AB0752 CHRONIC RECURRENT MULTIFOCAL OSTEOMYELITIS: A SINGLE-CENTER CASE SERIES
Authors: Dallagiacoma G. , Buzzegoli T. , Karner M. , Matzneller P. , Raffeiner B. , Dejaco C. 
Published: May 2021

Background:Chronic recurrent multifocal osteomyelitis (CRMO) is a chronic autoinflammatory disease that primarily affects the skeleton of children and adolescents in the absence of an infectious etiology[1]. CRMO lesions presentation varies widely ranging from episodic bone pain to growth disturbance; lytic and sclerotic bone lesions can be found on X-ray, however magnetic resonance imaging is very useful for evaluating the extent of disease and follow-up [2].Objectives:To report demographic, clinical and laboratory characteristics and response to therapy in a single center Italian cohort of CRMO patients.Methods:We reviewed retrospectively the clinical records of seven patients affected by CRMO diagnosed between 2008 and 2019 at rheumatologic service of South Tyrol region in Italy.Results:We identified 7 patients with CRMO, 4 were female patients, median age of onset of symptoms was seven years. Median delay in diagnosis was seven months; all patients had bone pain as initial symptom and 6 patients presented joint swelling. Median number of lesions was two; all patients had a recurrent pattern, 4 patient had multifocal distribution and 5 had appendicular skeleton involvement. None of our patients had antinuclear antibodies or HLA-B27 positivity. Mean erythrocyte sedimentation rate was 52 mm/h and C-reactive protein 1,96 mg/dL. Regarding other organs involvement one patient presented palmoplantar pustulosis, one psoriatic arthritis and one psoriasis guttata; three patient referred familiarity for psoriasis. Histopathological diagnosis was confirmed in 3 patients. NSAIDs were used in six patients, methotrexate in two patients and bisphosphonates in 6 patients. Among biological DMARDs Adalimumab was used in two patients, one patient was treated subsequently with Secukinumab and Ustekinumab. 3 patients achieved remission (Table 1).Table 1.Demographic, clinical and laboratory characteristics of patients with chronic recurrent multifocal osteomyelitis.Total (n=7)Demographics Female (%)4 (57) Age at disease onset, years, median (range)7 (6-24) Delay in diagnosis, months, median (range)7 (2-14) Follow-up, months, median (range)69 (11-151)Initial symptoms Bone pain, n (%)7 (100) Swelling, n (%)5 (71) Limp, n (%)3 (43) Fever, n (%)1 (14)Clinical features Number of lesions, median (range)2 (1-10) Axial skeleton involvement, n (%)2 (29) Appendicular skeleton involvement, n (%)5 (71)Distribution of involvement Femur, n (%)3 (43) Radius/ulna, n (%)2 (29) Humerus, n (%)1 (14) Tibia/fibula, n (%)5 (5) Tarsal bones, n (%)1 (14) Others, n (%)3 (43)Laboratory tests Hemoglobin, g/dL, mean ± SD13.1±0.6 Leukocytes × 103/mm3, mean ± SD8.48 ±1.7 Platelets × 103/mm3, mean ± SD384±130 Erythrocyte sedimentation rate mm/h, mean ± SD52±37 C-reactive protein, mg/dL, mean ± SD1.96±2.35 Positive antinuclear antibodies, n (%)0 (100) HLA-B27 positive, n (%)0 (100)Comorbidities Any type of autoimmunity, n (%)2 (29) Others, n (%)3 (43) Histological confirmation, n (%)3 (43)Treatment NSAIDs, n (%)6 (86) Glucocorticoids, n (%)0 (0) Bisphosphonates, n (%)6 (86) TNF blocking agents, n (%)2 (29) Biological DMARDs, n (%)1 (4) Methotrexate, n (%)2 (29) Antibiotics, n (%)3 (43) Reached remission, n (%) 3 (43)Conclusion:CRMO remains a rare diagnosis. From our experience most of the patients had delay in diagnosis, laboratory tests showed mild elevation of inflammatory parameters, was found association with psoriatic arthritis and psoriasis, remission was achieved with combination of bisphosphonate and immunosuppressive therapy in less than half of the cohortReferences:[1]A. Taddio, F. Zennaro, S. Pastore, e R. Cimaz, «An Update on the Pathogenesis and Treatment of Chronic Recurrent Multifocal Osteomyelitis in Children», Pediatr. Drugs, vol. 19, n. 3, pagg. 165–172, giu. 2017.[2]S. J. Menashe et al., «The Many Faces of Pediatric Chronic Recurrent Multifocal Osteomyelitis (CRMO): A Practical Location- and Case-Based Approach to Differentiate CRMO From Its Mimics», J. Magn. Reson. Imaging JMRI, pag. e27299, ago.2020Disclosure of Interests:None declared