Unexplained hypoglycemia during continuous nocturnal gastric drip-feeding in a patient with glycogen storage disease type ia: is it a dumping-like syndrome?

A 5 years old boy affected with Glycogen Storage Disease type Ia (GSD-Ia) with previous optimal metabolic control developed severe erratic hypoglycemic episodes during continuous nocturnal gastric drip-feeding (CNGDF) administered by nasogastric tube. The episodes of hypoglycemia were not related to pump failure or human errors or wrong position of the tube in the gastrointestinal tract. Hyperinsulinism was also considered in this patient but it was excluded mainly because hypoglycemia was only nocturnal. Moreover, hypoglycemic episodes disappeared when CNGDF was stopped and he was fed with normal meals. The fact that hypoglycemia resolved after stopping CNGDF when nocturnal meals were introduced led us to hypothesize that CNGDF rich with simple carbohydrates might have been the cause of a sort of dumping-like syndrome. Dumping syndrome (DS) develops when a large amount of carbohydrate reaches the small intestine due to rapid gastric emptying (Tack et al. 2009; Hejazi et al. 2010). We suppose that CNGDF induced a disturbance of gastric motility with a gastric accumulation of fluids at a certain time of the night followed by a rapid voiding of the stomach leading to DS.