Feeding Issues Still Common Among SMA Type 1 Infants, Despite New Therapy Options

Despite recent treatment advances, feeding difficulties are still one of the most common complications for infants with spinal muscular atrophy (SMA) type 1, an observational study has found.

The study, “Feeding and Swallowing Problems in Infants with Spinal Muscular Atrophy Type 1: an Observational Study,” was published in the Journal of Neuromuscular Diseases.

Infants with SMA type 1 — one of the most severe subtypes of the disease that usually manifests during the first six months of life — usually have difficulties swallowing, also called dysphagia, which compromises their ability to feed.

“Dysphagia in SMA type 1 may also lead to other problems such as poor weight gain, discomfort and risk of aspiration pneumonia,” the study’s researchers wrote.

Despite being very common, dysphagia has not been investigated in great depth.

To characterize dysphagia and feeding issues in infants with SMA type 1, the investigators monitored and recorded problems during feeding sessions in 16 infants with SMA type 1 who had been treated at the Netherlands SMA Center at the University Medical Center Utrecht from September 2016 to October 2018.

Of the 16 infants included in the study, 11 were receiving palliative care, and five supportive care in combination with Spinraza (nusinersen), the first disease-modifying treatment for SMA approved by the U.S. Food and Drug Administration. 

In addition to evaluating feeding difficulties, the investigators also explored their potential relationship with infants’ motor function. The Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) was used as a measure of motor function.

Infants on palliative care started experiencing the first symptoms of the disease slightly earlier than those who were on Spinraza along with supportive care (median age of onset of 14 vs. 38 days old).

 All infants who were receiving palliative care showed signs of fatigue and swallowing problems during feeding sessions. Almost three-fourths of the infants in this group were unable to take in the recommended volumes of milk, and their nursing sessions only lasted 10–15 minutes.

“Parents of six infants (55%) reported that they increased the frequency of feedings in order to compensate for feedings that were not finished,” the researchers wrote.

Nearly all (91%) coughed while drinking milk or eating pureed foods, and 64% had wet breathing (crackling sounds while breathing) during or after feeding.

Of the five infants who were on Spinraza along with supportive care, two were still asymptomatic by the time they started treatment. Like those who were on palliative care, the other three infants in this group showed signs of fatigue and dysphagia during nursing sessions.

Although treatment seemed to alleviate some of the feeding problems initially, they reappeared later in all five infants by the time they were 8 to 12 months old.

Although CHOP-INTEND scores rose within the first year of treatment in infants receiving Spinraza and supportive care, dysphagia worsened in all of them when they reached the ages of 8 to 12 months.

According to the authors, these findings indicate that “improvements of motor function does not imply similar gains in bulbar [head and neck] function.”

All infants in both groups eventually required tube feeding.

“Impaired feeding and swallowing remain important complications in infants with SMA type 1 after the start of nusinersen,” the researchers wrote. “Our data suggest that continuous monitoring of feeding problems in treated infants with SMA type is important.”