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

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

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is an inflammatory disorder of bone, typically arising adjacent to the physes of long bones but also seen throughout the skeleton. For patients with spinal involvement, CRMO lesions can cause compression deformities with a range of severity from minimal anterior wedging to circumferential height loss, known as vertebra plana. This study examines a large cohort of CRMO patients to determine the prevalence of spine involvement and vertebral deformity.

METHODS

This is a retrospective review of all patients with a diagnosis of CRMO seen at our institution between January 2003 and December 2020. These patients were identified through a prospectively maintained database of all CRMO patients seen at the institution. A retrospective review was undertaken to identify all patients with spinal involvement and determine the prevalence of CRMO in the spine and its effects on vertebral height and deformity.

RESULTS

Of 170 patients included in this study, 48 (28.2%) were found to have spinal involvement. Among patients with spinal involvement, vertebral body lesions were identified in 27 (56.3%) patients. The remaining lesions were in the sacrum or posterior elements. Radiographic evidence of the vertebral body height loss was noted in 23 of these 27 patients.

CONCLUSIONS

This cohort of CRMO patients demonstrates that 28% of patients have spinal involvement, and 48% of those patients have vertebral body height loss. While the ideal treatment for spinal CRMO has yet to be determined, imaging studies, including whole-body MRI and spine-specific MRI, are useful in identifying vertebral lesions and deformities. Identification and surveillance of these lesions are important as the disorder has a relapsing and remitting course, and patients can develop significant vertebral body height loss. Once deformity has developed, we have seen no evidence of reconstitution of the height of the collapsed vertebra. Bisphosphonates have been successful in preventing the progression of vertebral body height loss.

LEVEL OF EVIDENCE

Level II: Retrospective study investigating spinal involvement and prevalence of vertebral body deformity in patients diagnosed with CRMO.

Musculoskeletal symptoms and their impact on health-related quality of life in chronic nonbacterial osteomyelitis patients

INTRODUCTION

Chronic non-bacterial osteomyelitis (CNO) is a rare, non-infection- related inflammatory disorder that affects children and teens. Clinical manifestations of CNO range widely from moderate, time-limited, monofocal inflammation of the bone to extreme multifocal or chronically active inflammation of the bone.

OBJECTIVES

The main aim of this study was to explore the correlation between musculoskeletal (MSK) symptoms and health-related quality of life (HRQoL) in patients with CNO.

METHODS

Children and adults with CNO and their parents were asked to answer a web-based survey. The survey consisted of multiple questions centered around demographic, clinical and therapeutic data, MSK discomfort form based on the Nordic MSK Questionnaire and HRQoL based on Pediatric Quality of Life Inventory-4 (PedsQL-4) and PedsQL rheumatology module. The inclusion criteria included diagnosis of CNO before the age of 18. Patients who had malignancies or any chronic rheumatic, MSK, neurological disease prior to CNO onset were excluded.

RESULTS

There was a total of 68 participants, mostly females (66.2%), with median age 14 years and median disease duration 4.75 years. The median number of bones affected by CNO was 5 and ranged from 1 to 24 bones. Among the studied patients, 45 patients (66.2%) had MSK manifestations at the last month. The most commonly affected part was ankle and feet (26.5%). Regarding HRQoL, patients with MSK manifestations had lower scores than did patients without in PedsQL-4 (p < 0.001) including domains of physical functioning (p < 0.001), emotional functioning (p = 0.033), social functioning (p < 0.001) and school functioning (p = 0.007) in addition to lower scores in PedsQL rheumatology module (p < 0.001) including domains of pain and hurt (p < 0.001), daily activities (p < 0.001), treatment (p = 0.035), worry (p = 0.001) and communication (p < 0.001).

CONCLUSION

MSK manifestations have a negative impact on HRQoL in CNO patients. So, early identification and treatment are highly recommended.

Chronic Recurrent Multifocal Osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is an underrecognized autoinflammatory disease affecting the skeletal system. Its vague symptoms are often first attributed to growing pains, infection, or malignancy, which can lead to a delay in diagnosis for days to years. Untreated CRMO has the potential to cause debilitating skeletal deformities, arthritis, and chronic pain; hence early recognition and treatment are paramount. MRI is the gold standard for diagnosis. Treatment consists of various antiinflammatory medications and may also include bisphosphonates if vulnerable skeletal sites are involved. Even when treated, the disease may have a relapsing course lasting years.

Machine Learning Algorithm: Texture Analysis in CNO and Application in Distinguishing CNO and Bone Marrow Growth-Related Changes on Whole-Body MRI

OBJECTIVE

The purpose of this study is to analyze the texture characteristics of chronic non-bacterial osteomyelitis (CNO) bone lesions, identified as areas of altered signal intensity on short tau inversion recovery (STIR) sequences, and to distinguish them from bone marrow growth-related changes through Machine Learning (ML) and Deep Learning (DL) analysis.

MATERIALS AND METHODS

We included a group of 66 patients with confirmed diagnosis of CNO and a group of 28 patients with suspected extra-skeletal systemic disease. All examinations were performed on a 1.5 T MRI scanner. Using the opensource 3D Slicer software version 4.10.2, the ROIs on CNO lesions and on the red bone marrow were sampled. Texture analysis (TA) was carried out using Pyradiomics. We applied an optimization search grid algorithm on nine classic ML classifiers and a Deep Learning (DL) Neural Network (NN). The model's performance was evaluated using Accuracy (ACC), AUC-ROC curves, F1-score, Positive Predictive Value (PPV), Mean Absolute Error (MAE) and Root-Mean-Square Error (RMSE). Furthermore, we used Shapley additive explanations to gain insight into the behavior of the prediction model.

RESULTS

Most predictive characteristics were selected by Boruta algorithm for each combination of ROI sequences for the characterization and classification of the two types of signal hyperintensity. The overall best classification result was obtained by the NN with ACC = 0.91, AUC = 0.93 with 95% CI 0.91-0.94, F1-score = 0.94 and PPV = 93.8%. Between classic ML methods, ensemble learners showed high model performance; specifically, the best-performing classifier was the Stack (ST) with ACC = 0.85, AUC = 0.81 with 95% CI 0.8-0.84, F1-score = 0.9, PPV = 90%.

CONCLUSIONS

Our results show the potential of ML methods in discerning edema-like lesions, in particular by distinguishing CNO lesions from hematopoietic bone marrow changes in a pediatric population. The Neural Network showed the overall best results, while a Stacking classifier, based on Gradient Boosting and Random Forest as principal estimators and Logistic Regressor as final estimator, achieved the best results between the other ML methods.

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.

A Successful Bisphosphonates Monotherapy in Spinal Form of Paediatric Chronic Recurrent Multifocal Osteomyelitis (CRMO)—Case Report

Chronic recurrent multifocal osteomyelitis (CRMO) is a non-infectious inflammatory disorder resulting from the multifocal bone and bone marrow lesions with periodic relapses and remissions and with an uncertain prognosis. Treatment options in CRMO are based on expert opinion and relatively small groups of patients. A nine-year-old female patient with no significant past medical history presented with compression fractures and multifocal bone lesions in the thoracic and lumbar spine, as shown in imaging (CT, MRI). Densitometry revealed a diffuse decrease in bone density. Based on the patient’s clinical image and above examinations, the other possible aetiologies—infectious (including tuberculosis), neoplasms, Langerhans cell histiocytosis—were ruled out, which led to eventual final diagnosis—CRMO. The patient was successfully treated with pamidronate infusion initiated in cycles over three consecutive days every 3 months. In addition to clinical improvement, there was a significant remission of inflammation and bone structure healing assessed by MRI after four treatment cycles. Intravenous bisphosphonates usage seems to be a good therapeutic option in CRMO paediatric patients with spinal localization of the lesions complicated by compressive fractures. However, more data, based on larger patient populations, are needed to provide a detailed paediatric CRMO treatment algorithm.

Sickle cell bone disease and response to intravenous bisphosphonates in children

Children with sickle cell disease (SCD) have the potential for extensive and early-onset bone morbidity. This study reports on the diversity of bone morbidity seen in children with SCD followed at three tertiary centers. IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

INTRODUCTION

To evaluate bone morbidity and the response to intravenous (IV) bisphosphonate therapy in children with SCD.

METHODS

We conducted a retrospective review of patient records from 2003 to 2019 at three Canadian pediatric tertiary care centers. Radiographs, magnetic resonance images, and computed tomography scans were reviewed for the presence of avascular necrosis (AVN), bone infarcts, and myositis. IV bisphosphonates were offered for bone pain management. Bone mineral density was assessed by dual-energy X-ray absorptiometry (DXA).

RESULTS

Forty-six children (20 girls, 43%) had bone morbidity at a mean age of 11.8 years (SD 3.9) including AVN of the femoral (17/46, 37%) and humeral (8/46, 17%) heads, H-shaped vertebral body deformities due to endplate infarcts (35/46, 76%), and non-vertebral body skeletal infarcts (15/46, 32%). Five children (5/26, 19%) had myositis overlying areas of AVN or bone infarcts visualized on magnetic resonance imaging. Twenty-three children (8/23 girls) received IV bisphosphonate therapy. They all reported significant or complete resolution of bone pain. There were no reports of sickle cell hemolytic crises, pain crises, or stroke attributed to IV bisphosphonate therapy.

CONCLUSION

Children with SCD have the potential for extensive and early-onset bone morbidity. In this series, IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

Chronic nonbacterial osteomyelitis: the role of whole-body MRI

Background

Chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is a noninfectious autoinflammatory disorder that occurs primarily in children and adolescents and is characterized by episodic musculoskeletal pain with a protracted course.

Main body

Traditionally, the diagnosis of CNO is made by exclusion and commonly requires bone biopsy to rule out infection and malignancy. However, bone biopsy may be avoided when imaging and clinical characteristic features are present, such as multifocal bone lesions at typical sites, no constitutional symptoms and no signs of infection in laboratory test results. Whole-body magnetic resonance imaging (WB-MRI) can assess signs of acute and chronic inflammation and enables the detection of CNO typical patterns of lesion location and distribution, thereby helping to exclude differential diagnosis. The goal of the present study paper is to review the main clinical and imaging aspects of the disease with emphasis on the role of WB-MRI in the diagnosis, assessment of disease burden and follow-up monitoring.

Conclusion

Radiologists need to be familiar with the imaging features to suggest the diagnosis as the early therapy may help to avoid irreversible secondary damage of skeletal system.

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

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSION

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

Chronic recurrent multifocal osteomyelitis, a rare disease. Case report

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

Management of chronic recurrent multifocal osteomyelitis: review and update on the treatment protocol

INTRODUCTION

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disorder primarily affecting children. It is characterized by a peripheral involvement of the metaphysis of long bones rather than axial involvement. Due to the scarcity of the disease, there are no guidelines regarding its management.

AREAS COVERED

This review aims to provide an overview of the different therapeutic alternatives and recent protocols. For this reason, first-line and second-line treatment, as well as the impact of new therapies, are discussed in depth. We conducted a search through PubMed on the different aspects of CRMO. Outcomes were categorized as first and second-line treatments.

EXPERT OPINION

Non-steroidal anti-inflammatory drugs remain the keystone of CRMO management and are proposed as the first-line treatment. In the case of vertebral involvement, bisphosphonate should be considered, even as a first-line treatment. Several case series and retrospective studies highlight the efficacy of anti-TNF agents. Their use could be an optimal treatment choice for CRMO with comorbid immune-mediated diseases. The potentially favorable effect of interleukin-1 antagonists remains to be determined.

Prophylactic Effects of NFκB Essential Modulator–Binding Domain Peptides on Bone Infection: An Experimental Study in a Rabbit Model

Introduction

Methods

Results

Conclusion

Chronic Osteomyelitis With Proliferative Periostitis of the Mandible in a Child: Report of a Case Managed by Immunosuppressive Treatment

BACKGROUND

Osteomyelitis with proliferative periostitis is a relatively uncommon inflammatory condition of the jaws, mainly characterized by periosteal formation of reactive bone. It primarily affects children and adolescences, also referred to as Garre's osteomyelitis, more frequently involving the molar region of the mandible. Cases lacking an obvious source of infection may have an immunologically mediated etiopathogenesis, falling under the spectrum of primary chronic osteomyelitis or chronic recurrent multifocal osteomyelitis (CRMO).

CASE REPORT

Herein, we present a case of chronic osteomyelitis in a 6.5-year-old girl, who suffered from recurrent painful episodes of swelling of the mandible for the last 2 years, previously requiring hospitalization and administration of intravenous (IV) antibiotics and NSAIDs with limited responsiveness. The biopsy showed features consistent with osteomyelitis with proliferative periostitis. The patient was initially managed with an IV combination antibiotic regimen with only partial improvement. The possibility of an autoimmune mechanism in the context of primary chronic osteomyelitis or CRMO was considered, and immunosuppressive therapy (TNF inhibitor etanercept along with corticosteroids and methotrexate) was administered, resulting in clinical resolution.

CONCLUSIONS

Osteomyelitis and its childhood variants are relatively rare and their management presents several challenges. Although typically treated with administration of antibiotics, possibly along with surgical intervention, other treatment modalities may be necessary for resilient and persistent cases. In a subset of cases, especially in the absence of local infectious factors, immunologically mediated mechanisms may play an important role and appropriate immunosuppressive therapy may be effective.

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.

Patient-reported effectiveness and safety of Pamidronate in NSAIDs-refractory chronic recurrent multifocal osteomyelitis in children

To evaluate patient-reported effectiveness, safety and social influence of Pamidronate in the therapy of NSAIDs-refractory Chronic Recurrent Multifocal Osteomyelitis in children. Authors reviewed self-created questionnaires, which asked patients for symptoms alleviation, adverse drug reactions frequency and degree of severity and daily activities self-reliance. Only surveys with complete answers, which were returned to authors by an e-mail from juvenile patients treated for NSAIDs-refractory Chronic Recurrent Multifocal Osteomyelitis at the University Children’s Hospital of Cracow were analyzed. Between 2010 and 2019, 61 children were diagnosed with NSAIDs-refractory Chronic Recurrent Multifocal Osteomyelitis at our department. Out of 61 requests sent, 42 complete replies (33 females, 9 males) were gathered and analyzed. All patients included in this research were administered with at least one set of Pamidronate intravenously in the dose of 1 mg/kg/day for 3 consecutive days. Our analysis shows remarkable in terms of patient’s impressions decrease of pain intensity after 2.5 series of Pamidronate on average, and total pain resolution after 5.9 series on average. Overall number of adverse drug reaction events reported by responders was 105. One patient developed drug-dependent renal insufficiency in the course of therapy. Outcome assessment indicates that nearly 50% of the studied population was more eager to participate in social life just after the first infusion of the drug. 95% of the surveyed unanimously agreed to recommend Pamidronate therapy to cure NSAIDs-refractory CRMO. 39 out of 42 (93%) patients considered Pamidronate effective at the end of the treatment. Onset of Pamidronate’s action is gradual and differs in terms of symptoms alleviation between sexes. The therapy can induce considerable number of adverse drug reactions (2.5 per patient). Only 3 out of 42 (7%) patients were free from any ADRs. To demonstrate the impact of the use of Pamidronate on daily activities more precisely, further research with quantification of the quality of life is warranted.

Primary chronic osteomyelitis of the jaw: Rapid improvement after hormonal suppression in a girl with precocious puberty

Primary chronic osteomyelitis (PCO) of the jaw is a non-infectious, inflammatory state of the jawbone of unknown etiology. In recurrent periods, these patients often exhibit swelling of the cheek, impaired ability to open their mouth as well as pain. Available treatments today include anti-inflammatory or antiresorptive drugs, hyperbaric oxygen, surgical decortication or resection followed by reconstruction where none of them have been described to lead to restored anatomy and complete relief of symptoms. We here report the unexpected complete regression of all clinical symptoms of PCO within three months after initiating pubertal suppression therapy with a gonadotropin-releasing hormone analogue in a 9-year-old girl with PCO of the jaw and early onset of pubertal development. Radiology of the jawbone confirmed complete PCO remission when performed 18 months after starting the hormone suppression therapy. To our knowledge, total regression of PCO in such a short period of time has not been described earlier suggesting an effect of the anti-hormonal therapy per se. In this case report, we discuss possible underlying mechanisms and hypothesize that anti-hormonal treatment could be a potential effective treatment in patients with PCO of the jaw.

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.

Similarities and Differences between Clavicular Bacterial Osteomyelitis and Nonbacterial Osteitis: Comparisons of 327 Reported Cases

Background

Currently, both clavicular bacterial osteomyelitis (BO) and nonbacterial osteitis (NBO) remain not well understood owing to their much lower incidences. This study is aimed at summarizing similarities and differences between clavicular BO and NBO based on comparisons of literature-reported cases.

Methods

We searched the PubMed and Embase databases to identify English published literature between January 1^st, 1980, and December 31^st, 2018. Inclusion criteria were studies evaluating clinical features, diagnosis, and treatment of clavicular BO and NBO, with eligible data for synthesis analysis.

Results

Altogether, 129 studies with 327 patients were included. Compared with BO, clavicular NBO favored females (P < 0.001) and age below 20 years (P < 0.001) and mostly presented in a chronic phase (disease term exceeding 2 months) (P < 0.001). Although local pain and swelling were the top two symptoms for both disorders, fever, erythema, and a sinus tract were more frequently found in BO patients (P < 0.01). Although they both favored the medial side, lesions in the clavicular lateral side mostly occurred in BO patients (P = 0.002). However, no significant differences were identified regarding the serological levels of white blood cell count (P = 0.06), erythrocyte sedimentation rate (P = 0.27), or C-reactive protein (P = 0.33) between BO and NBO patients before therapy. Overall, the BO patients achieved a statistically higher cure rate than that of the NBO patients (P = 0.018).

Conclusions

Females, age below 20 years, and a long duration of clavicular pain and swelling may imply NBO. While the occurrence of a sinus tract and lesions in the lateral side may be clues of BO, inflammatory biomarkers revealed limited values for differential diagnosis. BO patients could achieve a better efficacy than the NBO patients based on current evidence.

Whole-body MRI in the diagnosis of paediatric CNO/CRMO

Chronic recurrent multifocal osteomyelitis (CRMO) is an auto-inflammatory disorder affecting the skeleton of children and adolescents. Whole-body MRI (WBMRI) is key in the diagnosis and follow-up of CRMO. Imaging protocols should include sagittal short Tau inversion recovery of the spine, imaging of the hands and feet, and T1 images for distinguishing normal bone marrow. CRMO lesions can be metaphyseal, epiphyseal and physeal-potentially causing growth disturbance and deformity. Spinal lesions are common, important and can cause vertebral collapse. Lesion patterns include multifocal tibial and pauci-focal patterns that follow a predictable presentation and course of disease. Common pitfalls of WBMRI include haematopoietic marrow signal, metaphyseal signal early on in bisphosphonate therapy and normal high T2 signal in the hands and feet. Pictorial reporting assists in recording lesions and follow-up over time. The purpose of this paper is to review the different WBMRI protocols, imaging findings, lesion patterns and common pitfalls in children with CRMO.

Chronic nonbacterial osteomyelitis - clinical and magnetic resonance imaging features

BACKGROUND

Chronic nonbacterial osteomyelitis (CNO) is a rare autoinflammatory bone disorder. Little information exists on the use of imaging techniques in CNO.

MATERIALS AND METHODS

We retrospectively reviewed clinical and MRI findings in children diagnosed with CNO between 2012 and 2018. Criteria for CNO included unifocal or multifocal inflammatory bone lesions, symptom duration >6 weeks and exclusion of infections and malignancy. All children had an MRI (1.5 tesla) performed at the time of diagnosis; 68 of these examinations were whole-body MRIs including coronal short tau inversion recovery sequences, with additional sequences in equivocal cases.

RESULTS

We included 75 children (26 boys, or 34.7%), with mean age 10.5 years (range 0-17 years) at diagnosis. Median time from disease onset to diagnosis was 4 months (range 1.5-72.0 months). Fifty-nine of the 75 (78.7%) children presented with pain, with or without swelling or fever, and 17 (22.7%) presented with back pain alone. Inflammatory markers were raised in 46/75 (61.3%) children. Fifty-four of 75 (72%) had a bone biopsy. Whole-body MRI revealed a median number of 6 involved sites (range 1-27). Five children (6.7%) had unifocal disease. The most commonly affected bones were femur in 46 (61.3%) children, tibia in 48 (64.0%), pelvis in 29 (38.7%) and spine in 20 (26.7%). Except for involvement of the fibula and spine, no statistically significant differences were seen according to gender.

CONCLUSION

Nearly one-fourth of the children presented with isolated back pain, particularly girls. The most common sites of disease were the femur, tibia and pelvic bones. Increased inflammatory markers seem to predict the number of MRI sites involved.

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

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

Chronic recurrent multifocal osteomyelitis in pediatrics: A diagnostic challenge

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disease that presents with aseptic bone inflammation and can be accompanied by multisystemic symptoms. We present the case of a 14-year-old male with a 2-week history of pain located at the tibial metaphysis and fever. X-ray revealed a lytic lesion in the tibial metaphysis. MRI revealed an intramedullary bone lesion with perilesional bone oedema. CT-guided biopsy discounted malignancy and microbiological cultures were negative. The patient's symptoms and fever worsened after the biopsy; therefore antibiotherapy was commenced for a suspected superinfection. A body MRI was performed given the persistence of the fever, which found a second active lesion in the spine that was diagnosed as CRMO and progressed well with anti-inflammatories. CRMO is an entity that is difficult to diagnose. Differential diagnosis is extensive with infectious diseases, tumours and other autoinflammatory diseases. Prompt diagnosis and appropriate treatment are crucial to prevent sequelae.

Response of Different Treatment Protocols to Treat Chronic Non-Bacterial Osteomyelitis (CNO) of the Mandible in Adult Patients: A Systematic Review

(1) Background: Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disease of finally unknown etiology, which can occur alone or related with syndromes (chronic recurrent multifocal osteomyelitis—CRMO; synovitis, acne, pustulosis, hyperostosis and osteitis syndrome—SAPHO). The involvement of the mandible is rather rare. (2) Methods: We carried out a systematic literature search on CNO with mandibular involvement, according to the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines, considering the different synonyms for CNO, with a special focus on therapy. (3) Results: Finally, only four studies could be included. A total of 36 patients were treated in these studies—therefore, at most, only tendencies could be identified. The therapy in the included works was inconsistent. Various therapies could alleviate the symptoms of the disease. A complete remission could only rarely be observed and is also to be viewed against the background of the fluctuating character of the disease. The success of one-off interventions is unlikely overall, and the need for long-term therapies seems to be indicated. Non-steroidal anti-inflammatory drugs (NSAIDs) were not part of any effective therapy. Surgical therapy should not be the first choice. (4) Conclusions: In summary, no evidence-based therapy recommendation can be given today. For the future, systematic clinical trials on therapy for CNO are desirable.

Periodic fever syndromes and the autoinflammatory diseases (AIDs)

Innate immune system represents the ancestral defense against infectious agents preserved along the evolution and species; it is phylogenetically older than the adaptive immune system, which exists only in the vertebrates. Cells with phagocytic activity such as neutrophils, macrophages, and natural killer (NK) cells play a key role in innate immunity. In 1999 Kastner et al. first introduced the term “autoinflammation” describing two diseases characterized by recurrent episodes of systemic inflammation without any identifiable infectious trigger: Familial Mediterranean Fever (FMF) and TNF Receptor Associated Periodic Syndrome (TRAPS). Autoinflammatory diseases (AIDs) are caused by self-directed inflammation due to an alteration of innate immunity leading to systemic inflammatory attacks typically in an on/off mode. In addition to inflammasomopathies, nuclear factor (NF)-κB-mediated disorders (also known as Rhelopathies) and type 1 interferonopathies are subjects of more recent studies.

This review aims to provide an overview of the field with the most recent updates (see “Most recent developments in..” paragraphs) and a description of the newly identified AIDs.

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Autoinflammatory diseases are caused by self-directed inflammation.

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Alteration of innate immunity leads to systemic inflammation attacks.

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The autoinflammatory field is exponentially expanding.

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The advances in AIDs have led to new insights into immune system understanding.

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Autoimmunity and autoinflammation features may be simultaneously present.

Non-surgical treatment of adults with chronic diffuse sclerosing osteomyelitis/tendoperiostitis of the mandible

Non-surgical therapy has proved to be effective in chronic diffuse sclerosing osteomyelitis (DSO) of the mandible in children. Therefore we aimed to investigate the effect of non-surgical therapy in adult DSO patients. We included consecutive patients with DSO who received non-surgical therapy in our center. They all received occlusal splint therapy, counselling about the disease, and/or physiotherapy by a specialised team. The use of analgesics, preferably nonsteroidal anti-inflammatory drugs, was advised for symptomatic control during periods of exacerbation. Sixteen patients (11/5 female/male) aged 39.9 ± 15.0 years with DSO of the mandible were included. The mean duration of symptoms was 39.7 ± 26.3 months before referral to our center. Patients were treated with a broad range of treatments before referral. All patients underwent non-surgical treatment. In 12 patients this led to remission. Four patients still had complaints after 12 months of non-surgical therapy and started with intravenous bisphosphonate therapy. In our center, DSO of the mandible was successfully treated with non-surgical therapy, despite a long duration before referral and extensive pre-treatment. Considering this high success rate, we recommend this non-surgical approach as the first treatment option for DSO of the mandible. In case of persistence, alternative treatments such as bisphosphonates should be explored.

A complicated path to the CRMO diagnosis - case of a 9 year old girl whose story comes full circle

Background

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare idiopathic autoinflammatory bone disease that mostly affects children and adolescents. It is a diagnosis of exclusions since no clinical signs and symptoms are pathognomonic. Radiological tests are often essential, but bone biopsy may be needed in unclear cases.

Case presentation

A 9-year-old Caucasian girl with a history of bone pain. The data from the history and results of laboratory tests suggested osteomyelitis, but no adequate response to the treatment was observed. A number of imaging tests did not confirm the diagnosis, therefore a bone biopsy was necessary.

Conclusions

Differential diagnosis of CRMO is challenging and it is based on exclusions. Since it might be misdiagnosed or mistreated, bone biopsy should be considered in patients reporting bone pain who are unresponsive to treatment.

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.

Painful transient edema in the tibial diaphysis: the challenges and the essence of biopsy in treatment

BACKGROUND

Some patients experience a non-traumatic pain in the tibial diaphysis similar to that in the clinical and radiological findings of a tumor, an infection or a stress fracture and cannot be definitively diagnosed even after biopsy. In this study, our aim was to exhibit the challenges in the diagnosis of this patient group and to evaluate this type of patients with a limited population in the literature.

METHODS

Eighteen extremities of 16 patients, whose complaints of non-traumatic pain in the tibial diaphysis were evaluated by our tumor council and T2-weighted MR scans of the medullary bone had shown hyperintense signal changes or tumor-like appearances, were evaluated with histological, radiological, and clinical results.

RESULTS

Lesions were detected in 18 extremities of the 16 patients (seven males, nine females; mean age 23 [range 7 to 51] years). Four of the lesions were in the right tibial diaphysis, ten were in the left, and two were bilateral. Laboratory findings of the patients were normal. Based on the decision of the tumor council, biopsy was performed on 12 patients. All patients' complaints were gone and MRI findings decreased during the follow-up period. The complaints of the three patients who did not have a biopsy decreased after a mean period of three months.

CONCLUSIONS

Medullary stress syndrome has been reported in the literature in various forms and in a limited number of cases, including longitudinal stress fracture and transient medullary edema of the bone. In light of our findings, we deduced that biopsy of the diaphyseal lesions in this patient group is essential and that the complaints of this patient group declined in the earlier term in comparison to the patients who were not performed biopsy.

Chronic recurrent multifocal osteomyelitis: a case report

Background

Chronic recurrent multifocal osteomyelitis (CRMO), also known as chronic nonbacterial osteomyelitis, is a rare, noninfectious inflammatory disorder that causes multifocal bone lesions with swelling and pain. Lytic and sclerotic bone lesions could be found on X-ray. Short tau inversion recovery magnetic resonance imaging (STIR MRI) shows bone marrow oedema, bone expansion, lytic areas and periosteal reaction. CRMO is characterized by periodic exacerbations and remissions of unclear/unknown pathogenesis.

Case presentation

A 10 years old girl, suffering from pain in her right shoulder since the age of 9 years presented to our Department. Thanks to clinical data, laboratoristic and radiological findings and bone biopsy CRMO was diagnosed. So patient started anti-inflammatory treatment and her conditions improved.

Conclusions

In a child with bone pain should be considered also rare condition as CRMO to perform a correct diagnosis and start an adequate treatment avoiding complications such as bone damage. This condition should be suspected in a child with recurrent bone pain, modest increase of inflammatory indices, lytic or sclerotic bone lesion on X Ray. Typical CRMO localizations are metaphyses of long bones, pelvis, clavicle, vertebral column, sternum, ribs, jaw, but any bone can be involved. The most common CRMO differential diagnosis is represented by infections, malignant bone tumors, Langerhans Cells Histiocytosis (LCH).

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.

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.