Hyper-insulinemic hypo-glycemia is an important late complication of gastric bypass surgery that is increasingly recognized in patients who have undergone Roux-en-Y gastric bypass. It is a condition characterized by shortage of glucose in the brain (neuroglycopenia) and abnormal elevated insulin concentrations experienced mainly after eating a meal.
Hyperinsulinemic hypoglycemia is caused by unregulated secretion of insulin by the pancreatic beta-cels. The obesrved postprandial hyperglycemia is caused from the rapid digestion and absorption of ingested carbohydrates. This is a common phenomenon in gastric bypass patients and is related to the dumping syndrome—the result of food passing too quickly from the stomach to the small intestine.
Post-gastric bypass hyperinsulinemic hypoglycemia causes confusion, lightheadedness and loss of consciousness after a carbohydrate-rich meal.
Although the treatment of the disorder remains elusive, a number of studies have investigated the following three approaches
- Low carb diet
- Surgical Removal of Pancreas
Low Carb Diet
Since the symptoms of hyperinsulinemic hypoglycemia are exacerbated by carbohydrate consumption, low carb diet has been investigated as treatment of the condition.
A recent study described the effect of high and low carbohydrate meals on plasma glucose in 3 patients diagnosed with hyperinsulinemic hypoglycemia 15 to 37 months after Roux-en-Y gastric bypass.
Although the fasting glucose levels of these patients were within the normal range (70-99mg/dL), when they consumed a high carb meal all three developed hypoglycemia with plasma glucose reaching as low as 28 mg/dL, 2 hours after eating. The high carb meals consisted of orange juice, milk, bread, toast or donuts.
In contrast, when the patients ate a low carbohydrate meal, they exhibited no hypoglycemia, and the change in their glucose and serum insulin levels was minimal. The low carb meals included black coffee, eggs, meat, and cheese.
The authors concluded:
Our data suggest that a low carbohydrate diet may be effective treatment for this disorder, and we have recommended such a diet to all our patients.
A similar and more recent study confirmed these results. Fourteen patients who had reported episodes consistent with hyperinsulinemic hypoglycemia were given a meal high in carbohydrates on one day and low in carbohydrates on another day. Both meals were equivalent in calories (410 calories).
Within 30 minutes following the high carb meal, the patients became hyperglycemic and hyperinsulinemic. At 2 hours, glucose levels reached an all time low and subsequently returned to normal levels.
Interestingly, after the low-carb meal, insulin increased only modestly and plasma glucose changed very little.
Todd Andrew Kellogg, MD, who spearheaded the project, commented:
The hyperinsulinemic hypoglycemia noted in some patients after RYGB … can be significantly improved through dietary intervention.
Medication has been successfully used in a few cases for treatment of hyperinsulinemic hypoglycemia. A 2009 study by Dr Spanakis, reports on the successful management of post-gastric bypass hyperinsulinemic hypoglycemia with Diazoxide. The subject was a 52-year-old woman who had undergone gastric bypass surgery 4 years ago.
Diazoxide has been successfully used in the treatment of a similar condition in infants and children.
Patients taking other medications after a gastric bypass procedure should express extreme caution as some may cause potential harm. For instance, patients with diabetes may commonly use medications such as Januvia. In fact, DrugNews.net has just recently focused the health spotlight on the cases of pancreatic cancer Januvia has been causing, which some diabetic patients fear. Glyburide, a common diabetes medication taken orally, is also worrisome to doctors as it can completely alter a diabetic person’s blood sugar.
Removal of Pancreas
Partial pancreatectomy has been used to control the symptoms of hyperinsulinemic hypoglycemia. In such cases, some patients benefited from partial pancreatectomy while others experienced recurrent hypoglycemia that required total removal of their pancreas.
In general, studies do not support the use of pancreatectomy as a treatment for hyperinsulinemic hypoglycemia because pancreatectomy causes diabetes.
Dr Spanakis, explains that although there is a growing tendency to treat hyperinsulinemic hypoglycemic patients with pancreatic resection, it is often unsuccessful resulting in total pancreatic removal. “The end result of this approach is to cause iatrogenic diabetes, necessitating lifelong treatment with insulin”
Hypoglycemia after eating a meal is being increasingly recognized in post-gastric bypass patients. While the etiology of this condition is not entirely understood, ongoing research suggests that approaches to treatment should involve a low-carbohydrate diet rather than pancreatectomy.