What Is Gastric Outlet Obstruction?
Gastric outlet obstruction (GOO) is a condition in which a blockage prevents food and digestive contents from passing normally from the stomach into the small intestine. The blockage may occur in the lower part of the stomach, the pylorus (the opening between the stomach and small intestine), or the first part of the small intestine, called the duodenum.
Gastric outlet obstruction can develop for a number of reasons. Some causes are benign, meaning they are not cancerous, while others are related to cancer or other serious conditions.
Causes of Gastric Outlet Obstruction
The causes of gastric outlet obstruction can generally be divided into benign and malignant (cancerous) conditions.
Benign Causes
Common benign causes include:
- Peptic ulcer disease, which can cause inflammation and scarring that narrows the pylorus
- Gastric polyps that block the passage of stomach contents
- Pyloric stenosis, particularly in infants
- Crohn's disease affecting the stomach or duodenum
- Pancreatitis causing inflammation or narrowing near the stomach outlet
- Bezoars or other foreign material that becomes trapped in the stomach
Malignant Causes
Cancer-related causes may include:
- Gastric (stomach) cancer
- Pancreatic cancer, particularly tumors involving the head of the pancreas
- Gastrointestinal stromal tumors (GIST)
- Lymphoma
How Does Gastric Outlet Obstruction Affect the Body?
When the gastric outlet becomes blocked, food and digestive fluids cannot pass normally into the small intestine. As a result, these contents can build up in the stomach, causing it to become enlarged over time.
This buildup can lead to nausea, vomiting, abdominal discomfort, and a feeling of fullness after eating only a small amount. Prolonged vomiting can also cause dehydration and changes in the body's electrolyte levels, including low potassium and chloride levels.
Symptoms of Gastric Outlet Obstruction
Symptoms can vary depending on the cause and severity of the obstruction. Common symptoms include:
- Persistent nausea and vomiting, often involving undigested food
- Feeling full quickly when eating
- Abdominal bloating or fullness
- Upper abdominal discomfort or pain
- Unintentional weight loss
- Dehydration caused by ongoing vomiting
- Weakness or fatigue related to fluid and electrolyte loss
Signs of Gastric Outlet Obstruction
During a physical examination, a healthcare provider may look for signs such as:
- Visible movement of the stomach through the abdominal wall in some cases
- A characteristic "splashing" sound from fluid and air in an enlarged stomach
- Tenderness or, less commonly, a palpable mass in the upper abdomen
- Significant weight loss or muscle wasting in longstanding cases
How Is Gastric Outlet Obstruction Diagnosed?
Your healthcare provider will consider your symptoms, medical history, and physical examination findings when evaluating for gastric outlet obstruction. Several tests may be used to identify the blockage and determine its underlying cause.
Blood Tests
Blood tests may help identify dehydration and electrolyte abnormalities caused by prolonged vomiting. These may include low levels of potassium and chloride and changes associated with metabolic alkalosis.
Imaging and Other Tests
Depending on the suspected cause, diagnostic testing may include:
- Upper GI endoscopy: Allows the physician to directly examine the stomach and gastric outlet, identify a blockage, and obtain a biopsy when needed.
- CT scan of the abdomen: Can help identify blockages, inflammation, tumors, and other problems outside the stomach that may be causing the obstruction.
- Abdominal X-ray: May show an enlarged stomach and other findings associated with obstruction.
- Upper GI series or barium study: Uses contrast material to evaluate how contents move through the stomach and identify areas of narrowing or obstruction.
Treatment for Gastric Outlet Obstruction
Treatment depends on what is causing the obstruction, how severe it is, and your overall health. The initial goal is usually to relieve pressure in the stomach, restore hydration, and correct any electrolyte abnormalities.
Initial Treatment
Initial supportive treatment may include:
- Temporarily avoiding food and liquids by mouth
- A nasogastric tube to remove fluid and air from the stomach
- Intravenous fluids to treat dehydration
- Replacement of electrolytes when needed
- Medications such as proton pump inhibitors (PPIs) when appropriate
Once the patient is stabilized, treatment is directed at the underlying cause of the obstruction.
Treatment for Benign Causes
Depending on the cause, treatment may include:
- Endoscopic balloon dilation: A small balloon is used during endoscopy to widen a narrowed area, particularly in certain ulcer-related strictures.
- Endoscopic treatment: Some obstructions caused by polyps or other lesions may be treated during endoscopy.
- Surgery: Surgical procedures may be recommended when the obstruction cannot be adequately treated with less invasive approaches.
Treatment for Malignant Causes
When cancer is responsible for the obstruction, treatment depends on the type and stage of cancer and the patient's overall health. Options may include:
- Endoscopic stent placement: A stent can help keep the narrowed passage open and may provide relief of symptoms in appropriate patients.
- Surgical bypass: A gastrojejunostomy creates a new pathway for food to pass from the stomach into the small intestine, bypassing the obstruction.
- Cancer-directed treatment: Chemotherapy, radiation therapy, surgery, or other treatments may be recommended depending on the specific cancer.
What Is the Prognosis for Gastric Outlet Obstruction?
The outlook for gastric outlet obstruction depends largely on its underlying cause. Many benign causes can be successfully treated once the blockage is identified. When gastric outlet obstruction is caused by cancer, the prognosis depends on the type of cancer, its stage, and whether it can be treated or removed.
Early evaluation is important because ongoing vomiting and difficulty eating can lead to dehydration, nutritional problems, and electrolyte imbalances. Identifying the cause of the obstruction allows your healthcare team to develop the most appropriate treatment plan.
