine converting enzyme) inhibitors. Anticoagulants were prescribed for deep vein thrombosis. After 1.5 years of treatment, the patient is free of complaints. All microelement and parathormone levels are within normal range. Kidney function is now normal. To date, there are no clinical or diagnostic signs of deep vein thrombosis.

CONCLUSIONS

This case report presents a complex immunodysregulatory disorder with both auto-inflammatory and autoimmune processes. We hypothesize that the long lasting active inflammation of CRMO may induce an autoimmune response and result in concomitant diseases like C-ANCA-associated vasculitis in our patient. Any potential specific pathogenic relationships between these two rare pathologies may need to be further studied. Furthermore, there is a lack of specific biomarkers for CRMO and more studies are necessary to identify CRMO's characteristic patterns and how to best monitor disease progression.

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.

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

OBJECTIVES

Chronic non-bacterial osteomyelitis (CNO) or chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder characterized by sterile bone osteolytic lesions. The aim of this study was to evaluate the demographic data and clinical, instrumental and therapeutic features at baseline in a large series of CNO/CRMO patients enrolled in the Eurofever registry.

METHODS

A web-based registry collected retrospective data on patients affected by CRMO/CNO. Both paediatric and adult centres were involved.

RESULTS

Complete baseline information on 486 patients was available (176 male, 310 female). The mean age of onset was 9.9 years. Adult onset (>18 years of age) was observed in 31 (6.3%) patients. The mean time from disease onset to final diagnosis was 1 year (range 0-15). MRI was performed at baseline in 426 patients (88%), revealing a mean number of 4.1 lesions. More frequent manifestations not directly related to bone involvement were myalgia (12%), mucocutaneous manifestations (5% acne, 5% palmoplantar pustulosis, 4% psoriasis, 3% papulopustular lesions, 2% urticarial rash) and gastrointestinal symptoms (8%). A total of 361 patients have been treated with NSAIDs, 112 with glucocorticoids, 61 with bisphosphonates, 58 with MTX, 47 with SSZ, 26 with anti-TNF and 4 with anakinra, with a variable response.

CONCLUSION

This is the largest reported case series of CNO patients, showing that the range of associated clinical manifestations is rather heterogeneous. The study confirms that the disease usually presents with an early teenage onset, but it may also occur in adults, even in the absence of mucocutaneous manifestations.

Sinogenic intracranial complications: is adalimumab a culprit?

We present two 11-year-old girls with chronic recurrent multifocal osteomyelitis, treated with adalimumab. Both developed severe intracranial complications to sinusitis. Patient 1 had been treated with adalimumab for 15 months when she developed acute sinusitis complicated by an orbital abscess, forehead swelling, a subdural empyema and osteomyelitis of the frontal bone. She was treated with a rhinosurgical and neurosurgical approach with intravenous antibiotics.Patient 2 had been in adalimumab treatment for 10 weeks. Adalimumab was discontinued 8 weeks prior to developing subdural empyema and subcortical abscesses in combination with sinusitis. She was treated with endoscopic sinus surgery and intravenous antibiotics. Both patients had developed psoriasis and episodes of infection during treatment. They were non-septic and had low fever on presentation. None of the patients suffered any long-term neurological sequelae. The immunosuppressive treatment with adalimumab is considered to be the cause of the sinogenic intracranial complications in our cases.

Dealing with Chronic Non-Bacterial Osteomyelitis: a practical approach

BACKGROUND

Chronic Non-Bacterial Osteomyelitis (CNO) is an inflammatory disorder that primarily affects children. Although underestimated, its incidence is rare. For these reasons, no diagnostic and no therapeutic guidelines exist. The manuscript wants to give some suggestions on how to deal with these patients in the every-day clinical practice.

MAIN BODY

CNO is characterized by insidious onset of bone pain with local swelling. Systemic symptoms such as fever, skin involvement and arthritis may be sometimes present. Radiological findings are suggestive for osteomyelitis, in particular if multiple sites are involved. CNO predominantly affects metaphyses of long bones, but clavicle and mandible, even if rare localizations of the disease, are very consistent with CNO diagnosis. CNO pathogenesis is still unknown, but recent findings highlighted the crucial role of cytokines such as IL-1β and IL-10 in disease pathogenesis. Moreover, the presence of non-bacterial osteomyelitis among autoinflammatory syndromes suggests that CNO could be considered an autoinflammatory disease itself. Differential diagnosis includes infections, malignancies, benign bone tumors, metabolic disorders and other autoinflammatory disorders. Radiologic findings, either with Magnetic Resonance or with Computer Scan, may be very suggestive. For this reason in patients in good clinical conditions, with multifocal localization and very consistent radiological findings bone biopsy could be avoided. Non-Steroidal Anti-Inflammatory Drugs are the first-choice treatment. Corticosteroids, methotrexate, bisphosphonates, TNFα-inhibitors and IL-1 blockers have also been used with some benefit; but the choice of the second line treatment depends on bone lesions localizations, presence of systemic features and patients' clinical conditions.

CONCLUSION

CNO may be difficult to identify and no consensus exist on diagnosis and treatment. Multifocal bone lesions with characteristic radiological findings are very suggestive of CNO. No data exist on best treatment option after Non-Steroidal Anti-Inflammatory Drugs failure.

Chronic Recurrent Multifocal Osteomyelitis (CRMO): Presentation, Pathogenesis, and Treatment

PURPOSE OF REVIEW

Chronic non-bacterial osteomyelitis (CNO) with its most severe form chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder. We summarize the clinical presentation, diagnostic approaches, most recent advances in understanding the pathophysiology, and available treatment options and outcomes in CNO/CRMO.

RECENT FINDINGS

Though the exact molecular pathophysiology of CNO/CRMO remains somewhat elusive, it appears likely that variable defects in the TLR4/MAPK/inflammasome signaling cascade result in an imbalance between pro- and anti-inflammatory cytokine expressions in monocytes from CNO/CRMO patients. In this context, we present previously unpublished data on cytokine and chemokine expression in monocytes and tissues. CNO/CRMO is an autoinflammatory bone disorder resulting from imbalanced cytokine expression from innate immune cells. Though the exact molecular pathophysiology remains unclear, variable molecular defects appear to result in inflammasome activation and pro-inflammatory cytokine expression in monocytes from CNO/CRMO patients. Recent advances suggest signaling pathways and single molecules as biomarkers for CNO/CRMO as well as future treatment targets.

Biologic treatment for chronic recurrent multifocal osteomyelitis: report of four cases and review of the literature

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare non-infectious inflammatory disorder with unpredictable clinical course, characterized by acute exacerbations and spontaneous remissions. There are no randomized-controlled trials about treatment options. Non-steroidal anti-inflammatory drugs (NSAID) are the first-line treatment option; glucocorticoids seem to be effective; positive outcomes have been obtained with bisphosphonates. In the last few years successful use of biologic agents like anti-TNF agents has been reported. We report the cases of 3 children suffering from CRMO who were treated with NSAID, steroid, bisphosphonates and eventually received etanercept and 1 case without vertebral involvement treated with etanercept after NSAID and steroid; all cases showed clinical improvement. The mean ages at symptoms onset and diagnosis were 8 and 10 years and 10 months, respectively. Two patients presented with back pain and three had vertebral lesions. Mean interval from diagnosis to the onset of anti-TNF treatment was 14 months. According to our small experience, we suggest considering therapy with etanercept for the treatment of severe cases with persistently active disease despite multiple treatments.

Native join Propionibacterium septic arthritis

Propionibacterium species are associated with normal skin flora and cultures may be dismissed as contaminants. They are increasingly recognized as a cause of septic arthritis following shoulder arthroplasty and arthrotomy. We identified three cases of Propionibacterium septic arthritis in native joints mimicking atypical osteoarthritis and review the literature, clinical course, and treatment of 18 cases. Two cases of Propionibacterium acne in native knee joints and one in a sternoclavicular joint are described. A literature search for Propionibacterium septic arthritis was performed. Clinical course, treatment, and outcome are reviewed for all cases. Our three cases were combined with 15 cases from the literature. Fourteen cases showed few signs of acute infection, slow culture growth, and delayed diagnosis. In 3 cases an early culture was dismissed as a contaminant. Six cases were reported as caused by recent arthrocentesis. Fifteen cases were cured with antibiotics, although 5 of these 15 also required surgical intervention. Two patients were diagnosed while undergoing surgery for osteoarthritis. Four patients required arthroplasty and two of our patients will require arthroplasty for good functional results. Propionibacterium as a cause of septic arthritis in native joints demonstrates few signs of acute infection, presents with prolonged course, and is often misdiagnosed or unsuspected. Anaerobic growth may be delayed or missed altogether, and outcomes are consequently poor. Consider Propionibacterium septic arthritis in atypical osteoarthritis prior to arthroplasty.

Adult-onset Chronic Recurrent Multifocal Osteomyelitis with High Intensity of Muscles Detected by Magnetic Resonance Imaging, Successfully Controlled with Tocilizumab

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder that generally occurs in children and predominantly affects the long bones with marginal sclerosis. We herein report two cases of adult-onset CRMO involving the tibial diaphysis bilaterally, accompanied by polyarthritis. Magnetic resonance imaging (MRI) showed both tibial osteomyelitis and high intensity of the extensive lower leg muscles. Anti-interleukin-6 therapy with tocilizumab (TCZ) effectively controlled symptoms and inflammatory markers in both patients. High intensity of the lower leg muscles detected by MRI also improved. These cases demonstrate that CRMO should be included in the differential diagnosis of adult patients with bone pain, inflammation, and high intensity of the muscles detected by MRI. TCZ may therefore be an effective therapy for muscle inflammation of CRMO.

Bone metabolism and inflammatory characteristics in 14 cases of chronic nonbacterial osteomyelitis

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is a multifocal autoinflammatory disease that often impairs daily life in children. This study aimed to investigate the bone metabolic and inflammatory characteristics of patients with CNO, and to assess the differences between responders and nonresponders to conservative treatment.

METHODS

We investigated the clinical symptoms; laboratory data including inflammatory and bone metabolic biomarkers; and imaging findings from plain radiography, magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), and dual-energy x-ray absorption (DEXA) in 14 patients with CNO. All patients underwent first-line treatment comprising systemic nonsteroidal anti-inflammatory drugs with or without bisphosphonate. According to the response to the first-line treatment, the patients were divided into the clinical remission/partial response group and the no response group. The differences in bone metabolic and inflammatory characteristics between the two groups were assessed.

RESULTS

All patients had low bone mineral density assessed with DEXA. The bone metabolic biomarkers (bone-specific alkaline phosphatase and tartrate-resistant acid phosphatase 5b) were increased in boys of all ages and in young girls. Multiple inflammatory regions were detected in all patients by using FDG-PET including asymptomatic regions. The no response group had higher immunoglobulin G (IgG) and a greater number of bone inflammatory lesions detected on MRI than the clinical remission/partial response group.

CONCLUSION

Our data indicate the involvement of abnormal bone turnover, necessity of whole-body scanning, and association of higher serum IgG levels and greater numbers of inflammatory lesions with prolonged disease activity in patients with CNO.

Chronic nonbacterial osteomyelitis involving the mandible: A case report

INTRODUCTION

Chronic nonbacterial osteomyelitis (CNO) or chronic recurrent multifocal osteomyelitis (CRMO), is a very rare condition of unknown aetiology. It is characterised by focal sterile inflammatory disease with prolonged, self-limiting and recurrent episodes.

CASE PRESENTATION

We report the discovery of this very rare disease following a mandibular abscess in a 10-year-old female. We initially focus on the difference between the preoperative orthopantomography and the maxillofacial computed tomography and magnetic resonance images obtained, and then on the improvement of strategies for correct diagnosis and treatment of this disease.

DISCUSSION

Bone pain and localised swelling can occur in a single bone or can spread to soft tissue and adjacent bone; areas commonly affected by CMRO include the metaphyseal plates of the long bones, as well as the spine, clavicle and, rarely, the maxillofacial area. The clinical presentation of CMRO includes pain, functional impairment, and swelling, similar to our case.

CONCLUSIONS

We report a very rare case of this unifocal mandibular disease in a child who presented for an abscess and was then diagnosed and treated for CNO.

Vasculitis in the autoinflammatory diseases

PURPOSE OF REVIEW

This article addresses the prevalence and relationship between autoinflammatory diseases and vasculitis.

RECENT FINDINGS

Autoimmune diseases (AIDs) are a group of syndromes characterized by episodes of unprovoked inflammation due to dysregulation of the innate immune system. Despite the common occurrence of rashes and other skin lesions in these diseases, vasculitis is reported in only a few. On the other hand, neutrophilic dermatoses are more prevalent. Large vessel vasculitis is reported in patients with Behcet's and Blau's syndromes. Small and medium size vasculitides are reported in familial Mediterranean fever mainly as Henoch-Schonlein purpura and polyarteritis nodosa, respectively. It is rarely described in hyper IgD with periodic fever syndrome, cryopyrin associated periodic syndromes, TNF receptor-associated periodic syndrome, deficiency of interleukin-1 receptor antagonist and pyoderma gangrenosum and acne syndrome. In most AID where bones and skin are mainly involved (CRMO, Majeed syndrome, Cherubism and DITRA) - vasculitis has not been described at all. In AID small vessel vasculitis affects mainly the skin with no involvement of internal organs.

SUMMARY

In AID, neutrophilic dermatoses are more common and prominent than vasculitis. This may reflect a minor role for interleukin-1 in the pathogenesis of vasculitis. The rarity of vasculitis in AID suggests that in most reported cases its occurrence has been probably coincidental rather than being an integral feature of the disease.

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

Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic non-bacterial osteomyelitis (CNO), is a rare inflammatory disorder that primarily affects children. It is characterized by pain, local bone expansion, and radiological findings suggestive of osteomyelitis, usually at multiple sites. CRMO predominantly affects the metaphyses of long bones, but involvement of the clavicle or mandible are suggestive of the diagnosis. CRMO is a diagnosis of exclusion, and its pathogenesis remains unknown. Differential diagnosis includes infection, malignancies, benign bone tumors, metabolic disorders, and other autoinflammatory disorders. Biopsy of the bone lesion is not often required but could be necessary in unclear cases, especially for differentiation from bone neoplasia. Non-steroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment. Alternative therapies have been used, including corticosteroids, methotrexate, bisphosphonates, and tumor necrosis factor (TNF)-α inhibitors. No guidelines have been established regarding diagnosis and treatment options. This manuscript gives an overview of the most recent findings on the pathogenesis of CRMO and clinical approaches for patients with the condition.

Treatment Response and Longterm Outcomes in Children with Chronic Nonbacterial Osteomyelitis

Objective.

The autoinflammatory bone disorder chronic nonbacterial osteomyelitis (CNO) covers a wide clinical spectrum, ranging from mild self-limited presentations to chronically active or recurrent courses, which are then referred to as chronic recurrent multifocal osteomyelitis (CRMO). Little is known about treatment options and longterm outcomes. We investigated treatment responses and outcomes in children with CNO.

Methods.

A retrospective chart review was conducted in a tertiary referral center, covering 2004–2015. Disease activity was measured at 0, 3, 6, 12, and 24 months after treatment initiation, and at the last recorded visit.

Results.

Fifty-six patients with CNO were identified; 44 had multifocal CNO. Fifty percent of patients relapsed after a median of 2.4 years, and as few as 40% remained relapse-free after 5 years. Nonsteroidal antiinflammatory drugs were used as first-line treatment in 55 patients, inducing remission after 3 months in all individuals with relapse rates of 50% after 2 years. Further treatment included corticosteroids (n = 23), tumor necrosis factor-α (TNF-α) inhibitors (n = 7), and bisphosphonates (n = 8). While 47% of patients with CNO relapsed within 1 year after corticosteroid therapy, favorable outcomes were achieved with TNF-α inhibitors or bisphosphonates (pamidronate).

Conclusion.

CNO is a chronic disease with favorable outcomes within the first year, but high relapse rates in longterm followup. Particularly, patients with CRMO with long-lasting, uncontrolled inflammation were at risk for the development of arthritis. Our findings underscore the importance of a timely diagnosis and treatment initiation. Prospective studies are warranted to establish evidence-based diagnostic and therapeutic approaches to CNO.

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.

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

Background/Purpose. Understanding the practices of pediatric rheumatologists in diagnosing and treating chronic nonbacterial osteomyelitis (CNO) can provide important information to guide the development of consensus treatment plans. The objectives of this study were to determine physicians' approaches to (1) diagnosing and monitoring CNO, (2) ordering a bone biopsy, and (3) making treatment decisions. Methods. A survey was distributed among members of the Childhood Arthritis and Rheumatology Research Alliance using a web-based questionnaire. Results. 121 of 277 (41%) attending physician members completed the survey. Plain radiographs (89%) were most commonly used followed by regional MRI (78%), bone scintigraphy (43%), and whole-body MRI (36%). The top three reasons for performing a biopsy were constitutional findings (66%), unifocal bone lesions (64%), and nocturnal bone pain (45%). Nearly all responders (95%) prescribed nonsteroidal anti-inflammatory drugs (NSAIDs) as initial therapy. For patients who failed NSAID treatment, methotrexate (67%), tumor necrosis factor inhibitors (65%), and bisphosphonates (46%) were the next most commonly used treatments. The presence of a spinal lesion increased the use of bisphosphonate treatment. Conclusion. The diagnostic approach and disease activity monitoring for CNO varied among surveyed physicians. Our survey findings provided important background for the development of consensus treatment plans for CNO.

Successful treatment of chronic recurrent multifocal osteomyelitis using low-dose radiotherapy : A case report

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, which lacks an infectious genesis and predominantly involves the metaphysis of long bones. Common treatments range from nonsteroidal anti-inflammatory drugs (NSAIDs) and corticosteroids at first onset of disease, to immunosuppressive drugs and bisphosphonates in cases of insufficient remission. The therapeutic use of low-dose radiotherapy for CRMO constitutes a novelty.

CASE REPORT

A 67-year-old female patient presented with radiologically proven CRMO affecting the right tibia/talus and no response to immunosuppressive therapy. Two treatment series of radiation therapy were applied with an interval of 6 weeks. Each series contained six fractions (three fractions per week) with single doses of 0.5 Gy, thus the total applied dose was 6 Gy. Ten months later, pain and symptoms of osteomyelitis had completely vanished.

CONCLUSION

Radiotherapy seems to be an efficient and feasible complementary treatment option for conventional treatment refractory CRMO in adulthood. The application of low doses per fraction is justified by the inflammatory pathomechanism of disease.

Unexpectedly high incidences of chronic non-bacterial as compared to bacterial osteomyelitis in children

Historically, osteomyelitis was considered an infectious disorder. More recently, inflammatory mechanisms were recognized causing a significant proportion of pediatric osteomyelitis. This study was to compare characteristics of children with chronic non-bacterial (CNO) and bacterial osteomyelitis (BOM). A chart review of osteomyelitis patients from the departments of pediatrics, pediatric surgery, orthopedic surgery, and oral and maxillofacial surgery was conducted in a tertiary referral center, covering the years 2004-2014. Institutional incidences of CNO (n = 49) and BOM (n = 56) were comparable. Differentiation between CNO and BOM based on clinical or laboratory findings was mostly impossible. However, children with BOM more frequently presented with local inflammatory signs (47 vs. 68 %, p = 0.040), fever (12 vs. 38 %, p = 0.003), and abscesses (0 vs. 39 %, p < 0.001). Peripheral arthritis (14 vs. 0 %, p < 0.001), inflammatory bowel disease (10 vs. 2 %, p = ns), and hyperostosis (29 vs. 4 %, p = 0.001) were more common in CNO. Whole-body MRI was performed in 76 % of CNO patients, unveiling multifocal lesions in 80 % (CRMO). Though considered a rare disorder, institutional incidences of CNO were comparable to BOM, and the discrimination between CNO and BOM solely based on clinical aspects was mostly impossible. This is of special interest, since a correct and timely diagnosis is of utmost importance for long-term outcomes in both disorders. Whole-body MRIs should be considered in chronic osteomyelitis to (1) detect clinically inapparent lesions in CNO and (2) indirectly exclude (usually unifocal) chronic bacterial infections. Prospective studies are warranted to establish evidence-based diagnostic and therapeutic approaches to CNO.

Chronic nonbacterial osteomyelitis may be associated with renal disease and bisphosphonates are a good option for the majority of patients

AIM

The aim of this Italian study was to describe the clinical features, treatment options and outcomes of a cohort of patients with chronic nonbacterial osteomyelitis (CNO).

METHODS

This was a retrospective cohort study. Laboratory data, diagnostic imaging, histological features and clinical course are reported.

RESULTS

We enrolled 47 patients diagnosed with CNO. Bone pain was the leading symptom, and multifocal disease was present in 87% of the patients. The majority of the bone lesions were located in the appendicular skeleton (58%). Extraosseous manifestations were present in 34% of the patients, and renal involvement was detected in four patients. Inflammatory indices were increased in 80%, and bone x-rays were negative in 15% of the patients. Nonsteroidal anti-inflammatory drugs (NSAIDs) were the first therapy for all patients, achieving clinical remission in 27%. A good response to NSAIDs was significantly associated with a better prognosis. Bisphosphonates were used in 26 patients, with remission in 73%. Only six patients (13%), all with spine involvement, developed sequelae.

CONCLUSION

We found a possible association between CNO and renal disease. Bisphosphonates were more likely to lead to clinical remission when NSAIDs and corticosteroids had failed. Vertebral localisation was the only risk factor for potential sequelae.

Pediatric Chronic Nonbacterial Osteomyelitis of the Jaw: Clinical, Radiographic, and Histopathologic Features

PURPOSE

Chronic nonbacterial osteomyelitis (CNO) is a focal sterile inflammatory osteitis in children that most commonly develops in the long bones, but can occur in any bone. The disease course is variable, ranging from acute and self-resolving isolated lesions to chronic recurrent multifocal osteomyelitis (CRMO), which is frequently associated with extraosseous inflammatory disease. The purpose of this study was to present our clinical experience with CNO of the mandible in children. The specific aims were to 1) document the clinical characteristics, radiographic findings, and histologic features of CNO and 2) determine the percentage of our sample with multifocal disease (CRMO).

MATERIALS AND METHODS

This is a retrospective case series of patients with mandibular CNO. To be included, patients had to have a mandibular lesion radiographically consistent with osteomyelitis without infection, onset before aged 18 years, and complete records. Medical records were reviewed for history, clinical features, imaging, and pathology. Descriptive data were summarized.

RESULTS

The sample included 22 patients (13 female and 9 male patients) with disease onset at a mean age of 9.05 ± 2.4 years. On presentation, all patients reported mandibular pain and swelling, and 45% had trismus. All had clinical and/or radiographic findings of multifocal intraosseous disease and/or extraosseous inflammatory lesions. Of the patients, 12 (54%) had a documented family history of autoimmune or autoinflammatory disease and 15 (68%) had elevated erythrocyte sedimentation rates during a flare. Computed tomography scans typically showed expansion of the affected mandible with sclerosis of the medullary space, small foci of poorly defined lytic destruction with a lamellated periosteal reaction, and swollen muscles of mastication. Four distinct histologic features were noted including parallel and interconnected osteoid seams, atypical osteoid, areas of woven bone and hypocellular fibroblastic stroma resembling fibrous dysplasia, and patchy nodular fibrosis.

CONCLUSION

Pediatric CNO of the mandible has characteristic radiographic and pathologic features and is usually found as one of multiple disease foci in CRMO rather than as an isolated lesion.

Whole-body MRI: non-oncological applications in paediatrics

Whole-body magnetic resonance imaging (WBMRI) is a fast and accurate method for detecting and monitoring of diseases throughout the entire body without exposure to ionizing radiation. Among emerging non-oncological potential applications of WBMRI, rheumatological diseases play an important role. Rheumatological WBMRI applications include the evaluation of chronic multifocal recurrent osteomyelitis, dermatomyositis, fever of unknown origin, arthritis, and connective tissue diseases. Aim of this review is to give an overview of the use of WBMRI in rheumatological field.

Chronic recurrent multifocal osteomyelitis with an atypical presentation in an adult man

We present the case of a 33-year-old man with no significant medical history who developed right scapular pain, left-sided sacroiliac joint pain, and lower back pain, and was eventually diagnosed with chronic recurrent multifocal osteomyelitis (CRMO). Imaging demonstrated multiple scattered T2-hyperintense lesions on MRI at the spine and the left SI joint, some of which progressed and one regressed in size on follow-up. Histopathology demonstrated only non-specific chronic inflammation compatible with CRMO. No evidence of infectious organisms or neoplastic processes was found. The pain was relapsing and remitting in nature. Laboratory investigations were notable for no evidence of hematologic malignancy or infection, but only a mild increase in alkaline phosphatase. This case highlights that CRMO, despite being thought of as a childhood-onset disease, can present in adults as well, and also provides illustrative examples of imaging and histological findings.

Chronic recurrent multifocal osteomyelitis: a rare skeletal disorder

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare non-infectious inflammatory bone disease of unknown aetiology. CRMO mainly affects the metaphyses of long bones and spine in children and young adolescents. It presents with recurrent episodes of bone pain and fever, resembling bacterial osteomyelitis, but cultures of lesions are sterile and it is unresponsive to antibiotic therapy. We report a case of a 3-year-old boy diagnosed with CRMO, who was initially treated for bacterial osteomyelitis, and received prolonged antibiotic therapy for chronic pain, and swelling of mandible and ulna. CRMO should be kept in mind in the differential diagnosis of chronic bone pain and osteomyelitis unresponsive to antibiotic treatment.

Nonbacterial osteitis of the clavicle: longitudinal imaging series from initial diagnosis to clinical improvement

Nonbacterial osteitis is a rare autoinflammatory disease. Often it is mistaken for a tumor or osteomyelitis. We present a case of a twelve-year-old girl referred to our hospital because of a lesion of the right clavicle. The differential diagnoses were sarcoma, osteitis, and Langerhans cell histiocytosis. After biopsy the diagnosis nonbacterial osteitis (NBO) was established. Treatment of choice is a nonsteroidal anti-inflammatory drug. This case report gives a complete follow-up of the disease, showing the pitfalls of the diagnosis.