Afferent loop syndrome after partial gastrectomy with Roux-en-Y reconstruction

Surgical Rounds®, September 2007, Volume 0, Issue 0

Randeep S. Jawa, Assistant Professor of Surgery; Lyndsay Guiterrez, Surgical Resident; Rafael Toro-Serra, Surgical Resident; Mahmoud N. Kulaylat, Associate Professor of Surgery, Department of Surgery, SUNY Buffalo, Buffalo General Hospital, Buffalo, NY

Randeep S. Jawa, MD

Assistant Professor of Surgery

Lyndsay Guiterrez, MD

Surgical Resident

Rafael Toro-Serra, MD

Surgical Resident

Mahmoud N. Kulaylat, MD

Associate Professor of Surgery

Department of Surgery

SUNY Buffalo

Buffalo General Hospital

Buffalo, NY

Introduction: Afferent loop syndrome (ALS) is a well-described complication of Billroth II reconstruction following distal gastrectomy; however, it is rarely reported after other forms of gastric reconstruction.

Results and discussion: This paper reports the case of ALS in a patient who had an extensive surgical history, which included Roux-en-Y reconstruction after partial gastrectomy for peptic ulcer disease. It also discusses the salient features of ALS following Billroth II reconstruction and ALS following Roux-en-Y reconstruction.

Conclusion: Surgical treatment of ALS secondary to mechanical obstruction is recommended.

Afferent loop syndrome (ALS) is a complication that results from a mechanical obstruction of the afferent loop of a Billroth II loop gastrojejunostomy performed after partial gastric resection for peptic ulcer disease or gastric malignancy. This relatively infrequent complication is seldom reported after other types of procedures, such as Roux-en-Y reconstruction. We report one such case of chronic ALS in a patient who underwent Roux-en-Y reconstruction after partial gastrectomy for peptic ulcer disease.

Case report

A 76-year-old woman presented to the emergency department after experiencing a week of postprandial abdominal cramping and hours of severe epigastric pain that radiated to her back. The epigastric pain was associated with nonbilious emesis occurring approximately 2 hours after eating. The patient had experienced similar symptoms several months earlier, at which time pancreatitis was diagnosed.

Her surgical history was significant for an open cholecystectomy in the 1950s; a partial gastric resection for peptic ulcer disease in the 1960s, with subsequent revision of the gastrojejunal reconstruction for unclear reasons; a biliary-enteric drainage procedure for common bile duct stones several years later; a Hartmann's type colon resection for colon cancer in the 1990s, with subsequent reversal of the colostomy; coronary artery bypass graft surgery; and a thyroidectomy. Her medical history was remarkable for gastroesophageal reflux disease.

On physical examination, the patient was afebrile. Her abdomen was slightly distended and soft on palpation, and there were diminished bowel sounds on auscultation. There were no incisional hernias. A complete blood count revealed a white blood cell (WBC) count of 19.2x109/L (normal, 4.5 to 11.0x109/L) and a hemoglobin of 9.7 g/dL (normal, 12.0 to 15.0 g/dL). Other laboratory findings included a serum amylase of 912 U/L (normal, 25 to 85 U/L), lipase of 1,810 U/L (normal, 14 to 280 U/L), total bilirubin of 1.9 mg/dL (normal, 0.3 to 1.2 mg/dL), direct bilirubin of 1.4 mg/dL (normal, < 0.2 mg/dL), alkaline phosphatase of 151 U/L (normal, 50 to 120 U/L), aspartate aminotransferase (AST) of 866 U/L (normal, 20 to 48 U/L), and alanine aminotransferase (ALT) of 271 U/L (normal, 10 to 40 U/L). A computed tomography (CT) scan of the abdomen and pelvis performed with oral Gastrografin? contrast and intravenous contrast demonstrated dilated small bowel loops; dilated intrahepatic, extrahepatic, and common bile ducts; pneumobilia; a prominent pancreatic duct; and splenic lesions (Figure 1).


Endoscopic examination of the upper gastrointestinal tract revealed a moderately sized gastric remnant and a widely patent gastrojejunostomy. The small bowel was intubated, and the common bile duct-duodenal anastomosis was visualized, but the ampulla of Vater could not be identified. There were no strictures. A subsequent upper gastrointestinal contrast study with small bowel follow through demonstrated opacification of the afferent loop within 15 minutes of oral contrast administration and mild, generalized small bowel dilation. The contrast reached the cecum in less than 1 hour, and no strictures or transition points were visualized (Figure 3). Cholescintigraphy showed the radionuclide tracer in the afferent loop of the Roux-en-Y within 30 minutes after administration and in the small intestine within 1 hour (Figure 4). The radionuclide demonstrated good clearance from the liver within 4 hours and was observed in the large intestine within 24 hours. Figure 5 provides a diagrammatic representation of the patient's anatomy, as delineated by these studies.

The patient's condition continually improved throughout her hospitalization. Her abdominal pain subsided, and she was able to tolerate an oral intake. Her serum amylase and lipase levels returned to normal by hospital day 3. Her serum bilirubin, AST, ALT, alkaline phosphatase, and WBC levels normalized by hospital day 6. Magnetic resonance cholangiopancreatography (MRCP) performed on hospital day 6 showed a pancreatic duct that entered the proximal portion of the afferent loop and pancreatic and biliary ducts that were less dilated than they appeared on the CT scan at admission (Figure 6). The patient was discharged to home on hospital day 6. She underwent a CT enteroclysis study as an outpatient, which demonstrated mild focal dilatation of the distal duodenum (Figure 7).

The patient was readmitted to the hospital 6 months later with a similar clinical picture and radiographic and endoscopic findings. Her condition rapidly improved with nonoperative management, and she was discharged to home after 3 days.


ALS is a well-described complication of distal gastric resection with Billroth II reconstruction for benign or malignant gastric disease. The syndrome may be acute or chronic.

Etiogenesis and clinical manifestations

Acute ALS affects about 1% of patients and commonly occurs in the early postoperative period, but it has been reported to arise years later.1 Obstruction of the outflow tract of the afferent loop, which extends from the closed duodenal stump to the gastrojejunostomy, may be caused by adhesions, herniation, or torsion of the afferent loop, resulting in a closed-loop obstruction. In the early postoperative period, perianastomotic inflammation, hemorrhage, or proximal efferent limb obstruction due to edema may result in preferential emptying of the gastric contents into the afferent loop and subsequent development of ALS.1-3 The obstructed afferent loop accumulates up to 2 L of pancreatobiliary secretions daily.1 This results in dilatation of the loop and an increase in its intraluminal pressure, eventually impeding the flow of biliary and pancreatic secretions, which causes dilatation of the biliary tree and pancreatic duct. Jaundice, cholangitis, and acute pancreatitis develop. The high intraluminal pressure also may lead to ischemia and gangrene of the afferent loop.1,2 Patients typically present with a sudden onset of epigastric or right or left upper quadrant abdominal pain, nausea, and nonbilious vomiting.1 Patients may become dehydrated. Left untreated, the mortality rate of acute ALS exceeds 50%.1 Treatment is emergency laparotomy.

Chronic ALS presents months to years after surgery. Unlike acute ALS, chronic ALS results from a low-grade or partial obstruction caused by anastomotic kinking or stenosis, carcinomatosis, or isch?emic strictures that may occur between the ligament of Treitz and the gastrojejunal anastomosis.2-4 The ischemic strictures result from repeated kinking of an excessively long afferent loop. The partial obstruction is aggravated by the accumulation of pancreatobiliary secretions. The symptoms of chronic ALS are often nonspecific and include postprandial epigastric or right upper quadrant pressure or a bursting sensation, or colicky pain that radiates to the back.4 A classic presentation of chronic ALS is bilious emesis, which provides relief of the abdominal pain.4,5 The vomitus usually does not contain food.1 Bacterial overgrowth may occur in a chronically partially obstructed afferent loop. The bacteria deconjugate stagnant biliary secretions, resulting in steatorrhea, malnutrition, and vitamin B12 deficiency; this is known as the blind loop syndrome.4 Surgical treatment is necessary to relieve the obstruction of the Billroth II reconstruction.


Laboratory investigation of ALS commonly reveals elevated serum amylase and lipase levels, perhaps due to the inability of the pancreas to secrete these enzymes against the increased intraluminal pressure in the obstructed afferent loop. Biliary enzymes also may be elevated. These abnormal laboratory findings may lead to the erroneous diagnosis of biliary pancreatitis.1,4 Prolonged vomiting and dehydration can lead to hemoconcentration, elevated blood urea nitrogen, and electrolyte abnormalities.1 In chronic cases involving partial obstruction, patients may show stigmata of the blind loop syndrome.

Abdominal radiographs may show a dilated, transversely oriented portion of small bowel located anterior to the spine; however, the study may be unrevealing when the obstructed afferent loop is fluid-filled and gasless.6 Failure of the afferent loop to fill with contrast during an upper gastrointestinal and small bowel follow- through study suggests afferent loop obstruction. This study is nonspecific, however, because 20% of patients without ALS may fail to demonstrate filling of the afferent loop. Conversely, preferential filling and retention of contrast for more than 60 minutes in a dilated afferent loop is thought to be highly suggestive of ALS.2,6 Transcutaneous ultrasonography may show dilated bile ducts and a dilated, fluid-filled round, oval, or tubular structure crossing the midline between the superior mesenteric artery and the aorta, where bowel distention flattens the mu?cosal folds.6

On CT scanning, the afferent loop appears as a fluid-filled, dilated, U-shaped, transversely oriented cystic mass located in the middle of the abdomen, anterior to the spine. This mass is located behind the superior mesenteric artery and is continuous with the biliary system.7,8 In cases of chronic ALS, CT scans may also demonstrate enteroliths.4,9 Radionuclide biliary excretion scans may show a tortuous afferent loop that is distended and elongated. Stasis and delayed washout of the tracer from the afferent loop (more than 1 to 4 hours) may serve as a relatively reliable indicator that an obstruction exists.4,10-12

Surgical management options for ALS after Billroth II gastrojejunostomy depend on the etiology and acuity of ALS and the patient's stability. Conversion to a Billroth I anastomosis, Roux-en-Y reconstruction, and construction of a Braun-type ente?roenterostomy between the afferent and efferent limbs are commonly used techniques. Other treatment options include resection of the stenotic or is?chemic segment with reconstruction of the afferent loop, revision of the gastric stoma, and interposition of a jejunal segment between the gastric pouch and duodenum.4,5 In patients with carcinomatosis, where formal surgical correction is not feasible, percutaneous transhepatic duodenal drainage and percutaneous tube enterostomy under ultrasound-fluoroscopic guidance have been described.11,13

ALS after Roux-en-Y reconstruction

ALS rarely occurs in patients with a Roux-en-Y reconstruction after nonbariatric gastric resection. A Medline literature search identified only a few case reports. Zissin described ALS in a patient with a history of subtotal gastrectomy with Roux-en-Y reconstruction.14 The patient's liver enzymes were elevated, and a CT scan showed a dilated afferent loop and dilated intra- and extra-hepatic bile ducts. Laparotomy revealed dilatation of both the afferent loop and efferent limb and an obstructive adhesive band at the anastomosis. Wada and associates de?scribed ALS in a patient who presented with recurrent episodes of pancreatitis and obstructive jaundice years after total gastrectomy and Roux-en-Y reconstruction.15 A CT scan revealed a dilated jejunal limb of the Roux-en-Y anastomosis. Technetium scintigraphy showed retention of radionuclide in the dilated jejunal limb at 30 and 120 minutes. At laparotomy, a cholesterol stone was found impacted at a slightly stenotic anastomosis. Wada and associates also recalled an article in the Japanese literature describing jaundice secondary to ALS in a patient who had undergone Roux-en-Y reconstruction.15,16 Finally, Sandrasegaran and associates described eight cases of afferent loop obstruction that occurred after a variety of surgical procedures.17 Two patients had undergone gastrectomy with Roux-en-Y reconstruction; in one patient, obstruction was caused by an adhesive band, and bleeding from a suture line and hematoma resulted in the other patient's obstruction. This study highlighted the utility of coronal CT scans in diagnosing ALS.

Our patient presented with a clinical picture suggestive of chronic ALS. Her biliary and pancreatic enzymes were elevated. The CT scan demonstrated a transversely oriented dilated afferent loop segment between the aorta and the superior mesenteric vessels in conjunction with biliary and pancreatic ductal dilatation. CT scanning was the most helpful imaging modality in confirming the diagnosis of ALS, because we were able to reformat the scans to provide coronal views. The etiology of our patient's ALS is not clear, because none of the radiographic or endoscopic studies demonstrated significant organic obstructive lesions. Furthermore, manifestations of the syndrome resolved with expectant management. The obstruction could have been a low-grade adhesive obstruction. Bowel rest and Gastrografin? could have resolved the obstruction.18,19 More likely, it was a functional obstruction caused by atonicity or dysmotility of the afferent loop.

Altered motility in the upper gastrointestinal tract has been reported to occur after Roux-en-Y reconstructions. In animal experiments, Karlstrom and Kelly found that dogs undergoing vagotomy and gastric resection with Roux-en-Y reconstruction exhibited marked myoelectric abnormalities in the Roux limb (efferent limb) with orad propagation of pacesetter potentials in contrast to dogs that had undergone Billroth II reconstruction.20 Perino and colleagues described dysmotility of the Roux limb with resultant inability to tolerate oral feedings in eight patients who had undergone a variety of gastric procedures that culminated with Roux-en-Y reconstruction.21 They noted complete absence of the migrating motor complex in the Roux limb in three patients and moderate disruption of motility in three others. In the three patients with absent migrating motor complexes, motility of the distal intestine was found to be normal. Altered motility of the Roux limb or afferent loop may affect emptying of the afferent loop, resulting in ALS.


ALS is a relatively infrequent complication of a partial gastrectomy with Billroth II reconstruction and is extremely rare after Roux-en-Y reconstruction. We found only a few other cases reported in the literature. ALS can be difficult to diagnose, but we found CT scanning helpful in visualizing this condition, especially when the scans were reformatted to show the coronal plane. In the usual case of chronic ALS secondary to mechanical obstruction, surgical intervention is generally indicated. In contrast, the treatment of chronic ALS without mechanical obstruction after Roux-en-Y reconstruction has yet to be determined. Possibly, a modified Braun enteroenterostomy or a revision to a Billroth II anastomosis with a shortened afferent loop with or without a Braun-type enteroenterostomy may be helpful under these circumstances.


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