Leg and heart muscles get much of the early attention in DMD, but as the disease progresses, the respiratory muscles also begin to weaken. This can cause difficulties with breathing, coughing, and sleeping.
Eventually, these weakened muscles can cause serious health problems.
But there are ways to manage the respiratory risks those with DMD face, including breathing support and airway clearance. This site is here to help you understand the potential respiratory concerns in DMD, to help you understand these options, and to help make sure you or your loved one are getting the best care possible.
Knowing more about respiratory health can help you support those with DMD and have meaningful conversations with your healthcare provider.
Download a guide to respiratory health for more information about the role of respiratory muscles in DMD.
The impact grows as time goes on.
DMD can affect respiratory health in various ways. In the early stages, these effects can be subtle, but with time become more pronounced.
At diagnosis most boys with DMD breathe normally and have normal respiratory function.
As long as boys with DMD are able to walk, they are less likely to have serious respiratory problems. At this stage, being knowledgeable about respiratory health and getting a baseline measurement of their lung function helps you better understand the tests that you may need to take down the road. View respiratory monitoring.
Once those with DMD begin to use a wheelchair, the loss of ambulation can be a precursor to the development of scoliosis, which is a condition where the spine curves sideways. This modified posture changes how the ribs move during breathing, and alters the shape of the chest cavity--which can make breathing difficult. Boys treated with corticosteroids generally have milder spine curves than those not treated with steroids.
Talk to your doctor about whether steroid therapy is an option.
Read about the importance of respiratory monitoring and respiratory devices to improve breathing.
People living with DMD have a higher risk of facing a range of respiratory problems. Read about some of the symptoms they may face.
Eventually respiratory-related symptoms begin to show, especially when a boy becomes non-ambulatory. These symptoms can be subtle--like not being able to cough hard enough--but may grow more serious.
Ineffective cough is also a respiratory-related symptom since coughing is the body’s way of clearing the airways. When mucus and other secretions build up, coughing helps remove them. The stronger and more forceful the cough, the more effective it is at keeping the airway clear of secretions.
A strong cough requires strong muscles. When the muscles weaken, the lungs can’t take in as much air as they should. Weakened muscles also can’t create a cough strong enough to clear the airway. And that can lead to infections, which tend to last longer in people with DMD because of their weaker muscles. The weaker the muscles get, the more they need help.
There are ways you can manage a weak cough, like using cough assist devices or manual cough techniques.
Weakened respiratory muscles can also lead to sleep-disordered breathing for people with DMD. These abnormal breathing patterns can disrupt sleep, impacting the ability to think, how the body grows, and quality of life. Plus, lying flat on the back makes the abdominal contents move upward against the diaphragm, which makes the already weakened muscle work harder.
OSA is a partial or complete blockage of the upper airway that occurs while a person sleeps. It’s usually caused by weakness of the upper airway muscles. OSA can cause a drop in oxygen in the blood (hypoxemia) or an elevation of carbon dioxide levels (hypercapnia). Why does this matter? Well, the lungs are tasked with providing oxygen to the body and getting rid of carbon dioxide. So they want to keep oxygen high and carbon dioxide low because that helps the major organs function as well as possible. In people with DMD, this drop in oxygen can lead to sleeping problems. Another symptom of OSA is snoring, which can also lead to waking up frequently during the night.
Normally, when a person goes to sleep their breathing slows down. But for those with DMD, that normal slower breathing is complicated by having weakened breathing muscles, causing them to breathe even more shallowly. They may not be able to breathe deeply enough to bring in the oxygen needed or to remove the carbon dioxide that the body produces. This is called hypoventilation.
Hypoventilation causes people with DMD to wake up during the night, preventing them from getting sustained, restful sleep. This may result in daytime fatigue and sleepiness.
There are tests boys and men can take to gauge their level of disrupted breathing. Watch this video created by Parent Project Muscular Dystrophy to learn more about these tests and nighttime breathing.
This occurs when a part of the lung “collapses” and doesn’t properly inflate. If only a small part of the lung collapses in those with DMD, they might not have any signs or symptoms.
For people with DMD, a partial collapse in the lungs can occur when airways in the lungs become blocked, typically with mucus, and the cough is not strong enough to clear the airway. A blocked airway means air sacs (called alveoli) in the lungs don’t inflate properly and thus they shrink and collapse — this partial collapse is called atelectasis.
Besides a mucus blockage, another cause of atelectasis is when the lungs don’t fully expand and fill with as much air as they should. Shallow breathing can cause this type of atelectasis.
Weakened breathing muscles mean the levels of oxygen and carbon dioxide in your blood start to shift in ways that aren’t good for the body. Initially this shift in levels happens at night. But as the respiratory muscles continue to weaken, the resulting shallow breathing will lead to reduced levels of oxygen (known as hypoxemia) and high levels of carbon dioxide (hypercapnia) during the day.
The continual weakening of the respiratory muscles makes it harder for the lungs to take in enough oxygen and get rid of enough carbon dioxide, so people with DMD might need increasing levels of support to breathe.
When it comes to breathing assistance, you have options and ways to support your loved one.
Read about ventilation devices.