Hypoglycaemia after gastric bypass: mechanisms and treatment.
Hypoglycaemia after gastric bypass can be severe, but is uncommon, and is sometimes only revealed through monitoring glucose concentrations. The published literature is limited by the heterogeneity of the criteria used for diagnosis, arguing in favour of the Whipple triad with a glycaemia threshold of 55 mg/dl as the diagnostic reference. Women who lost most of their excess weight after gastric bypass, long after the surgery was performed, and who did not have diabetes before surgery are at the greatest risk. In this context, hypoglycaemia results from hyperinsulinism, which is either generated by pancreas anomalies (nesidioblastosis) and/or caused by an overstimulation of β cells by incretins, mainly glucagon-like peptide-1 (GLP-1). Glucose absorption is both accelerated and increased because of the direct communication between the gastric pouch and the jejunum. This is a post-surgical exaggeration of a natural adaptation that is seen in patients who have not undergone surgery in whom glucose is infused directly into the jejunum. There is not always a correspondence between symptoms and biological traits; however, hyperinsulinism is constant if hypoglycaemia is severe and there are neuroglucopenic symptoms. The treatment relies firstly on changes in eating habits, splitting food intake into five to six daily meals, slowing gastric emptying, reducing the glycaemic load and glycaemic index of foods, using fructose and avoiding stress at meals. Pharmacological treatment with acarbose is efficient, but other drugs still need to be validated in a greater number of subjects (insulin, glucagon, calcium channel blockers, somatostatin analogues and GLP-1 analogues). Lastly, if the surgical option has to be used, the benefits (efficient symptom relief) and the risks (weight regain, diabetes) should be weighed carefully.
Pôle Cardio-vasculaire et métabolique, Centre Intégré de l'obésité, Inserm U1027, CHU de Toulouse, Hôpital Larrey, Toulouse, France.
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Ritz
Pôle Cardio-vasculaire et métabolique, Centre Intégré de l'obésité, Inserm U1027, CHU de Toulouse, Hôpital Larrey, Toulouse, France.
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Vaurs
Pôle Cardio-vasculaire et métabolique, Centre Intégré de l'obésité, Inserm U1027, CHU de Toulouse, Hôpital Larrey, Toulouse, France.
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Barigou
Pôle Cardio-vasculaire et métabolique, Centre Intégré de l'obésité, Inserm U1027, CHU de Toulouse, Hôpital Larrey, Toulouse, France.
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Hanaire
D020909:Acarbose / Q000627:therapeutic use; D000222:Adaptation, Physiological; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D004035:Diet Therapy / Q000379:methods; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D065089:Glycoside Hydrolase Inhibitors / Q000627:therapeutic use; D006801:Humans; D006946:Hyperinsulinism / Q000150:complications; D007003:Hypoglycemia / Q000209:etiology* / Q000628:therapy*; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D054795:Incretins / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007583:Jejunum / Q000503:physiopathology; D008297:Male
D001786:Blood Glucose; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D054795:Incretins; D052216:Glucagon-Like Peptide 1; D020909:Acarbose
bariatric surgery; continuous glucose monitoring; glucose load; hyperinsulinism; hypoglycaemia