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

SAPHO syndrome: current clinical, diagnostic and treatment approaches

This review provides an overview of SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis), a rare autoinflammatory disease that primarily affects bones, skin, and joints. We conducted a search on Medline/PubMed using keywords such as SAPHO syndrome, chronic recurrent multifocal osteitis/osteomyelitis, and related terms. SAPHO syndrome is rare, with a reported frequency of 1 in 10,000 in the Caucasian population. However, the actual incidence of SAPHO syndrome is unknown, and the incidence of the disease is likely higher. The pathogenesis of SAPHO syndrome remains incompletely understood. Current evidence suggests that SAPHO results from a complex interplay between immune dysregulation, genetic susceptibility, and environmental factors. It's not clear if SAPHO syndrome is an autoimmune disease or an autoinflammatory disease, but current evidence suggests that it's more likely an autoinflammatory disease because of things like neutrophil hyperactivity, fewer natural killer (NK) cells, high levels of interleukin (IL)-1, and a good response to treatments that block IL-1. Osteo-articular (OA) involvement is a key clinical feature of SAPHO. It affects the anterior chest wall, axial skeleton, peripheral joints, mandible, long bones of the extremities, and pelvis. Dermatological involvement is a common target in SAPHO, with lesions observed in 60-90% of cases. Common skin lesions include psoriasis and acne, with hidradenitis suppurativa and neutrophilic dermatoses being less commonly seen. Other clinical findings include constitutional symptoms caused by systemic inflammation, such as fever, weight loss, and fatigue. There is no specific laboratory finding for SAPHO syndrome. However, during active disease, there may be an increase in positive acute phase markers, such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complement levels, mild leukocytosis, and thrombocytosis. Diagnosis is crucial for SAPHO syndrome, which lacks a specific diagnostic finding and is often underrecognized. A comprehensive evaluation of a patient's medical history and physical examination is crucial. Treatment options include non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, conventional and synthetic disease-modifying agents (cDMARDs and sDMARDs), biological therapies, bisphosphonates, and antibiotics. Biological treatments have emerged as a viable alternative for SAPHO patients who do not respond to conventional treatments.

An improved understanding of pediatric chronic nonbacterial osteomyelitis pathophysiology informs current and future treatment

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease that primarily affects children and young people. It can cause significant pain, reduced function, bone swelling, and even (vertebral body) fractures. Because of a limited understanding of its pathophysiology, the treatment of CNO remains empiric and is based on relatively small case series, expert opinion, and personal experience. Several studies have linked pathological NOD-kike receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome activation and the resulting imbalance between pro- and anti-inflammatory cytokine expression with CNO. This agrees with elevated pro-inflammatory (mostly) monocyte-derived protein signatures in the blood of CNO patients that may be used as future diagnostic and/or prognostic biomarkers. Recently, rare variants in the P2RX7 gene, encoding for an ATP-dependent transmembrane channel, were linked with increased NLRP3 inflammasome assembly and prolonged monocyte/macrophage survival in CNO. Although the exact molecular mechanisms remain unclear, this will inform future target-directed and individualized treatment. This manuscript reviews most recent developments and their impact on diagnostic and therapeutic strategies in CNO.

Current and future advances in practice: SAPHO syndrome and chronic non-bacterial osteitis (CNO)

Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome is a rare, underdiagnosed disease with a wide clinical spectrum. Sterile bone inflammation, predominantly of the anterior chest, and skin manifestations (palmoplantar pustulosis, psoriasis vulgaris and acne) are the key features of SAPHO, which shares certain similarities with SpA. SAPHO is closely related to paediatric chronic non-bacterial osteitis (CNO), a spectrum of autoinflammatory bone diseases. The aetiology of SAPHO is considered multifactorial based on a complex interplay of genetic, immune and infectious factors. Despite the increasing awareness of SAPHO/CNO, diagnostic delay is common, as validated classification and diagnostic criteria are lacking. Treatment of SAPHO represents a challenge and includes anti-inflammatory drugs, antibiotics, bisphosphonates, synthetic conventional DMARDs and off-label use of anti-cytokine biologics and Janus kinase inhibitors. This review summarizes the current diagnostic and practical treatment approach to SAPHO/CNO and highlights the ongoing research endeavours concerning the definition and validation of diagnostic criteria, core domains and treatment.

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.

Defining the imaging diagnostic criteria for adult chronic non-bacterial osteitis

Osteitis of the sternocostoclavicular (SCC) region, referred to as sternocostoclavicular hyperostosis (SCCH), is the clinical expression of chronic non-bacterial osteitis (CNO) in adults with this rare chronic auto-inflammatory disorder of the axial skeleton. The diagnosis is based on distinctive computerized tomography (CT) features of sclerosis and hyperostosis of the SCC region, and local increases in osteoid formation visualized by high radiopharmacon uptake on skeletal scintigraphy but clear radiologic diagnostic criteria are lacking. In a cross-sectional study, CT scans and whole-body skeletal scintigraphy images obtained in 169 patients seen at the Center for Bone Quality of the Leiden University Medical Center between 2008 and 2018 with a suspected diagnosis of CNO of the SCC region were re-evaluated by 2 skeletal radiologists and 2 nuclear physicians. The diagnosis was confirmed in 118 (70%) predominantly female patients (n = 103, 89.2%); median age at first symptoms 45 years (range 20-73). The diagnosis was excluded in the remaining 51 "non-CNO" patients. Increased radiopharmacon uptake at the SCC region was observed in 82% CNO patients, with the manubrium sterni having the highest predictive ability to discriminate on both imaging modalities. The prevalence of sclerosis of the clavicles, manubrium and first ribs was significantly higher in CNO patients (P < 0.001). Hyperostosis was not observed in non-CNO patients. 46 CNO versus only 2 non-CNO patients had costoclavicular ligament calcification. Our findings identify CT scan features of sclerosis and hyperostosis of manubrium sterni, medial end of clavicles and first ribs, and calcification of costoclavicular ligaments, associated with increased tracer uptake on skeletal scintigraphy at the SCC region, specifically manubrium sterni, as well-defined imaging diagnostic criteria for adult CNO. Pitfalls encountered in the diagnosis of CNO are highlighted. These defined imaging diagnostic criteria for adult CNO should facilitate the diagnosis of this rare auto-inflammatory bone disease across the spectrum of its early to late stages.

[Arthritis and osteomyelitis in childhood and adolescence-Bacterial and nonbacterial]

Bacterial arthritis and osteomyelitis are usually acute diseases, which in this way differ from the often insidious course of nonbacterial osteomyelitis; however, there is often an overlap both in less acute courses of bacterial illnesses and also in nonbacterial osteitis. The overlapping clinical phenomena can be explained by similar pathophysiological processes. In bacteria-related illnesses the identification of the pathogen and empirical or targeted anti-infectious treatment are prioritized, whereas no triggering agent is known for nonbacterial diseases. The diagnostics are based on the exclusion of differential diagnoses, clinical scores and magnetic resonance imaging (MRI). An activity-adapted anti-inflammatory treatment is indicated.

P2RX7 gene variants associate with altered inflammasome assembly and reduced pyroptosis in chronic nonbacterial osteomyelitis (CNO)

Chronic nonbacterial osteomyelitis (CNO), an autoinflammatory bone disease primarily affecting children, can cause pain, hyperostosis and fractures, affecting quality-of-life and psychomotor development. This study investigated CNO-associated variants in P2RX7, encoding for the ATP-dependent trans-membrane K+ channel P2X7, and their effects on NLRP3 inflammasome assembly. Whole exome sequencing in two related transgenerational CNO patients, and target sequencing of P2RX7 in a large CNO cohort (N = 190) were conducted. Results were compared with publicly available datasets and regional controls (N = 1873). Findings were integrated with demographic and clinical data. Patient-derived monocytes and genetically modified THP-1 cells were used to investigate potassium flux, inflammasome assembly, pyroptosis, and cytokine release. Rare presumably damaging P2RX7 variants were identified in two related CNO patients. Targeted P2RX7 sequencing identified 62 CNO patients with rare variants (32.4%), 11 of which (5.8%) carried presumably damaging variants (MAF <1%, SIFT "deleterious", Polyphen "probably damaging", CADD >20). This compared to 83 of 1873 controls (4.4%), 36 with rare and presumably damaging variants (1.9%). Across the CNO cohort, rare variants unique to one (Median: 42 versus 3.7) or more (≤11 patients) participants were over-represented when compared to 190 randomly selected controls. Patients with rare damaging variants more frequently experienced gastrointestinal symptoms and lymphadenopathy while having less spinal, joint and skin involvement (psoriasis). Monocyte-derived macrophages from patients, and genetically modified THP-1-derived macrophages reconstituted with CNO-associated P2RX7 variants exhibited altered potassium flux, inflammasome assembly, IL-1β and IL-18 release, and pyroptosis. Damaging P2RX7 variants occur in a small subset of CNO patients, and rare P2RX7 variants may represent a CNO risk factor. Observations argue for inflammasome inhibition and/or cytokine blockade and may allow future patient stratification and individualized care.

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.

Pediatric mandibular chronic nonbacterial osteomyelitis: A case report with 12 years of radiologic follow-up

Chronic nonbacterial osteomyelitis (CNO) is histologically characterized by nonspecific osteitis. This inflammatory disorder, which lacks an infectious origin, typically presents with chronic pain and swelling at the affected site that can persist for months or even years. However, it is rare for CNO to affect the mandible. A 10-year-old girl presented with a primary complaint of pain in her left mandible. She had no significant medical or dental history. On examination, swelling was visible on the left buccal side, and imaging revealed radiolucent bone deterioration within the left mandible. This case report presents the radiological changes observed over a 12-year follow-up period. Variations in radiopacity, radiolucency, and periosteal reactions were noted periodically. This case highlights the radiological characteristics and findings that are crucial for the diagnosis of CNO, a condition for which no clear diagnostic criteria are currently available.

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.

Treatment and monitoring of SAPHO syndrome: a systematic review

BACKGROUND AND OBJECTIVES

Synovitis acne pustulosis hyperostosis osteitis (SAPHO) is a rare heterogeneous disease of unknown aetiopathology. Externally validated and internationally agreed diagnostic criteria or outcomes and, as a result, prospective randomised controlled trials in SAPHO are absent. Consequently, there is no agreed treatment standard. This study aimed to systematically collate and discuss treatment options in SAPHO.

METHODS

Following 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' guidance, a systematic literature search was conducted using PubMed, Scopus and Web of Science databases. Prospective clinical studies and retrospective case collections discussing management and outcomes in SAPHO involving five or more participants were included. Articles not published in English, studies not reporting defined outcomes, and studies solely relying on patient-reported outcomes were excluded.

RESULTS

A total of 28 studies (20 observational, 8 open-label clinical studies) reporting 796 patients of predominantly European ethnicity were included. Reported therapies varied greatly, with many centres using multiple treatments in parallel. Most patients (37.1%) received non-steroidal anti-inflammatory drugs alone or in combination. Bisphosphonates (22.1%), conventional (21.7%) and biological (11.3%) disease-modifying antirheumatic drugs were the next most frequently reported treatments. Reported outcomes varied and delivered mixed results, which complicates comparisons. Bisphosphonates demonstrated the most consistent improvement of osteoarticular symptoms and were associated with transient influenza-like symptoms. Paradoxical skin reactions were reported in patients treated with TNF inhibitors, but no serious adverse events were recorded. Most treatments had limited or mixed effects on cutaneous involvement. A recent study investigating the Janus kinase inhibitor tofacitinib delivered promising results in relation to skin and nail involvement.

CONCLUSIONS

No single currently available treatment option sufficiently addresses all SAPHO-associated symptoms. Variable, sometimes descriptive outcomes and the use of treatment combinations complicate conclusions and treatment recommendations. Randomised clinical trials are necessary to generate reliable evidence.

Golimumab in Children with Chronic Recurrent Multifocal Osteomyelitis: A Case Series and Review of the Literature

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory bone disease requiring immunosuppressive treatment in half of patients. Monoclonal tumor necrosis factor inhibitors (TNFi) are often used as effective second-line off-label therapies. However, paradoxical psoriasis can occur in a subset of patients exposed to monoclonal TNFi and can prompt conversion to alternate therapy if severe.

OBJECTIVE

The aim of this study was to determine the efficacy and safety of golimumab, a fully humanized TNFi, in children with CRMO, including those who develop paradoxical psoriasis after exposure to other monoclonal TNFi.

METHODS

A retrospective chart review was conducted of patients with CRMO who received golimumab in a single center between 01 June, 2018 and 31 December, 2020. Patients who were diagnosed before 21 years of age and followed up for CRMO at least once after receiving ≥ 3 months of golimumab were included. Extracted data included patient demographics, whole-body MRI lesion counts, clinically relevant data, laboratory results, patient-reported outcomes, and psoriasis burden. Linear mixed models with log-transformed outcomes were used to assess changes in the outcomes over time. The random effect is included in the model to account for the within-subject correlation of repeated measures. p-values and 95% confidence intervals were reported.

RESULTS

Eighteen patients were included. Patients were observed for a median of 9.95 months [interquartile range 3.84-15.64]. The median age at the initiation of golimumab was 10.95 years [9.86-13.77] and the median duration of disease between the disease onset and the initiation of golimumab was 2.60 years [1.66-3.62]. Ten patients received golimumab via intravenous route and eight patients received golimumab via subcutaneous route. The median dose was 1.64 mg/kg/month [1.46, 2]. Fourteen patients were previously treated with disease-modifying antirheumatic drugs and 17 with other TNFi. Patients treated with golimumab showed significant improvement in median physician global assessment for CRMO from 2.00 [1.00-3.00] to 0.00 [0.00-0.25] by the fourth visit (p < 0.001), with median erythrocyte sedimentation rate (ESR) decreasing significantly from 12.00 [6.75-23.75] to 5.00 [3.00-10.00] by the fourth visit (p < 0.05). The median number of lesions on MRI decreased significantly from 3.50 [2.00-5.50] to 0.50 [0.00-4.25] lesions per patient (p < 0.01). Nine out of 12 patients who had previous paradoxical psoriasis associated with adalimumab or infliximab had persistent active psoriasis at study baseline. For patients with psoriasis at study baseline, the prevalence of psoriasis had decreased from 100% to approximately 50-57% at the following visits. Of the 18 patients initiated on golimumab in this study, there was only one new case of mild psoriasis in a patient with previously resolved infliximab-associated paradoxical psoriasis. No serious infections or adverse events were noted during the study. Two patients in the study showed clinical improvement with concomitant golimumab and ustekinumab with no reported adverse side effects or increased effects in these patients over a 16-month interval, showing that this combination can be safe and effective for children with CRMO.

CONCLUSION

In our experience, golimumab has been shown to be a safe and effective therapy for CRMO and demonstrated improvement in paradoxical psoriasis in many patients. Longer follow-up periods would be helpful to develop longer term outcomes data for patients with CRMO and overall paradoxical psoriasis risk.

Update on treatment responses and outcome measure development in chronic nonbacterial osteomyelitis (CNO)

PURPOSE OF REVIEW

To review recent trends in treatment and recent progress in developing outcome measures needed for chronic nonbacterial osteomyelitis (CNO) clinical trials.

RECENT FINDINGS

CNO is an autoinflammatory bone disease. In a minority of patients, the disease is genetically driven, and diagnosis can be made by DNA sequencing. However, for nonsyndromic CNO there is no diagnostic test. The number of children with CNO appears to be increasing and damage is common. Increases in CNO diagnosis is due to raised awareness, increased availability of whole-body magnetic resonance imaging and rising incidence. Treatment remains empiric and it is unclear which second line treatment is superior. Tumor necrosis factor inhibitors (TNFi) and bisphosphonates continue to be used as second line agents for nonsteroidal anti-inflammatory drugs (NSAID) refractory CNO; newer immune modulatory medications are used if this fails. Validated classification criteria, clinical outcome measures and imaging scoring standards are needed for successful clinical trials.

SUMMARY

Best treatment for NSAID refractory CNO remains unclear. Classification criteria, clinical outcomes measures and standardized imaging scoring have been developed or are near completion. This will facilitate robust clinical trials in CNO with the goal of having approved medications for this painful disease.

Priorities in Chronic nonbacterial osteomyelitis (CNO) - results from an international survey and roundtable discussions

OBJECTIVE

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disorder that predominantly affects children and young people. The pathophysiology and molecular mechanisms of CNO remain poorly understood, and diagnostic criteria and biomarkers are lacking. As a result, treatment is empiric and follows personal experience, case series and expert consensus plans.

METHODS

A survey was designed to gain insight on clinician and patient experiences of diagnosing and treating CNO and to collate opinions on research priorities. A version containing 24 questions was circulated among international expert clinicians and clinical academics (27 contacted, 21 responses). An equivalent questionnaire containing 20 questions was shared to explore the experience and priorities of CNO patients and family members (93 responses).

RESULTS

Responses were used to select topics for four moderated roundtable discussions at the "International Conference on CNO and autoinflammatory bone disease" (Liverpool, United Kingdom, May 25-26^th, 2022). The group identified deciphering the pathophysiology of CNO to be the highest priority, followed by clinical trials, necessary outcome measures and classification criteria. Surprisingly, mental wellbeing scored behind these items.

CONCLUSIONS

Agreement exists among clinicians, academics, patients and families that deciphering the pathophysiology of CNO is of highest priority to inform clinical trials that will allow for the approval of medications for the treatment of CNO by regulatory agencies.

Pediatric autoinflammatory bone disorders-a mini review with special focus on pathogenesis and inborn errors of immunity

Autoinflammatory bone disorders are a group of diseases characterized by sterile osteomyelitis. This includes chronic nonbacterial osteomyelitis and the monogenic forms, Majeed syndrome and deficiency of the interleukin-1 receptor antagonist. These disorders result from innate immune system dysregulation and cytokine imbalance that triggers inflammasome activation causing downstream osteoclastogenesis and excessive bone remodeling. In this review, we will summarize the immunopathogenesis of pediatric autoinflammatory bone diseases with a special focus on the genetics and inborn errors of immunity, while briefly touching on the clinical manifestations and management of each disease as well as areas for future research.

Cachexia, chorea, and pain in chronic nonbacterial osteitis and inflammatory bowel disease: a case report

BACKGROUND

Inflammatory bowel disease is an inflammatory disorder that primarily impacts the gastrointestinal tract, leading to malnutrition and chronic microscopic intestinal blood loss. Uncontrolled systemic inflammation can impact other parts of the body, known as extraintestinal manifestations. Up to 25% of patients with inflammatory bowel disease are reported to have these complications in their skin, joints, bones, eyes, liver, lung, and pancreas (Rogler et al. in Gastroenterology 161(4):1118-1132, 2021). Neurologic involvement as extraintestinal manifestations are less common, reported at 3-19%, including neuropathies, demyelination, and cerebrovascular events (Morís in World J Gastroenterol. 20(5):1228-1237, 2014).

CASE PRESENTATION

A 13-year-old Caucasian boy presented with 1 month of progressive lower-extremity pain, weakness, and weight loss. His physical examination was notable for cachexia, lower-extremity weakness, and chorea. Labs revealed normocytic anemia and systemic inflammation. Imaging revealed symmetric abnormal marrow signal in the pelvis and upper femurs. Pathologic examination of the bone revealed chronic inflammation consistent with chronic nonbacterial osteitis. Endoscopy revealed colonic inflammation consistent with inflammatory bowel disease.

CONCLUSIONS

Children and adolescents with musculoskeletal pain lasting more than 2 weeks with systemic signs or symptoms like weight loss should prompt evaluation for systemic inflammatory disorders such as chronic nonbacterial osteitis, which can occur in isolation or associated with inflammatory bowel disease. This patient also had a nonspecific neurologic abnormality, chorea, which resolved with treatment of underlying inflammatory disorder. These extraintestinal manifestations may be concurrent with or precede intestinal inflammation, requiring a high index of suspicion when investigating nonspecific systemic inflammation.

Gathering expert consensus to inform a proposed trial in chronic nonbacterial osteomyelitis (CNO)

Chronic nonbacterial osteomyelitis (CNO) is an autoinflammatory bone disease that primarily affects children and adolescents. CNO is associated with pain, bone swelling, deformity, and fractures. Its pathophysiology is characterized by increased inflammasome assembly and imbalanced expression of cytokines. Treatment is currently based on personal experience, case series and resulting expert recommendations. Randomized controlled trials (RCTs) have not been initiated because of the rarity of CNO, expired patent protection of some medications, and the absence of agreed outcome measures. An international group of fourteen CNO experts and two patient/parent representatives was assembled to generate consensus to inform and conduct future RCTs. The exercise delivered consensus inclusion and exclusion criteria, patent protected (excludes TNF inhibitors) treatments of immediate interest (biological DMARDs targeting IL-1 and IL-17), primary (improvement of pain; physician global assessment) and secondary endpoints (improved MRI; improved PedCNO score which includes physician and patient global scores) for future RCTs in CNO.

Acute care diagnostics in children for general radiologists - not alone in the hospital at night

BACKGROUND

Radiologic care for children and adolescents during night and weekend shifts is challenging. This is especially true when a dedicated pediatric radiology front or background service is not available.

METHODS

The purpose of this review is to present the approach, the most relevant diagnoses, and their differential diagnoses based on four common example cases - abdominal pain, respiratory/chest pain, headache, and refusal to walk. Essentials such as clinical classification (e. g., disease dynamics) and practical instructions (e. g., necessity of acute cross-sectional imaging) are presented.

RESULTS AND CONCLUSION

For the abdomen, appendicitis ranks first among acute diseases. Other important diseases are intussusception and volvulus. Far more frequently, however, gastroenteritis is the cause of abdominal pain. Usually no imaging is required in this case. In unclear clinical situations, ultrasound may be indicated. In suspected pulmonary infections, chest imaging is limited to inconclusive cases and suspicion of complications such as pleural empyema. Major emergencies include (spontaneous) pneumothorax and aspiration. Headache is a common symptom. Immediate imaging is only necessary in cases of suspected acute inflammatory (meningitis/encephalitis) or vascular disease (e. g., hemorrhage due to vascular malformations). MRI is the primary imaging modality in these cases. Restricted walking/refusal to walk is a classic nonspecific sign, particularly of acute musculoskeletal disease, especially in younger children. Clinical examination is essential to narrow down the field of investigation. Besides the frequent and symptomatic coxitis fugax, the rare but serious (septic) arthritis/osteomyelitis must not be overlooked.

KEY POINTS

· Radiological care of children and adolescents is challenging, especially during night and weekend shifts.. · However, in close cooperation with the referring colleagues/clinics, the appropriate approach can be effectively determined even if the symptoms are not clear.. · The selection of the optimal imaging method is based on guidance and guidelines, but also on the condition of the child/adolescent.. · A silent or whimpering child is cause for alarm..

CITATION FORMAT

· Beer M, Mentzel H, Steinborn M et al. Acute care diagnostics in children for general radiologists - not alone at night in the hospital. Fortschr Röntgenstr 2023; 195: 205 - 216.

Clinical characteristics and predictors for recurrence in chronic nonbacterial osteomyelitis: a retrospective multicenter analysis

Background/aim

Chronic nonbacterial osteomyelitis (CNO) is a rare disease of unknown etiology and most commonly occurs during childhood or adolescence. The purpose of this study is to collect data on the clinical features, outcomes, and management of the disease and to identify the factors affecting recurrence.

Materials and methods

This is a retrospective multicenter cross-sectional study of pediatric patients diagnosed with CNO. A total of 87 patients with a diagnosis of CNO followed for at least 6 months in 8 pediatric rheumatology centers across the country between January 2010 and December 2021 were included in this study.

Results

The study included 87 patients (38 girls, 49 boys; median age: 12.5 years). The median follow-up time was 20 months (IQR: 8.5-40). The median time of diagnostic delay was 9.9 months (IQR: 3-24). Arthralgia and bone pain were the most common presenting symptoms. Multifocal involvement was detected in 86.2% of the cases and a recurrent course was reported in one-third of those included in the study. The most commonly involved bones were the femur and tibia. Vertebrae and clavicles were affected in 19.5% and 20.6% of cases, respectively. The erythrocyte sedimentation rate (ESR) values of 60.9% of the patients were above 20 mm/h and the C-reactive protein values of 44.8% were above 5 mg/L. The remission rate was 13.3% in patients using nonsteroidal antiinflammatory drugs and 75.0% in those using biological drugs. Vertebral and mandibular involvement and high ESR values at the time of diagnosis were associated with recurrence.

Conclusion

In this multicenter study, CNO with vertebral and mandibular involvement and high ESR at diagnosis were associated with recurrence.

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 (CRMO) and Juvenile Spondyloarthritis (JSpA): To What Extent Are They Related?

Chronic recurrent multifocal osteomyelitis (CRMO) is an autoinflammatory disease occurring mainly in the pediatric age group (before 16 years) and generally presents as a separate entity. Synovitis, acne, pustulosis, hyperostosis and osteitis (SAPHO) syndrome combines osteoarticular and cutaneous involvement, similar to CRMO, and falls into the spectrum of spondyloarthritis (SpA). The fact that a patient can progress from one disease to another raises the question of whether CRMO, like SAPHO, could fall within the spectrum of SpA, ranging from a predominantly osteoarticular form to an enthesitic form with more or less marked skin involvement. In this review, we set out to discuss this hypothesis by highlighting the differences and similarities between CRMO and juvenile SpA in clinical, radiological and pathophysiological aspects. A common hypothesis could potentially consider intestinal dysbiosis as the origin of these different inflammatory diseases. Interindividual factors such as gender, environment, genetics and/or epigenetic background could act as combined disease modifiers. This is why we suggest that pathophysiology, rather than clinical phenotype, be used to reclassify these diseases.

Nonbacterial and bacterial osteomyelitis in children: a case-control retrospective study

Purpose

Osteomyelitis is a group of bone infectious (bacterial osteomyeilitis-BO) and noninfectious inflammatory diseases (nonbacterial osteomyelitis-NBO) with similar clinical, radiology, and laboratory features. Many patients with NBO are misdiagnosed as BO and receive unnecessary antibiotics and surgery. Our study aimed to compare clinical and laboratory features of NBO and BO in children, to define key discriminative criteria, and to create an NBO diagnostic score (NBODS).

Methods

The retrospective multicenter cohort study included clinical, laboratory, and instrumental information about histologically confirmed NBO (n = 91) and BO (n = 31). The variables allowed us to differentiate both conditions used to construct and validate the NBO DS.

Results

The main differences between NBO and BO are as follows: onset age-7.3 (2.5; 10.6) vs. 10.5 (6.5; 12.7) years (p = 0.03), frequency of fever (34.1% vs. 90.6%, p = 0.0000001), symptomatic arthritis (67% vs. 28.1%, p = 0.0001), monofocal involvement (28.6% vs. 100%, p = 0.0000001), spine (32% vs. 6%, p = 0.004), femur (41% vs. 13%, p = 0.004), foot bones (40% vs. 13%, p = 0.005), clavicula (11% vs. 0%, p = 0.05), and sternum (11% vs. 0%, p = 0.039) involvement. The following four criteria are included in the NBO DS: CRP ≤ 55 mg/l (56 points), multifocal involvement (27 points), femur involvement (17 points), and neutrophil bands ≤ 220 cell/μl (15 points). The sum > 17 points allowed to differentiate NBO from BO with a sensitivity of 89.0% and a specificity of 96.9%.

Conclusion

The diagnostic criteria may help discriminate NBO and BO and avoid excessive antibacterial treatment and surgery.

Case report: Child chronic nonbacterial osteomyelitis with rapid progressive scoliosis-an association with disease?

Background

Chronic nonbacterial osteomyelitis (CNO) is an auto-inflammatory bone disease that usually develops in childhood. Spinal involvement is a common manifestation of CNO, but it is rare for CNO to lead to rapid progression of scoliosis deformity. Here we present a 9-year-old girl with acute scoliosis with CNO and scoliosis progressed rapidly in 2 months.

Case Presentation

A 9-year-old girl presented bilateral shoulder inequality with pain in the left hypochondrium for 2 months. Standing spinal x-rays showed right convex scoliosis with a 25° Cobb angle. Chest magnetic resonance imaging (MRI) showed that the T8 vertebra was flattened and local bone was destroyed with bone marrow edema. The bone biopsy showed evidence of fibrosis and chronic inflammatory changes with no specific diagnosis. One month later, her scoliosis and bone destruction deteriorated obviously. Thoracic vertebra MRI showed that the T8 vertebra had a compression fracture. ^99mTc-MDP whole-body bone scintigraphy showed intense uptake at T8/9 and the right sacroiliac joint. She was diagnosed with CNO accompanied by rapidly progressive scoliosis. The scoliosis was successfully treated with adalimumab and zoledronic acid, which showed significant improvement after 6 months of follow-up.

Conclusion

Zoledronic acid and adalimumab successfully treated CNO with rapidly progressive scoliosis, but could not prevent vertebral compression.

Whole-body MRI at initial presentation of pediatric chronic recurrent multifocal osteomyelitis and correlation with clinical assessment

BACKGROUND

Chronic recurrent multifocal osteomyelitis (CRMO) is a diagnosis of exclusion, relying heavily on whole-body magnetic resonance imaging (WB-MRI) for diagnosing and evaluating response to therapy. Information with respect to disease distribution and imaging correlation with clinical disease severity at initial presentation is lacking.

OBJECTIVE

To retrospectively characterize distribution of disease on WB-MRI and to correlate imaging findings with disease severity at initial rheumatology presentation.

MATERIALS AND METHODS

Using a modified version of a recently devised imaging-based scoring system, we evaluated disease distribution and correlation between findings on WB-MRI and clinical disease severity in 54 patients presenting for initial evaluation of CRMO. Symptomatic lesion sites were extracted from chart review and physician global assessment was determined by the consensus of two rheumatologists.

RESULTS

Sites of CRMO involvement evident on imaging at initial presentation had a strong predilection for the pelvis and lower extremities. There was significant correlation between the number of lesions detected on WB-MRI and total clinical severity score at initial rheumatology presentation (P&lt;0.01). However, no other imaging parameter correlated with disease severity.

CONCLUSION

While the overall number of lesions identified on MRI correlates with clinical severity scores at initial imaging, other MR parameters of CRMO lesions may not be reliable indicators of disease severity at initial presentation. Further research is needed to assess whether these parameters are implicated in longitudinal disease severity or overall response to therapy.

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.

Chronic recurrent multifocal osteomyelitis. A narrative and pictorial review

Chronic recurrent and multifocal osteomyelitis (CRMO) is a nonsporadic autoinflammatory disorder. Currently, it is diagnosed based on clinical, radiologic, pathological, and longitudinal data. Numerous aspects should be highlighted due to increased knowledge in imaging and immunology. We emphasize the use of whole-body MRI, which is a non-invasive diagnostic strategy. A literature review was carried out on longitudinal studies. Commonly, the mean age at diagnosis is 11 years, ranging between 3 and 17. The most common sites are the long bone metaphysis, particularly femoral and tibial metaphysis. In addition, the pelvis, spine, clavicle, and mandible may be involved. In long bones, the radiologic appearance can show typical structure, mixed lytic and sclerotic, sclerotic or lytic. It is frequently metaphyseal or juxta-physeal, with hyperostosis or periosteal thickening. The involvement of the vertebral skeleton is often multifocal. Therefore, whole-body MRI is essential in identifying subclinical lesions. CRMO is a polymorphic disorder in which whole-body MRI is beneficial to demonstrate subclinical edema. Vertebral collapse requires long-term monitoring.

Nanotechnology in the Diagnosis and Treatment of Osteomyelitis

Infection remains one of the largest threats to global health. Among those infections that are especially troublesome, osteomyelitis, or inflammation of the bone, typically due to infection, is a particularly difficult condition to diagnose and treat. This difficulty stems not only from the biological complexities of opportunistic infections designed to avoid the onslaught of both the host immune system as well as exogenous antibiotics, but also from changes in the host vasculature and the heterogeneity of infectious presentations. While several groups have attempted to classify and stage osteomyelitis, controversy remains, often delaying diagnosis and treatment. Despite a host of preclinical treatment advances being incubated in academic and company research and development labs worldwide, clinical treatment strategies remain relatively stagnant, including surgical debridement and lengthy courses of intravenous antibiotics, both of which may compromise the overall health of the bone and the patient. This manuscript reviews the current methods for diagnosing and treating osteomyelitis and then contemplates the role that nanotechnology might play in the advancement of osteomyelitis treatment.

Chronic nonbacterial osteomyelitis in children: a multicentre Belgian cohort of 30 children

BACKGROUND

To evaluate clinical characteristics, imaging findings, therapeutic approach and outcome of paediatric patients with Chronic Non-Bacterial Osteomyelitis (CNO).

METHODS

Retrospective review of 30 children diagnosed with CNO at two tertiary care centres in Belgium. Imaging data were evaluated by blinded paediatric radiologists.

RESULTS

Mean age at onset was 10.3 years and mean age at diagnosis was 11.7 years. Bone pain was the leading symptom (29/30 patients). Out of 180 symptomatic lesions, 131 were confirmed on MRI as hyperintense geographic lesions on STIR images at the metaphysis and epiphysis adjacent to growth plates of tubular bones. The most common sites of involvement were the lower limbs, spine, sternoclavicular joint and humerus. For nearly half of the patients (14/30) monotherapy with NSAIDs was sufficient to obtain remission. The remaining 16 patients received second-line therapy: bisphosphonates (n = 15/30), disease-modifying antirheumatic drugs (n = 7/30), etanercept (n = 4/30) and tocilizumab (n = 1/30). Remission was reached after a mean time of 37.6 months in 26/30 patients. The prognosis was worse for patients with spinal involvement, resulting in more long-term sequelae.

CONCLUSIONS

We present a multicentre paediatric cohort of 30 CNO patients. A typical pattern of bone involvement could be found on MRI. NSAIDs were administered as first-line treatment. Second-line strategies included bisphosphonates, corticosteroids, methotrexate, etanercept and tocilizumab.

TRIAL REGISTRATION

Retrospectively registered. Registratienummer EC KUL: MP018023.

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.

TNF-inhibitors or bisphosphonates in chronic nonbacterial osteomyelitis? - Results of an international retrospective multicenter study

Chronic nonbacterial osteomyelitis (CNO) can cause significant morbidity, including bone pain and damage. In the absence of clinical trials, treatments include non-steroidal anti-inflammatory drugs, corticosteroids, TNF-inhibitors (TNFi) and/or bisphosphonates. In a retrospective chart review in the United Kingdom and Germany, we investigated response to TNFi and/or pamidronate. Ninety-one patients were included, receiving pamidronate (n = 47), TNFi (n = 22) or both sequentially (n = 22). Patients with fatigue [p = 0.003] and/or arthritis [p = 0.002] were more frequently treated with TNFi than pamidronate. Both therapies were associated with clinical remission at 6 months, and reduction of bone lesions on MRI at 12 months. While not reaching statistical significance, pamidronate resulted in faster resolution of MRI lesions. Fewer flares were observed with TNFi. Failure to respond to pamidronate was associated with female sex [p = 0.027], more lesions on MRI [p = 0.01] and higher CRP levels [p = 0.03]. Randomized clinical trials are needed to confirm observations and generate evidence.

Clinical and Genetic Features of Chinese Adult Patients With Chronic Non-Bacterial Osteomyelitis: A Single Center Report

Objectives

Chronic non-bacterial osteomyelitis (CNO) is a rare polygenic autoinflammatory bone disease. We aimed to characterize the clinical manifestations and gene variants of Chinese adult patients with CNO.

Methods

By reviewing data of all CNO patients being diagnosed and followed up at the Center for Adult Autoinflammation Diseases, Department of Rheumatology, Peking Union Medical College Hospital, clinical and genetic features of these patients were evaluated and concluded.

Results

The median age of disease onset was 19 (6-64) years old, and adult-onset was observed in 6 (60%) patients. The mean time of diagnosis delay was 92 ± 78 months. The common symptoms were bone pain (10, 100%), fever (9, 90%), and arthritis (6, 60%). In total, there were 54 skeletal lesions, and each patient had no less than 2 lesions. The most frequently affected sites included lower limbs (20.5%), mandible, vertebrae and pelvis (17.5%, separately). Variants of 4 genes were detected in our study including COL1A1, PSTPIP1, LRP5 and CLCN7. In seven patients who were treated with combination therapy containing tumor necrosis factor (TNF) α inhibitors, five (55.6%) had a complete response and 2 (44.4%) had a partial response.

Conclusion

This is the first and largest case series of CNO in the Chinese adult patients. Four novel genetic mutations potentially associated with CNO were identified. Notably, CNO should be considered in the differential diagnosis of adult patients with long disease course and recurrent multifocal osteomyelitis of unknown cause, and these patients might benefit from combination therapy containing TNFα inhibitors.

MRI in the Diagnosis and Treatment Response Assessment of Chronic Nonbacterial Osteomyelitis in Children and Adolescents

PURPOSE OF REVIEW

To explain the central role of magnetic resonance imaging (MRI) in the diagnosis and follow-up of chronic nonbacterial osteomyelitis (CNO) in children and adolescents, centering on practical technical aspects and salient diagnostic features.

RECENT FINDINGS

In the absence of conclusive clinical features and widely accepted laboratory tests, including validated disease biomarkers, MRI (whether targeted or covering the entire body) currently plays an indispensable role in the diagnosis and therapy response assessment of CNO. Whole-body MRI, which is the reference imaging standard for CNO, can be limited to a short tau inversion recovery (STIR) coronal image set covering the entire body and a STIR sagittal set covering the spine, an approximately 30-min examination with no need for intravenous contrast or diffusion-weighted imaging. The hallmark of CNO is periphyseal (metaphyseal and/or epi-/apophyseal) osteitis, identified as bright foci on STIR, with or without inflammation of the adjacent periosteum and surrounding soft tissue. Response to bisphosphonate treatment for CNO has some unique MRI findings that should not be mistaken for residual or relapsing disease. Diagnostic features and treatment response characteristics of MRI in pediatric CNO are discussed, also describing the techniques used, pitfalls encountered, and differential diagnostic possibilities considered during daily practice.

The effect of Vitamin B6 in the prevention of hematological adverse effects of linezolid in patients with chronic osteomyelitis: A randomized double-blind placebo-controlled clinical trial

Background:

Due to the contradictory results of the effects of Vitamin B6 in reducing the hematotoxic effects of linezolid, the present study aimed to investigate the possible role of Vitamin B6 administration in reducing linezolid-related hematological toxicities in patients with chronic osteomyelitis.

Materials and Methods:

In a randomized double-blind placebo-controlled clinical trial, patients with chronic osteomyelitis were randomly divided into two groups (n = 40 each): the intervention group received Vitamin B₆40 mg twice daily from the beginning of treatment with linezolid and the control group received placebo with linezolid, both for 21 days. Blood variables including hemoglobin (Hb), white blood cells (WBC), and platelets (PLT) were measured at baseline and at the end of the 1^st, 2^nd, and 3^rd weeks (days 7, 14, and 21) of the intervention.

Results:

There was no significant difference between the groups regarding the count of WBC and PLT and level of Hb at evaluated time points. Furthermore, there was a significant decreasing trend in all parameters within both groups; however, the decreasing trend of both PLT and WBC was slower in the intervention (Vitamin B6) group compared to the placebo group.

Conclusion:

Vitamin B6 has no significant effect in the reduction of hematological adverse effects of linezolid in chronic osteomyelitis patients. However, it could retard the decreasing trend of WBC and PLT counts.

First-year follow-up of children with chronic nonbacterial osteomyelitis-an analysis of the German National Pediatric Rheumatologic Database from 2009 to 2018

OBJECTIVE

To assess the first-year features of patients with chronic nonbacterial osteomyelitis (CNO).

METHODS

Patients with a diagnosis of CNO, disease duration of under 13 months, and first registration in the German National Pediatric Rheumatologic Database (NPRD) between 2009 and 2018 were included in this cross-sectional analysis.

RESULTS

Of 774 documented patients, 62.8% were female, and all patients had a median age of 11 years. The most affected clinical sites were the tibia (29.7%), pelvis (28.0%), and femur (27.8%). HLA-B27 was positive in 48 of 314 analyzed patients (15.3%). In 406 patients, an X-ray was performed at the first visit; X-ray results showed osteosclerosis/-lysis in 34.0% and hyperostosis in 14.5% of the patients. MRI scans (focal and whole-body scans) were performed in 648 patients, and 81.5% showed a positive TIRM/STIR signal. A total of 84.7% of the patients were administered nonsteroidal anti-inflammatory drugs, 9.6% were administered oral glucocorticoids, 10.8% were administered disease-modifying anti-rheumatic drugs (DMARDs), and 6.1% were administered bisphosphonates. An evaluation of the patient's questionnaire showed an overall well-being (NRS 0-10) of 2.0. The PedCNO disease "activity" score revealed a 70% improvement in variables in 43% of patients in the initial 1-year follow-up. Copresentation with diagnostic criteria of pediatric enthesitis-related arthritis was rare.

CONCLUSION

To our knowledge, the NPRD cohort seemed to be the largest cohort of children and adolescents suffering from CNO worldwide. Most patients were treated effectively with NSAIDs, and only a small group of patients was administered additional medication. The patient-defined measures of disease activity had a moderate impact on patients' daily lives.

TRIAL REGISTRATION

Not applicable.

Inflammasomes in Alveolar Bone Loss

Bone remodeling is tightly controlled by osteoclast-mediated bone resorption and osteoblast-mediated bone formation. Fine tuning of the osteoclast-osteoblast balance results in strict synchronization of bone resorption and formation, which maintains structural integrity and bone tissue homeostasis; in contrast, dysregulated bone remodeling may cause pathological osteolysis, in which inflammation plays a vital role in promoting bone destruction. The alveolar bone presents high turnover rate, complex associations with the tooth and periodontium, and susceptibility to oral pathogenic insults and mechanical stress, which enhance its complexity in host defense and bone remodeling. Alveolar bone loss is also involved in systemic bone destruction and is affected by medication or systemic pathological factors. Therefore, it is essential to investigate the osteoimmunological mechanisms involved in the dysregulation of alveolar bone remodeling. The inflammasome is a supramolecular protein complex assembled in response to pattern recognition receptors and damage-associated molecular patterns, leading to the maturation and secretion of pro-inflammatory cytokines and activation of inflammatory responses. Pyroptosis downstream of inflammasome activation also facilitates the clearance of intracellular pathogens and irritants. However, inadequate or excessive activity of the inflammasome may allow for persistent infection and infection spreading or uncontrolled destruction of the alveolar bone, as commonly observed in periodontitis, periapical periodontitis, peri-implantitis, orthodontic tooth movement, medication-related osteonecrosis of the jaw, nonsterile or sterile osteomyelitis of the jaw, and osteoporosis. In this review, we present a framework for understanding the role and mechanism of canonical and noncanonical inflammasomes in the pathogenesis and development of etiologically diverse diseases associated with alveolar bone loss. Inappropriate inflammasome activation may drive alveolar osteolysis by regulating cellular players, including osteoclasts, osteoblasts, osteocytes, periodontal ligament cells, macrophages, monocytes, neutrophils, and adaptive immune cells, such as T helper 17 cells, causing increased osteoclast activity, decreased osteoblast activity, and enhanced periodontium inflammation by creating a pro-inflammatory milieu in a context- and cell type-dependent manner. We also discuss promising therapeutic strategies targeting inappropriate inflammasome activity in the treatment of alveolar bone loss. Novel strategies for inhibiting inflammasome signaling may facilitate the development of versatile drugs that carefully balance the beneficial contributions of inflammasomes to host defense.

Chronic Nonbacterial Osteomyelitis of the Sternocostoclavicular Region in Adults: A Single-Center Dutch Cohort Study

Sternocostoclavicular hyperostosis (SCCH) is a rare autoinflammatory bone disorder caused by chronic nonbacterial osteomyelitis (CNO), which is associated with sclerosis and hyperostosis primarily affecting the sternum, the medial end of the clavicles, and the first ribs. Other areas of the axial skeleton may also be affected. The more severe synovitis–acne–pustulosis–hyperostosis–osteitis (SAPHO) syndrome is additionally associated with dermatoses and joint manifestations. This Dutch retrospective cross‐sectional single‐center cohort study characterizes the spectrum of clinical features in adult CNO/SCCH patients at the time of diagnosis. The only inclusion criteria was the availability of complete sets of clinical and imaging data systematically collected over three decades using in‐house protocols. Data from 213 predominantly female patients (88%) with a median age of 36 years at presentation were studied. The mean diagnostic delay was 5 ± 5 years. The main symptoms were chronic pain (92%), bony swelling (61%), and restricted shoulder girdle function (46%); 32% had palmoplantar pustulosis and 22% had autoimmune disease. The majority (73%) had isolated SCCH; 59 (27%) had additional localizations in vertebrae (19%), the mandible (9%), or both (2%); 4 had SAPHO. The prevalence of current or past smoking was high (58%), particularly for patients with palmoplantar pustulosis (76%). There was a significant relationship between delay in diagnosis and both the extent of affected skeletal sites (p = 0.036) and erythrocyte sedimentation rate levels (p = 0.023). Adult‐onset CNO is characterized by distinctive clinical and radiological features, but diverse aspects of its spectrum are currently not fully captured by a comprehensive classification. Delayed diagnosis is still common and potentially associated with irreversible structural changes and debilitating chronic symptoms, increasing the burden of illness and negatively impacting on quality of life. It is hoped that findings from this study will dispel confusion about nomenclature and classification of adult‐onset CNO and increase awareness of its distinctive clinical and radiological features, and thus facilitate early diagnosis and referral for treatment, which should positively impact prognosis by preventing disease progression, although this remains to be established. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

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

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

•

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

•

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

•

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

•

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

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.

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.

TNAP as a New Player in Chronic Inflammatory Conditions and Metabolism

This review summarizes important information on the ectoenzyme tissue-nonspecific alkaline phosphatase (TNAP) and gives a brief insight into the symptoms, diagnostics, and treatment of the rare disease Hypophosphatasia (HPP), which is resulting from mutations in the TNAP encoding ALPL gene. We emphasize the role of TNAP beyond its well-known contribution to mineralization processes. Therefore, above all, the impact of the enzyme on central molecular processes in the nervous system and on inflammation is presented here.