Duchenne Muscular Dystrophy (DMD)
Thanks to advances in many areas of medicine, such as cardiology and pulmonology, people with Duchenne muscular dystrophy (DMD) in the 21st century are living longer than in previous decades, often well into adulthood. DMD treatment requires multidisciplinary care to coordinate the multiple specialized assessments and interventions needed to maximize function and quality of life for patients.
The use of available treatments can help to maintain comfort and function and prolong life. MDA Care Center physicians can help create individualized care plans regarding all medical and assistive aspects DMD patients require.
People with DMD may have unexpected adverse reactions to certain types of anesthesia. It is important that the surgical team know about the patient's DMD so that complications can be avoided or quickly treated. Also, patients with DMD (as well as patients diagnosed with BMD) should have preoperative evaluations by pulmonary, anesthesia, and cardiac specialists prior to any surgery.1,2
Braces, standing frames, and wheelchairs
Braces, also called orthoses, support the ankle and foot, or may extend up over the knee. Ankle-foot orthoses (AFOs) are sometimes prescribed for night wear to keep the foot from pointing downward and keep the Achilles tendon stretched while the child is sleeping.
Standing for a few hours each day, even with minimal weight bearing, promotes better circulation, healthier bones, and a straight spine. A standing walker or standing frame can assist people with DMD to stand. Some wheelchairs will raise the user into a standing position.
Sooner or later, a wheelchair is needed in DMD, typically by about age 12. Unless there is an injury, such as a broken leg, wheelchair use usually is gradual. Many at first use wheelchairs for long distances, such as at school or the mall, and continue to walk at home.
Although a child and parents may dread the wheelchair as a symbol of disability, most people find that when they start to use one, they are actually more mobile, energetic, and independent than when trying to walk without assistance.
Other mobility and positioning aids can help parents and caregivers. Among the simplest aid is a transfer board for helping to move a person move in and out of a wheelchair. Mechanical lifts, shower chairs, and electronic beds also can be useful.
The American Academy of Pediatrics recommends that people with DMD have a complete cardiac evaluation (including an electrocardiogram and noninvasive imaging) by a specialist beginning in early childhood and again at least every other year until age 10. After that, the evaluations should be done every year or at the onset of symptoms of heart weakness, such as fluid retention or shortness of breath.1
Female carriers of DMD are at higher-than-average risk of developing cardiomyopathy. It is recommended that female carriers should undergo a complete cardiac evaluation in their late adolescence or early adulthood, or sooner if symptoms occur. The evaluation should include cardiac MRI and should be repeated at least every five years.
Treatment with angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARB) and beta blockers can slow the course of cardiac muscle deterioration in DMD if the medications are started as soon as abnormalities on an echocardiogram (ultrasound imaging of the heart) appear but before symptoms occur. Some data suggest that corticosteroids delay the onset of cardiomyopathy. The mineralocorticoid receptor antagonist eplerenone has some evidence of being effective for attenuating the decline in heart function but further studies are needed to confirm these findings.3
- Doctors Talk Heart to Heart (pediatric cardiologists and other experts at an MDA-sponsored meeting exchanged information and planned studies regarding the heart in DMD and Becker muscular dystrophy [BMD])
- Revising Cardiac Care in Muscular Dystrophies
The impact of DMD can be minimized significantly by keeping the body as flexible, upright, and mobile as possible. There are several ways to do this.
As muscle deteriorates, a person with muscular dystrophy often develops fixations of the joints, known as contractures. If not treated, these will become severe, causing discomfort and restricting mobility and flexibility. Contractures can affect the knees, hips, feet, elbows, wrists, and fingers.
However, there are many ways to minimize and postpone contractures. Range-of-motion exercises, performed on a regular schedule, help delay contractures by keeping tendons from shortening prematurely. It is important that a physical therapist show you how to do range-of-motion exercises correctly.
Braces on the lower legs also can help keep the limbs stretched and flexible, delaying the onset of contractures.
When contractures have advanced, surgery may be performed to relieve them. A tendon release procedure, also called heel cord surgery, is often done to treat ankle and other contractures while the child is still walking. Usually the boy will need to wear lower leg braces after this.
Diet and nutrition
No special dietary restrictions or additions are known to help in DMD. Most doctors recommend a diet similar to that for any growing boy but with a few modifications. However, some suggest the intake of dietary calcium and vitamin D in the form of dairy products, other foods rich in calcium, a supplementation, and sunshine exposure. Depending on the circumstances and the treatment route (such as glucocorticoids), patients are at risk of malnutrition and weight imbalance. Therefore, it is recommended patients see a nutritionist/dietician at every clinic visit.4
For boys who use power wheelchairs, take prednisone, or are not very active, excessive weight gain can become a problem. For these boys, caloric intake should probably be somewhat restricted to keep weight down. Obesity puts greater stress on already weakened skeletal muscles and the heart. Doctors have found that a low-calorie diet does not have any harmful effect on the muscles.
A combination of immobility and weak abdominal muscles can lead to severe constipation, so the diet should be high in fluids and fiber, with fresh fruits and vegetables dominant. Patients with DMD may also develop dysphagia (difficulty with swallowing). When dysphagia is suspected, the patient should be referred to a speech and language therapist for swallowing assessment.
In the case that a patient experiences weight loss, dehydration, malnutrition, aspiration, and moderate or severe dysphagia, the patient may need a gastrostomy tube (a feeding tube inserted directly to the stomach). Individuals taking prednisone and those with heart problems may need a sodium-restricted diet.
- Nutritional Considerations While on Corticosteroids (includes meal planning guides and suggested food options)
Exercise can help build skeletal muscle, keep the cardiovascular system healthy, and contribute to feeling better. But in muscular dystrophy, too much exercise could damage muscle. Consult with your doctor about how much exercise is best. A person with DMD can exercise moderately but should not go to the point of exhaustion.
Many experts recommend swimming and water exercises (aquatic therapy) as a good way to keep muscles as toned as possible without causing undue stress. The buoyancy of the water helps protect against certain kinds of muscle strain and injury.
Before undertaking any exercise program, make sure to have a cardiac evaluation.
Cognitive and behavioral disorders
Children with DMD who are suspected of having a learning disability can be evaluated by a developmental or pediatric neuropsychologist, either through their school system’s special education department or at a medical center with a referral from the MDA Care Center. DMD is associated with increased rates of autism spectrum disorders, attention deficit hyperactivity disorder, anxiety, and depression, which may also require adequate medical management.
- When Neuromuscular Disease Affects the Brain
- The Brain in Duchenne Muscular Dystrophy: Are learning disabilities part of the picture?
- A Teacher's Guide to Neuromuscular Disease
Medications that lessen the workload on the heart are sometimes prescribed for DMD (see "Cardiac care” above).
Medications belonging to a group known as corticosteroids are the mainstay of pharmacologic treatment as they have been found to be effective in slowing the course of DMD. Children should be started on these medications before substantial physical decline.4
The corticosteroids prednisone and deflazacort are beneficial in the treatment of DMD. The FDA on Feb. 9, 2017, approved deflazacort (brand name Emflaza), an oxazoline derivative of prednisone, to treat DMD. The potency of 1 mg of prednisone is approximately equivalent to 1.3 mg of deflazacort. For more, see FDA Approves Emflaza for Treatment of Duchenne Muscular Dystrophy.
Several studies of all these medications in DMD showed a significant increase in strength (11% with prednisone vs. placebo). This increase strength reached the maximum after three months of treatment and was maintained for 18 months; also, there was evidence of improvement in timed muscle function (such as the time it took to climb 4 stairs, 43% faster with prednisone vs. placebo) and in pulmonary function. Corticosteroids also reduce the risk of scoliosis and delay the loss of ambulation. Three studies found that glucocorticosteroid treatment was associated with improved survival. However, a fourth study did not show a clear association to the increase in survival.5,6,7,8
Pulmonary function has also been shown to improve with prednisone treatment vs. placebo. Forced vital capacity (FVC) improved significantly (11%) after six months of daily prednisone treatment.9
Glucocorticoids may delay the development of scoliosis and reduce the need for surgery to correct scoliosis in patients with DMD. The risk of developing scoliosis may be significantly lower for patients receiving daily deflazacort treatment vs. placebo, and the need for spine surgery is also significantly decreased for patients treated with deflazacort. Fracture prevalence is similar between patients who are treated with glucocorticoids and those who are not.10 There is some evidence that glucocorticoid treatment for DMD improves survival,8,11 however other evidence shows no relation between survival and glucocorticoid treatment.12
Chronic use of corticosteroids is part of the standard of care for DMD, but such treatment can lead to side effects such as weight gain, short stature, acne, behavioral changes, osteoporosis, and long bone and vertebral compression fractures. It is appropriate to monitor patients on corticosteroid therapy with periodic spine imaging as they may be asymptomatic. Children who develop vertebral or long bone fractures should be referred to a pediatric endocrinologist or bone specialist.
Rapid withdrawal of corticosteroids can result in life-threatening complications. The PJ Nicholoff Steroid Protocol guides withdrawal from corticosteroids following long-term treatment.
In September 2016, the US Food and Drug Administration (FDA) granted accelerated approval of Eteplirsen, an exon skipping drug that has shown to increase dystrophin in patients with a mutation of the dystrophin gene amenable to exon 51 skipping.
Ataluren (also known as PTC124) is an orally administered drug being developed for the treatment of genetic defects caused by nonsense mutations, allowing bypass of the nonsense mutation and continuation of the translation process to production of a functioning protein, which has been demonstrated in several studies. This approach could benefit the estimated 10% to 15% of patients with DMD/BMD who harbor nonsense (stop) mutations. Ataluren is licensed in the European Union and United Kingdom to treat patients age 2 years and older with DMD caused by nonsense mutations.
The most common adverse effect of ataluren is vomiting. Others include decreased appetite, weight loss, headache, hypertension, cough, nose bleeding, nausea, upper abdominal pain, flatulence, abdominal discomfort, constipation, rash, limb pain, musculoskeletal chest pain, blood in urine, involuntary urination, and fever.
In December 2019, Vyondys 53, an "exon skipping" drug that targets a section of DNA called exon 53 was approved by the FDA for treatment of individuals who have a confirmed mutation of the DMD gene that is amenable to a therapeutic strategy called exon 53 skipping and may help up to 8% of individuals with DMD. For more, see https://www.mda.org/press-releases/mda-celebrates-fda-approval-vyondys-53-treatment-dmd-amenable-exon-53-skipping.
In August 2020, Viltepso, an "exon skipping" drug that targets a section of DNA called exon 53. was approved by the FDA for treatment of individuals who have a confirmed mutation of the DMD gene that is amenable to a therapeutic strategy called exon 53 skipping and may help up to 8% of individuals with DMD. For more, see https://strongly.mda.org/fda-approves-ns-pharmas-viltepso-for-treatment-of-dmd-amenable-to-exon-53-skipping
Children with DMD should receive all vaccinations recommended by the US Centers for Disease Control and Prevention. Some vaccines should be given before the start of glucocorticoid treatment, as some are contraindicated in patients with DMD receiving high-dose daily corticosteroids. Ask your doctor for more information.
Physical and occupational therapy
A physical therapy program is usually part of the treatment for DMD. Your MDA Care Center physician will refer you to a physical therapist for a thorough evaluation and recommendations. The primary goals of physical therapy are to allow greater motion in the joints and to prevent contractures and scoliosis.
While physical therapy emphasizes mobility and, where possible, strengthening of large muscle groups, occupational therapy focuses on specific activities and functions. Occupational therapy can help with tasks for work, recreation, or daily living, such as dressing or using a computer.
As the muscles that assist in breathing get weaker, the bronchial system must be kept free of secretions, either by using a cough assist device or by manual assisted coughing with the help of a caregiver. A respiratory therapist or pulmonologist can be consulted for the needed information. At some point, assisted ventilation may be needed to help provide sufficient air flow into and out of the lungs.
The first step in using assisted ventilation is usually a noninvasive device, meaning one that does not require any surgical procedures. The person receives air under pressure through a mask, nosepiece, or mouthpiece. Noninvasive ventilation usually is required only part time, often only during sleep.
If round-the-clock ventilatory support becomes necessary, it is possible to use noninvasive ventilation full time, under the care of a doctor knowledgeable in this practice. Some young men choose to switch to an invasive system, which means that a surgical opening called a tracheostomy is performed, allowing air to be delivered directly into the trachea (windpipe).
For more, see:
- Getting a Tracheostomy: My Story (a physician with mitochondrial myopathy describes undergoing and taking care of her tracheostomy)
- The Great Trach Escape: Is it for You? (portable but powerful equipment and skilled guidance make noninvasive ventilation an option for many)
In young men with DMD, the spine can be gradually pulled into a curved shape. The spine may curve from side to side (scoliosis) or forward in a “hunchback” shape (kyphosis).
Scoliosis usually appears after a boy has started using a wheelchair full time. The “swayback” curvature that's sometimes seen in those who are still walking is called lordosis.
Severe scoliosis can interfere with sitting, sleeping, and even breathing, so measures should be taken to try to prevent it.
Exercises to keep the back as straight as possible and advice about sitting and sleeping positions can be obtained from a physical therapist.
Spine-straightening surgery involves inserting metal rods with hooks into the spine.
Surgery for youngsters with DMD is usually performed in adolescence.
Standards of care
Updates to the 2010 Centers for Disease Control (CDC) Care Considerations for Duchenne muscular dystrophy were published in 2018.
- Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management
- Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac,
bone health, and orthopaedic management
- Diagnosis and management of Duchenne muscular dystrophy, part 3: primary care,
emergency management, psychosocial care, and transitions of care across the lifespan
Updates to the 2005 American Academy of Neurology (AAN) guideline on corticosteroid treatment of DMD were issued in 2016.
General recommendations for medical care in DMD were issued in 2010 by the DMD Care Considerations Working Group, under the auspices of the US CDC. These include:
- DMD: diagnosis, and pharmacological and psychosocial management
- DMD: implementation of multidisciplinary care
A family-friendly version of the guidelines is available courtesy of TREAT-NMD. MDA contributed to the development of the comprehensive guide.
Guidelines for care of people with DMD receiving anesthesia or sedation were released by the American College of Chest Physicians in 2007.
Recommendations for cardiovascular health supervision in BMD and DMD carriers were issued in 2005 by the American Academy of Pediatrics.
Guidelines for respiratory care in DMD were released by the American Thoracic Society in 2004.
- Birnkrant, D. J. et al. Diagnosis and management of Duchenne muscular dystrophy, part 2: respiratory, cardiac, bone health, and orthopaedic management. Lancet. Neurol. (2018). doi:10.1016/S1474-4422(18)30025-5
- Birnkrant, D. J. et al. American College of Chest Physicians consensus statement on the respiratory and related management of patients with Duchenne muscular dystrophy undergoing anesthesia or sedation. in Chest (2007). doi:10.1378/chest.07-0458
- Raman, S. V et al. Eplerenone for early cardiomyopathy in Duchenne muscular dystrophy: a randomised, double-blind, placebo-controlled trial. Lancet. Neurol. (2015). doi:10.1016/S1474-4422(14)70318-7
- Birnkrant, D. J. et al. Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and neuromuscular, rehabilitation, endocrine, and gastrointestinal and nutritional management. Lancet. Neurol. (2018). doi:10.1016/S1474-4422(18)30024-3
- McDonald, C. M. et al. Long-term effects of glucocorticoids on function, quality of life, and survival in patients with Duchenne muscular dystrophy: a prospective cohort study. Lancet (2018). doi:10.1016/S0140-6736(17)32160-8
- Biggar, W. D. et al. Deflazacort in Duchenne muscular dystrophy: A comparison of two different protocols. Neuromuscul. Disord. (2004). doi:10.1016/j.nmd.2004.05.001
- Angelini, C. et al. Deflazacort in Duchenne dystrophy: Study of long-term effect. Muscle Nerve (1994). doi:10.1002/mus.880170405
- Biggar, W. D., Harris, V. A., Eliasoph, L. & Alman, B. Long-term benefits of deflazacort treatment for boys with Duchenne muscular dystrophy in their second decade. Neuromuscul. Disord. (2006). doi:10.1016/j.nmd.2006.01.010
- JR, M. et al. Randomized, double-blind six-month trial of prednisone in Duchenne’s muscular dystrophy. in New England journal of medicine (1989). doi:10.1056/NEJM198906153202405
- Henricson, E. K. et al. The cooperative international neuromuscular research group Duchenne natural history study: Glucocorticoid treatment preserves clinically meaningful functional milestones and reduces rate of disease progression as measured by manual muscle testing and othe. Muscle and Nerve (2013). doi:10.1002/mus.23808
- Schram, G. et al. All-cause mortality and cardiovascular outcomes with prophylactic steroid therapy in Duchenne muscular dystrophy. J. Am. Coll. Cardiol. (2013). doi:10.1016/j.jacc.2012.12.008
- Bach, J. R., Martinez, D. & Saulat, B. Duchenne muscular dystrophy: The effect of glucocorticoids on ventilator use and ambulation. Am. J. Phys. Med. Rehabil. (2010). doi:10.1097/PHM.0b013e3181e72207