Afferent Loop Syndrome Treatment & Management

Updated: May 15, 2019
  • Author: Suresh Kumar Nayudu, MD; Chief Editor: BS Anand, MD  more...
  • Print

Medical Therapy

Acute ALS

In patients with acute ALS, a favorable outcome is correlated with an expedient diagnosis and corrective surgery. Medical therapy has no role, although nasogastric tube drainage may temporarily provide relief of symptoms while patients are resuscitated before surgery. Kim et al reported a case of a 67-year-old patient with ALS and coexisting acute pancreatitis who was not considered to be an ideal surgical candidate. [55] As a result, the patient was treated with an endoscopically placed nasogastric/enteric tube, with excellent relief of symptoms.

Chronic ALS

Patients with chronic ALS can be severely malnourished and anemic. These patients may benefit from preoperative specialized nutritional support or transfusion before undergoing corrective surgery. However, surgery should not be delayed if symptoms and signs consistent with complete obstruction develop.


Surgical Therapy

The treatment of ALS is surgical. Conservative measures can be temporarily used to resuscitate the patient, but the definitive treatment is corrective surgery. When ALS is caused by recurrent or unresectable malignancies, successful palliation is frequently accomplished using interventional radiologic techniques. Several references are provided in the preceding section.

Surgical correction is accomplished by deconstructing the Billroth II gastrojejunostomy and restoring gastrointestinal continuity with an alternate method. Several procedures have been described, but the two predominant operations are Billroth I gastroduodenostomy and Roux-en-Y gastrojejunostomy.

Interestingly, based on their retrospective study of 19 patients with postgastrectomy syndromes of whom 3 had ALS, Borrelli et al reported that a significant proportion of patients required minor surgical intervention. [56] The authors raised the question that in selected patients, laparoscopic surgery may be considered.

Vettoretto and associates reported a case of afferent loop obstruction caused by an adhesive band following distal gastrectomy and reconstruction for gastric cancer. [57] The authors performed diagnostic laparoscopy and laparoscopic lysis of adhesions, resulting in resolution of the ALS.

Aimoto and colleagues described two cases of malignant ALS in patients who had undergone pancreaticoduodenectomy. [58] In both patients, recurrence of the pancreatic cancer was found at laparotomy. Bypass procedures were performed in each case to achieve palliation.

Korean investigators have suggested that placement of partially covered self-expandable dual stents may be effective in patients who develop afferent loop syndrome following different types of surgical procedures. [59] The investigators retrospectively evaluated data from 13 consecutive patients who underwent placement of dual-stents (15 dual stents, 1 fully covered esophageal stent) via either the percutaneous transhepatic biliary drainage tract (n = 9) or the perioral route (n = 4). The stent placements were technically successful in all 13 patients, with 12 of 13 achieving postprocedure normalization of their blood tests and bowel decompression. The single patient that showed no change following stent placement subsequently underwent surgical jejunojejunostomy. [59]


Early consultation with a surgeon is mandatory.


Indications and Contraindications


Surgery is indicated in most cases of ALS. Recently, successful management of ALS in cases of advanced or recurrent malignancy using image-directed percutaneous drainage techniques has been reported. The fact remains that ALS is a purely mechanical complication consisting of varying degrees of obstruction of the afferent loop and will not resolve without surgery or other interventional techniques.


Surgical correction of ALS has no absolute contraindications. Relative contraindications include severe debilitation or extensive intra-abdominal malignancies. Patients with these conditions can be effectively treated with nonsurgical drainage procedures as described in Treatment.


Preoperative Details

The patient is properly identified. The patient (or a legal representative) is counseled about the operation and signs the informed consent documents.

Intravenous access is established, and intravenous fluid resuscitation is begun. A nasogastric tube is placed to decompress the stomach, and preoperative antibiotics are administered.


Intraoperative Details

Billroth I gastroduodenostomy

This procedure creates a direct anastomosis between the stomach and duodenum. It is the most physiologic procedure and is therefore the operation of choice. Several factors may preclude its use, including previous subtotal gastrectomy or extensive scarring around the duodenum. In these situations, the surgeon may be unable to gain enough mobility on the stomach and duodenum to create an anastomosis without excessive tension.

Roux-en-Y gastrojejunostomy

For a Roux-en-Y gastrojejunostomy, the jejunum is divided several centimeters distal to the ligament of Treitz. The proximal portion of the distal jejunal segment is anastomosed to the stomach. The distal end of the Roux limb is anastomosed to the distal jejunal segment. This jejunojejunostomy is created approximately 40 cm downstream from the gastrojejunostomy in order to minimize the possibility of developing alkaline (bile) reflux gastritis.

Van Stiegmann and Goff described a variant of this operation in which the jejunum is not divided. [60] This is the so-called uncut Roux-en-Y gastrojejunostomy. The procedure was developed to avoid Roux stasis syndrome, which was thought to be caused by interruption of the jejunal intestinal pacesetting potentials.

In an uncut Roux procedure, a loop gastrojejunostomy is fashioned. The afferent limb of this loop is occluded—but not divided—by a staple line. A jejunojejunostomy is made between the afferent and efferent jejunal limbs just proximal to the occluding staple line. This operation has not gained wide acceptance, partially because of the problem of dehiscence of the occluding staple line, as reported by Mulholland and colleagues. [61]

Other surgical procedures

The following remedial operations have also been used:

  • Revision of the gastrojejunostomy

  • Side-to-side enteroenterostomy

  • Jejunal segment interposition (between the gastric remnant and duodenum to create a modified Billroth I–type anastomosis)

  • Resection of the redundant portion of the afferent jejunal loop

Poor candidacy for surgery

In patients who are poor surgical candidates, such as those with disseminated unresectable malignancies, percutaneous transhepatic biliary or direct transperitoneal catheter placement and drainage can be performed for palliation of afferent loop syndrome. [48, 62, 63, 64, 65, 66] However, percutaneous transhepatic biliary drainage of an obstructed afferent loop may precipitate cholangitis and septic shock as a result of increased intrabiliary pressure and reflux of the infected duodenal contents into the bile duct. [48, 66, 67] An additional catheter should be placed into the bile duct in cases of biliary stasis. [66]


Postoperative Details

Intravenous fluids

Resuscitative and maintenance intravenous fluids are provided postoperatively. These are usually administered as a balanced salt solution (eg, lactated Ringer solution). If the patient has hypochloremic metabolic alkalosis due to nasogastric suctioning or other causes, normal saline can be substituted. Intravenous fluid support is continued until the patient successfully resumes oral intake.


Early activity, including arising from the bed to a chair and ambulating frequently, is encouraged.

Diet and nutrition

Patients are kept nil per os (NPO) for varying durations depending on the preference of the operating surgeon. Because correction of ALS entails reoperative gastric and small bowel surgery, many surgeons choose to advance patients' diets slowly.

Following nasogastric tube removal, patients can be started on liquids and advanced to a full diet as tolerated. Postgastrectomy diet counseling by a registered dietitian is helpful. Patients may find that they tolerate 5-6 smaller feedings per day better than the traditional 3 meals.

Depending on the patient's preoperative nutritional status, a period of specialized nutritional support might be warranted. This can range from enteral tube feedings to peripheral hyperalimentation to total parenteral nutrition. In addition, multivitamin and iron supplementation may be indicated.


A nasogastric tube is typically left in place postoperatively. Ensuring that the tube functions continuously and remains unclogged is crucial. Criteria for removal of the nasogastric tube include diminishing output and return of bowel function as manifested by bowel sounds or the passage of flatus.

A Foley catheter remains in place in the early postoperative period to monitor the hydration status and to serve as a guide for fluid resuscitation. Once the patient is stabilized and no further major fluid shifts occur, the catheter can be removed.

Pulmonary toilet

Instruct patients to cough and to take frequent deep breaths. The incentive spirometer is an important adjunct and should be used every 1-2 hours while the patient is awake. Early mobilization of the patient assists with maintaining good pulmonary toilet.


Vital signs are monitored per protocol. Intake and output records are kept to monitor intravenous fluids given, oral intake, and urine and nasogastric tube outputs. Pulse oximetry may be used to measure oxygen saturation.


Unless bowel perforation has occurred, a single dose of antibiotics as prophylaxis against wound infection usually suffices. Patients with abdominal catastrophes, such as bowel perforation or infarction, require a full course of antibiotic therapy aimed at gut flora.

Pain control

An epidural catheter can be placed by anesthesia personnel for postoperative pain control. Alternately, a patient-controlled anesthesia regimen can be ordered.

Deep venous thrombosis prophylaxis

Prophylaxis against deep venous thrombosis is crucial because deep venous thrombosis and pulmonary embolism are significant sources of postoperative morbidity and mortality. Available modalities include subcutaneous heparin, subcutaneous fractionated heparin preparations, and sequential compression stockings.

Aspiration precautions

The head of the bed can be kept elevated at 30-45° or sometimes higher in elderly patients or during sleep.



The operating surgeon should monitor patients to ensure that wound healing is complete and that no signs of infection arise. Patients are questioned about eating and elimination habits and are weighed to ensure that proper nutritional status is maintained.

Gastric emptying

Patients with persistent delayed gastric emptying or gastroparesis may report early satiety, epigastric fullness, nausea, or vomiting. Abdominal pain may be present. According to Gustavsson and associates, up to 30% of patients undergoing revision with a Roux-en-Y gastrojejunostomy develop one or more of these symptoms. [7] This has been termed Roux stasis syndrome.

The workup for Roux stasis syndrome or simple gastric atony begins with upper gastrointestinal contrast studies to exclude a source of mechanical obstruction. Upper endoscopy can help determine if the patient has a mechanical problem (eg, anastomotic stricture). Radionuclide imaging is useful to confirm the diagnosis.

Conversely, patients may develop signs and symptoms of dumping syndrome following corrective surgery. While the diagnosis is primarily made based on clinical findings, radionuclide imaging helps confirm the diagnosis by demonstrating rapid gastric emptying.

Treating altered gastric emptying

For delayed gastric emptying, agents such as erythromycin and metoclopramide have been used with varying degrees of success. Patients with dumping syndrome can be given a low-carbohydrate diet and are instructed to limit fluid intake during meals. A somatostatin analog administered before meals has been successful in controlling dumping-related symptoms.


CBC count and RBC characteristics are monitored. Patients with loss of parietal cell mass and bypass of the proximal small bowel may require supplemental iron and vitamin B-12.