Dumping syndrome refers to a constellation of postprandial symptoms resulting from rapid delivery of undigested hypertonic stomach contents into the small bowel that causes intravascular fluid shift into the bowel lumen. It is most often caused by gastric surgery, such as procedures for peptic ulcer disease, gastric cancer, and gastric bypass.^1,2

• Postgastrectomy syndrome
• Rapid gastric emptying
• Postprandial hyperinsulinemic hypoglycemia (PHH; late dumping syndrome)
• Postgastric bypass hypoglycemia (PGBH; late dumping syndrome)
• Post-bariatric hypoglycemia (PBH; late dumping syndrome)

20% to 50% of postgastric surgery patients are estimated to suffer from dumping-related symptoms.^1,2 10% with more pronounced symptoms that warrant diagnosis,² 1% to 5% with severe symptoms.³

• •Vagotomy with pyloroplasty (10% to 20%)^1,2
• •Esophagectomy (up to 50%)¹
• •Antrectomy (10%)²
• •Roux-en-Y gastric bypass or partial gastrectomy (up to 40%)¹
• •Males and females are affected equally

• •Early dumping syndrome: Symptoms start within 60 min after eating:
  1. 1.No symptoms in fasting state
  2. 2.Early satiety, nausea, vomiting, and belching
  3. 3.Epigastric fullness, cramping, and diarrhea
  4. 4.Dizziness, flushing, diaphoresis, and syncope
  5. 5.Palpitations and tachycardia
• •Late dumping syndrome: Symptoms occurring 1 to 3 h after eating:
  1. 1.Dizziness, diaphoresis
  2. 2.Irritability, fatigue
  3. 3.Difficulty in concentration
  4. 4.Tremulousness, anxiety, palpitations
  5. 5.Hypoglycemia and associated weakness, confusion, seizure, coma
• •It should be noted that, although the symptoms of dumping syndrome are categorized as early or late, the disease presents as a spectrum where patients can develop only early or late dumping symptoms, or both. Early dumping symptoms can also resolve before the late symptoms present.¹

Dumping syndrome occurs almost exclusively in patients who have had gastric surgery.¹

• •Systemic symptoms in early dumping syndrome are thought to be partially due to hypovolemia caused by rapid shifts of fluid from the intravascular space into the lumen of the bowel as well as increased release of GI hormones that disrupt motility and hemodynamic status.
• •Increase in vasoactive substances related to rapid gastric emptying is thought to play a role in dumping syndrome.
• •Late dumping symptoms are thought to be due to rapid carbohydrate delivery to the small intestine inducing GLP-1-mediated reactive hyperinsulinemia and hypoglycemia and release of counterregulatory hormones, especially norepinephrine. However, the full mechanism is not entirely understood.^1,2,4

• •Gastroparesis
• •Pancreatic insufficiency
• •Inflammatory bowel disease
• •Afferent loop syndromes
• •Bile acid reflux after surgery
• •Bowel obstruction
• •Gastroenteric fistula
• •Intestinal ischemia

Diagnosis is typically made on clinical grounds. In certain clinical settings in which patients exhibit symptoms with no prior history of gastric surgery, oral glucose challenge and imaging studies may be pursued and aid in establishing the diagnosis.

Oral glucose challenge test:

• •After at least 10 h of fasting, oral intake of 50 g of glucose is followed by serial measurements of heart rate, serum glucose, and hydrogen breath test every 15 to 30 min for 3 to 6 h. A 30-min hematocrit can also be taken.¹
• •An increase in the heart rate >10 beats/min and a rise in hydrogen breath excretion have a sensitivity of 100% and specificity >94%. An increase of >3% in the 30-min hematocrit is also suggestive of a positive test. A nadir blood glucose <3.3 mmol/L (<59 mg/dl) was present in 75% of late dumpers.¹

Mixed-meal tolerance testing or 3-day continuous glucose monitoring may also have some clinical utility, particularly in late dumping syndrome.⁵

• •Upper GI series properly defines anatomy.¹
• •Radionucleotide scintigraphy rapid gastric emptying tests may be useful in patients with dumping syndrome and no history of gastric surgery, but have limited utility in most patients.^1,2

• •Diet modification is first-line treatment in dumping syndrome:¹
  1. 1.Divide caloric intake over six small meals
  2. 2.Limit fluid intake with meals (avoid fluids 30 min before and after)
  3. 3.Meals should be eaten slowly and chewed well
  4. 4.Decrease carbohydrate intake and avoid simple sugars
  5. 5.Increase protein and fat intake
  6. 6.Increase or supplement dietary fibers
  7. 7.Avoid milk and milk products
  8. 8.Avoid alcohol
• •Lying down for 30 min after a meal to slow gastric emptying and diminish symptoms of hypovolemia may be helpful.⁵

• •Acarbose 50 mg PO daily can be tried if dietary modification does not help, particularly for late dumping syndrome (grade of recommendation: B).¹
• •Octreotide 25 to 50 mg subcutaneously 30 min before meals is effective in relieving symptoms of dumping syndrome and is recommended in patients who fail dietary modification and acarbose (grade of recommendation: B).¹
  • •Lanreotide is effective in treating early postoperative dumping symptoms, but does not have a significant effect on quality of life.⁶
  • •Pasireotide has been demonstrated to treat postprandial hypoglycemia associated with dumping syndrome after esophageal and gastric surgery, and it also improves quality of life.⁷
• •Pectin and guar have been used to increase viscosity of intraluminal contents and relieve symptoms from rapid emptying and absorption; however, the tolerability of these supplements tends to be poor.¹
• •Diazoxide 50 mg PO twice daily can be used to inhibit insulin secretion and can be used to treat late dumping hypoglycemia when acarbose/diet modifications are inadequate² (grade of recommendation: C).¹

• •Surgery is considered in patients with severe symptoms refractory to the above-mentioned dietary and acute general treatment.¹
• •Surgical procedures include reconstruction of the pylorus, converting Billroth II to a Billroth I anastomosis, Roux-en-Y reconstruction, enteral tube feedings, and reversal of gastric bypass.
• •In severe cases, can consider depot long-acting-release octreotide, given as 10 mg intramuscularly every 4 wk for symptom relief.

• •Patient symptoms of dumping syndrome may improve over time, so conservative management is recommended.¹
• •Dietary modification effectively treats the majority of patients.³

• •A GI specialist consult is recommended in patients suspected of having dumping syndrome.
• •If medical management is unsuccessful, a general surgical consultation is warranted.

• •The majority of patients usually manifest with early dumping symptoms or a combination of early and late symptoms, but patients can manifest with late dumping symptoms alone.
• •Octreotide and its analogs have an inhibitory effect on the release of insulin and other vasoactive substances released by the gut. It also works by decreasing gastric emptying.
• •Notable nonsurgical associations with dumping syndrome are diabetes mellitus and viral illness; idiopathic cases have been reported.
• •Malnutrition is a primary concern for patients with dumping syndrome. Patients may modify their eating habits as a result of dumping syndrome, but there is no evidence that dumping syndrome improves weight loss after bariatric surgery.¹