Chronic recurrent multifocal osteomyelitis associated with chronic inflammatory bowel disease in children

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.

Pyoderma gangrenosum following anti-TNF therapy in chronic recurrent multifocal osteomyelitis: drug reaction or cutaneous manifestation of the disease? A critical review on the topic with an emblematic case report

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disease, clinically characterized by chronic and recurrent episodes of osteoarticular inflammation, that generally presents in children and adolescents. From a dermatological point-of-view, CMRO can be associated with skin rashes mainly including psoriasis, palmoplantar pustulosis and acne. Pyoderma gangrenosum (PG) is a rare immune-mediated inflammatory skin disease classified within the spectrum of neutrophilic dermatoses that, in some cases, has been reported as cutaneous manifestation in CMRO patients. This paper presents a 16-year female patient diagnosed with CMRO, who presented PG lesions located on the lower leg, that arose after the administration of the tumour necrosis factor (TNF)-α inhibitor adalimumab. Cases of PG have been reported in patients being treated with certain medications, including TNF-α antagonists, leading to classified them in a setting aptly termed "drug-induced PG." In this paper, we discuss the co-occurrence of PG and CRMO, in the light of recent evidence on the pathogenesis of both diseases and giving ample space to a literature review on drug induced PG. In our case, it is plausible that PG could be considered a cutaneous manifestation of CRMO, although the mechanisms underlying this intriguingly relationship remain to be fully unraveled.

Chronic Nonbacterial Osteomyelitis and Inflammatory Bowel Disease: A Literature Review-Based Cohort

Background: Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory bone disorder that mainly involves children and adolescents. The association with other inflammatory disorders, such as inflammatory bowel disease (IBD), psoriasis, and arthritis, has been reported in the literature. In particular, the relationship between bone and intestinal inflammation is still poorly understood. For this purpose, our review aims to describe the cases reported in the literature concerning this association and to compare them with data from our single-center cohort of patients. Methods: We conducted a literature review of published cases of CNO associated with IBD. Eligible articles were identified through a Medline search in the PubMed database until December 2022. We retrospectively reviewed medical records of patients with CNO referred to G. Pini Hospital and compared them with the literature-review-based cohort. Results: Fifty-seven patients with a defined diagnosis of CNO and associated IBD were described in the literature (female 55%). The median age of onset of the disease (CNO or IBD) was 11 years. In 32/53 (60%), a diagnosis of Crohn’s disease (CD) was made, while 18 (34%) patients were classified as suffering from ulcerative colitis (UC) and 3 (6%) from undifferentiated IBD. The diagnosis of CNO preceded the diagnosis of IBD in 59% of cases; while in 24%, IBD anticipated CNO; and in 17%, the two conditions appeared simultaneously. The median time between the two events was 24 months. In our Italian cohort (n = 23 patients), no diagnosis of IBD was made. No significant differences were found when comparing clinical and demographical characteristics of the Italian vs. review-based cohort, except for a significant involvement of rachis in the Italian group. Conclusions: The correlation between autoinflammatory bone disease and intestinal inflammation should be further investigated. It is essential to promote awareness among pediatric rheumatologists and gastroenterologists about this possible association to facilitate the diagnosis and better optimize treatment.

Clinical characteristics and outcomes of chronic nonbacterial osteomyelitis in children: a multicenter case series

OBJECTIVE

The aim of this study was to evaluate demographic, clinical, laboratory, imaging, histopathology characteristics, and treatment responses of children with Chronic nonbacterial osteomyelitis (CNO).

METHODS

Retrospective multi-center case series study of pediatric patients diagnosed with CNO treated at five tertiary centers in south China.

RESULTS

Totally there were 18 patients diagnosed as CNO between 2014 and 2020. The median age of onset was 9.2 years (range 3.7-13.1) and 55.6% were female. Median delay in diagnosis was 10.9 months (range 1.0-72.0). The most frequent presenting symptoms were bone pain (100%) and fever (44.4%). Most patients had more than one lesion (median of 5, range 1-7). Most frequently affected bones were tibiofibula (88.9%) and femur (77.8%). The MRI characteristics mainly presented as bone edema and hyperintensity in bone marrow. Bone biopsy was conducted in 11 patients (61.1%) with inflammatory cells infiltration manifested as chronic osteomyelitis, and none showed bacterial infection or tumor. In treatment, non-steroid anti-inflamatory drugs (NSAIDs) is used as the first-line drug followed by steriods, methotexate (MTX), salazosulfadimidine (SASP), Bisphosphonates and TNF-α inhibitor. Two refractory cases received combination therapy with Bisphosphonates and TNF-α inhibitor, and achieved good therapeutic effect.

CONCLUSIONS

The present study described a multicenter series of CNO from south China and highlighted the clinical features, laboratory tests, imaging characteristics and treatment outcomes. Increasing awareness of this disease is important to decrease time to diagnosis, improve access to treatment, and reduce complications.

Pediatric Patients with a Dual Diagnosis of Inflammatory Bowel Disease and Chronic Recurrent Multifocal Osteomyelitis

ABSTRACT

There is a paucity of information about the epidemiology, pathophysiology, and treatment of patients with a dual diagnosis of inflammatory bowel disease (IBD) and chronic recurrent multifocal osteomyelitis (CRMO). A retrospective chart review was performed of patients at McMaster Children's Hospital with a diagnosis of either IBD or CRMO, to identify those with the dual diagnosis over a 10-year period. A dual diagnosis was identified in seven patients. Most patients (6/7) had a diagnosis of IBD first and were subsequently diagnosed with CRMO. At the time of CRMO diagnosis, IBD treatment regimens included one or more of, sulfasalazine (1/6), infliximab (3/6), adalimumab (1/6), or no treatment (1/6). Although the etiology of the link remains unknown, there does not seem to be an association to a specific IBD subtype, age, or treatment. Our patient population demonstrated a response to biologic agents, specifically tumor necrosis factor-α inhibitors, as treatment for both conditions.

Chronic recurrent multifocal osteomyelitis of the left femur associated with ulcerative colitis: a case report

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare condition characterized by chronic relapsing noninfectious bone inflammation of unknown etiology. Although CRMO is considered an extraintestinal manifestation in patients with inflammatory bowel disease, most cases of CRMO are associated with Crohn’s disease; very few are associated with ulcerative colitis (UC). We herein describe a 21-year-old patient with UC who developed recurrent left thigh pain. The patient was diagnosed with CRMO associated with UC, which was well controlled with azathioprine treatment.

Assessment of disease activity using a whole-body MRI derived radiological activity index in chronic nonbacterial osteomyelitis

BACKGROUND

Based on the recently developed ChRonic nonbacterial Osteomyelitis MRI Scoring tool (CROMRIS), we developed a radiological activity index (RAI-CROMRIS) to obtain a quantification of the overall bone involvement in individual patients.

METHODS

Whole Body Magnetic Resonance Imaging (WB-MRI) images were scored according to parameters included in the RAI-CROMRIS: bone marrow hyperintensity, signal extension, soft tissue/periosteal hyperintensity, bony expansion, vertebral collapse. These parameters were evaluated for each bone unit yielding a score from 0 to 7 and summed up as RAI-CROMRIS including all bone units. We assessed clinical disease activity using a physician global assessment (PGA) and radiological findings in 76 treatment-naïve patients; 46 of 76 were evaluated at 6 and 12 months after initial WB-MRI. Quantitative variables were compared using the Mann-Whitney U test for unmatched groups and the Wilcoxon signed-rank test for paired groups. Correlation was evaluated using Spearman's rank coefficient (r_s).

RESULTS

There was a significant correlation between RAI-CROMRIS and PGA (r_s = 0.32; p = 0.0055), between RAI-CROMRIS and presence of elevated erythrocyte sedimentation rate (p = 0.013) and C-reactive protein (p = 0.0001) at baseline. The RAI-CROMRIS decreased from a median of 17 at baseline to 12 at 6 months (p = 0.004) and remained stable (median 11) at 12 months. A correlation between the RAI-CROMRIS and the PGA was observed at baseline (r_s = 0.41; p = 0.004) and during follow up at 6 months (r_s = 0.33; p = 0.025) and 12 months (r_s = 0.38; p = 0.010). The baseline RAI-CROMRIS (median 20) was significantly higher in patients who subsequently received bisphosphonates than in patients who received other treatments (median 12) and decreased significantly after bisphosphonates (p = 0.008).

CONCLUSIONS

The RAI-CROMRIS was correlated with clinical and laboratory measures of disease activity showing significant short-term changes following treatment with bisphosphonates. This tool could be used in clinical practice and clinical trials after validation.

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.

Chronic recurrent multifocal osteomyelitis and primary sclerosing cholangitis with type 1 autoimmune hepatitis in a child with ulcerative colitis: a case report

Background

Chronic Recurrent Multifocal Osteomyelitis (CRMO) is a condition characterized by sterile bone inflammation, usually occurring in childhood. Although the etiology remains unclear, this condition has been associated with inflammatory bowel disease (IBD). Primary sclerosing cholangitis (PSC) and Autoimmune Hepatitis (AIH) are also uncommon pediatric conditions with a known association with IBD.

Case presentation

We present a unique case of a pediatric patient with an initial diagnosis of CRMO, with subsequent diagnosis of autoimmune hepatitis and PSC overlap, and eventually IBD.

Conclusions

Patients with CRMO may also develop PSC in addition to IBD, further highlighting the importance of IBD pathophysiology in both conditions. Clinical screening of associated gastrointestinal findings may be of value in patients with CRMO.

Chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO)

Chronic nonbacterial osteomyelitis (CNO) is an inflammatory bone disorder that most frequently affects children and adolescents. Chronic recurrent multifocal osteomyelitis (CRMO) is a severe form of CNO, usually characterized by symmetrical inflammatory bone lesions and its waxing and waning character. Sometimes severe and chronic pain can significantly affect the quality of life and psychosocial development of individuals affected. In the absence of prospectively tested and widely accepted diagnostic criteria or disease biomarkers, CNO remains a diagnosis of exclusion, and infections, malignancy and other differentials require consideration (1). The pathophysiology of CNO is not fully understood, but imbalanced cytokine expression and increased inflammasome activation in monocytes from CNO patients contribute to a pro-inflammatory phenotype that contributes to bone inflammation (2). Currently, no medications are licensed for the use in CNO. Most patients show at least some response to nonsteroidal anti-inflammatory drugs, others require more aggressive treatment that can include corticosteroids, cytokine-blocking agents and/or bisphosphonates (3). While under the care of an experienced team and sufficient treatment, the prognosis is good, but some patients will develop sequalae which can include vertebral compression fractures (1).

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CNO is an autoinflammatory bone disorder mostly affecting children and adolescents.

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Dysregulated cytokine expression and pathological activation of inflammasomes play a central role.

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Treatment is based on experience from case series and expert consensus treatment plans.

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Understanding the exact molecular pathophysiology will allow patient stratification and individualized treatment.

Chronic Recurrent Multifocal Osteomyelitis of the Hand: A Rare Pediatric Condition

Background: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory condition characterized by bone pain and swelling, secondary to sterile bone osteolytic lesions. Estimated incidence is 1:1 000 000, with ~2% involving the hand. We present a case series of CRMO of the hand and review the available literature, with the aim of educating and raising awareness of this condition. Methods: A retrospective chart review was conducted for all patients presenting to the institution diagnosed with CRMO involving the hands. Subsequently, a literature review was performed. Results/Case Series: Three cases of CRMO of the hand were identified. Age ranged from 20 months to 6 years, with 1 female. Time from presentation to diagnosis ranged from 3 to 15 months. Two had a single lesion, with the remaining patient having a second lesion on full-body magnetic resonance imaging (MRI). Three lesions involved phalanges, and one involved a metacarpal. Two received antibiotics without improvement prior to diagnosis. After diagnosis of CRMO, two received intravenous pamidronate. They both later showed improvement on MRI. Conclusion: CRMO is a rare disease with scarce literature to guide management. We present a series of CRMO specifically of the hand. The cases educate key stakeholders, raise awareness of the diagnosis, and illustrate challenging aspects of managing these patients. This includes the special functional and anatomical consideration essential in managing cases involving the hand.

Rare presentation of chronic recurrent multifocal osteomyelitis of the Iliac wing mimicking Ewing's sarcoma

This report describes a case of chronic recurrent multifocal osteomyelitis (CRMO) in an 11-year-old girl, involving the iliac bone as an initial, solitary site. Atypical imaging features were suspicious of a bone tumour, such as Ewing's sarcoma. Chronic recurrent multifocal osteomyelitis is a great masquerader and can present atypically. Radiologists should be familiar with both typical and atypical presentations, to determine an accurate diagnosis and guide appropriate management. Timely diagnosis may avoid invasive bone biopsy and inappropriate long-term antibiotic prescription for children.

[Chronic nonbacterial osteomyelitis : Imaging and differential diagnoses]

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease in childhood and adolescence with a preference for the female gender. It is manifested with multiple osseous lesions, with a predilection for the metaphyseal end zones of the long bones of the lower extremities. These bone lesions usually occur multifocally, can recur and develop a different appearance depending on the bone structure affected. Patients present with a longer disease history, changing clinical symptoms and unspecific paraclinical signs. Magnetic resonance imaging (MRI) is the imaging of choice and particularly as a whole body examination can speed up the diagnosis and is an important component of follow-up controls. Differential diagnoses include numerous inflammatory, benign and malignant bone diseases. Therefore, it is essential to know the diagnosis of CNO and to take it into consideration in cases of an unclear inflammatory bone process in young patients.

New Insights into Adult and Paediatric Chronic Non-bacterial Osteomyelitis CNO

Purpose of Review

To describe in detail the clinical synopsis and pathophysiology of chronic non-bacterial osteomyelitis and SAPHO syndrome.

Recent Findings

Chronic non-bacterial osteomyelitis (CNO) has been identified as a disease entity for almost 50 years. This inflammatory bone disorder is characterized by osteolytic as well as hyperostotic/osteosclerotic lesions. It is chronic in nature, but it can present with episodic flairs and phases of remission, which have led to the denomination “chronic recurrent osteomyelitis”, with its severe multifocal form “chronic recurrent multifocal osteomyelitis” (CRMO). For almost three decades, an infectious aetiology had been considered, since especially Propionibacterium acnes had been isolated from bone lesions of individual patients. However, this concept has been challenged since long-term antibiotic therapy did not alter the course of disease and modern microbiological techniques (including PCR) failed to confirm bone infection as an underlying cause. Over recent years, a profound dysregulation of cytokine expression profiles has been demonstrated in innate immune cells of CNO patients. A hallmark of monocytes from CNO patients is the failure to produce immune regulatory cytokines interleukin-10 (IL-10) and IL-19, which have been linked with genetic and epigenetic alterations. Subsequently, a significant upregulation of pro-inflammatory, NLRP3 inflammasome-dependent cytokines (IL-1β and TNF-α), has been demonstrated.

Summary

The current knowledge on CNO, the underlying molecular pathophysiology, and modern imaging strategies are summarized; differential diagnoses, treatment options, outcome measures, as well as quality of life studies are discussed.

A severe presentation of chronic non-infectious osteomyelitis associated with ulcerative colitis: a case report

Background

Chronic Non-Infectious Osteomyelitis (CNO) is a chronic, relapsing, self-limiting inflammation of the bone. Although it is rare, CNO has been associated with inflammatory bowel disease and frequently precedes the initial diagnosis. We present a case of CNO in a patient with known ulcerative colitis in clinical remission who presented with purulent multifocal joint effusions in the setting of elevated inflammatory markers and fever suspicious for bacterial osteomyelitis.

Case presentation

Our patient is a 12-year-old girl with ulcerative colitis who presented with fevers and insidious onset of joint pain at multiple sites. She had multiple joint effusions on imaging and blood and joint cultures were negative. Biopsy of the left acromion demonstrated acute and chronic osteomyelitis with areas of necrosis and granulomatous inflammation suggestive of CNO. Patient was started on high dose corticosteroids as well as methotrexate injections with marked improvement in symptoms.

Conclusion

This case highlights that while purulent effusions are often indicative of bacterial osteomyelitis, the consideration of CNO in a patient with inflammatory bowel disease (IBD) with multifocal small bone involvement and negative blood cultures should be considered.

Favorable outcome of extended curettage for the treatment of unifocal chronic sclerosing osteomyelitis of clavicle: a case series

BACKGROUND

Chronic sclerosing osteomyelitis (CSO) of the clavicle, especially its unifocal subset, is scarcely reported, and little is known about its characteristic features and treatment. We aim to describe the characteristic features and outcome of treatment in a series of patients with unifocal CSO of the clavicle.

MATERIALS AND METHODS

In a retrospective study, we identified 6 patients with a diagnosis of unifocal CSO of the clavicle. All patients underwent a core needle biopsy, and histologic examination confirmed the diagnosis. Laboratory investigations included the white blood cell count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and bacteriologic culture. We used plain radiographs, computed tomography scanning, and magnetic resonance imaging for the radiologic evaluation.

RESULTS

The median age of the patients was 16.5 years (range, 10-29 years). The ESR and CRP level were elevated in 5 cases. The bacterial culture results were negative in all cases. Sclerosis was the main radiologic symptom. Other radiologic features such as bone expansion, cystic change, periosteal reaction, cortex destruction, and soft-tissue edema could accompany sclerosis. Anti-inflammatory medications temporarily and slightly reduced the symptoms. Four patients underwent extended curettage, in whom the clinical, radiologic, and laboratory symptoms considerably subsided. In the 2 patients who did not agree to undergo surgical intervention, the clinical and radiologic symptoms fluctuated at the follow-up visits.

CONCLUSION

Unifocal CSO of the clavicle is associated with negative bacterial culture results, but the ESR and CRP level are frequently elevated. The symptoms fluctuate if not adequately treated. Extended curettage could be regarded as the treatment of choice.

Chronic non-bacterial osteomyelitis: a comparative study between children and adults

BACKGROUND

To compare clinical presentation, diagnostic and treatment strategies, and outcome between pediatric and adult patients with chronic non-bacterial osteomyelitis (CNO).

METHODS

Retrospective single-centre comparative study of pediatric and adult patients diagnosed with chronic recurrent multifocal osteomyelitis (CRMO)/CNO or synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome treated at the Medical University of Graz.

RESULTS

24 pediatric patients diagnosed with CRMO/CNO and 10 adult patients diagnosed with SAPHO syndrome were compared. Median age at diagnosis was 12.3 years (range 7.9-18.9) in the pediatric group and 32.5 years (range 22-56) in the adult group. Median time to diagnosis was shorter in children than in adults (0.3 vs. 1.0 years). Initial clinical presentation, laboratory and histopathological findings were similar in children and adults. Mean numbers of bone lesions were comparable between pediatric and adult patients (3.1 vs. 3.0), as were rates of skin involvement (33% vs. 30%). Sternal involvement was more frequent in adults whereas involvement of clavicle and long bones was more frequent in children (41.7% vs.10, 33% vs. 10%). Computerized tomography (CT) was used more often in adults, whereas whole-body magnetic resonance imaging (MRI) was used only in children. Bisphosphonates were applied more often in children and outcome was better in children than in adults (62.5% vs.30%).

CONCLUSION

Results of our study suggest that CNO/CRMO and SAPHO syndrome in children and adults might represent a single clinical syndrome that needs a similar diagnostic and therapeutic approach.

Chronic recurrent multifocal osteomyelitis-case report of two patients and review of literature

Background

Chronic Recurrent Multifocal Osteomyelitis (CRMO) is an autoinflammatory skeletal disease characterized by unifocal or multifocal nonbacterial inflammatory bone lesions in the metaphysis of long bones. Common sites of CRMO are tibia, pelvis, proximal femur, clavicle, calcaneum and vertebrae. However, unifocal presentation or presentation in adults, atypical locations, and absence of recurrence have also been reported.

Methods and Findings

We describe two cases of female patients with unifocal presentation of nonbacterial inflammatory bone lesions in the upper and lower extremity. Furthermore, a review of literature is presented.

Conclusion

Although CRMO is seen primarily in children and adolescents, and usually occurs in a multifocal pattern, our cases illustrate that this disease can arise in adult patients and in a single location. The diagnosis of CRMO should be made in a multi-disciplinary approach amongst orthopedic surgeons, radiologists and pathologists.

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.

Radionuclide Imaging of Infection and Inflammation in Children: a Review

With the exception of radiolabeled monoclonal antibodies, antibody fragments and radiolabeled peptides which have seen little application in the pediatric population, the nuclear medicine imaging procedures used in the evaluation of infection and inflammation are the same for both adults and children. These procedures include (1) either a two- or a three-phase bone scan using technetium-99m methylene diphosphonate; (2) Gallium 67-citrate; (3) in vitro radiolabeled white blood cell imaging (using ¹¹¹Indium-oxine or ^99mTechnetium hexamethyl-propylene-amine-oxime-labeled white blood cells); and (4) hybrid imaging with ¹⁸F-FDG. But children are not just small adults. Not only are the disease processes encountered in children different from those in adults, but there are developmental variants that can mimic, but should not be confused with, pathology. This article discusses some of the differences between adults and children with osteomyelitis, illustrates several of the common developmental variants that can mimic disease, and, finally, focuses on the increasing use of ¹⁸F-FDG PET/CT in the diagnosis and response monitoring of children with infectious and inflammatory processes. The value of and need for pediatric specific imaging protocols are reviewed.

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.

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.

CT and MRI of Rare Extraintestinal Manifestations of Inflammatory Bowel Disease in Children and Adolescents

Inflammatory bowel disease (IBD) is associated with a spectrum of extraintestinal manifestations (EIMs) affecting many organ systems. EIMs can occur in more than 40% of patients with IBD and are associated with significant morbidity. They occur at any time point in the course of disease, often during an active phase of bowel inflammation, but sometimes preceding bowel disease. Prompt recognition of EIMs enables timely and more effective therapy. Physicians who image patients with IBD should be aware of the myriad extraintestinal conditions that may be detected on imaging studies, both within and outside of the abdomen, as they may predate the diagnosis of IBD. Cross-sectional imaging of unusual conditions associated with IBD will be presented, including pathology in the hepatobiliary, pancreatic, genitourinary, musculoskeletal, mucocutaneous, vascular, neurologic, and pulmonary systems.

Characteristics and outcomes of chronic non-bacterial osteitis in children

OBJECTIVE

To determine patient characteristics, clinical presentation, pattern of involvement, treatment, and outcome of patients with chronic non-bacterial osteitis (CNO).

MATERIAL AND METHODS

Consecutive cases of CNO were analyzed at a single center for pediatrics and adolescent medicine from 2006 to 2013 in terms of patient characteristics, clinical presentation, pattern of involvement, treatment, and outcome.

RESULTS

We identified 32 children aged 1.5-15 years who were diagnosed with CNO between 2006 and 2013. A maximum of 12 bones per patient were affected in a total of 114 documented locations. The pelvis and clavicle (affecting 34% of patients each) were the most frequently affected bones. The foot skeleton was the most commonly affected region in 60% of patients. Skin manifestations were found in 7 (21%) patient. Increased inflammatory signs at presentation were detected in 18 patients. Pathological findings were found in all 30 children examined using magnetic resonance imaging (MRI), in 10 of 11 children examined using radiography, and in 8 of 10 patients examined using skeletal scintigraphy. Bone biopsy was performed in 9 patients. For initial treatment, non-steroidal anti-inflammatory drugs (NSAIDs) or coxibs were used in 28 (87.5%) patients. Remission or satisfactory follow-up was achieved in all patients.

CONCLUSION

Today, CNO is increasingly diagnosed using MRI and rarely through histological examinations. Therapeutic strategies include NSAIDs, which are often highly effective. All patients in the present study showed good clinical outcomes.

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

OBJECTIVE

To document more fully the characteristics of chronic recurrent multifocal osteomyelitis (CRMO) in pediatric patients, to collect data on the outcomes and management of the disease, and to define prognostic factors.

METHODS

One hundred seventy-eight patients were included (123 female patients and 55 male patients), with a mean ± SD age at diagnosis of 10.9 ± 2.9 years. Inclusion criteria were a diagnosis of CRMO, evidence of at least one lesion of osteitis confirmed by imaging, and development of the syndrome before age 18 years.

RESULTS

Longitudinal clinical and imaging studies revealed that only 12 of 178 CRMO patients (7%) had unifocal lesions at the last medical visit. We were able to apply the clinical chronic nonbacterial osteomyelitis score to 110 of 178 patients (62%), which indicated that bone biopsy could have been avoided in 27 cases (25%). At the last medical visit, disease was in remission in only 73 of 171 patients (43%) (41% receiving therapy) after a mean ± SD of 47.9 ± 38.9 months; 44 of 171 patients (26%) experienced sequelae. Using cluster analysis, the CRMO cohort was separated into 3 homogeneous phenotypes (severe, mild, and intermediate). Patients with the severe phenotype had the worst prognosis. This group was entirely composed of male patients, most of whom had the multifocal form of CRMO and inflammatory syndrome. Patients with the mild phenotype had the best prognosis. This group was primarily composed of female patients with a unifocal form of CRMO and infrequent clavicle involvement and inflammatory syndrome. Patients with the intermediate phenotype had a good prognosis but greater reliance on treatment. This group primarily included female patients with multifocal lesions and inflammatory syndrome.

CONCLUSION

This is the largest CRMO cohort described in the literature to date. Clinical evolution and imaging investigations confirmed the multifocal pattern of the disease. Three distinct subgroups of CRMO patients were distinguished, with very different prognoses.

Chronic recurrent multifocal osteomyelitis and inflammatory bowel disease

Chronic recurrent multifocal osteomyelitis (CRMO) has been reported in association with inflammatory bowel disease (IBD), mostly in children. We describe the UK paediatric experience of CRMO and IBD and review the global literature. Three cases of CRMO and IBD were identified in UK children during the last 10 years. This adds to the previously published 24 cases worldwide (15 children). We provide further evidence for the true association of CRMO and IBD, and a greater understanding of disease course. CRMO may be considered a rare extraintestinal complication of IBD.

New discoveries in CRMO: IL-1β, the neutrophil, and the microbiome implicated in disease pathogenesis in Pstpip2-deficient mice

Chronic non-bacterial osteomyelitis (CNO), chronic recurrent multifocal osteomyelitis (CRMO) and synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome are autoinflammatory disorder(s) in which sterile osteomyelitis is frequently accompanied by inflammatory conditions of the joints, skin, or intestine. Patients with CRMO commonly have a personal or family history of psoriasis, inflammatory bowel disease, and inflammatory arthritis, suggesting shared disease pathogenesis. Work by our group and others has demonstrated that dysregulation of interleukin-1 (IL-1) signaling can drive sterile osteomyelitis in the two human monogenic forms of the disease. Recent work in the chronic multifocal osteomyelitis (cmo) mouse model demonstrates that the disease is IL-1-mediated, that neutrophils are critical effector cells and that both caspase-1 and caspase-8 play redundant roles in mediating the cleavage of pro-IL-1β into its biologically active form. Recent data in the cmo mouse demonstrate that dietary manipulation alters the cmo microbiome and can prevent the development of osteomyelitis. Further investigation is needed to determine the specific components of the diet that result in protection from disease and if this finding can be translated into a treatment for human CRMO.

Autoinflammatory bone disorders: update on immunologic abnormalities and clues about possible triggers

PURPOSE OF REVIEW

To provide an update on the genetics and immunologic basis of autoinflammatory bone disorders including chronic recurrent multifocal osteomyelitis including the monogenic forms of the disease.

RECENT FINDINGS

Ongoing research in murine, canine and human models of sterile bone inflammation has solidified the hypothesis that sterile bone inflammation can be genetically driven. Mutations in Pstpip2, LPIN2 and IL1RN have been identified in monogenic autoinflammatory bone disorders that have allowed more detailed dissection of the immunologic defects that can produce sterile osteomyelitis. Recent studies in murine chronic multifocal osteomyelitis, deficiency of the interleukin-1 receptor antagonist (DIRA), Majeed syndrome and SAPHO syndrome reveal abnormalities in innate immune system function. IL-1 pathway dysregulation is present in several of these disorders and blocking IL-1 therapeutically has resulted in control of disease in DIRA, Majeed syndrome and in some cases of SAPHO and CRMO. Basic research demonstrates the importance of the innate immune system in disease pathogenesis and offers clues about potential disease triggers.

SUMMARY

Research and clinical data produced over the last several years support the important role of innate immunity in sterile osteomyelitis. Based on what has been learned in the monogenic autoinflammatory bone disorders, IL-1 is emerging as an important pathway in the development of sterile bone inflammation.

A systematic review of SAPHO syndrome and inflammatory bowel disease association

BACKGROUND

The association between inflammatory bowel disease (IBD) and synovitis, acne, pustulosis, hyperostosis, osteitis syndrome (SAPHO syndrome) was first reported in 1992. To date, only case reports and short series have been published.

AIMS

The purpose of this study was to report new cases and systematically review the literature on this association.

MATERIALS AND METHODS

All patients with concomitant diagnosis of SAPHO syndrome and IBD were identified from the databases of the rheumatology and gastroenterology departments of our institution. In addition, we systematically searched for published full articles in Medlars Online International Literature via PubMed. Relevant information of each positive match was collected and all authors were contacted for additional clinical data.

RESULTS

Three patients sharing both SAPHO syndrome and IBD were identified among the 62 patients with SAPHO syndrome (4.8 % of the SAPHO cohort) and the 1,309 patients with IBD (0.2 % of the IBD cohort) from our hospital database. After a systematic review, a total of 39 reported patients with concomitant diagnosis of SAPHO syndrome and IBD were identified. There was a female predominance and most had Crohn's disease with colonic involvement.

CONCLUSIONS

The association of SAPHO syndrome and IBD seems to be rare among IBD patients but not so among SAPHO patients. SAPHO could be underdiagnosed because of the similarity of its clinical manifestations and some more common extraintestinal manifestations or drug-related side effects in IBD.

Autoinflammatory bone disorders

Autoinflammatory bone disorders are characterized by chronic non-infectious osteomyelitis and inflammation-induced bone resorption and result from aberrant activation of the innate immune system. Sporadic chronic non-bacterial osteomyelitis (CNO) is the most common disease subtype. The clinical picture is highly variable and the exact underlying pathophysiology remains to be determined. Recently, novel insights in the pathophysiology of sterile bone inflammation have been gathered by analyzing patients with rare, monogenic inflammatory diseases. In this overview CNO and Majeed syndrome, cherubism, hypophosphatasia and primary hypertrophic osteoarthropathy will be discussed. For the latter four disorders, a genetic cause affecting bone metabolism and leading to chronic bone inflammation has been described. The exact pathophysiology of CNO remains to be determined. Insights from monogenic autoinflammatory bone diseases and the identification of distinct inflammatory pathways may help to understand the pathogenesis of bone inflammation and inflammation-induced bone resorption in more common diseases.

Chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease occurring primarily in children and adolescents. Episodes of systemic inflammation occur due to immune dysregulation without autoantibodies, pathogens or antigen-specific T cells. CRMO is characterised by the insidious onset of pain with swelling and tenderness over the affected bones. Clavicular involvement was the classical description; however, the metaphyses and epiphyses of long bones are frequently affected. Lesions may occur in any bone, including vertebrae. Characteristic imaging includes bone oedema, lytic areas, periosteal reaction and soft tissue reaction. Biopsies from affected areas display polymorphonuclear leucocytes with osteoclasts and necrosis in the early stages. Subsequently, lymphocytes and plasma cells predominate followed by fibrosis and signs of reactive new bone forming around the inflammation. Diagnosis is facilitated by the use of STIR MRI scanning, potentially obviating the need for biopsy and unnecessary long-term antibiotics due to incorrect diagnosis. Treatment options include non-steroidal anti-inflammatory drugs and bisphosphonates. Biologics have been tried in resistant cases with promising initial results. Gene identification has not proved easy although research in this area continues. Early descriptions of the disease suggested a benign course; however, longer-term follow up shows that it can cause significant morbidity and longer-term disability. Although it has always been thought of as very rare, the prevalence is likely to be vastly underestimated due to poor recognition of the disease.

Chronic recurrent multifocal osteomyelitis: a first report from Saudi Arabia

BACKGROUND AND OBJECTIVES

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare, systemic, aseptic, inflammatory disorder that involves different sites. Pathogenesis of chronic recurrent multifocal osteomyelitis is currently unknown. To our knowledge, there are no reports of CRMO from Saudi Arabia. We describe the clinical and laboratory features and treatment of a cohort of children with CRMO.

DESIGN AND SETTING

Retrospective, patients referred to pediatric rheumatology clinic at a tertiary care center in Riyadh, Saudi Arabia.

PATIENTS AND METHODS

The diagnosis of CRMO was based on evidence of recurrent osteomyelitis with radiographic evidence of chronic osteomyelitis involving at least two sites in the absence of infectious cause in a child less than 14 years old.

RESULTS

Ten patients (9 female, 1 male) with CRMO; 2 patients presented in infancy. The referral diagnosis was inaccurate in all patients. All of them presented with pain and 8 of them had associated swelling and were found to have multifocal lesions. Imaging studies showed findings consistent with chronic osteomyelitis. Histopathological and microbiological examination confirmed the diagnosis in 9 patients. Cyclic pamidronate infusions induced good improvement in 6 patients.

CONCLUSION

This report indicates that CRMO may be overlooked in our community. Early diagnosis and treatment are required to avoid potential complications.

Low-grade osteomyelitis of the fifth metatarsal with possible concomitant Freiberg's disease of the metatarsal head

Freiberg's disease, metatarsal avascular necrosis, is most often seen in healthy athletic adolescent girls. Presenting symptoms include vague pain, swelling, and loss of motion in the involved metatarsophalangeal joints. Low-grade osteomyelitis often is difficult to identify. In this case report, we present a 14-year-old girl with low-grade osteomyelitis of the fifth metatarsal accompanied by possible Freiberg's disease in the same metatarsal.

Sternocostal involvement in chronic recurrent multifocal osteomyelitis associated with ulcerative colitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a chronic, relapsing, inflammatory, non-infectious disorder of the skeletal system and is of unknown origin. Early diagnosis of the disease is essential to exact treatment. The relationship between inflammatory bowel disease and CRMO is understood as extraintestinal rheumatic manifestations. CRMO associated with ulcerative colitis (UC) is very rarely reported. This case is first report of sternocostal involvement in CRMO associated with UC.

Current understanding of the pathogenesis and management of chronic recurrent multifocal osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory disorder that primarily affects children. Its hallmark is recurring episodes of sterile osteomyelitis. The clinical presentation is insidious onset of bone pain with or without fever. Laboratory studies typically reveal nonspecific evidence of inflammation. Radiologic imaging and histologic appearance resemble those of infectious osteomyelitis. There is a strong association with inflammatory disorders of the skin and intestinal tract in affected individuals and their close relatives, suggesting a shared pathophysiology and supporting a genetic component to disease susceptibility. Two genetic syndromes have CRMO as a prominent phenotype-Majeed syndrome and deficiency of the interleukin-1 receptor antagonist-and suggest that interleukin-1 may be a key cytokine in disease pathogenesis. This review briefly summarizes the main clinical and radiologic aspects of the disease and then focuses on genetics and pathophysiology and provides an update on treatment.