emDOCs – Episode 145: Post Bariatric Surgery Complications Part 2

Anastomotic/staple line leak:

• Common surgical complications and a leading cause of death in these patients in the early postoperative period. Usually presents in the first week of surgery in patents who underwent RNYGB or sleeve gastrectomy.
• Five potential sites for an anastomotic leak in patients who have undergone RNYGB: the gastrojejunostomy, gastric pouch staple line, gastric remnant staple line, roux limb staple line, and jejunojejunostomy.
• Range of symptoms: asymptomatic (50%), but may be critically ill with fever, abdominal pain, tachycardia, peritonitis, and septic shock. Tenderness may not be present.
• Literature suggests tachycardia, fever, and leukocytosis are the most reliable findings.
• Imaging: CT chest, abdomen, pelvis with IV and oral contrast to evaluate for PE and leak; sensitivity depends on several different factors. Highly sensitive in bariatric centers, but sensitivity is less than 70% in other settings.
• Management: resuscitation, antibiotics, and surgical consultation. If unstable, OR necessary. In other patients who are stable, other options include percutaneous drain and endoscopic stent placement.

Small bowel obstruction/internal hernia:

• Bowel obstruction common; associated with worse outcomes in patients with bariatric surgery, especially internal hernia.
• Internal hernia: protrusion of bowel, most commonly the small bowel, through a normal or abnormal peritoneal or mesenteric aperture within the abdominal or pelvic cavity. May lead to a closed-loop bowel obstruction, which can result in strangulation and perforation.
• Incidence of internal hernia after laparoscopic RNYGB 3-16%.
• Occur any time after surgery; patients at the highest risk are those who have had more significant weight loss at least 1-3 years out from their surgery.
• Small bowel obstruction resulting from internal hernia is more common with laparoscopic compared to open gastric bypass; may be due to fewer intraabdominal adhesions with a laparoscopic approach.
• Most common clinical symptom is intermittent, postprandial abdominal pain (up to 90%); nausea and vomiting occurs in 65%. Less than 50% present with diffuse abdominal tenderness; 20% have no tenderness.
• Internal hernias can self-reduce; they may not be present when imaging obtained.
• First line imaging test is CT abdomen/pelvis with IV and PO contrast.
• No imaging study can reliably exclude internal hernia; false negative studies are common.
  • Accuracy for upper GI series 25-100%; CT 33-100%.
  • CT findings: crowding/engorgement of mesenteric vessels and twisting of the mesenteric vessels and bowel (whirl sign), clustered loops of bowel in the left upper quadrant, small bowel loop lying behind the superior mesenteric artery, or the presence of the jejunojejunal anastomosis to the right of midline (should be on the left typically).
  • No sign highly sensitive or specific; up to 30% of patients with confirmed internal hernia in the OR have normal imaging. Consult the bariatric surgeon.
• Less common causes of bowel obstruction: intussusception and stricture.
• Any postoperative small bowel obstruction is concerning for internal hernia; requires emergent surgical evaluation for operative intervention. Herniated bowel can rapidly progress to ischemia and necrosis if not promptly reduced; NG tube will not decompress the blind pouch limb and gastric remnant in gastric bypass patients.
• Early-occurring small bowel obstruction after laparoscopic gastric bypass rarely due to adhesions; more commonly due to technical error with narrowing or kinking of the jejunojejunal anastomosis, intraluminal obstruction from hematoma, or port-site hernia. Need surgical correction.

Marginal ulcers:

• Late complication of RNYGB; defined as ulcers that occur at or in close contact with the gastrojejunal anastomosis.
• Most marginal ulcers develop 6-12 months after surgery; may be diagnosed as early as one month or as late as 20 years post-operatively.
• Likely due to exposure of jejunal tissue to highly acidic gastric contents; worsened with Helicobacter pyloriinfection or smoking, alcohol consumption, and nonsteroidal anti-inflammatory drug use.
• May be asymptomatic, but often result in abdominal or epigastric pain (60%), nausea and vomiting (up to 60%), dysphagia (< 40%), or bleeding. Most common presenting symptom in patients with perforated marginal ulcer is abdominal pain; < 50% with perforation have fever, tachycardia, peritonitis.
• Consult bariatric surgeon; may require scope/admission.
• Perforation: OR, broad-spectrum antibiotics, resuscitation.

Biliary disease:

• Rapid weight loss following bariatric surgery is an independent risk factor for gallstones.
• 30-53% develop gallstones within 12-18 months of surgery. Up to 14% present with biliary colic or cholecystitis; 10% develop choledocholithiasis.
• Present similar to other patients with biliary disease with RUQ pain.
• US miss up to 36% of gallstones in post bariatric patients; other imaging like endoscopic US and CT may be needed.
• In post RNYGB and BPD-DS patients, conventional ERCP cannot reach duodenum.
• Need an alternative endoscopic approach, combined endoscopic and surgical methods, percutaneous transhepatic access to the biliary tree, or cholecystectomy with bile duct exploration.
• Consult bariatric surgeon.

Gastric balloon and LAGB complications:

• Presenting symptoms of pouch enlargement: lack of satiety, heartburn, feelings of regurgitation, and chest pain.
• Signs and symptoms of band slippage and intragastric balloon intolerance: dysphagia, vomiting, inability to tolerate oral intake, and dehydration.
  • 23-72% of the patients with gastric balloons have nausea; 20-50% abdominal pain.
  • Most patients with band erosion are asymptomatic. If symptoms occur, may include loss of restriction, nonspecific epigastric pain, or GI bleeding.
• Upright KUB helpful to evaluate for a slipped adjustable gastric band by determining phi angle (angle between a vertical line through the spine and another line along the long axis of the lap band). Normal phi angle between 4-58 degrees. Angle outside this range suggests slippage. ‘O’ sign on AP view represents the gastric band visible end on; strongly suggestive of posterior band slippage.
• CT is the test of choice though if concern for a more deadly complication.

Dumping syndrome:

• Rapid gastric emptying and entry of a food bolus into the small intestine; causes symptoms like abdominal pain, bloating, nausea, diarrhea, fatigue, flushing, palpitations, sweating, tachycardia, hypotension, syncope, hypoglycemia.
• Occurs in up to 40% of those with LSG or RNYGB.
• Typically managed with dietary modification alone (limiting intake of simple carbohydrates). Patients with severe diarrhea and hypotension may need IV fluids.

Summary:

• Bariatric surgeries include restrictive procedures like adjustable gastric banding, endoscopic gastric balloon insertion, and sleeve gastrectomy and mixed restrictive and malabsorptive procedures. These include RNYGB and BPD-DS.
• There are several complications associated with severe morbidity and mortality in the post-bariatric patient, including (1) anastomotic/staple line leaks, (2) small bowel obstruction and internal hernia, (3) marginal ulceration, (4) biliary disease, and (5) device-related complications.
• History is important. What was performed, when was it performed, who performed it, and have they had prior complications.
• Clinical signs of intra-abdominal complications are often absent or nonspecific, and symptoms can be intermittent. Patients with post-bariatric anastomotic leaks often won’t have tenderness with palpation or peritonitis.
• Tachycardia and tachypnea can be the initial signs of significant intra-abdominal complications in postoperative bariatric patients like anastomotic leak and also PE. Persistent vomiting in the post bariatric patient is concerning for an acute surgical emergency, especially an obstruction with internal hernia.
• When these patients come to the ED, consult the bariatric surgeon early. This can help guide imaging and management.
• If an anastomotic leak or internal hernia is suspected, CT of the abdomen/pelvis with PO and IV contrast is recommended. If they present in the early postoperative phase, add a CT of the chest to look for PE as well.
• Initial management in the ED for patients with anastomotic leaks is similar to those for intestinal perforation. The unstable patient with signs of uncontained leak needs the OR, and ED resuscitate and give broad-spectrum antibiotics.
• Managing small bowel obstructions in the bariatric patient population differs from other patient populations. In the gastric bypass patient, any postoperative SBO should undergo emergent surgery specialist consultation due to the risk of internal hernia.