Children with spinal muscular atrophy (SMA) who are able to sit (i.e., “sitters”) often encounter substantial difficulties with chewing, choking, coughing, and food aspiration. While these issues are less severe in sitters than they are in non-sitters, providers must evaluate and closely follow feeding and swallowing in sitters nonetheless.1
In a survey of 102 patients with spinal muscular atrophy type 2 between the ages of one and 47, almost 4 in 10 sitters with SMA developed growth failure from malnutrition.2 Of this group, 28% had difficulty chewing and 30% were unable to fully open their mouths. The symptoms increased in frequency with age. A quarter of patients in the survey had difficulty swallowing.
The SMA Care Group panel of experts recommends that sitters undergo careful assessment for symptoms of dysphagia, aspiration, or problems with feeding. Clinical clues to these issues include a weak suck, fatigue while eating, “choking,” a “wet” voice, or even frank cases of aspiration pneumonia. The bar should be low for attaining a video fluoroscopic swallow study to evaluate swallowing function in children with suspected dysphagia.
If the patient successfully passes the swallow study in the context of dysphagia symptoms, close follow-up with a specialist in this area is warranted.1 If, on the other hand, the patient fails the swallow study, a nasojejunal tube may be necessary. It is common for patients to use feeding tubes for supplemental nutrition, but relatively uncommon for them to use feeding tubes for total nutrition.1 That said, patients who are unable to safely swallow may ultimately require a gastrostomy tube. This is an issue that should be explored thoroughly with caregivers and adult patients.
A dietitian should follow patients with SMA type 2 throughout their lives. The frequency of evaluation depends on the age of the patient and the patient’s degree of difficulty with swallowing and feeding. A dietitian should evaluate younger children, people with severe dysphagia, and individuals on specialized diets every 3 to 6 months. Older children, adults, and people with mild/moderate dysphagia may only require yearly evaluations.
Establishing the proper nutritional regimen in sitters can be especially difficult for providers. On the one hand, chewing and swallowing difficulties can lead to malnutrition. On the other hand, overweight and obesity is common in this patient population, though usually at older ages. Standardized growth charts for infants, toddlers, and children are only slightly helpful in tracking growth trends in children with SMA, and can be quite inaccurate.3,4 The difficulty arises from the fact that people with SMA can have generalized malnutrition yet excessive fat distribution. In other words, total body weight may be normal or high, yet the patient may be suffering from protein or caloric malnutrition.4 Alternative body composition measures3 and nutrition laboratories may be needed along with longitudinal assessments of weight and height/length to verify the adequacy of diet and/or nutritional interventions.1 Caloric, fluid, macronutrient, and micronutrient intake should be adjusted to the patient’s growth and development while being vigilant for overweight and obesity.
While fasting is not recommended in non-sitters, limited fasting may be appropriate for sitters during acute illness; however, fasting times should be kept to a minimum and tailored to pre-existing nutritional status and the nature and severity of the event.1 Fluids and electrolytes should be tracked closely during acute illness.
Individuals with SMA type 2 may experience problems with GI motility. Consequently, experts recommend that patients have a diet that is rich in fiber and fluids (oral or through feeding tubes) to maintain bowel regularity. Bowel regulating medications are generally safe and the patient population and should be used accordingly. Experts are mixed about the safety and usefulness of pro-kinetic/pro-motility agents in the treatment of GI motility; these are generally reserved for the most severe cases.1
1. Mercuri E, Finkel RS, Muntoni F, et al. Diagnosis and Management of Spinal Muscular Atrophy: Part 1: Recommendations for Diagnosis, Rehabilitation, Orthopedic and Nutritional Care. Neuromuscul Disord. 2018;28(2):103-115. doi:10.1016/j.nmd.2017.11.005
2. Messina S, Pane M, De Rose P, et al. Feeding Problems and Malnutrition in Spinal Muscular Atrophy Type II. Neuromuscular Disorders. 2008;18(5):389-393.
3. Sproule DM, Montes J, Dunaway SL, et al. Bioelectrical Impedance Analysis Can Be a Useful Screen for Excess Adiposity in Spinal Muscular Atrophy. J Child Neurol. 2010;25(11):1348-1354. doi:10.1177/0883073810365185
4. Sproule DM, Montes J, Montgomery M, et al. Increased Fat Mass and High Incidence of Overweight Despite Low Body Mass Index in Patients with Spinal Muscular Atrophy. Neuromuscul Disord. 2009;19(6):391-396. doi:10.1016/j.nmd.2009.03.009