What is Bone Marrow Edema?
Bone Marrow Edema, also known as Bone Marrow Edema Syndrome, or BMES, is a disorder that causes the marrow of the bones to swell up and take on fluid. This is extremely painful, as it puts pressure against the interior of the bones and is found to reduce the marrow's ability to produce new blood cells. It quite literally doesn't have the room that it needs to fulfill its function, though the initial onset of the excess fluid serves to help blood cells that were already created in circulation. Thankfully, BMES is a self-limiting disorder which fades an average of three weeks after the initial onset. Diagnosis is performed with MRI technology.
Osteoarthritis is a chronic disease wherein the connective tissue of the joints is slowly eroded. This occurs through the buildup of waste minerals around the joints as well as by wear and tear over time. A correlation is present that in almost 80% of BMES cases, the patient also had osteoarthritis. Typically, the site of BMES was at the head of the femur which connects into the knee. It's postulated that this might be a coping mechanism. The body could be trying to reduce the mineral deposits in the joints by swelling the bone marrow with fluid, which has the side effect of pushing newly produced blood cells (red and white) out of the bone and into immediate use throughout the body.
In those situations where osteoarthritis is not present in the BMES sufferer, the patient usually sustained a broken bone shortly before the disorder's onset. BMES is different from normal edema in that, while it does include an increase in the fluid mass of the bone marrow, it also involves an inflammatory response from the immune system. It is possible, though not proven, that BMES is part of the immune system's self defense mechanism. It would prevent infection of the broken bone and bone marrow by inflaming the bone marrow, increasing its internal temperature to a point which would discourage the reproduction of bacteria and viruses, just like a fever.