Gastric bypass may lead to low blood sugar

• A least six patients who underwent the most popular type of obesity surgery have developed an apparent complication -- blood sugar so perilously low that it causes confusion, tunnel vision and blackouts, doctors say.
• The condition was corrected with further surgery and no lasting effects, and the researchers and other experts said the problem is probably too rare to warrant cutting back on the weight-loss procedure.
• "If we can understand the molecular details here, we can bottle them," said Dr. David Cummings, a hormone researcher at the University of Washington.
• A small pouch is stapled off from the rest of the stomach and then connected directly to the small intestine.
• This technique accounts for the vast majority of the roughly 140,000 gastric-bypass operations performed each year in the United States.
• Researchers at the Mayo Clinic of Rochester, Minn., focused on six Roux-en-Y patients who developed severe low blood sugar, or neuroglycopenia.
• The researchers suspect the effect happens like this: Barely digested food rushes right into the intestine.
• Its hormones then overstimulate the insulin-oozing beta cells of the pancreas.
• The excess of insulin, the same hormone that fails in diabetics, removes too much sugar from the blood.
• To correct the condition, doctors had to remove most of the pancreas from the patients.
• But that put the patients in danger of developing diabetes, an illness that is often cured by gastric bypass surgery.
• Dr. Neil Hutcher, a stomach-bypass surgeon who is president of the American Society for Bariatric Surgery, said he has never seen the possible complication in his roughly 3,000 operations.
• "Do I think it can be called a substantial complication of gastric bypass at this time?
• Do I think it's a reason to modify gastric bypass at this time?
• Cummings said this insulin-boosting complication could explain why gastric bypass generally cures diabetes, and could also point the way to new treatments.