Afferent Loop Syndrome

Afferent loop syndrome is a complication of several different types of stomach surgery. If you have had or are going to have a procedure called gastrojejunostomy, also known as Billroth II gastrectomy procedure, you should know that afferent loop syndrome can occur after this type of stomach surgery.

During a Biliroth II type of operation, your surgeon will remove or bypass the lower part of your stomach and attach the remaining part of your stomach to a loop of intestine downstream. The area where the stomach and intestine are attached is called the anastomosis. The intestine downstream from the anastomosis is called the efferent limb.

What happens in afferent loop syndrome

After surgery, the bile and pancreatic digestive juices enter the afferent loop All these juices flow downstream and need to pass the anastomosis and enter your digestive system. Afferent loop syndrome occurs when something traps the flow of these juices up to and past the anastomosis.

These are common causes of afferent loop syndrome:

  • An improperly made anastomosis

  • Twisting or kinking of the afferent loop

  • Trapping of the afferent loop secondary to scar tissue in an area near the surgery

  • Scarring from ulceration at the site where the afferent loop joins the stomach

  • Cancer that recurs and blocks the afferent loop

Symptoms of afferent loop syndrome

Symptoms will start to appear when the secretions from the pancreas and bile fill the afferent loop and are unable to pass the anastomosis. The secretions build up in the afferent limb causing pressure. This is especially true after a meal. Afferent loop syndrome can occur anywhere from days to years after surgery. Afferent loop syndrome that occurs soon after surgery—within the first few weeks—is called acute afferent loop syndrome; this usually means the afferent loop is completely obstructed. Afferent loop syndrome that occurs weeks or even years after surgery is called chronic afferent loop syndrome; this usually means there is a partial obstruction.

The most common symptoms are:

  • Abdominal pain, especially in the upper right side of the abdomen

  • Nausea and fullness, especially after eating

  • Sudden and severe vomiting of bilious fluid that occurs when the obstruction of the distended afferent loop is relieved and the afferent loop decompresses its content into the stomach. This relieves the abdominal pain

If you experience these symptoms after stomach surgery, contact your doctor immediately.

Diagnosis and treatment of afferent loop syndrome

Your doctor may suspect afferent loop syndrome if you have symptoms any time after gastrojejunostomy surgery. Although blood tests and basic X-rays can help with the diagnosis, the best tests a CT scan which will show the fluid-filled, swollen afferent loop, or an upper GI endoscopy which will show obstruction of the afferent limb.

Treatment is almost always surgery. In acute afferent loop syndrome, emergency surgery may be necessary to prevent rupture of the loop. The type of surgery will depend on what's causing the actual obstruction. In some cases, the anastomosis may need to be taken apart and redone. If the afferent loop has become scarred and narrowed, it may need to be removed.

To better understand the complications of gastrectomy surgery, ask your doctor to explain all the risks and benefits of the surgery before your procedure. After surgery, carefully follow all your medical team's instructions. And always call your doctor right away if you have any symptoms that could indicate afferent loop syndrome.