GI Complications in Patients With Spinal Muscular Atrophy

Crystal Proud, MD: Another aspect of care for our children includes their feeding and nutrition. Julie, can you review some of the challenges that might be encountered surrounding these things for our patients with SMA [spinal muscular atrophy]?

Julie Parsons, MD: Sure, that depends on what SMA type they have and how severe their weakness is. In a profoundly weak baby, as Nancy was talking about, if they can't breathe, they have difficulty eating as well. It's hard to do both of those things at the same time. Many of the babies with profound weakness do have the risk of aspiration pneumonias and aspirating consistently. Many of the babies who have profound weakness will end up having alternative methods of feeding, including gastrostomy tubes, over time to prevent them from having recurrent pneumonias.

As patients get a little bit older, interestingly, there are other issues that come up in terms of gastrointestinal problems. A couple of them are that, for the young adults and older patients, many of them have restricted mouth opening, so they will have difficulty having fluid movement of their masseter in terms of chewing and swallowing food. Some patients are not hungry. Some patients don't have a lot to do but eat, so we tend to have undernourished patients and over-nourished patients as well.

Working on having a healthy diet and making certain that the caloric intake meets the expenditure is just as important in patients with SMA as it is in all of us. Some of the patients who are older are not able to keep up with their caloric demands as well and still will need to have gastrostomy tubes to help them have good nutrition. We do want to make certain that we watch kids closely with their chewing and swallowing to make certain that they're not having aspiration.

The other huge issue that has to do with nutrition is constipation. From very early on, weak babies tend to be constipated, and children and adults who have neuromuscular weakness also have big issues with constipation. Keeping on top of that and being very proactive in terms of diet, fluid, nutrition—many of our patients are on MiraLAX [polyethylene glycol 3350] or some other supplement to help them have soft stools—has been an issue as well in terms of helping with quality of life.

We also understand that it's extremely important for patients with SMA, particularly as they get older, to stay very well hydrated so that they have good urine production and good urine flow. Many of our young adults are kids who are in high school, and they are seated and are not interested in drinking a lot because they don't want to have to go to the bathroom. Consequently, the incidence of kidney stones is higher in this population of patients. Starting with good nutrition and fluid balance early on in diagnosis is also important for these patients over a lifespan.