Spinal Muscular Atrophy (SMA) is a degenerative neuromuscular disease that, in its most severe manifestations (i.e., SMA types 0 and 1), will progress to bulbar paralysis.1 Some clinicians suggest that gastroesophageal reflux and aspiration risk are universal features in SMA type 1. 2,3
A current consensus statement from a consortium of SMA experts explains that “[s]afe swallowing is one of the most important aspects to consider” for the most severely affected patients with SMA.4 If a patient with SMA fails a swallow study or exhibits growth failure, the expert panel recommends placement of a temporary nasogastric or nasojejunal tube until a long-term gastrostomy tube can be placed.4 Nasogastric or gastrostomy feeding can provide overnight supplementation to oral feeding and anticipate inevitable bulbar paralysis and loss of safe and productive oral feeding.5 Though it is not a universal recommendation, gastrostomy tube placement can be performed with a Nissen fundoplication to address reflux concerns.4 With appropriate pre- and post-surgical management, these procedures are generally well tolerated in patients with SMA.3,6 The most debilitated SMA type 0 and 1 patients with respiratory compromise may pose a higher anesthesia risk, and thus the benefits of a long-term feeding portal would need to be weighed against the risk of surgical complications and death.5
The placement of a gastrostomy tube in patients with severe, fatal forms of SMA was not always as common a practice, but more proactive interventions such as gastrostomy placement appear to have prolonged survival in SMA.7,8 Gastrostomy placement appears to significantly increase weight gain, improve symptomatic reflux, reduce incidences of aspiration pneumonia and reduce risk of death.9
There are ethical concerns about artificial prolongation of life using invasive ventilation at the cost of quality of life in SMA,10 but there does not appear to be as much controversy with tube feeding. According to a survey of type 1 SMA patients, 43 out of 44 utilized a feeding tube for essential nutrition. Experts advise that the decision to place a gastrostomy tube be the outcome a dialogue between a multidisciplinary care team and the family.5 There is no data to suggest that gastrostomy feeding is superior to nasogastric feeding.5
Even less severe forms of SMA (i.e., types 2 and 3) can exhibit bulbar dysfunction.11,12 Estimates range as high as 44% of type 2 and 3 SMA patients report swallowing difficulties.9 For these patients, less invasive treatment strategies such as postural repositioning4 or strengthening exercises for the neck may ameliorate swallowing dysfunction.11 Underfeeding and overfeeding may occur in approximately 30-40% of patients with SMA types 2 and 3,13,14 leading some to suggest that an individualized approach with regular re-evaluation to address nutritional needs is best in these patient populations.4,13
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