Dumping syndrome (DS) occurs when the stomach empties food into the small bowel at a faster rate than normal. It is frequently related to the rapid emptying of hyperosmolar gastric content into the small bowel. Although the precise mechanism of DS is not known, dumping is a phenomenon usually caused by the destruction or bypass of the pyloric sphincter. DS can occur in post–gastric bypass patients when high levels of simple carbohydrates are ingested. The condition can also develop in people who have had esophageal surgery. Clinically significant dumping symptoms occur in about 20% of patients after pyloroplasty or distal gastrectomy. Patients younger than age 35 years or with a BMI <25 kg/m² are more likely to be symptomatic than are older or more obese patients.^1-3

It is believed that the osmotic gradient draws fluid into the intestine, and this may release one or more vasoactive hormones, such as serotonin and vasoactive intestinal polypeptide. Most people with DS develop abdominal cramps and diarrhea within 10 to 30 minutes after eating. Others experience such symptoms 1 to 3 hours after eating, and yet others experience both early and late symptoms.

CLINICAL PRESENTATION

There are two clinical manifestations of DS: gastrointestinal (GI) symptoms that include early satiety, crampy abdominal pain, nausea, vomiting, and explosive diarrhea; and vasomotor symptoms that include diaphoresis, flushing, dizziness, palpitations, and an intense desire to lie down.^3,4

Types

Early DS: Early DS refers to dumping that usually happens within 10 to 30 minutes after eating.² It is the result of rapid emptying of food into the duodenum. Due to the hyperosmolality of the food, fast fluid shifts from the plasma into the bowel occur, causing hypotension and a sympathetic nervous system response. Patients often present with cramping, abdominal pain, diarrhea, nausea, and tachycardia, as well as vasomotor symptoms such as diaphoresis, palpitations, and flushing.³ Dietary modifications (TABLE 1) are typically recommended as part of treatment. Usually, early dumping is self-limiting and resolves within 7 to 12 weeks.^4,5

Late DS: Late DS is currently referred to as postprandial hyperinsulinemic hypoglycemia (PHH) and is a rare complication of bariatric surgery. It occurs in 0.1% to 0.3% of patients, most commonly after bariatric surgery. Symptoms of PHH include dizziness, fatigue, diaphoresis, and weakness, and they usually occur 1 to 3 hours after ingestion of a carbohydrate-rich meal, typically months to years after surgery, and are associated with documented hypoglycemia. This phenomenon is not strictly due to alterations of osmotic gradients across the GI tract, but rather is thought to result from hypoglycemia following a postprandial insulin peak. Most patients with PHH can be managed with the same dietary modifications suggested for early DS (TABLE 1). Patients refractory to dietary modification can be treated with medications such as nifedipine, acarbose, diazoxide, and octreotide, gastrostomy tube feeding, or revisional bariatric surgery. Overall, dumping may contribute to weight loss, in part by causing the patient to modify his or her eating habits.^3-5

DIAGNOSIS

A suggestive pattern of symptoms in a patient who has undergone gastric surgery should raise the possibility of DS. The diagnosis is made primarily on clinical grounds. Monitored glucose challenge, upper GI series, and gastric-emptying studies have been used to support a DS diagnosis.^5,6

TREATMENT

Treating for DS includes changes in how and what patients eat, medications, and, in some cases, surgery. In many cases people have mild DS, and symptoms improve over time with simple changes in eating habits and diet; see TABLE 1.⁵ If changing eating habits and diet does not improve symptoms, patients may be prescribed medications, most commonly octreotide or acarbose.

Pharmacotherapy

Octreotide (Sandostatin): Somatostatin and its synthetic analogue octreotide have been used with short-term success in patients with DS. A study of 30 patients with DS treated with either SC octreotide, three times a day, or monthly octreotide LAR depot (a long-acting octapeptide with pharmacologic properties mimicking those of the natural hormone somatostatin) significantly reduced dumping symptoms and improved quality of life. Patients preferred monthly treatments.⁷

The short-acting form is injected under the patient’s skin two to four times a day before meals. A healthcare professional may inject the medicine or may train patients, a friend, or a relative to inject it. The long-acting form is injected into the patient’s buttock muscle once every 4 weeks. Side effects may include pain at the injection site, diarrhea, weight gain, gallstones, and steatorrhea.⁷ The usual initial dose of octreotide is 50 mcg administered SC bid or tid 30 minutes prior to each meal.

Acarbose (Precose): Acarbose is an inhibitor of alpha glycosidase that is approved for treatment of diabetes mellitus. It inhibits the upper GI enzymes (alpha-glucosidases), which convert carbohydrates into monosaccharides. It is believed to reduce the symptoms of late DS by interfering with carbohydrate absorption and thus decreasing the time delay between hyperglycemia and insulin response. This may lead to peak glucose and insulin levels coinciding and thus prevent hypoglycemic symptoms in patients with late dumping.⁸

Acarbose use may be limited by the occurrence of diarrhea secondary to fermentation of unabsorbed carbohydrates, as manifested by increased breath-hydrogen excretion and symptoms such as flatulence. In healthy individuals, acarbose in doses of 100 mg to 200 mg significantly blunts the postprandial rise in glucose, insulin, and triglycerides.⁹

Surgery

Patients with intractable dumping symptoms in whom dietary and medical therapy are unsuccessful may require reoperation. In patients who had a distal gastrectomy, conversion from a loop gastrojejunostomy to a Roux-en-Y reconstruction is the procedure of choice. Roux-en-Y gastric bypass is a weight-loss surgery that reduces the size of the stomach and restricts the amount of food a person can eat. It involves creating a stomach pouch out of a small portion of the stomach and attaching it directly to the small intestine, bypassing a large part of the stomach and duodenum. It is often done as a laparoscopic surgery, with small incisions in the abdomen.^3,4 This operation slows gastric emptying by impairing motility of the Roux loop.¹⁰

The type of surgery recommended depends on the type of surgery that led to the DS. Surgery to correct DS does not always work.¹¹

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions, including digestive diseases.¹²

Patients can find clinical studies on DS at www.ClinicalTrials.gov. In addition to searching for federally funded studies, patients can expand or narrow their search to include clinical studies from industry, universities, and individuals; however, the NIH does not review these studies and cannot ensure they are safe. Patients should talk with their healthcare provider before they participate in or choose a clinical study.¹²

REFERENCES

1. Ukleja A. Dumping syndrome: pathophysiology and treatment. Nutr Clin Pract. 2005;20:517-525.
2. National Institute of Diabetes and Digestive and Kidney Diseases. Dumping syndrome. www.niddk.nih.gov/health-information/digestive-diseases/dumping-syndrome/symptoms-causes. Accessed November 20, 2020.
3. Elsmere JC. Late complications of bariatric surgical operations. UpToDate, Inc. www.uptodate.com/contents/late-complications-of-bariatric-surgical-operations. Accessed December 2, 2020.
4. Tack J, Arts J, Caenepeel P, et al. Pathophysiology, diagnosis and management of postoperative dumping syndrome. Nat Rev Gastroenterol Hepatol. 2009;6(10):583-590.
5. National Institute of Diabetes and Digestive and Kidney Diseases. Dumping syndrome. Eating, diet, & nutrition for dumping syndrome. www.niddk.nih.gov/health-information/digestive-diseases/dumping-syndrome/eating-diet-nutrition. Accessed November 20, 2020.
6. Kanth R. Dumping syndrome treatment and management. https://emedicine.medscape.com/article/173594-treatment#d7. Accessed November 20, 2020.
7. Arts J, Caenepeel P, Bisschops R, et al. Efficacy of the long-acting repeatable formulation of the somatostatin analogue octreotide in postoperative dumping. Clin Gastroenterol Hepatol. 2009;7:432-437.
8. De Cunto A, Barbi E, Minen F, Ventura A. Safety and efficacy of high-dose acarbose treatment for dumping syndrome. J Pediatr Gastroenterol Nutr. 2011;53(1):113-114.
9. Cadegiani FA, Sa Silva O. Acarbose promotes remission of both early and late dumping syndromes in post-bariatric patients. Diabetes Metab Syndr Obes. 2016;9:443-446.
10. Nielsen JB, Pedersen AM, Gribsholt SB, et al. Prevalence, severity, and predictors of symptoms of dumping and hypoglycemia after Roux-en-Y gastric bypass. Surg Obes Relat Dis. 2016;12:1562-1568.
11. Eisenberg D, Azagury DE, Ghiassi S, et al. ASMBS position statement on postprandial hyperinsulinemic hypoglycemia after bariatric surgery. Surg Obes Relat Dis. 2017;13:371-378.
12. National Institute of Diabetes and Digestive and Kidney Diseases. Dumping syndrome. Clinical trials. www.niddk.nih.gov/health-information/digestive-diseases/dumping-syndrome/clinical-trials. Accessed November 24, 2020.

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