Why does Dumping Syndrome cause Hypoglycemia?

The stomach acts as a reservoir for digestion. Food will be stored and broken down in it via acid and proteases. The resulting chyme is released in a controlled manner into the small intestines. Alteration of gastric anatomy (i.e gastric bypass or bypass of the pylorus) can have profound effects on GI motility.

Early dumping occurs immediately after eating (within 10-30 mins); it is characterized by vomiting, bloating, cramping, dizziness, nausea, diarrhea, etc. The cause is thought to be due to neuroendocrine changes from a hyperosmolar load being “dumped” rapidly into the small bowel.

Late dumping typically happens 1–3 hours after a meal and is characterized by hypoglycemia, weakness, sweating, and dizziness.

WHY HYPOGLYCEMIA?

The rapid movement of food into the small intestine leads to a marked increase of carbohydrates into the small bowel.

• This causes rapid absorption of glucose into the blood stream
• A reactive release of insulin (hyperinsulinemic response) transpires (GLP-1 mediated) resulting in subsequent reactive hypoglycemia

REFERENCES

1. Ukleja, A. Dumping Syndrome: Pathophysiology and Treatment.  Nutrition in Clinical Practice Vol 20, Issue 5, Oct 2005 pp. 517 – 525.
2.  Chapter 18: Disorders of Gastric & Small Bowel Motility. Walter W. Chan; Robert Burakoff. CURRENT Diagnosis & Treatment: Gastroenterology, Hepatology, & Endoscopy, 3e.