Article Text
Abstract
Chronic recurrent multifocal osteomyelitis (CRMO) is a rare autoinflammatory condition presenting with gradual onset bony pain, localised tenderness and swelling. Bone marrow inflammation and lytic bone lesions are seen, with elevated inflammatory markers and sterile cultures. The exact aetiology is unclear; however, it is thought to be caused by a disruption in innate immunity regulation because of cytokine imbalances.1
We present a case of a 7-year-old female who presented with an 8-month history of chronic diarrhoea, nocturnal stooling, occasional bloody and mucous stool and recurrent mouth ulcers. No abdominal pain or weight loss was reported. Initial investigations showed a raised ESR of 16mm/hr, raised faecal calprotectin of 1200mcg/g and a raised platelet count of 449 × 109/L. Upper GI endoscopy, ileo-colonoscopy and histology were in keeping with a diagnosis of Crohn’s disease (CD). The MRI small bowel showed significantly thickened small bowel loop, lying to the left of the midline with no retroperitoneal lymphadenopathy or pelvic free fluid. Initial treatment involved exclusive enteral nutrition and azathioprine was commenced later. Prednisolone was started due to lack of improvement, but investigations demonstrated high disease activity. Infliximab at 5 mg/kg was started due to failure to induce remission. She responded to infliximab and over the next 3 years, the patient’s GI symptoms were well controlled.
She then developed a non-tender right-sided clavicular head swelling and a cervical lymph node. CRP and LDH were normal, ESR was slightly raised at 22mm/h but normalised. Ultrasound of the neck showed features of a reactive lymph node. MRI of right clavicle confirmed CRMO affecting the medial end of right clavicle. She had no GI symptoms, with a reassuring repeat endoscopy. Infliximab infusions were stopped, and the patient was started on methotrexate following rheumatology advice. At the time of writing, the patient has clinically improved with well controlled CD.
CRMO treatment can include NSAIDs, corticosteroids, methotrexate, bisphosphonates, and tumour necrosis factor (TNF)-α inhibitors.2 However, our patient was in CD remission at the time of CRMO symptom onset and improved after infliximab was stopped and replaced by methotrexate. A case series by Cordesse et al.3 supports this approach, demonstrating a paradoxical CRMO reaction occurring in 3 patients in remission of CD through anti-TNFα efficiency. The exact physiopathology remains unclear, and management can be complex. As the GI disease was under control in our patient, stopping TNF-α inhibitors was possible and this may be useful in other patients. Detailed multi-professional management will be required for these cohort of patients.
References
Hedrich CM, Hofmann SR, Pablik J, et al. Autoinflammatory bone disorders with special focus on chronic recurrent multifocal osteomyelitis (CRMO). Pediatr Rheumatol Online J 2013: published online Dec 23. DOI: 10.1186/1546-0096-11-47.
Taddio A, Zennaro F, Pastore S, et al. An update on the pathogenesis and treatment of chronic recurrent multifocal osteomyelitis in children. Pediatr Drugs 2017;19:165–172.
Cordesse A, Ecochard-Dugelay E, Melki I, et al. Chronic recurrent multifocal osteomyelitis in pediatric crohn disease, a paradoxical effect to antitumor necrosis factor alpha. JPGN Reports 2020 1:e007.