Bone inflammation and chronic recurrent multifocal osteomyelitis

Abstract

Chronic recurrent multifocal osteomyelitis (CRMO) is a sporadic condition of inflammatory bone pain that occurs as recurrent flares because of osteomyelitis, which presents in the form of multiple aseptic foci. The estimated prevalence of CRMO is 1-2 per million, affecting mostly children, in the age group of 2 to 17. Main symptoms of CRMO are bone inflammation and pain, which are generally worse at night. Other symptoms seen on radiographs indicate osteolytic lesions surrounded by sclerosis, at later stages of the disease. Markers of inflammation, viz. tumor necrosis factor a and C-reactive protein are elevated in many cases. Because of similar symptoms, differential diagnosis is needed to confirm CRMO from infectious osteomyelitis, bone tumors, and other diseases. The genetic component is likely in some cases such as Majeed syndrome, deficiency of IL-1 antagonist, etc. Imaging is the essential part of diagnosing CRMO, and magnetic resonance imaging of the whole body is the most widely used and recommended method for the evaluation of multiple foci, as compared to radiography for reasons of sensitivity as well as prevention of excessive exposure of affected children to radiation. CRMO is considered an autoimmune and auto-inflammatory disorder, but its precise pathophysiology is not clear. Current treatment options are non-steroid anti-inflammatory drugs like naproxen, as the primary choice, and the bisphosphonates such as pamidronate as the second choice, to counter the symptoms and to reduce bone lesions. The surgical option is the choice for recalcitrant cases, even though recurrence may still be a problem.