Fibrous Dysplasia

Fibrous dysplasia is a disorder of the bone wherein abnormal, fibrous tissue develops in a part of a bone instead of normal bone. This disorder starts sometime during the development of the fetus. Although fibrous dysplasia starts before birth, it is usually not detected until later, during childhood, or adolescence, or sometimes even adulthood. As the affected bone continues to grow, the fibrous tissue, which is weaker, enlarges thus causing the whole bone to become weak, brittle, painful, and even deformed.

Fibrous dysplasia can affect any bone in the body, and several bones may be affected at a time. When a number of bones are affected, it is often observed that they are all located on one side of the body. Nevertheless, the condition does not spread from one affected bone to another. Some of the bones that fibrous dysplasia usually affects are: the bones in the face; the skull; the ribs; the arm bone, or humerus; the pelvis; the thighbone, or femur; the shinbone, or tibia; and less often, the spinal vertebrae.

What Causes Fibrous Dysplasia?

Fibrous dysplasia develops in the fetal stage and its occurrence has been associated to a mutation of a gene that affects the cells that make bone. Although it is still not known exactly what causes this mutation, however, it is known that it is not a hereditary disease, so, you do not inherit it from your parents, neither will your children inherit it from you, if you are affected with it.

Bones are made up of tissue that is living. Therefore, the bones renew themselves continuously even after one stops growing. In the renewal process, particular types of bone cells, known as osteoclastic, break down, or reabsorb bone, whereas other types of bone cells, known as osteoblastic, build it up again. When fibrous dysplasia affects a bone, this process is disrupted, resulting in old bone breaking down faster, and normal bone tissue being replaced by weaker, fibrous tissue.

What are the Signs of Dysplasia?

Although the symptoms of fibrous dysplasia may be experienced differently by different people, given below are some of the common ones:

• Pain in the affected bone due to the expansion of the fibrous tissue
• Deformity in the bone
• Fractures of the affected bone
• Scoliosis, which is an abnormal lateral curvature of the spinal column, resulting in the person seeming to lean towards one side
• A tottering walk

As is quite evident, these symptoms can also occur in other types of bone disorders, hence a doctor should be consulted in order to confirm the diagnosis of fibrous dysplasia.

How is Fibrous Dysplasia Treated?

There is no cure yet for fibrous dysplasia, and hence the treatment basically involves relieving the symptoms of the condition.

If there are no symptoms in a person affected with fibrous dysplasia, the condition is observed with X-rays taken periodically, with no further treatment if it is found that the condition is not progressing. Sometimes braces may be used in order to prevent the bone from fracturing, although they have not been able to prevent the bone from getting deformed.

However, if the condition does progress, it is usually treated by medication and surgery.

Medications: Medications known as bisphosphonates, such as alendronate and pamidronate, help in slowing the breakdown of bone, maintaining bone mass, and increasing the density of the bone in the hip and spine, thus lowering the chances of fractures. While these medications are usually used in adults for treating osteoporosis and increasing the density of bones, however, they also help in reducing the pain that accompanies fibrous dysplasia, and sometimes may even help in improving the formation of bone.

Although not much is know about how bisphosphonates affect adolescents and children, however, according to some studies it may help in relieving pain in them.

Surgery: Surgery may include the affected area of the bone being removed and followed by bone being grafted, wherein a healthy bone from another area of the body is transplanted into the area affected by fibrous dysplasia. However, over a periods of time, the grafted bone too is absorbed, with more fibrous dysplasia replacing it.

Also, the affected bone may be stabilized with the help of a rod placed inside the bone, along with screws and plates, which can be useful in fixing a deformity or fracture, or also to prevent the bone from breaking.