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

What Role Does PET/MRI Play in Musculoskeletal Disorders?

Musculoskeletal disorders of nononcological origin are one of the most frequent reasons for consultation. Patients suffering from musculoskeletal disorders also consult more than once for the same reason. This results in multiple clinical follow-ups after several radiological and serum examinations, the main ones including X-rays targeting the painful anatomical region and inflammatory serum parameters. As part of their work up, patients suffering from musculoskeletal disorders often require multisequence, multi-parameter MRI. PET/MRI is a promising imaging modality for their diagnosis, with the added advantage of being able to be performed in a single visit. PET/MRI is particularly useful for diagnosing osteomyelitis, spondylodiscitis, arthritis, many pediatric pathologies, and a wide range of other musculoskeletal pathologies. PET/MRI is already used to diagnose malignant bone tumors such as osteosarcoma. However, current knowledge of the indications for PET/MRI in nononcological musculoskeletal disorders is based on studies involving only a few patients. This review focuses on the usefulness of PET/MRI for diagnosing nononcological musculoskeletal disorders.

Sterile osteomyelitis: a cardinal sign of autoinflammation

Autoinflammatory bone disorders (ABDs) are characterized by sterile bone inflammation stemming from dysregulated innate immune responses. This review focuses on the occurrence of sterile osteomyelitis in ABDs and related diseases, notably chronic nonbacterial osteomyelitis (CNO) and its sporadic and monogenic forms, such as deficiency of the interleukin-1 (IL-1) receptor antagonist, Majeed syndrome, CNO related to FBLIM1 mutation, and pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA syndrome). Additionally, other autoinflammatory disorders (AIDs) are discussed, including classical periodic fever syndromes (e.g., familial Mediterranean fever, cryopyrin-associated periodic syndromes), monogenic rare AIDs (such as hyperostosis-hyperphosphatemia syndrome, H syndrome, interferonopathies, and Singleton-Merten's syndrome), polygenic AIDs with bone involvement (e.g., Schnitzler's syndrome, systemic juvenile idiopathic arthritis, adult-onset Still's disease, and calcium pyrophosphate deposition disease), and bone dysplastic syndromes. Sterile osteomyelitis emerges as a cardinal sign of autoinflammation, aiding clinicians in both diagnosis and management of ABDs. Treatment typically involves tumor necrosis factor inhibitors or IL-1 antagonists.

Chronic recurrent multifocal osteomyelitis in pediatric patients: A Chinese single center observational study and literature review

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory disorder that commonly poses diagnostic challenges due to its atypical symptomatology. This observational study aimed to investigate the clinical features, laboratory test results, imaging features, and treatment strategies for pediatric patients with CRMO. We retrospectively analyzed 7 pediatric patients with CRMO treated at the Department of Pediatric Orthopedics, First Affiliated Hospital of Guangzhou University of Chinese Medicine between January 2018 and February 2022. This study aimed to enhance current understanding of CRMO by exploring in-depth clinical data. The study cohort comprised 5 males and 2 females, aged 3 to 13 years. All patients experienced symptoms for a median duration of 6 months prior to hospitalization, at which point they presented with recurrent pain and various accompanying signs including hypothermia (14.28%), swelling (42.85%), localized skin warmth (42.85%), and plantar pustules (14.28%). The femurs (71.42%) and tibia (71.42%) were frequently affected. Radiographic and computed tomography scans revealed osteosclerosis and osteolytic lesions, while magnetic resonance imaging revealed bone marrow edema. Histological examination of bone biopsies from 4 patients revealed fibrous tissue hyperplasia and lymphocytic and neutrophilic infiltration, despite negative bacterial cultures. Laboratory test results were either normal or slightly elevated. Symptomatic improvement was observed in 6 patients (85.72%) treated with nonsteroidal anti-inflammatory drugs, while 1 patient (14.28%) resistant to nonsteroidal anti-inflammatory drugs responded well to tumor necrosis factor inhibitors. The clinical presentation of CRMO lacks specificity, with unexplained bone pain being the most common symptom. Precise diagnosis and timely intervention depend on a thorough magnetic resonance imaging evaluation for lesion detection, which facilitates CRMO diagnosis. This study offers valuable insights into the clinical manifestations, laboratory findings, imaging features, and treatment strategies of CRMO in pediatric patients.

Primary chronic osteomyelitis of the jaw - a descriptive study of the condition and its occurrence in Sweden between 2012 and 2018

PURPOSE

Primary chronic osteomyelitis (PCO) of the jaw is a non-infectious, inflammatory state of the jawbone of unknown etiology.  This study aimed to investigate the occurrence of PCO in Sweden between the years 2012 and 2018, the characteristics of the condition, treatment methods, and outcomes.  Material and methods: The search for patients with PCO in Sweden 2012-2018 was performed at 24 oral and maxillofacial surgery units in Sweden.

RESULTS

During this 6-year period, 17 patients were identified as diagnosed with PCO in Sweden. The mean age was 10.6 years at diagnosis, and the female:male ratio was 4:1.

CONCLUSION

We conclude that PCO is a very rare disease in Sweden, and that standardized, well-defined criteria are necessary to calculate incidence rates but also to increase knowledge about etiology, clinical characteristics, and treatment outcomes in rare conditions such as PCO.

Diagnostic Value of Whole-Body MRI in Pediatric Patients with Suspected Rheumatic Diseases

Background and Objectives: The diagnosis of rheumatic diseases in children is challenging and requires the use of advanced imaging examinations such as whole-body magnetic resonance imaging (MRI). Whole-body MRI allows visualization of bone marrow edema (BME), muscle edema, joint effusion and changes in the soft tissues surrounding the joints. The aim of this study was to collect and compare whole-body MRI findings, laboratory results and clinical manifestations of pediatric patients with suspected rheumatic disease. Materials and methods: In this retrospective single-center study, 33 patients who underwent whole-body MRI were included. Their age ranged from 9 to 17 years, and 24 (72.73%) of the patients were female. Patients were diagnosed as follows: juvenile idiopathic arthritis (27.27%), juvenile idiopathic inflammatory myopathies (21.21%), chronic nonbacterial osteomyelitis (21.21%) and other medical conditions (30.30%), such as arthritis associated with infection, scleroderma, Takayasu arteritis, polyarteritis nodosa and joint damage. Results: The most common symptom reported by 26 (79.79%) patients was pain. On physical examination, the limitation of joint mobility was examined in 17 (51.51%), swelling of the joints was observed in 12 (36.36%) patients and decreased muscle strength was noticed in 11 (33.33%) patients. An increase in the C-reactive protein (12%), erythrocyte sedimentation rate (9%), leukocyte count (9%) and creatine kinase (CK) (18%) was observed. Whole-body MRI revealed myositis (30%), joint effusion (27%) and BME (24%). The statistical analysis showed a significant relationship between myositis and the elevated CK level (p < 0.05). Conclusions: The most common symptom in the studied population was pain, while the limitation of joint mobility was found in more than half of patients. Myositis was the most commonly imaged lesion on the whole-body MRI and it was related to an increase in the CK level.

Diagnostic Role of FDG PET/CT in Pediatric Patients With Chronic Recurrent Multifocal Osteomyelitis

PURPOSE

Chronic recurrent multifocal osteomyelitis (CRMO), or chronic nonbacterial osteomyelitis, is difficult to diagnose. The accurate diagnosis of CRMO relies on comprehensive imaging examinations because of its multifocal nature. In this regard, 18 F-FDG PET/CT has demonstrated significant utility in inflammatory diseases. This study tries to determine the value of FDG PET/CT in the evaluation of CRMO.

PATIENTS AND METHODS

We retrospectively collected imaging data from pediatric CRMO patients who underwent FDG PET/CT scans. Lesions exhibiting abnormal metabolism with/without structural abnormalities on FDG PET/CT were identified as CRMO lesions, and their location and SUV max were recorded.

RESULTS

A total of 21 pediatric patients with CRMO were included in this study. The median age at diagnosis was 9.4 years. Total 131 foci of abnormal activity were identified using FDG PET/CT imaging. The distribution pattern showed a higher prevalence of lower limbs and pelvis involvement. Among all identified lesions, abnormalities were detected on both PET and CT images of 93 lesions, whereas exclusively positive findings on 18 F-FDG PET alone were observed for 38 of them.

CONCLUSIONS

Our study findings suggest a higher prevalence of lesions in the bones of the lower limbs and pelvis among children with CRMO. Compared with CT scans, FDG PET exhibits superior sensitivity in detecting these lesions.

Molecular Imaging with PET-CT and PET-MRI in Pediatric Musculoskeletal Diseases

Molecular imaging has emerged as an integral part of oncologic imaging. Given the physiologic changes that precede anatomic changes, molecular imaging can enable early detection of disease and monitoring of response. [18F] Fluorodeoxyglucose (FDG) Positron emission tomography (PET) is the predominant molecular imaging modality used in oncologic assessment and can be performed using PET/CT or PET/MR. In pediatric patients, PET/MRI imaging is generally preferred due to low radiation exposure and PET/MRI is particularly advantageous for imaging musculoskeletal (MSK) diseases, as MRI provides superior characterization of tissue changes as compared to CT. In this article, we provide an overview of the typical role of PET CT/MRI in assessment of some common pediatric malignancies and benign MSK diseases with case examples. We also discuss the relative advantages of PET/MRI compared to PET/CT, and review published data with a primary focus on the use of PET/MR.

A clinico-radiological review of chronic non-bacterial osteomyelitis in paediatrics, adolescents, and adults: demystifying a forgotten differential

Chronic non-bacterial osteomyelitis (CNO), also known as non-bacterial osteitis, is a chronic autoinflammatory disease of unknown aetiology that primarily occurs in the paediatric population, although rare cases of adult-onset disease also exist. CNO has non-specific clinical and radiological presentations, and the affected population often present with bone pain of insidious onset secondary to sterile bony inflammation that can be associated with swelling, focal tenderness, and warmth at the affected sites. The pattern of bony involvement appears to be dependent on the age of onset, with adults frequently having axial skeletal lesions and children and adolescents often being affected in the appendicular skeletal sites. CNO is a diagnosis of exclusion, and imaging is heavily relied on to identify and characterise the bony lesions in addition to exclude diseases that can mimic CNO. Magnetic resonance imaging is often the reference standard with biochemical and histopathological findings being complementary. Although combining imaging methods can be used to facilitate the diagnosis, a single technique could be adequate depending on the clinical picture. Given the relatively rare incidence of CNO, limited awareness of the disease among care providers, and its similarity in clinical and radiological presentation to various bony diseases, there are often long delays in diagnosis, with adults being unfavourably affected compared to paediatrics and adolescents. This review of CNO will describe the condition, overview its clinical presentation, highlight the radiological features, and emphasise clinical pearls that can aid in diagnosis and ruling out the mimics.

How Have the Diagnosis and Treatment of Chronic Recurrent Multifocal Osteomyelitis Changed Over Time?

PURPOSE

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory condition characterized by sterile bone lesions. There appears to be a shift in the diagnostic modalities and treatment over the past decades despite insufficient published data. The purpose of this study was to document: 1) the number of patients diagnosed with CRMO, 2) patient demographics, 3) disease characteristics at presentation, 4) diagnostic modalities employed, and 5) treatments prescribed at our institution over a 30-year period.

METHODS

This single-center, retrospective cohort study included children diagnosed with CRMO who presented between 1990 and 2020. The electronic medical records were queried using numerous search terms. Patients were excluded if CRMO was included in the differential diagnosis but was not confirmed at the time of chart review or if CRMO was suspected early in the disease course but the patient was ultimately diagnosed with another condition. The predictor (time in years) and outcome variables (diagnostic modalities and treatment types) were tested using bivariate analyses using IBM SPSS, Version 27 (IBM Corp., Armonk, NY).

RESULTS

A total of 224 patients were diagnosed with CRMO during the observation period (68.3% female; 67.4% white). The number of patients diagnosed over the past decade rose by 215%, as compared to the previous 2 decades (1990 to 2010). Regional magnetic resonance imaging (83.8%) and biopsy (66.5%) were the most utilized diagnostic modalities over the past decade, with a statistically significant decline in the proportion of biopsies performed (66.5% during the past decade vs 84.9% in the previous 2 decades, P = .01). Over the past decade, nonsteroidal anti-inflammatory drugs (40.1%), disease-modifying antirheumatic drugs (27.1%), and tumor necrosis factor inhibitors (21.1%) were the most commonly used treatments, with a statistically disproportionate increase in the use of tumor necrosis factor inhibitors (21.1% during the past decade vs 3.8% in the previous 2 decades, P < .001).

CONCLUSIONS

This is one of the largest CRMO cohort studies and the only study to observe changes in diagnostic modalities and treatment over a 30-year period. Future studies should assess the impact of variations in clinical presentation, time to diagnosis, diagnostic modalities, and management as predictors of disease outcomes.

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.

Chronic recurrent multifocal osteomyelitis: diagnosis and treatment

PURPOSE OF REVIEW

The aim of this article is to review recent findings regarding the diagnosis and treatment of chronic recurrent multifocal osteomyelitis (CRMO).

RECENT FINDINGS

An adequate understanding of pathophysiology along with the new advances in MRI imaging make it possible to determine the extent of disease and establish early treatment. TNF-α inhibitors and bisphosphonates have shown to be a well-tolerated and efficient treatment for CRMO providing both symptomatic relief and normalization of bone morphology.

SUMMARY

The results of recent studies suggest that a better knowledge of the genetic and molecular factors will allow early diagnosis and the development of more effective individualized treatments in the future.

The Effect of Inflammation on Bone

Bone remodeling is the continual process to renew the adult skeleton through the sequential action of osteoblasts and osteoclasts. Nuclear factor RANK, an osteoclast receptor, and its ligand RANKL, expressed on the surface of osteoblasts, result in coordinated control of bone remodeling. Inflammation, a feature of illness and injury, plays a distinct role in skewing this process toward resorption. It does so via the interaction of inflammatory mediators and their related peptides with osteoblasts and osteoclasts, as well as other immune cells, to alter the expression of RANK and RANKL. Such chemical mediators include TNFα, glucocorticoids, histamine, bradykinin, PGE2, systemic RANKL from immune cells, and interleukins 1 and 6. Conditions, such as periodontal disease and alveolar bone erosion, aseptic prosthetic loosening, rheumatoid arthritis, and some sports related injuries are characterized by the result of this process. A thorough understanding of bone response to injury and disease, and ability to detect such biomarkers, as well as imaging to identify early structural and mechanical property changes in bone architecture, is important in improving management and outcomes of bone related pathology. While gut health and vitamin and mineral availability appear vitally important, nutraceuticals also have an impact on bone health. To date most pharmaceutical intervention targets inflammatory cytokines, although strategies to favorably alter inflammation induced bone pathology are currently limited. Further research is required in this field to advance early detection and treatments.

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.

Unusual case of chronic recurrent multifocal osteomyelitis

BACKGROUND

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

CASE PRESENTATION

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

CONCLUSIONS

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