Managing osteoporosis with Duchenne muscular dystrophy

Last updated Aug. 8, 2024, by Marisa Wexler, MS
Fact-checked by Patrícia Silva, PhD

 
People with Duchenne muscular dystrophy (DMD) are at an increased risk of osteoporosis — weakened, brittle bones — because of the disease itself, as well as from some of the medications used to treat it.

Osteoporosis substantially increases the risk of fractures and related health problems. Taking measures to maintain bone health is an important part of managing the disease.

Why people with DMD are prone to osteoporosis

There are two main reasons people with DMD are prone to developing osteoporosis: One is from the disease itself, and the other is from corticosteroids commonly prescribed as part of DMD treatment.

DMD is a genetic disorder that primarily affects the muscles, causing muscle weakness and wasting.

Muscle and bone health are closely connected. When a muscle contracts, it pulls on bones to induce movement. When this happens it releases biochemical signals that help maintain bone strength and structure. In a typically developing person, this feedback loop helps ensure bones are consistently strengthened. But in people with DMD, the feedback loop is disrupted. As a result, bones are more prone to weakening.

Some medications that help manage DMD can also increase the risk of osteoporosis, specifically corticosteroids, which are anti-inflammatory medicines that are now a standard part of DMD care. Corticosteroids have been proven to help preserve muscle strength in people with DMD, but long-term use can cause side effects, including weakened bones.

Problems caused by osteoporosis in DMD

Osteoporosis makes you more likely to have fractures or broken bones. Compared with the general population, people with DMD are about four times more likely to experience any type of fracture.

When you have DMD, fractures may affect bones in the body extremities, particularly the femur (the large bone in the thigh) and the tibia and fibula (the two long bones in the lower leg). Although most people with DMD eventually lose their ability to walk, breaks in these bones can lead to this at an earlier age.

Breaks in large bones also can set the stage for fat embolism syndrome, a condition where fat droplets get into the bloodstream and block blood flow. This syndrome can cause symptoms including difficulty breathing, a purplish rash, and changes in behavior. It can also be life-threatening, so if you are experiencing symptoms you should immediately seek emergency medical care.

People with DMD also commonly experience vertebral fractures, which are breaks in the bones of the spine. The risk of vertebral fractures in people with DMD is more than 500 times higher than in the general population. Vertebral fractures often don’t cause any noticeable issues, particularly in early stages. But when not addressed, these breaks can contribute to chronic back pain and spinal deformities such as scoliosis, an abnormal sideways curve of the spine, or kyphosis, a pronounced forward curve in the upper spine.

Data have also shown that people with DMD who have one vertebral fracture are more likely to have additional fractures in the future.

Treating and managing osteoporosis

Current guidelines for managing osteoporosis in DMD focus on early, routine monitoring to detect any signs of weakened bones. By doing this, if osteoporosis does develop, it can be treated as soon as possible.

Monitoring bone health

Under current guidelines, the main method used to monitor bone health in people with DMD is by X-rays of the spine. Spinal imaging can help detect and track abnormal spine curvatures, such as scoliosis or kyphosis, as well as spinal fractures.

Because spinal fractures often don’t cause obvious symptoms, it’s recommended people with DMD have X-rays of the spine at least once every year, especially if they are taking corticosteroids or have other osteoporosis risk factors.

Spinal X-rays also should be considered for symptoms such as back pain, which could be a sign of a vertebral fracture.

Previously, guidelines for managing bone health in DMD recommended monitoring bone density (also called bone mineral density) as a primary method to screen for osteoporosis. However, recent data have shown fractures can develop even in DMD patients with normal bone density measurements. For this reason, current guidelines prioritize spinal X-rays over bone density measurements. That said, it may still be used as an add-on test to help detect early signs of bone weakness.

Another key part of monitoring bone health is managing the nutrients needed for proper bone health, particularly calcium and vitamin D. If a person isn’t getting enough of these nutrients in their diet, doctors or dietitians may recommend taking supplements. Blood and urine tests may be done to check calcium and vitamin D levels. It’s recommended vitamin D (specifically 25-hydroxyvitamin D) levels be checked at least once per year.

Treating muscular dystrophy osteoporosis and fractures

The recommended treatment for people with DMD who have developed osteoporosis or experience a clinically significant fracture is intravenous (IV, into-the-vein) bisphosphonates. They are a class of medicines that can help strengthen the bones and slow down or prevent bone loss.

It’s recommended that IV bisphosphonates be given to people with DMD-related osteoporosis because oral formulations of bisphosphonates do not seem to be as effective.

In older boys and teenagers with DMD, management of osteoporosis may involve the use of testosterone (the male sex hormone). Because corticosteroids can delay the onset of puberty, which can further contribute to weakened bones, testosterone may be given to help trigger a more typical pubertal development and possibly help maintain bone health.

For those with DMD who experience a fracture or broken bone, it’s recommended they see an orthopedic specialist who has experience in treating people with Duchenne. If a person with DMD who is still able to walk breaks a bone in their leg, surgery may be recommended over casting the leg. This may allow the person to start walking sooner, helping preserve muscle and bone health in the legs.

In addition to care for the bones themselves, treatment for bone issues in DMD may include medications and other therapies that address complications of broken bones, e.g., pain management for chronic pain.

Can DMD osteoporosis be prevented?

Although it’s well known osteoporosis and broken bones can be a major health issue for people with DMD, currently there isn’t much known about how to prevent these problems from developing. Research is ongoing to identify preventive strategies.

Still, according to the Parent Project Muscular Dystrophy, there are some ways to help maintain bone health and prevent fractures, including safety strategies that minimize the risk of falls and other injuries, including:

• using mobility devices (scooters, wheelchairs, etc.) as needed
• wearing a seat belt whenever one is available (such as in cars, wheelchairs, etc.)
• practicing safe transfers when moving in and out of chairs, beds, showers, etc.
• avoiding overexertion by being mindful of energy levels and resting as often as necessary
• minimizing tripping hazards and using assistive devices, such as boot grips when it’s slippery.

Getting regular exercise, in particular weight-bearing exercises, also may minimize the risk of having bone problems. Weight-bearing exercises are exercises that require muscles and bones to support a person’s own body weight, such as walking.

Regularly stretching is another important part of maintaining muscle and bone health in DMD. It can help prevent problems such as joint pain and joint contractures, when joints become fixed in place. But you should always consult with an expert such as a doctor or physical therapist to ensure exercises are being done safely. Doing exercises incorrectly can lead to falls and other injuries.

In addition to safety practices and exercise, getting enough nutrients, especially calcium and vitamin D, also may be key to maintaining bone health and controlling the development of osteoporosis.

Because the use of corticosteroids is a major risk factor for osteoporosis in DMD, some studies have explored lower or less frequent doses of corticosteroids. Although results have suggested that these strategies may help reduce the risk of broken bones, it has also shown that taking fewer corticosteroids result in less therapeutic benefits regarding the maintenance of muscle strength and mobility. For this reason, the risks and benefits of any corticosteroid regimen need to be considered on a case-by-case basis.

Muscular Dystrophy News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.