Background:
We describe an evaluation of the effects of partial Roux-en-Y gastric bypass (RYGB) reversal on postprandial hyperinsulinaemic hypoglycaemia, insulin and GLP-1 levels.
Case summary:
A 37 year old man was admitted with neuroglycopenia (plasma-glucose 1.6mmol/l) 18 months after RYGB, with normal 72h fasting test and abdominal CT. Despite dietary modifications and medical treatment, the hypoglycaemic episodes escalated in frequency. Feeding by a gastrostomy tube positioned in the gastric remnant did not prevent severe episodes of hypoglycaemia. A modified reversal of the RYGB was performed. Mixed meal tests were done perorally (PO), through the gastrostomy tube 1 (GT1), 4 weeks (GT2) after placement and 4 weeks after reversal (POr), with assessment of glucose, insulin and GLP-1 levels.
Results:
Plasma-glucose increased to a maximum of 9.6, 5.4, 6.5 and 5.8mmol/l at the PO, GT1, GT2 and POr tests respectively. The corresponding insulin levels were 2939, 731, 725 and 463pmol/l. A decrease of plasma-glucose followed: 2.2, 3.0, 3.9 and 2.9mmol/l respectively and insulin levels were suppressed at 150min: 45, 22, 21 and 14pmol/l, respectively. GLP-1 levels increased in the PO test (60min: 122pmol/l, 21 fold of basal), but was attenuated in the two latter tests (12-23pmol/l at 60min).
Conclusions:
Reduction of plasma-glucose, insulin and GLP-1 excursions and symptoms were seen after gastric tube placement and partial RYGB reversal. This attenuation of GLP-1 response to feeding could reflect an adaptation to nutrients.