Bethanechol for neonatal transient gastrointestinal dismotility in two cases of congenital myotonic dystrophy

Although gastrointestinal symptoms are frequently observed in congenital myotonic dystrophy (congenital MD) during early neonatal periods, there are few reports of gastrointestinal smooth muscle involvement and its management. We report two cases with congenital MD treated with bethanechol (0.25 mg/kg/dose 30 min before breast milk, 8 doses/day) for gastrointestinal dismotility. Two patients showed gastrointestinal symptoms characterized by increased gastric residua prior to the next feeding and gasless abdomen with relative gastric dilatation on abdominal X ray. Treatment with bethanechol resolved the gastrointestinal symptoms and allowed increase of daily feeding volume. We speculate that the main pathogenesis of transient gastrointestinal dismotility in neonates with congenital MD is gastroparesis probably due to "maturation arrest" of smooth muscle. Bethanechol may be one of the alternative prokinetic drugs to increase gastric emptying.