Last reviewed: March 2026
Contents
MDM Templates
Post-Bariatric Abdominal Pain
Patient with history of *** (Roux-en-Y gastric bypass / sleeve gastrectomy) performed *** presents with abdominal pain, nausea, and vomiting. Hemodynamically stable. Abdomen is soft without peritoneal signs.
Dangerous complications of bariatric surgery considered including anastomotic leak, internal hernia, small bowel obstruction, marginal ulcer perforation, and intra-abdominal infection. Labs and imaging obtained to evaluate.
If workup reassuring:
Labs and imaging without evidence of anastomotic leak, obstruction, internal hernia, or perforation. Patient’s pain improved with symptomatic management. Tolerating PO liquids.
Disposition: Discharge with return precautions for worsening pain, fever, bilious emesis, or inability to tolerate PO. Follow up with bariatric surgeon within 24–48 hours.
If concern for surgical complication:
Imaging concerning for ***. Surgery consulted emergently regarding operative management. IV antibiotics initiated. Patient made NPO with IV fluid resuscitation.
Disposition: Admit to surgery.
Dumping Syndrome
Patient with history of gastric bypass presents with postprandial epigastric pain, nausea, diaphoresis, and loose stools consistent with dumping syndrome. Symptoms occur within 30 minutes of eating. Well appearing at time of evaluation with symptoms resolving in the ED.
History and exam not consistent with anastomotic leak, internal hernia, marginal ulcer, or bowel obstruction.
Plan: Dietary modification counseling — small, frequent, low-carbohydrate meals; avoid simple sugars and liquids with meals.
Disposition: Discharge with follow up with bariatric surgeon and nutritionist. Return for persistent vomiting, fever, or worsening pain.
Marginal Ulcer
Patient with history of gastric bypass presents with epigastric pain consistent with marginal ulcer at the gastrojejunal anastomosis. No signs of perforation — no peritoneal signs, no free air on imaging.
If uncomplicated:
Plan: PPI initiated (pantoprazole 40 mg BID). Sucralfate 1 g QID. Smoking and NSAID cessation counseled. H. pylori testing sent.
Disposition: Discharge with GI and bariatric surgery follow-up for endoscopy. Return for hematemesis, melena, worsening pain, or fever.
If perforation or hemorrhage:
Imaging demonstrates free air / patient with hemodynamic instability and GI bleeding. Surgery consulted emergently. IV PPI drip initiated.
Disposition: Admit to surgery.
Clinical Education
Deadly Complications
Anastomotic leak is the most feared early complication (typically days 1–10 post-op, but can present weeks later). Presents with tachycardia (often the earliest sign), fever, abdominal pain, and left shoulder pain. Tachycardia out of proportion to other findings in a post-bariatric patient should be assumed to be a leak until proven otherwise.[1]
Internal hernia is the most dangerous late complication. After Roux-en-Y, mesenteric defects allow small bowel to herniate through the Petersen space or jejunojejunal mesenteric defect. Presents with intermittent, severe, colicky abdominal pain — often with a “swirl sign” on CT. Can lead to closed-loop obstruction and bowel necrosis. CT can be falsely negative in up to 10–20% of cases. If clinical suspicion is high, surgical exploration may be warranted despite normal imaging.[2]
Small bowel obstruction occurs in ~5% of Roux-en-Y patients. Adhesions are the most common cause. CT with oral and IV contrast is the imaging of choice. Treat as any SBO — NPO, NGT if vomiting, surgery consult.
Imaging Approach
CT abdomen/pelvis with IV contrast is the workhorse. Oral contrast can be added if leak is suspected (water-soluble contrast, not barium). Look for: free fluid, mesenteric swirl sign (internal hernia), transition point (SBO), free air (perforation), and anastomotic fluid collections (leak/abscess).[3]
Upper GI series with water-soluble contrast is more sensitive than CT for small anastomotic leaks in the early postoperative period. Consider if CT is equivocal and leak suspicion remains high.
Dumping Syndrome Pearls
Early dumping (within 30 minutes of eating) results from rapid transit of hyperosmolar chyme into the small bowel, causing fluid shifts and vasoactive peptide release. Symptoms: cramping, nausea, diarrhea, diaphoresis, tachycardia. Occurs in up to 50% of Roux-en-Y patients.[4]
Late dumping (1–3 hours after eating) is reactive hypoglycemia from exaggerated insulin release after rapid carbohydrate absorption. Symptoms: weakness, diaphoresis, confusion, tremor. Check a glucose — it may be profoundly low.
Treatment is dietary. Small, frequent, high-protein, low-carbohydrate meals. Avoid drinking liquids with meals. Avoid simple sugars. For refractory late dumping, acarbose 50–100 mg before meals can blunt the glycemic spike.
Marginal Ulcer Pearls
Marginal ulcers occur at the gastrojejunal anastomosis in 1–16% of Roux-en-Y patients. Risk factors include smoking (the strongest modifiable risk factor), NSAIDs, H. pylori, and large gastric pouch. Presentation mimics PUD — epigastric pain, nausea, GI bleeding.[5]
Perforation is the feared complication. Free air on CT is diagnostic. These patients need emergent surgery — not medical management alone.
Nutritional Deficiencies
Post-bariatric patients are at risk for deficiencies that can present to the ED. Iron deficiency (fatigue, anemia), B12 deficiency (neuropathy, macrocytic anemia), thiamine deficiency (Wernicke encephalopathy — give thiamine before glucose in any altered post-bariatric patient), and calcium/vitamin D deficiency (osteoporosis, tetany). Wernicke encephalopathy from thiamine deficiency is the most dangerous ED presentation — it can occur after prolonged vomiting in a malnourished patient.[6]
Adjustable Gastric Band Complications
Band slippage/prolapse: Stomach herniates through the band, causing obstruction. Presents with acute dysphagia, vomiting, and epigastric pain. X-ray shows “phi sign” (band tilted > 58° from horizontal). Requires urgent surgical intervention.[7]
Band erosion: Band gradually erodes into the gastric lumen. Often insidious — presents with port site infection, failure to maintain restriction, or abdominal pain. Diagnosis is by endoscopy. Requires surgical removal.
Port complications: Port infection, port flipping, or tubing disconnection. Port site erythema or pain suggests infection — treat with antibiotics and surgical referral.
Disposition
Admit if: Concern for anastomotic leak, internal hernia, SBO, perforation, GI bleeding with hemodynamic instability, or Wernicke encephalopathy.
Discharge if: Dumping syndrome with resolved symptoms, uncomplicated marginal ulcer without bleeding or perforation, mild dehydration that responds to IV fluids, tolerating PO, reliable follow-up with bariatric surgeon.
Always call the bariatric surgeon. These patients have complex anatomy and the surgical team often has specific preferences for imaging, antibiotics, and disposition that differ from standard algorithms.
References
- Bellorin O et al. Management of complications after Roux-en-Y gastric bypass. Surgery. 2010;148(3):499-504.
- Lockhart ME et al. Internal hernia after gastric bypass: sensitivity and specificity of seven CT signs with surgical correlation and controls. AJR Am J Roentgenol. 2007;188(3):745-750. PubMed
- Levine MS, Carucci LR. Imaging of bariatric surgery: normal anatomy and postoperative complications. Radiology. 2014;270(2):327-341. PubMed
- Tack J et al. Pathophysiology, diagnosis and management of postoperative dumping syndrome. Nat Rev Gastroenterol Hepatol. 2009;6(10):583-590. PubMed
- Coblijn UK et al. Development of ulcer disease after Roux-en-Y gastric bypass, incidence, risk factors, and patient presentation: a systematic review. Obes Surg. 2014;24(2):299-309. PubMed
- Mechanick JI et al. Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures — 2019 update. Endocr Pract. 2019;25(12):1346-1359. PubMed
- Chandler RC et al. Band erosion, migration, and related complications of adjustable gastric banding: imaging findings. Abdom Imaging. 2008;33(2):218-227. PubMed
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