Dumping occurs when the pyloric sphincter mechanism has been altered so that an ingested meal is not properly processed and is discharged into the upper intestine prematurely. It may result from resection of the distal stomach that usually includes the sphincter, ablation of the sphincter (from pyloroplasty), or bypass of the sphincter (as in gastroenterostomy). The vasomotor (tachycardia, palpitations, diaphoresis, lightheadedness, and flushing) and gastrointestinal (nausea, vomiting, abdominal cramping, and diarrhea) manifestations evoked by this premature emptying are collectively called the dumping syndrome. Both early (within 10 to 30 minutes of eating) and late (usually 2 to 3 hours after eating) forms of dumping have been identified.

While the precise mechanisms responsible for dumping are still debated, the early form is thought to be a consequence of the rapid passage of food of high osmolality into the upper small intestine from the stomach, while the late form is related to a high carbohydrate load in the intestinal lumen that evokes hyperglycemia that then induces hypoglycemia from insulin overproduction. Fortunately, both forms of dumping can be effectively managed medically by limiting the amount of liquids in a meal, avoiding hyperosmolar substances, and eliminating “trigger” foods if these can be identified. Occasionally carbohydrate gelling agents (such as pectin) or the somatostatin inhibitor, octreotide, may need to be employed as adjunctive therapy to the dietary modifications. In 99% of patients with dumping symptoms, these conservative measures will prove efficacious. Thus, surgery is truly a “last resort” approach to treatment and should only be employed when non-operative management has been tried, and proven ineffective, for a sustained period of time (usually, at least a year).