The link between DMD and gastrointestinal issues

Last updated July 15, 2024, by Susie Strachan
Fact-checked by Patrícia Silva, PhD

People with Duchenne muscular dystrophy (DMD) often have gastrointestinal issues (GI) as the muscles that help move food through the digestive system weaken.

Muscle weakness in the digestive system can lead to gastrointestinal problems such as constipation and difficulty swallowing (dysphagia). These issues can make eating and digestion uncomfortable and challenging.

Treating DMD gastrointestinal problems starts with good nutritional intake and a good bowel regimen.

Why are people with DMD prone to gastrointestinal issues?

DMD is caused by mutations in the DMD gene that disrupts the production of a protein called dystrophin. When there isn’t enough dystrophin, muscle fibers are easily damaged, resulting in progressive muscle weakness throughout the body, including the gastrointestinal system.

Certain medications taken by people with DMD also may cause GI issues. For example, corticosteroid side effects may increase the risk for constipation and stomach irritation.

Kent Williams, MD, a pediatric gastroenterologist at Nationwide Children’s Hospital in Columbus, Ohio, treats patients with DMD. According to Williams, GI issues may start at a young age in children with DMD, although he believes these early GI problems may have more to do with underlying behavioral conditions often associated with DMD.

“For instance, a lot of kids have autistic-like tendencies, so it’s not uncommon for me to be talking to families with young kids who are having problems with toileting, constipation, toilet training,” he says. “There are behavioral and developmental issues that go along with it, such as sensory issues and anxiety.”

Concerns about not being able to feed themselves and go to the bathroom independently become a greater issue as children get older.

Williams says progressive muscle weakness can cause teenagers and young adults with DMD to become tired from trying to chew food, which can interfere with getting proper nutrition.

“Once you start losing function in your arms and you’re not able to bring the spoon and fork up to your mouth as much, you start to take longer to do it, or depend upon others to feed you,” he says.

People with DMD in their late teens and early 20s also may have trouble with bowel movements.

“If you lose muscle mass in your stomach and abdomen, your core muscles, you can’t push out the stool,” Williams says. “Plus, you’re not able to get up from your wheelchair and get on a toilet whenever you know you need to.”

While the damage primarily affects skeletal muscles, it may also cause smooth muscle dysfunction. These are muscles in the walls of the digestive tract from the last two-thirds of the esophagus through to the stomach and intestines.

Williams says the connection between dystrophin deficiency and smooth muscle cell function related to bowel problems is an area of ongoing research.

“One of the areas is how much does the dystrophin mutation affect smooth muscle over time,” he says. “And the next step is going to be, if we can figure that out, how are gene therapies then affecting replacement of dystrophin in the smooth muscle?”

Currently, there is one gene therapy approved in the U.S. for the treatment of DMD, and several others are being investigated.

Common gastrointestinal issues

In addition to other common DMD symptoms, there are a number of common gastrointestinal issues related to DMD, including constipation, abdominal pain, and bloating, along with gastrointestinal reflux disease (GERD).

They all can cause discomfort and chronic pain and affect the ability to eat and go to the bathroom.

DMD gastrointestinal problems include:

• problems swallowing (dysphagia) as throat muscles weaken, which increase the risk of choking as well as food or liquid entering lungs (aspiration)
• GERD, which can cause heartburn, regurgitation, and damage to the esophagus over time, and may increase the risk of aspiration pneumonia from inhaling the contents of the stomach
• constipation as weak bowel muscles have trouble moving stool through the intestines.

Other less common gastrointestinal issues include:

• gastroparesis from paralyzed stomach muscles, which can slow down food moving out of the stomach and into the intestines
• an intestinal pseudo-obstruction, a condition where symptoms are similar to an actual obstruction of the intestines but there isn’t physical blockage; it’s caused by damage to the nerves or muscles in the intestines
• impaired gastrointestinal motility, which can cause diarrhea.

GI issues can lead to malnutrition, poor growth, and weight loss. In more severe cases, there may be complications, such as aspiration pneumonia or an intestinal obstruction, which require prompt medical intervention.

Prevalence

Many people living with DMD will have a GI issue at some point. It becomes more common as the disease progresses.

Williams says he sees an average of six children and teens a month in the pediatric clinic at National Children’s Hospital who have been screened for help with a GI problem. He also sees young adults with DMD for the same issues at the hospital.

Treatment and management

Managing GI issues for better nutrition and bowel functioning in DMD may involve dietary modifications, medications, and surgery.

“It depends on your level of function. Once you get into a wheelchair and can’t feed yourself, then we start having conversations about how we can help make changes in your life,” he explains. “We anticipate you’ll need help supplementing their nutrition. We know you won’t want to spend so much time in the bathroom, so we’ll talk about bowel regimens.”

Management strategies to improve nutrition and bowel health include:

• eating a balanced diet high in fiber to manage constipation and prevent malnutrition
• eating meals at consistent times to promote regular bowel movements
• taking medications to help with constipation, gastroparesis, and GERD, including proton pump inhibitors to reduce stomach acid
• following a scheduled enema routine for cleaning the colon
• doing gentle movement or exercises to help stimulate bowel function.

As more teenagers with DMD become young adults, Williams says a relatively new area of treatment in this population is surgery for a gastrostomy tube (G-tube).

Williams says he addresses the idea of a G-tube early on with his patients and families to help them feel better prepared and supported in case it becomes necessary.

A G-tube provides nutrition directly to the stomach, ensuring a person with DMD still gets proper nutrition when they are having problems eating and swallowing.

But having a G-tube doesn’t mean you have to stop eating food the normal way. It’s a way to improve and maintain a good quality of life, Williams says. Once a person with DMD has a G-tube and is getting supplemental nutrition, it helps maintain muscle and prolongs the ability to eat.

“One of the patients that I talked to told me they went for the G-tube that I had recommended. Once he got that, he put on 15, 20 pounds. He was alert, his cardiac function improved, his respiratory function improved, and he actually then qualified for gene therapy,” he says.

Williams also speaks with his patients about a different surgery: a colostomy or an ileostomy. These operations, which are similar, bring a part of either the large or small intestine through the abdominal wall so stool can bypass the intestines and be collected outside the body.

“When you have to spend two to three hours a day in the bathroom, that adds up,” Williams explains. “I’ve had people tell me that having this operation dramatically changed their lives, made them less dependent on others.”

Nutritional solutions

Getting proper nutrition and hydration can be a problem for people with DMD, causing malnutrition and weight loss.

“What used to take 30 minutes to eat dinner is now taking an hour and a half,” Williams says. “Or the other thing that happens is you start skipping meals because it takes too long. You don’t have time for three meals a day, so you go down to two meals. Or just one.”

Williams advises parents and their children to stop weight loss right away, when it is still 5 or 10 pounds.

“Kids with Duchenne are on steroids and tend to be overweight. So if you start losing weight, people are happy for you,” he says. “But my concern is that you’re not losing weight because you want to. You’re doing this because you’re gradually becoming malnourished.”

Malnourishment can lead to cardiac and respiratory complications, he says. It also makes you susceptible to infections and needing to go to the hospital.

A registered dietitian can share strategies for a well-balanced and nutritious diet, and ways to manage fluid intake, acid reflux, and heartburn.

A better bowel regimen

Working with your doctor to have a bowel regimen that promotes independence from common issues like constipation and requiring help in the bathroom is especially important for young adults living with DMD.

“Young adults want to have a job, to go to college. You can’t do that if you have to spend many hours a day in the bathroom dealing with bowel issues. I like to tell people, ‘I want you to be able to control your bowels, not have your bowels control you,’” he says.

Setting up a good bowel regimen should start when children with DMD are being toilet trained. It may include:

• increasing the amount of fiber in the diet, including fruits, vegetables, and whole grains, to reduce constipation
• increasing the amount of fluids to reduce constipation and aid digestion
• establishing a regular bathroom routine at the same time every day.

As children begin to lose mobility, the regimen might change to include:

• taking fiber supplements or probiotics
• taking laxatives or stool softeners
• having enemas.

Caregivers play an important part in figuring out and maintaining a bowel regimen, Williams says. For example, as children with DMD lose mobility, they will need help transferring from a wheelchair to the toilet.

“When I’m working with a teenager who has DMD, we talk about how you’re going to go to the bathroom in a wheelchair. What can you do if you’re in a classroom? What can you do if you’re at a family function?” he says. “We talk about coming up with a bowel regimen that can keep you functioning.”

He may also introduce the idea of having colostomy or ileostomy surgery at this point. He tries to have parents and caregivers start thinking ahead about how a bowel regimen may have to change and adapt for their child. Although the thought of surgery may be daunting, he believes the benefits outweigh the risks.

“I’ve had families tell me that they will be able to go places, and start visiting people again,” Williams says. “One parent told me they could visit her parents again. Her husband is the only one strong enough to pick up their son and put him on the toilet, and he can’t always come on the visit.”

Additional support and adaptive equipment

Additional support for gastrointestinal issues for people with DMD include physical therapy, occupational therapy, and speech therapy. These specialists can work with you on swallowing therapy by showing you exercises and techniques to strengthen the muscles involved in swallowing and going to the bathroom.

Both physical and occupational therapists also can help you learn how to use assistive devices and adaptive aids for eating and maintaining a good bowel regimen.

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