Afferent loop syndrome (ALS) is a post-surgical complication associated with gastric resections with Billroth II, or Roux-en-Y reconstructions, and pancreaticoduodenectomies which result in the creation of a blind loop. ALS occurs when there is distal obstruction of the afferent limb that results in its distension secondary to the accumulation of bile, pancreatic fluid, or small bowel secretions. Our case demonstrates a rare presentation of afferent loop syndrome that posed both diagnostic and therapeutic challenges. Understanding the pathophysiology of ALS, its cause and the role of endoscopic interventions is crucial in diagnosing and managing ALS.
Afferent loop syndrome (ALS) is a post- surgical complication associated with Billroth II, or Roux-en-Y reconstructions, and pancreaticoduodenectomies (Whipple procedure). The gastro-jejunal anastomosis creates an afferent and efferent limb to the stomach; for Roux- en-Y reconstruction, the afferent limb is the biliopancreatic limb. ALS is a rare complication, occurring in 0.2%-1.0% of patients with partial gastrectomy and Billroth II or Roux-en-Y reconstruction.1 Patients who undergo Whipple have a combination of afferent intestine loop and biliary-enteric anastomosis. The incidence of ALS is significantly higher in patients with Whipple and has been estimated up to 13%, rapidly increasing three years post-surgery.2
Etiologies for obstruction include adhesions, internal hernias, prior gastrojejunostomy ulceration, and recurrent malignancy in those who underwent surgery for cancer.3 Less common causes include intraluminal obstructions and afferent loop intussusception or volvulus, and radiation enteritis.3 We demonstrate the importance of a comprehensive evaluation for abdominal pain in patients with post- surgical anatomy and review management options for patients with ALS in the setting of an afferent limb stricture.
A 59-year-old male with a history of peptic ulcer disease (PUD) status post remote gastric antrectomy with Billroth II, alcohol abuse, and recurrent admissions for acute pancreatitis secondary to alcohol use presented to the hospital with one day of abdominal pain, nausea, and vomiting. Vitals on admission were normal with heart rate of 84 bpm and blood pressure of 103/52 mmHg. Physical examination demonstrated mild distress with tenderness to light palpation in the epigastrium without distension or jaundice. Laboratory results showed a leukocytosis of 24.3 (4.1-10.8 cells/ mm3), lipase of 382 (10-50 units/liter), aspartate aminotransferase of 1,285 (12-38 units/liter), alanine aminotransferase of 560 (>31 units/liter), alkaline phosphatase of 289 (34-106 units/liter), and blood cultures grew E. coli.
Abdominal ultrasonography from a recent admission demonstrated a dilated common bile duct of 1.3 cm and a right upper quadrant (RUQ) cystic structure which appeared as a gallbladder filled with gallstones. On current admission, abdominal computed tomography (CT) demonstrated that this cystic structure was actually the duodenal blind limb dilation with stones. Magnetic resonance cholangiopancreatography (MRCP) redemonstrated a distended duodenal stump with intraluminal stones without interval worsening biliary dilatation (Figure 1). Treatment for cholangitis was initiated with ceftriaxone, with clinical improvement.
Esophagogastroduodenoscopy (EGD) showed evidence of previous Billroth II gastroenterostomy and duodenal stricture in the blind limb (Figure 2).
Liver enzymes aspartate transaminase (AST) and alanine transaminase (ALT) down-trended as well, this elevation was believed to be secondary to an obstructing stone that caused a transient obstruction at the site of the stricture and ultimately passed on its own. Endoscopic intervention was deferred due to clinical improvement with medical management and resolving liver enzymes levels. Patient is now following with surgery for possible revision of Billroth II.
ALS occurs with distal obstruction of the afferent limb and subsequent distension secondary to the accumulation of bile, pancreatic fluid, and enteric secretions. Clinical presentation of ALS occurs across a wide spectrum depending on the acuity of the obstruction. Acute obstruction often presents as pancreatitis or ascending cholangitis.4 This most commonly occurs early in the post-operative course; abdominal pain is common and may be associated with sepsis or peritonitis. Chronic ALS occurs months to years after surgery with postprandial abdominal pain that may result in food avoidance, malabsorption, and weight loss.5 CT of the abdomen is the diagnostic gold standard for ALS, however MRCP can be a helpful adjunctive test in chronic ALS. An EGD was also performed to evaluate patency of the afferent loop in this case. Our patient posed a diagnostic challenge due to recurrent episodes of acute pancreatitis due to alcohol use and a new cholangitis that was present this admission. This case necessitated the use of multiple imaging modalities to appropriately identify the underlying cause of distal obstruction of the afferent limb, which was in our case a benign stricture. Our patient was particularly challenging given his remote surgical history, making a presentation of chronic ALS with both acute pancreatitis and acute cholangitis atypical. Given the numerous etiologies for developing chronic ALS, diagnostic accuracy is imperative to provide appropriate treatment, which historically has been surgical. By identifying the stricture, problem-directed treatment via endoscopicguided stenting or dilation is a potential therapy that may
not initially demand immediate surgical intervention.6 Newer, lumen-apposing metal stents (LAMS) are potentially useful in synchronous biliary and duodenal malignant obstruction. The advent of LAMS in the treatment of ALS has been precipitated by streamlining their use from a multiple, to one-step technique.
In one recent case report, two techniques were successfully used in deployment of LAMS: one was placed across a gastroenterostomy, bypassing the stricture; another utilized intraluminal placement directly across a stenosis, placing a transmural stent.7 There are prior case reports documenting successful use of LAMS in the treatment of ALS,4 however only one study evaluates the efficacy and safety profile of LAMS in ALS.8 This trial had 18 patients, 100% technical success was reported and abdominal pain as an adverse event was reported in 16.7% of patients.8 Furthermore, patients with LAMS placement were compared
indirectly in this trial to patients with enteroscopyassisted luminal stenting, and patients with LAMS placement required fewer repeat interventions in this comparison.8
There is little in the literature regarding chronic ALS resulting in both acute pancreatitis and acute cholangitis. Prompt diagnosis of the underlying etiology precipitating ALS is crucial, as the landscape of management options is under evolving and under active research. CT of the abdomen remains the gold standard for the diagnosis of ALS, which is a post-surgical complication of multiple surgeries including Billroth II, or Rouxen-Y reconstructions, and Whipple procedures. The advent of LAMS as an endoscopic intervention in the treatment of ALS is promising, but longitudinal studies are needed to better understand the benefits and risk profile.
- Aoki, M., Saka, M., Morita, S., Fukagawa, T. and Katai, H., 2010. Afferent Loop Obstruction After Distal Gastrectomy with Roux-en-Y Reconstruction. World Journal of Surgery, 34(10), pp.2389-2392.
- Benallal, D., Hoibian, S., Caillol, F., Bories, E., Presenti, C., Ratone, J. and Giovannini, M., 2018. EUS–guided gastroenterostomy for afferent loop syndrome treatment stent. Endoscopic Ultrasound, 7(6), p.418.
- Grotewiel, R. and Cindass, R., 2022. Afferent Loop Syndrome. [online] Ncbi.nlm.nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK546609/ [Accessed 1 March 2022].
- Monino, L., Barthet, M. and Gonzalez, J., 2019. Endoscopic ultrasound-guided management of malignant afferent loop syndrome after gastric bypass: from diagnosis to therapy. Endoscopy, 52(03), pp.E84-E85.
- RK, G. and R, C., 2022. Afferent Loop Syndrome. [online] PubMed. Available at: [Accessed 1 March 2022].
- Blouhos, K., 2015. Management of afferent loop obstruction: Reoperation or endoscopic and percutaneous interventions. World Journal of Gastrointestinal Surgery, 7(9), p.190.
- DuBroff, J., McDonough, S. and Adler, D., 2020. Afferent Limb Syndrome Treated via Lumen Apposing Metal Stents: Report of Two Different Approaches in Two Patients – Practical Gastro. [online] Available at: [Accessed 1 March 2022].
- Brewer Gutierrez, O., Irani, S., Ngamruengphong, S., Aridi, H., Kunda, R., Siddiqui, A., Dollhopf, M., Nieto, J., Chen, Y., Sahar, N., Bukhari, M., Sanaei, O., Canto, M., Singh, V., Kozarek, R. and Khashab, M., 2018. Endoscopic ultrasound-guided entero-enterostomy for the treatment of afferent loop syndrome: a multicenter experience. Endoscopy, 50(09), pp.891895