Chronic recurrent multifocal osteomyelitis: Case report and review of the literature

BACKGROUNDS

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare inflammatory disease.

OBJECTIVE

This report aims to analyze the clinical characteristics of CRMO and enhance clinicians' comprehension. We present 3 atypical cases, highlighting their unique clinical features, diagnostic challenges, and effective treatment strategies.

METHODS

We retrieved 3 CRMO cases in our hospital from September 2019 to August 2022. The clinical features were analyzed retrospectively, and relevant literatures were reviewed.

RESULTS

All 3 cases initially presented with bone pain, normal leucocyte counts, negative rheumatoid factors and no signs of sclerotic or hyperostotic lesions. Case 1, a 12-year-old girl, exhibited concurrent acne on the forehead and historic necrotizing lymphadenitis, a previously unreported association with CRMO. Case 2, a 14-year-old boy, tested positive for human leukocyte antigen-B27 and displayed scoliosis along with multifocal osteomyelitis. Case 3, a 9-year-old girl, presented with scoliosis, and chest computed tomography revealed changes in the T8 vertebral body, initially suggesting Langerhans cell histiocytosis. Bone biopsy was conducted in case 1 and case 3, revealing chronic inflammation. All 3 cases affected long bones, pelvis, and vertebra, involving 8, 6 and 5 bones, respectively, identified by magnetic resonance imaging. Genetic analysis was undertaken in cases 1 and 2 but no pathogenic mutations were identified. Upon the confirmation of a CRMO diagnosis, all patients were initiated on a treatment regimen comprising nonsteroidal anti-inflammatory drugs and tumor necrosis factor-α inhibitors. In cases 1 and 2, due to the severity of their bone pain, they were also administered to disease-modifying anti-rheumatic drugs, specifically methotrexate. All 3 patients achieved remission of bone pain. To gain a more comprehensive understanding of CRMO, we conducted a thorough review of relevant literature.

CONCLUSION

CRMO is a rare autoinflammatory bone disorder with diverse clinical presentations and a lack of specific laboratory tests, which leads to potency to misdiagnosis or delayed diagnosis. By raising awareness and improving diagnostic criteria, physicians are now better equipped to identify CRMO. We contribute to share our understanding of CRMO by presenting 3 cases with untypical clinical features, highlighting the importance of recognizing this rare condition for timely and effective management.

Chronic non-bacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO) with a focus on pamidronate therapy

Chronic recurrent multifocal osteomyelitis (CRMO), also called chronic nonbacterial osteomyelitis (CNO) or nonbacterial osteomyelitis (NBO), is a rare autoinflammatory bone disease of unknown etiology. However, the number of patients properly diagnosed would increase with better knowledge of the disease. In this regard, whole-body magnetic resonance imaging (WB MRI) has been found to be a better predictor of active lesions than clinical examination. Importantly, the RINBO index (radiologic index for NBO) quantifies the involvement based on the WB MRI. Further, a chronic nonbacterial osteomyelitis MRI scoring (CROMRIS) has been developed as an online tool for assessing WB MRI. The therapy consists of non-steroidal anti-inflammatory drugs (NSAIDs), bisphosphonates (pamidronate, zoledronate, etc.) and other drugs, including biologics. Pamidronate is an appropriate and safe therapy. The first pilot prospective randomised controlled trial (RCT) on pamidronate vs. placebo was carried out in adults. No RCT has been done in children yet. Besides RCTs, there are a number of issues to be explored in future, i.e. predictors of therapy effect, optimal therapy duration, predictors of therapy discontinuation and evaluation of optimal therapy protocol. Recently, the CNO clinical disease activity score (CDAS) was constructed and validated but the classification criteria are still being developed. As collaboration on this rare disease is essential, a prospective Chronic Nonbacterial Osteomyelitis International Registry (CHOIR) was established to generate future comparative effectiveness research data.

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.

Bisphosphonate therapy in the management of diffuse sclerosing osteomyelitis of the mandible: a systematic review and narrative synthesis

Background

Diffuse sclerosing osteomyelitis (DSO) affecting the mandible is an uncommon condition characterised by recurrent pain and functional disturbances. Traditional treatments involving antibiotics, steroids, and analgesics have generally yielded unsatisfactory results. Numerous articles have proposed the utilisation of bisphosphonate therapy as an alternative approach to achieve sustained symptom relief. This study aims to consolidate the available evidence on the effectiveness of bisphosphonate therapy in managing DSO.

Methods

A systematic review protocol was registered with PROSPERO and reported in accordance with the Preferred Reporting for Items for Systematic Reviews and Meta-Analyses. Comprehensive electronic search strategies were devised, and studies were screened based on predefined inclusion and exclusion criteria.

Results

Ten articles met the eligibility criteria, encompassing a total of 135 patients diagnosed with DSO who received bisphosphonate treatment. All included studies consistently reported a reduction in pain levels and swelling, along with a decrease in the cumulative use of analgesics. The majority of patients reported long-lasting symptom improvement with bisphosphonate therapy. Notably, four studies documented improvements in maximal mouth opening, with one study reporting a mean increase of 9.6mm. Furthermore, six studies observed improvements in panoramic radiographs and cone beam computed tomography scans, with one publication describing two patients exhibiting near-normal bone architecture. Importantly, all studies reported the absence of long-term complications.

Conclusions

Bisphosphonate therapy emerges as a promising treatment modality for DSO, exhibiting efficacy in symptom alleviation and radiological enhancement while conferring lasting benefits. Nevertheless, further prospective studies are warranted to refine treatment protocols and substantiate these findings.

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.

Chronic Recurrent Multifocal Osteomyelitis: A Comprehensive Literature Review

Chronic recurrent multifocal osteomyelitis (CRMO) is a non-infectious, inflammatory disorder of the bones. CRMO typically affects children, with a predisposition to females. Bone-related pain is often felt in the metaphysis of long bones, particularly of the lower extremities, but it can also target other sites at varied time intervals. Patients are likely to complain of tenderness and swelling that may cause considerable disability and adversely impact quality of life. There are three main pathophysiological mechanisms that have been hypothesized to drive CRMO including imbalanced cytokine expression, increased inflammasome activation, and enhanced osteoclast differentiation. Therapies have been based on targeting and suppressing these key players in CRMO patients. The first step in management involves pain control. Non-steroidal anti-inflammatory drugs should provide initial relief, albeit temporarily. It is imperative to initiate immunosuppressive medication that will help limit bone involvement and thereby prevent the development of fractures or leg-length discrepancies, for example. The purpose of this literature review is to study the pathophysiology of CRMO and carefully dissect the agents that have been previously employed in the management of CRMO patients. This could allow for the purposeful formulation of individualized care plans and improving the overall well-being of patients. The authors included a multitude of PubMed-indexed articles published from 2000 onwards in this review.

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.

Bell's palsy with facial bone involvement: A rare presentation of chronic nonbacterial osteomyelitis with literature review

Chronic nonbacterial osteomyelitis (CNO) is a chronic, sterile, inflammatory disease. It primarily presents with nonspecific bone pain and swelling but ultimately can cause bone destruction and deformities, if left untreated. The involvement of the cranial bones (apart from the mandible) is rare in CNO. In this report, we present a rare case of CNO affecting facial and cranial bones presenting as facial palsy with a review of the literature about similar affection. A 10-year-old, previously healthy female was initially evaluated for swelling of the left side of her face with slight tenderness on palpation, but no fever. Her complete blood count was unremarkable, her inflammatory markers were elevated (C-reactive protein 7.5 mg/dl and erythrocyte sedimentation rate 104 mm/h), and CT of facial and skull bones and MRI of brain showed a destructive osseous process involving the left maxillary, zygomatic, sphenoid bones and the clivus. Bone biopsy of the left maxilla showed fibrous dysplasia with abscess formation, most consistent with an infectious aetiology (acute osteomyelitis). She was started on oral clindamycin for a 3-month course. The facial swelling improved after starting clindamycin, but on her sixth week of treatment, she developed right-sided Bell's palsy. An MRI of the brain showed hyperenhancement of the right seventh cranial nerve. A month later, she was evaluated for right wrist and knee swelling, pain, and limitation of movement. Skeletal survey and MRI showed multifocal lesions with mixed sclerosis and lucency. Her inflammatory markers continued to be elevated. Another bone biopsy of the right radius showed similar findings of destruction with no evidence of malignancy. She was ultimately diagnosed with CNO. She was started on nonsteroidal anti-inflammatory drugs with gastric protection and regular follow-up. Over more than a year of follow-up, the patient's inflammatory markers remain normal, and joint swelling/limitation has remained in remission. We found five additional cases in the literature that presented with a similar presentation. To our knowledge, our patient is the first reported case in the USA involving the cranial/facial bones apart from the mandible presenting with facial palsy. The affection of the facial bones (apart from the mandible) in CNO is very rare, but the awareness of such a presentation by the clinician is an important aspect of reaching the diagnosis.

Chronic Recurrent Multifocal Osteomyelitis in a Child’s Hand: Case Report and Review

We present a 9-year-old girl with persistent pain and swelling of the left wrist. X-ray, magnetic resonance imaging (MRI) and bone biopsy led to the diagnosis of chronic recurrent multifocal osteomyelitis (CRMO), affecting phalangeal and metacarpal bases and distal carpal bones on the ulnar side of the wrist. She was treated with non-steroidal anti-inflammatory drugs and complete remission with no long-term sequelae was achieved. CRMO is a rare auto-inflammatory condition with infrequent involvement of the hand. The current literature is discussed. The aim of this report is to raise awareness of the condition to reduce the time to diagnosis and unnecessary antibiotic treatment and to prevent permanent disability due to the progression of the disease.

Level of Evidence: Level V (Therapeutic)

Chronic Recurrent Multifocal Osteomyelitis: A Review of the Noninfectious Inflammatory Bone Disease and Lessons for More Timely Diagnosis

Chronic recurrent multifocal osteomyelitis (CRMO) is an idiopathic autoinflammatory disease of the bone that typically occurs in children and adolescents. CRMO is characterized by recurrent periods of exacerbation and remission of symptomatic, osteolytic/sclerotic sterile bone lesions and is often a diagnosis of exclusion. Treatment consists of multimodal anti-inflammatory medication management by rheumatology and rarely involves surgery. This review summarizes the clinical presentation, pathophysiology, diagnosis, and management of this disease and highlights the role of the orthopedic surgeon. With increased familiarity with CRMO, clinicians will be able to diagnose and treat the condition in a more timely manner. [Orthopedics. 202x;4x(x):xx-xx.].

Whole-body magnetic resonance imaging findings and patterns of chronic nonbacterial osteomyelitis in a series of Greek pediatric patients

Background:

Chronic nonbacterial osteomyelitis (CNO) is a pediatric autoinflammatory disorder presenting with sterile inflammatory bone lesions. Whole-body MRI (WBMRI) has most recently emerged for disease assessment, but data are limited.

Purpose:

The purpose is to evaluate the imaging findings and patterns of CNO on WBMRI in a series of Greek pediatric patients.

Material and Methods:

Whole-body magnetic resonance imaging studies of all children with documented CNO, performed in a single tertiary center, were retrospectively reviewed. WBMRI included coronal T1 and short-tau inversion recovery (STIR), whole spine sagittal STIR, and ankle/foot sagittal STIR images. High signal intensity lesions on STIR images corresponding to bone marrow edema were recorded. The SPSS v.20 statistical package was used for descriptive statistics.

Results:

Twenty children were included (mean age: 12, range: 6–16 years) with 1–31 lesions (mean: 11.8) on WBMRI. Two children had unifocal disease localized at the clavicle, three paucifocal (1–4 lesions), and 15 multifocal bone involvement. All but two children presented with ankle pain and exhibited lesions at the bones of the ankle joint (90%) followed by the knee (50%) and pelvis (10%). The tibia was the most frequently affected bone (70%) followed by calcaneus (60%), fibula (50%), femur (45%), talus, and metatarsals (45%). No lesions in the cervical, thoracic, lumbar spine, and mandible were documented. Only small sacral lesions were seen in 25% of patients with the extensive peripheral disease. Bilateral metaphyseal and epiphyseal involvement with transphyseal extension were common, but the periosteal reaction and well-defined lesion margins were rare.

Conclusion:

Frequent involvement of the foot and ankle and paucity of substantial spinal involvement were seen in Greek pediatric patients with CNO.

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.

Chronic Non-infectious Osteomyelitis Mimicking Scurvy as the Presenting Sign of Crohn's Disease: Case Report

Chronic non-infectious osteomyelitis (CNO) is a rare, inflammatory process associated with pediatric inflammatory bowel disease (IBD). Signs and symptoms of CNO parallel scurvy, a nutritional deficiency that can affect children with autism spectrum disorder (ASD). This is the first report of a child initially thought to have scurvy, then subsequently diagnosed with CNO as the presenting manifestation of Crohn's disease. This case enhances the literature elucidating extra-intestinal manifestations of IBD and pediatric nutritional deficiencies.

Whole-body MRI in pediatric undefined inflammatory conditions

BACKGROUND

Whole-body magnetic resonance imaging (WBMRI) is a multiregional imaging technique suitable for investigating the extent of multisystemic diseases without exposure to radiation, with a high sensitivity to bone alterations. The aim of our study was to evaluate the role of WBMRI in the workup of children with non-specific musculoskeletal features and non-indicative laboratory and instrumental data, who were suspected to have a rheumatologic disease.

METHODS

We retrospectively analyzed medical records, including laboratory tests and radiological data of 34 children who had been evaluated due to non-specific musculoskeletal manifestations, for which a WBMRI was prescribed.

RESULTS

We included 34 children, 19 females and 15 males, mean age 10 years (range 2-16 years), with the following clinical features: diffuse arthralgia (12 children), persistent fever (2 children), persistent fever and diffuse arthralgia (20 children). Serologic inflammatory markers were increased in 29/34 patients. Twenty-five children had already received X-ray and / or ultrasound before WBMRI, with a negative / uninformative result. WBMRI was performed 3-6 weeks (median, 3.5 weeks) after the initial presentation of symptoms. In 22/34 (65%) children, WBMRI revealed some abnormalities that supported the final diagnosis. Twelve out of 34 children (35%) were be affected by chronic recurrent multifocal osteomyelitis.

CONCLUSIONS

WBMRI is helpful in pediatric rheumatology for the differential diagnosis of undefined inflammatory conditions. It appears to be a promising tool, especially in the detection of multifocal bone lesions. The diagnosis that mainly benefits from WBMRI in our series is chronic recurrent multifocal osteomyelitis. WBMRI can also help in excluding neoplastic diseases.

Chronic recurrent multifocal osteomyelitis, central retinal artery occlusion and optic neuropathy: A new association

Purpose

To report a patient with chronic recurrent multifocal osteomyelitis (CRMO) complicated by optic neuropathy and central retinal artery occlusion (CRAO).

Observations

CRMO is a noninfectious, inflammatory bone disorder. It is thought to be an autoimmune condition related to an imbalance of pro- and anti-inflammatory cytokines. Retinal vasculitis has been reported in a patient with CRMO but not CRAO or optic neuropathy.

Conclusions

We expanded the list of ophthalmic involvement of CRMO to include CRAO and optic neuropathy.

Mind the Localized Skeletal Pain: Chronic Recurrent Multifocal Osteomyelitis

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare idiopathic aseptic inflammatory bone disorder affecting primarily children and adolescents characterized by an insidious onset of pain, swelling, and tenderness over the affected bones. The clinical signs and symptoms of CRMO are nonspecific, radiological and histopathological tests are essential for its diagnosis. We present a case of an 18-year-old young man who was diagnosed with CRMO by a combination of clinical data, laboratory results, radiological imaging, and bone biopsy. The patient started anti-inflammatory and immunosuppressant therapy, and his lower extremity pain and swelling improved. This report highlights to investigate promptly in children and adolescents with chronic leg pain, to emphasize the importance of combined clinical, laboratory, and imaging tests for early identification, to have a greater understanding of the imaging appearance and increasing knowledge of this condition, which help shorten time to reach a diagnosis and prevent permanent osseous damage and long-term disabilities.

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.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

[Extranodal B-cell lymphoma in the distal femur with pre-existing CRMO]

CRMO is a rare form of nonbacterial osteomyelitis, which is mainly found in children. The diagnosis is complex because bone tumors or lymphoma must also be excluded. The case report describes the development of a solitary femoral lymphoma on the basis of a known CRMO disease as well as the differential diagnostic pitfalls.

Chitosan-based drug delivery systems: From synthesis strategy to osteomyelitis treatment - A review

Osteomyelitis is a complex disease in orthopedics mainly caused by bacterial pathogens invading bone or bone marrow. The treatment of osteomyelitis is highly difficult and it is a major challenge in orthopedic surgery. The long-term systemic use of antibiotics may lead to antibiotic resistance and has limited effects on eradicating local biofilms. Localized antibiotic delivery after surgical debridement can overcome the problem of antibiotic resistance and reduce systemic toxicity. Chitosan, a special cationic polysaccharide, is a product extracted from the deacetylation of chitin. It has numerous advantages, such as nontoxicity, biocompatibility, and biodegradability. Recently, chitosan has attracted significant attention in bacterial inhibition and drug delivery. Because chitosan contains many functional bioactive groups conducive to chemical reaction and modification, some chitosan-based biomaterials have been applied as the local antibiotic delivery systems in the treatment of osteomyelitis. This review aims to introduce recent advances in the biomedical applications of chitosan-based drug delivery systems in osteomyelitis treatment and to highlight the perspectives for further studies.

Chronic non-bacterial osteomyelitis masquerading as fibrous dysplasia

Chronic non-bacterial osteomyelitis is a rare auto-inflammatory bone disease seen predominantly in the paediatric population. We describe a unique case of a 30-year-old female who presented with right-sided jaw pain and intermittent swelling over the course of 6 years. She was initially treated with antibiotics for possible osteomyelitis, then temporarily diagnosed with fibrous dysplasia. She underwent extensive investigations consisting of an infectious workup, numerous imaging modalities, and three separate biopsies of her right jaw. She was ultimately diagnosed with chronic non-bacterial osteomyelitis based upon her history of recurrent episodes of painful swelling, response to non-steroidal anti-inflammatories, previously raised acute phase reactants, and magnetic resonance imaging findings. Unfortunately, she became refractory to non-steroidal anti-inflammatory therapy. Consequently, she was successfully treated with pamidronate, achieving clinical remission with improvement in her imaging findings. This case highlights the difficulty of diagnosis of chronic non-bacterial osteomyelitis and the need for increased awareness of the disease in the adult population. Additionally, the effective treatment with pamidronate supports the use of a bisphosphonate as an early intervention for adult-onset chronic non-bacterial osteomyelitis in patients who have failed non-steroidal anti-inflammatory therapy.

Facial trauma followed by osteomyelitis - Case report

Introduction

Osteomyelitis is an inflammatory-infectious state that may involve trabecular bone, cortical bone, bone marrow and periosteum. The source of the infection may be hematogenic, acquired from an adjoining infectious focus or by direct inoculation into the bone. Its treatment involves antibiotic administration and surgery, but its management remains challenging.

Presentation of case

A 76-year-old male patient with a history of car accident 3 months earlier sought hospital care with nasal fracture and loss of substance in the right frontotemporal region, where a pectoral muscle free graft was performed to reconstruct the facial defect. The grafted region had hyperemic edges, necrotic appearance, purulent discharge and bone exposure in the nasal dorsum. The initial diagnostic hypothesis was an infectious process due to graft rejection, with likely evolution to osteomyelitis. The surgical procedure was performed by a multidisciplinary team and the patient received the antibiotic regimen according to the antibiogram, with hospital discharge after 39 days of hospitalization.

Discussion

Treatment of osteomyelitis requires the combination of antimicrobial therapy and surgery. Despite surgical and chemotherapeutic advances, it is a difficult condition to treat and there is no universally accepted protocol for treatment.

Conclusion

Surgical treatment was essential for stabilization of the condition. Due to the complexity of this type of infection in the craniofacial region, planning and execution must be carried out through a multidisciplinary team.

Clinical and Diagnostic Considerations for Atypical, Adult Onset Presentation of Chronic Recurrent Multifocal Osteomyelitis (CRMO)

Chronic recurrent multifocal osteomyelitis (CRMO) is the most severe form of chronic nonbacterial osteomyelitis (CNO) and is a rare autoinflammatory bone disorder that mostly affects children and adolescents. CRMO is a diagnosis of exclusion, resulting in often-delayed diagnosis with over one year on average from onset of symptoms to time of diagnosis. Initial diagnosis is rare in adults and previously undocumented in the elderly (age greater than 65). We highlight a case of a 74-year-old elderly Caucasian female with a history of palmoplantar pustular psoriasis who presented with pelvic and hip pain. Imaging findings included multiple bony lesions on x-rays, increased uptake in the left side of the pelvis, ileum, proximal sternum, and bilateral medial clavicles on nuclear bone scan. Bone biopsy histologic results of marrow fibrosis and plasma cell infiltrate indicative of chronic inflammation lead to the diagnosis of CRMO. This case highlights that while CRMO is typically a disease with childhood onset, it, while rare, can also present in adults and now has presented in the elderly, remaining an important part of the differential diagnosis of bone pain in adults and the elderly in addition to infectious osteomyelitis and malignancy when imaging reveals multiple bony lesions. This in turn will facilitate the reduction of unnecessary medical treatment and antibiotics.

Gain-of-function mutations in a member of the Src family kinases cause autoinflammatory bone disease in mice and humans

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disease that presents with bone destruction occurring primarily in children. In a mouse ENU mutagenesis screen, the Ali18 strain was isolated because of spontaneous inflammation in the joints and bones. Sequencing candidate genes in the Ali18 critical region identified a missense mutation in the C-terminal regulatory region of the Src family kinase (SFK) member, Fgr. Genome editing revealed Fgr dependency of the inflammatory phenotype in Ali18 mice. Further, whole exome sequencing in our CRMO cohort identified two patients with missense mutations in FGR. In vitro functional assays confirm altered protein function. This work identifies FGR as a CRMO susceptibility gene and suggests that targeting SFKs may be useful in its treatment.

Autoinflammatory syndromes are characterized by dysregulation of the innate immune response with subsequent episodes of acute spontaneous inflammation. Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory bone disorder that presents with bone pain and localized swelling. Ali18 mice, isolated from a mutagenesis screen, exhibit a spontaneous inflammatory paw phenotype that includes sterile osteomyelitis and systemic reduced bone mineral density. To elucidate the molecular basis of the disease, positional cloning of the causative gene for Ali18 was attempted. Using a candidate gene approach, a missense mutation in the C-terminal region of Fgr, a member of Src family tyrosine kinases (SFKs), was identified. For functional confirmation, additional mutations at the N terminus of Fgr were introduced in Ali18 mice by CRISPR/Cas9-mediated genome editing. N-terminal deleterious mutations of Fgr abolished the inflammatory phenotype in Ali18 mice, but in-frame and missense mutations in the same region continue to exhibit the phenotype. The fact that Fgr null mutant mice are morphologically normal suggests that the inflammation in this model depends on Fgr products. Furthermore, the levels of C-terminal negative regulatory phosphorylation of Fgr^Ali18 are distinctly reduced compared with that of wild-type Fgr. In addition, whole-exome sequencing of 99 CRMO patients including 88 trios (proband and parents) identified 13 patients with heterozygous coding sequence variants in FGR, including two missense mutant proteins that affect kinase activity. Our results strongly indicate that gain-of-function mutations in Fgr are involved in sterile osteomyelitis, and thus targeting SFKs using specific inhibitors may allow for efficient treatment of the disease.

Chronic nonbacterial osteomyelitis from a tertiary care referral center

Chronic nonbacterial osteomyelitis (CNO) is a little known autoinflammatory bone disorder primarily affecting children and sometimes young adults. Diagnosis is often delayed due to its varied and nonspecific initial symptoms. Very few cases are reported from India. The aim of this report is to increase the awareness of this disease among physicians, orthopedic surgeons, and rheumatologists. Four male patients were diagnosed with CNO in the past 3 years. The age at onset varied from 9 to 23 years with a median diagnostic delay of 3.5 years. All patients presented with recurrent bony pain with or without localized swelling over the affected bones. Two patients had previously undergone open surgical procedures with bone biopsies and three patients had received at least one course of antibiotics. Two patients responded well to nonsteroidal anti-inflammatory drugs alone, one patient required a short course of glucocorticoids, and another patient required methotrexate to control disease activity. This case series includes males, onset at a relatively later age in most, and a longer diagnostic delay. Thus, in addition to children and adolescents, CNO should be suspected in young adults presenting with recurrent bony pain with or without localized swelling.