Obesity Surgery

, 17:592 | Cite as

Hyperinsulinemic Hypoglycemia Developing Late after Gastric Bypass

  • John P. BantleEmail author
  • Sayeed Ikramuddin
  • Todd A. Kellogg
  • Henry Buchwald


Post-gastric bypass hyperinsulinemic hypoglycemia causing confusion and loss of consciousness was recently described, and appears to be an important late complication of gastric bypass surgery.We report 3 additional patients with this disorder, and describe their responses to high and low carbohydrate test meals.


The patients were 1 woman and 2 men ranging in age from 50 to 65 years who underwent Roux-en-Y gastric bypass (RYGBP) for morbid obesity. 15 to 37 months after surgery, they started to have episodes of postprandial confusion and loss of consciousness.


When given high carbohydrate mixed meals, all 3 demonstrated peak plasma glucose >200 mg/dl (11.1 mmol/l) and peak serum insulin >300 μU/l (1800 pmol/l). Although serum insulin declined rapidly, all 3 developed hypoglycemia with plasma glucose <42 mg/dl (2.3 mmol/l). Following low carbohydrate test meals, there was little change in plasma glucose or serum insulin and no hypoglycemia.


Our data suggest that low carbohydrate diets may be effective in treating post-gastric bypass hyperinsulinemic hypoglycemia.We hypothesize that rapid digestion and absorption of carbohydrate is an important feature of this disorder and may be treated with measures other than pancreatectomy.

Key words

Morbid obesity gastric bypass insulin hypoglycemia 


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Copyright information

© Springer Science + Business Media B.V. 2007

Authors and Affiliations

  • John P. Bantle
    • 1
    • 3
    Email author
  • Sayeed Ikramuddin
    • 2
  • Todd A. Kellogg
    • 2
  • Henry Buchwald
    • 2
  1. 1.Division of Endocrinology and Diabetes, Department of MedicineUniversity of MinnesotaMinneapolisUSA
  2. 2.Department of SurgeryUniversity of MinnesotaMinneapolisUSA
  3. 3.University of MinnesotaMinneapolisUSA

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