Gastric Bypass Risks & Complications

Surgical complications after gastric bypass surgery, though they are rare, can be divided in to: intra-operative, post-operative and late complications. The former generally is of particular concern for most patients because they can affect the patients overall quality of life. Here is a quick overview of possible complications.

Dumping syndrome After Gastric Bypass

Dumping syndrome is a common side effect after Roux-en-Y Gastric Bypass surgery. About 85% of gastric bypass patients will experience dumping syndrome at some point after surgery. Symptoms can range from mild to severe. It usually occurs due to poor food choices and is commonly related to ingestion of refined sugars, though it can also occur with dairy products, fats and fried foods. These foods empty rapidly from the gastric pouch into the small intestine which triggers a cascade of physiologic events. Dumping syndrome has a two-fold effect, both good and bad. A beneficial effect is that after eating the less healthy foods that can trigger dumping syndrome, they are usually avoided from that point on. The bad news is that patients usually feel awful. There are two types of dumping syndrome:

Early dumping

Early dumping occurs 30 to 60 minutes after eating and can last up to 60 minutes. Symptoms include sweating, flushing, lightheadedness, tachycardia, palpitations, sensation to lie down immediately, upper abdominal fullness, nausea, diarrhea, cramping and active audible bowel sounds. Symptoms are the result of rapid emptying of carbohydrates from the gastric pouch into the small intestine that triggers the release of hormones that affect blood pressure, heart rate, skin flushing and intestinal transit.

Late dumping

Late dumping occurs 1 to 3 hours after eating. Symptoms are related to reactive hypoglycemia (low blood sugar) which include sweating, shakiness, loss of concentration, hunger and fainting. Symptoms are related to increased blood insulin levels after oral glucose (sugar) with subsequent hypoglycemia.

The diagnosis of dumping syndrome is primarily made by obtaining a history of the presence of classic symptoms related to food intake. Management can be relatively straightforward: avoidance of refined sugars, or other foods that may be associated with the syndrome, usually takes care of the issue. If symptoms persist in spite of the above dietary measures, the patient may be treated with a small amount of sugar (such as one-half glass of fruit juice) one hour after a meal.

Bowel Function Changes Gastric bypass surgery can have some effect on bowel function. The effects can be acute and short-lived, or chronic and more problematic.

Diarrhea is not common but can occur as a result of several factors. Diet is a major influence on bowel movements. Reducing the amount of fat can have a beneficial effect on the number and quality of bowel movements. Some patients may also manifest previously unknown lactose intolerance after surgery. Management of chronic diarrhea involves detecting triggering food items and avoiding them. Many patients benefit from pro-biotics and medications such as Imodium. It is also reasonable to give the bowel time to adapt, so that absorption increases which in turn will allow the situation to improve.

Constipation After Gastric Bypass

Constipation is more common but because it is usually due to reduced intake of water it may simply be corrected by diligent attention to water intake and the addition of fiber products. It is important to recognize that some bowel function problems are not related to the bariatric surgery, and relationship should not be automatically assumed. Therefore, a recent change in bowel function that is not readily attributed to the bariatric operation or that is not easily corrected requires further diagnostic measures for complete evaluation as other etiologies need to be considered.

Avoiding Vomiting & Dysphagia After Gastric Bypass

Dysphagia is a medical term for difficulty swallowing. In gastric Bypass surgery a small gastric pouch is created at the upper normal stomach. This small pouch (les tan 1 ounce immediately following surgery) results in a significant reduction of food that can be consumed in one sitting. Disphagia is caused by eating too fast or not chewing well enough. Therefore foods backs up in to the esophagus and causes chest pressure. It is important to spot eating and drinking if the patient has dysphagia otherwise regurgitation and vomiting may ensue. Dysphagia can be avoided by following eating guidelines: Chewing well, small bites, pausing between swallows, not mixing solids and liquids and stopping when full. If dysphagia persists after 4 to 6 months after surgery or worsens, gastric stoma stricture has to be ruled out.

Gastric stricture

Gastric stricture is not uncommon after gastric bypass and results from the size of the opening between the gastric pouch and the intestinal limb attached to it (anastomosis) and the resulting swelling and scaring process that follows. Patients with a stricture can progress from difficulty tolerating solid food to complete intolerance of solids and in rare cases liquids. Endoscopy is the preferred evaluation method because it can diagnose and treat at the same time with endoscopic balloon dilatation of the narrowed anastomosis.


Ulcers between the stomach pouch and the intestine are called marginal ulcers and they can be a source of upper abdominal pain, blood loss and iron deficiency. The most likely causes are tension of the anastomosis, retained acid producing tissues in the gastric pouch, and the presence of H. Pylori bacteria in the pouch. Some non-steroidal anti-inflammatory medications such as aspirin may cause or exacerbate ulcers. Endoscopy is the preferred evaluation method because it can diagnose and treat at the same time.

Intestinal hernias and obstruction are usually related to the scaring process (adhesions) or the rearrangements to the intestinal tract performed during the procedure that create spaces in which the small bowel can move into. This in turn can create a blockage or obstruction that can be partial to total. This is not a frequent complication, but when it happens it is resolved quickly by laparoscopic surgery. The most common symptom is periumbilical pain or cramping. Abdominal wall hernias can also occur in surgery incision sites, and in most cases they create minimal discomfort. If this is the case, we prefer to wait until substantial and stable weight loss has occurred. If an incision site hernia is symptomatic, the appropriate time to correct this will be indicated by the treating surgeon.

Protein Deficient Meals After Gastric Bypass Surgery

Protein depletion remains the most important macronutrient deficiency. Protein deficient meals after gastric bypass surgery are common. This is noted 3 to 6 months after the surgery and it's largely attributed to the development of intolerance to protein rich foods. Fortunately most food intolerances diminish by one year after the surgery. Even patients who experienced complete resolution of food intolerances often do not meet the daily recommended intake of protein. Regular assessment of protein intake should be performed, and supplementation with protein modular sources should be pursued if protein intake remains below 60 grams daily.

Bone disease

Bone disease is insidious and results from a decreased intake of calcium rich foods, bypass of the duodenum and proximal jejunum where calcium is preferably absorbed, and mal-absorption of vitamin D. Not supplementing calcium and vitamin D can lead to loss of bone mass. Increased awareness, following dietary supplementation guidelines and monitoring are important to prevent bone disease.

Over the years, many weight loss surgery Tijuana patients have visited Obesity Control Center to receive top-quality care and excellent surgical results. Dr. Ortiz and Dr. Martinez are experienced bariatric surgeons who take pride in helping patients achieve their health goals. Some of the patients they treat include Lap Band, gastric bypass and gastric sleeve Mexico patients.


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