CHRONIC RECURRENT MULTIFOCAL OSTEOMYELITIS IN CHILDREN: A NATIONAL EXPERIENCE AT A TERTIARY REFERRAL CENTRE OVER 20 YEARS
Authors: Hughes I. , May J. , Carpenter C. 
Published: March 2023

IntroductionChronic recurrent multifocal osteomyelitis (CRMO) is a rare condition characterised by bony pain and swelling which may be initially mistaken for bacterial osteomyelitis. The episodic course of the disease may confound the diagnosis and potentially be mistaken for a partial response to antimicrobial therapy. It is an orphan disease and consequently results in many unclear aspects of diagnosis, treatment and follow up for patients. The aim of this study is to evaluate a national tertiary centre's experience with the clinical condition and present one of the largest cohorts to date, emphasizing the vast array of clinical spectrum, course and response to treatment.MethodsWe retrospectively evaluated all children identified with CRMO from the period 2000–2022 within Wales. Demographic data and clinical parameters were selectively identified through the utilisation of a national clinical platform (Welsh Clinical Portal). The diagnosis was based on clinical findings, radiological images, histopathological and microbiological studiesResultsA total of 21 patients were identified as suitable for inclusion. The mean age of diagnosis was 9.4 ±2 years. The age range of children being diagnosed was 6–14 years. Of the 21 patients, only 2 reported feeling unwell prior to their first presentation with generalized coryzal illness reported. The most common presenting site for CRMO was knee (33%) followed by back pain (28%). 19% of the included cases at initial presentation had localised warmth and had nocturnal pain. 4 of the patients went on to have dermatological conditions of which psoriasis was the most common (14%). Bilateral symptoms developed in 38% of the included patients. Biochemical investigations revealed only 19% of patients had a raised C-reactive protein level and erythrocyte sedimentation rate whilst 9/21 patients went on to have a bone biopsy to aid diagnosis. 100% of patients had MRI whilst whole body MRI was utilised in 8/21 patients. NSAID's were utilised for 81%, Pamidronate for 33% and methotrexate for 14%. Biologics were utilised for a further 24% of the total population in failed medical therapy. Surgical intervention was utilised for a single individual in this cohort of patients in the form of posterior spinal stabilisation. The most common referring speciality for these patients was Rheumatology (71%) followed by Orthopaedics (33%).DiscussionCRMO represents a challenging diagnosis to make with such varied clinical and biochemical presentations for this condition. The absence of diagnostic Radiological features on X-ray could argue over early MRI imaging. The utilisation of whole body-MRI can now identify multifocal disease burden which may facilitate a timely diagnosis and ensure that effective medical treatment is started promptly without delay. This study is the largest cohort of CRMO patients conducted in this country. Future work will serve to build upon a framework and national referral pathway so that these patients can be seen by the appropriate specialist in a timely manner.