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Risks of Gastric Bypass Surgery: Anastomotic Leaking

If you are severely obese and have had trouble losing weight, your doctor may recommend weight loss surgery. Weight loss surgery, also known as bariatric surgery, is an effective way to lose weight and reduce the risk for weight-related problems, such as heart disease, diabetes, high blood pressure, stroke, sleep apnea, and arthritis.

As with any surgery, gastric bypass carries some risks. Complications of surgery include infection, blood clots, and internal bleeding. Another risk is that the anastomosis, the new connection created in your intestines during the bypass surgery, will not fully heal and will leak. Leaking of digestive juices and partially digested food through an anastomosis is one of the most serious complications after bypass surgery.

Gastric bypass overview

Gastric bypass is the most common type of weight-loss surgery. During bypass surgery, a loop of your intestine is cut and brought up and reconnected to an area in your stomach.

Illustration of stomach and biliary system
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Food is then redirected to an area farther down in your digestive system, thereby bypassing the stomach. Because food will now bypass your stomach, your body does not absorb as many calories, and you will feel full much faster after eating.  

Your doctor may suggest this surgery if you have a body mass index (BMI) of 40 or higher or if you have a BMI of 35 or higher along with serious weight-related, health problems. A BMI of more than 40 typically means that you are at least 100 pounds overweight.

Symptoms of anastomotic leaking

Anastomotic leaks occur in 1% to 3% of bypass procedures, depending on the type of surgery. A leak may happen up to a month later, but most develop within 3 days after surgery. Symptoms of an anastomotic leak include:

  • Rapid heart rate

  • Fever

  • Abdominal pain

  • Drainage from a surgical wound

  • Nausea

  • Pain in the shoulder area

  • Low blood pressure

  • Decreased urine output

The more obese you are, the more at risk you are for an anastomotic leak. Other risk factors include being male, having other medical problems besides obesity, and having a history of previous abdominal surgery.

Diagnosis and treatment of anastomotic leaking

The most reliable diagnostic test for anastomotic leaking is a CT scan. This involves putting dye inside the upper digestive area and then taking computer-guided X-rays to see if the dye is leaking through the anastomosis. Even if you have a negative exam but still have symptoms, your doctor may do an emergency operation to look for a leak.

The medical team treating an anastomotic leak will likely take these steps:

  • Give you antibiotics through an IV.

  • Drain any infection caused by the leak, repair the leak, or make a new anastomosis by operating again.

  • Stop all oral feedings. You may be fed through a tube that goes directly into your intestine until the leak has healed.

Risks of anastomotic leaking         

A leaking anastomosis may cause bleeding and infection until it is treated. These leaks are serious and can be life-threatening. Long-term complications may include scarring and narrowing of the anastomosis (where the intestine is sewn into the stomach), known as a stricture. A drainage tract through the skin called a fistula may also develop. Pneumonia is another dangerous complication, because digestive juices can spill into the lungs. 

If you are considering gastric bypass surgery for obesity, discuss the procedure carefully with your doctor. The overall risk of serious complications should be weighed against the risk of continued obesity. Remember that gastric bypass surgery works best when combined with long-term, healthy lifestyle choices involving good nutritional eating habits and regular exercise.