Gastric dumping syndrome pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Umar Ahmad, M.D.[2]
Overview
The exact pathogenesis of dumping syndrome is not fully understood. Symptoms of early and late dumping syndrome appear to be caused by distinct pathophysiological mechanisms.
Pathophysiology
Pathogenesis
Dumping syndrome occurs secondary to various conditions such as after gastric surgery (especially on taking meals high in carbohydrates after the procudure), diabetes mellitus, Zolinger-Ellison syndrome, and Ehler-Danlos syndrome. The pathogenesis of dumping syndrome varies according to the etiology but the most essential component is the increased gastric emptying. The exact cause is not yet concluded, although several known phenomena may contribute to the development of early dumping symptoms.[1][2]
General pathogenesis
- Alterations in the storage function of the stomach and/or the pyloric emptying mechanism lead to rapid delivery of hyperosmolar material into the intestine. Fluid shifts from the intravascular compartment into the bowel lumen lead to rapid small bowel distention and an increased peristalsis (early dumping).
- Supraphysiologic release of GI peptides/vasoactive mediators lead to paradoxical vasodilation in a relatively volume-contracted state.
- Reactive hypoglycemia occurs secondary to hyperinsulinemia caused by high concentration of carbohydrates in the proximal small intestine and rapid absorption of glucose (late dumping)
- Pancreatic islet cell hyperplasia, rather than late dumping, is thought to be the underlying mechanism for hyperinsulinemic hypoglycemia with nesidioblastosis after gastric bypass. These patients do not respond to treatment for dumping syndrome, and it is difficult to confirm this rare diagnosis.
- A recent study showed glucagonlike peptide-1 (GLP1) played a key role in the pathogenesis of late hypoglycemia after gastric bypass
Surgical pathogenesis
- Removal of a part of the stomach can cause the contents to not digest and flow down undigested in a hyperosmolar manner. This hyperosmolar chyme will cause an osmotic shift from the blood circulation to the intestinal lumen . This my may cause hypotension which will in turn activate the sympathetic nervous system and its associated side effects.
- Alteration of the pyloric muscle that holds the gastric contents till complete digestion, will cause a free fall of gastric contents into the small intestine. This rapid descent will cause an osmotic shift leading to hypotension which will activate the sympathetic nervous system and its associated side effects.
- Removal of a part of the stomach and small intestine will cause bypassing of the gastric contents straight through to the ileum or jejunum which can cause rapid descent and osmotic shifting.
- Dumping syndrome is most common in patients with certain types of stomach surgery, such as a gastrectomy or gastric bypass surgery, that allow the stomach to empty rapidly. Dumping syndrome can also occur as a result of complications after a cholecystectomy (gallbladder removal).[1]
- Dumping is also common for esophageal cancer patients who have had an esophagectomy; surgery to remove the cancerous portion of their esophagus. The stomach is pulled into the chest and attached to what remains of the esophagus, leaving a short digestive tract.
Diseased pathogenesis
- Patients with Zollinger-Ellison syndrome, a rare disorder involving extreme peptic ulcer disease and gastrin-secreting tumors in the pancreas, may also have dumping syndrome.
- Patients with connective tissue conditions such as Ehlers-Danlos syndrome can experience "late" dumping as a result of decreased motility.
- In addition, people with this syndrome often suffer from low blood sugar, or hypoglycemia, because the rapid "dumping" of food triggers the pancreas to release excessive amounts of insulin into the bloodstream. This type of hypoglycemia is referred to as "alimentary hypoglycemia".
Flowchart
The following flow chart outlines the major events involved in the pathogenesis of dumping syndrome:[3][4]
| Hyperosmolar meal | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Rapid glucose absorption into the blood | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hyperglycemia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Rapid emptying of stomach | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Fluid shift from blood to gut | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Release of hormones : • VIP • GIP • PYY • GLP-1 • Neurotensin | Excessive insulin release | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Reactive hypoglycemia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Symptoms | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
References
- ↑ Vecht J, Masclee AA, Lamers CB (1997). "The dumping syndrome. Current insights into pathophysiology, diagnosis and treatment". Scand. J. Gastroenterol. Suppl. 223: 21–7. PMID 9200302.
- ↑ Machella TE (1949). "The Mechanism of the Post-gastrectomy "Dumping" Syndrome". Ann. Surg. 130 (2): 145–59. PMC 1616289. PMID 17859417.
- ↑ van Beek, A. P.; Emous, M.; Laville, M.; Tack, J. (2017). "Dumping syndrome after esophageal, gastric or bariatric surgery: pathophysiology, diagnosis, and management". Obesity Reviews. 18 (1): 68–85. doi:10.1111/obr.12467. ISSN 1467-7881.
- ↑ "www.practicalgastro.com" (PDF).