Chronic recurrent multifocal osteomyelitis
Description, Causes and Risk Factors:
Chronic recurrent multifocal osteomyelitis (CRMO) is the most severe form of chronic nonbacterial osteomyelitis. In children and adolescents, chronic nonbacterial osteomyelitis predominantly affects the metaphyses of the long bones, but lesions can occur at any site in the skeleton. Other organs (the skin, eyes, gastrointestinal tract and lungs) can also be affected. Clinical diagnosis is often difficult because the symptoms and course of disease vary significantly. We present a 10-year-old girl diagnosed with CRMO involving several vertebrae, the femur and the metatarsus.
This disease is rare and it mostly affects children. It is more common in girls than boys, at a ratio of five to one. However, the adults can also be affected. In children it may develop between the ages 4 and 14, with the age of 10 being the most common starting point for the development of this condition. No epidemiological data on incidence and prevalence have been published so far. However, the incidence might be estimated at 1:1,000,000.
The cause of this condition is unknown, despite the intensive investigation over a period of more than 30 years. Carefully done culture and tissue sampling on bone lesions in children with this disease, using the best available techniques, has failed to yield any apparent infectious agents.
The main suggestions for possible causes include:
- Autoimmune reaction (where white blood cells instead of seeking out and destroying foreign invaders turn on the body and attack normal cells instead) or
- A defect in the immune system.
Propionibacterium acnes has been postulated to be involved in the pathogenesis. However, in larger cohorts and by using state of the art microbial techniques, no apparent infectious agents have been detected at the site of the bone lesion in pediatric patients.
There are also some experts who believe it is an inherited condition and that genetics play a major role in its development. They have found a significant association of chronic recurrent multifocal osteomyelitiswith a rare allele of marker D18S60, resulting in a haplotype relative risk (HRR) of 18.
This suggests the existence of a gene in this region contributing in a significant manner to the etiology of CRMO and concomitantly demonstrates evidence for a genetic basis of CRMO. This gene is different from RANK, which is mutated in familial expansile osteolysis (FEO), but not in chronic recurrent multifocal osteomyelitis.
Young man suffering from pain in his shoulder. Isolated on white.
Chronic recurrent multifocal osteomyelitis is a disorder that damages the affected area of the bone and creates characteristic formations also known as bone lesions. The problem is that, when these lesions flare-up they cause
Deep aching pain.
- Possible constitutional upset,
- Skin redness.
The pain can be quite severe and may limit the child's activities. Not only that it may prevent the kid from going to school, but sometimes it may even require hospitalization. It mainly affects the metaphyses of the long bones, in addition to the spine, the pelvis and the shoulder girdle. Some bones seem to be more affected by CRMO than others and this includes the shinbone, thighbone and clavicle (collarbone). Many young people with CRMO have pain in more than one area of the bone.
Diagnosis of chronic recurrent multifocal osteomyelitis:
Clinical diagnosis in affected children can be difficult because the clinical picture and course of the disease may vary significantly. CRMO can have similar symptoms to other conditions, for example arthritis. Radiological and magnetic resonance imaging features of chronic recurrent multifocal osteomyelitis have been described, but differential diagnosis remains difficult, including rheumatic diseases, bacterial osteomyelitis, and malignancy. To get a diagnosis the person needs to have a series of tests and scans.
- Bone biopsy:Bone biopsy is often the best way to do this. During this procedure, a small sample of the inflamed bone is removed with a needle, usually under anesthetic, to be examined under the microscope. The gold standard for diagnosis of chronic recurrent multifocal osteomyelitis is histopathology of bony lesions. Lesions consist of chronic inflammatory cells and cultures are characteristically negative. In very early lesions granulocytes can be observed, and later on there are mainly lymphocytes or monocytes. All bacterial and fungal cultures from native biopsy tissues should be negative.
- Plain radiographic findings: Findings made by plain radiographic imaging are variable. CRMO can present as an osteolytic, sclerotic, or a mixed lytic-sclerotic lesion.
- MRI: This is a very good and effective diagnostic method. Magnetic resonance imaging scans have been used to evaluate the activity of lesions and to identify the most appropriate site for biopsy.
The effective and definite treatment is still impossible. The aim of the treatment is to try to prevent flare-ups and treat them if they occur. Long term treatment is usually required to monitor any growth disturbances in the affected bones.
Antibiotics are no good: Experience has shown that antibiotic treatment is not effective in dealing with chronic recurrent multifocal osteomyelitis flare-ups as there is no underlying infection to treat. This is probably because no bacteria can be found in the bone biopsy specimens.
Non-steroidal anti-inflammatory drugs (NSAIDs): Affected bones respond well to non-steroidal anti-inflammatory drugs (NSAIDs), and they are the primary choice for the effective treatment. Azithromycin has been used in the treatment of this condition because of its anti-inflammatory and immunomodulatory effects.
Physiotherapy: Physiotherapy has shown to be a very effective therapeutic method. It is proven that physiotherapy can also help improve movement and flexibility of the affected bones and the surrounding joints.
Steroids: Severe cases of chronic recurrent multifocal osteomyelitis can often be treated with regular doses of steroids, which damp down the inflammation and allow the bone to heal. Oral steroids, bisphosphonates, and sulfasalazine have been used in specific cases. Other medicines that have the same `damping down' effect may also be recommended, either alone or in the conjunction with steroids.
Surgical operations: If the bone lesions are obvious and cause problems, they can be removed with an operation. Aggressive surgical treatments, and procedures that increase the risk of pathological fracture in particular, should be avoided.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.