What is chronic recurrent multifocal osteomyelitis (CRMO)?

CRMO is where an area of young person’s bones gets inflamed and painful. The symptoms come and go, so there are times when there are no symptoms at all.

What are the symptoms of CRMO?

CRMO damages the area of bone affected and creates what’s known as bone lesions. When these lesions flare-up they cause pain, swelling and occasionally skin redness. The pain can be bad and stop the patient from going to school, or they might have to stay in hospital for treatment with medicines. Some bones seem to be more affected by CRMO than others. These include the shinbone, thighbone and clavicle (collarbone). Many young people with CRMO have pain in more than one area of bone.

How is it diagnosed?

CRMO can have similar symptoms to other conditions, like arthritis.  To get a diagnosis the person needs to have a series of tests and scans. A bone biopsy is often the best way to do this: a small sample of the inflamed bone is removed with a needle, usually under anaesthetic, to examine under the microscope.

What causes CRMO?

No one knows what causes CRMO. Some possible causes include infectious disease, autoimmune reaction (where the body’s immune system attacks the normal cells itself) or a problem in the immune system.

How common is CRMO and whom does it affect?

CRMO is rare. It seems to affect more girls than boys, but it’s not known why. It usually appears around the age of 10.

What treatments are available?

Treatment for CRMO tries to stop flare-ups and treats them if they occur. On-going checks ups are needed to make sure there are no problems in the affected bones.

Anti-inflammatory drugs work well and physiotherapy can also help improve movement of these bones and surrounding joints. Severe cases can often be treated with regular doses of steroids, which reduce the inflammation and allow the bone to heal. If the bone lesions are obvious and cause problems they can be removed in an operation.

What is the outlook for children and young adults with CRMO?

Most young people with CRMO go into remission (the bone heals, pain episodes stop and medication is no longer necessary) around puberty, but some have relapses in their late teens or early adulthood. Overall, the outlook for children and young adults with CRMO is excellent. Most respond well to treatment and have few long-term effects.

But if certain areas of bone are affected, this could mean the limb does not develop as it should, leaving one limb shorter than the other. But this can be treated with limb lengthening.

For more help and information

For more information about CMRO phone 080 8808 3555 or the website can be found at www.cafamily.org.uk  

Last reviewed by Great Ormond Street Hospital: 31 October 2005

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