Gastrointestinal complications of bariatric surgery: diagnosis and therapy.

Severe or morbid obesity, with body mass indexes exceeding 35 to 40, are often refractory to all therapies other than surgery. The increasing number of patients undergoing bariatric surgery will result in increasing numbers of patients with gastrointestinal complications. The types of complications vary with type of surgery, whether restrictive, malabsorptive, or both, depending on what anatomical and physiologic changes occur postoperatively. One complication of bariatric surgery (gallstones) is due to weight loss after surgery, not the surgery itself. Based on previous meta-analyses, most of the top 10 complications from bariatric surgery are gastrointestinal: dumping, vitamin/mineral deficiencies, vomiting (and nausea), staple line failure, infection, stenosis (and bowel obstruction), ulceration, bleeding, splenic injury, and perioperative death. Two other gastrointestinal complications of bariatric surgery are indirect consequences of the surgery: bacterial overgrowth and diarrhea. Awareness of the types and frequency of gastrointestinal complications of bariatric surgery allows for timely diagnosis and appropriate therapy. As new surgical, and even endoscopic, procedures to treat obesity are developed, new gastrointestinal complications will need to be recognized.