Gastric outlet obstruction: Difference between revisions
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Benign: 37 percent of cases, includes peptic disease | Benign: 37 percent of cases, includes peptic disease | ||
Malignant: 53 percent of cases | Malignant: 53 percent of cases | ||
Location of the stomach: Left upper quadrant of the abdomen | Location of the stomach: Left upper quadrant of the abdomen | ||
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Pancreatic cancer is the most common malignant cause of GOO | Pancreatic cancer is the most common malignant cause of GOO | ||
Incidence of GOO in cases with pancreatic cancer is approximately 20%. | Incidence of GOO in cases with pancreatic cancer is approximately 20%. | ||
==Historical Perspective== | ==Historical Perspective== | ||
Revision as of 19:53, 23 January 2018
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:
Overview
GASTRIC OUTLET OBSTRUCTION: Pyloric obstruction
Gastric outlet obstruction (GOO,) is the result of any pathology that provides mechanical obstruction to emptying of gastric contents. Two important causes of GOO include: Benign: 37 percent of cases, includes peptic disease Malignant: 53 percent of cases
Location of the stomach: Left upper quadrant of the abdomen Parts of the stomach: Cardia Body Antrum Pylorus
Etiology Benign causes:
Acquired: PUD: 5 % cases ( most commonly affecting pylorus and initial part of the duodenum): Acute- edema and inflammation Chronic- due to intrinsic obstruction as a result of fibrosis and scar formation Gastric polyps Caustic ingestion Obstruction by gallstones (Bouveret syndrome) Complication of acute pancreatitis: pancreatic pseudocyst formation bezoars
Congenital: Pyloric stenosis: most common cause in children more common in boys> girls due to hypertrophy of pyloric circular smooth muscles Congenital duodenal webs
Malignant causes- Malignancies involving neighbouring structures: Pancreas: Pancreatic cancer: most common malignancy leading to extrinsic obstruction of the pylorus, occurs in one fifth of patients Stomach: Gastric cancer Duodenum: Duodenal cancer Ampullary cancer Bile duct: Cholangiocarcinomas Secondary metastases to the gastric outlet by other primaries Epidemiology Incidence: less than 5% in patients with PUD. PUD is the most common benign cause of GOO. In the US, five percent PUD cases require an average of 2000 surgeries annually. Pancreatic cancer is the most common malignant cause of GOO Incidence of GOO in cases with pancreatic cancer is approximately 20%.
Historical Perspective
Classification
Pathophysiology
Gastric Outlet Obstruction (GOO) may be caused by intrinsic or extrinsic pathologies that involve the antrum and the pylorus.
- Intrinsic obstruction:
- Infiltration, scar formation or inflammation of these structures leads to intrinsic obstruction, resulting in GOO.
- Extrinsic obstruction:
- Malignancy of any of these neighboring structures may lead to extrinsic obstruction of the gastric outlet:
Causes
Differentiating Gastric outlet obstruction from Other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications, and Prognosis
Natural History
Complications
Prognosis
Diagnosis
History and Symptoms
The following history is relevant in patients with GOO:
- History of Peptic Ulcer Disease (PUD) or its complications
- Indigestion
- Anorexia
- Nausea, vomiting
- Epigastric pain
- History of abdominal pain and weight loss in cases of pancreatic cancer
Clinical presentation:
Early stages:
- Nausea
- Vomiting: characteristic feature
- Intermittent
- Occurs one hour after ingestion
- Non bilious
- Contains undigested particles of food
- Patient has intolerance to solids, followed by liquids
- Dehydration
- Electrolyte abnormalities
Late stages:
- Weight loss
- Malnutrition: more pronounced in patients with malignancy
- Abdominal distension
- Features of incomplete obstruction
- Gastric retention: presenting as early satiety
- Bloating
- Fullness of epigastrium
- Aspiration pneumonia: due to dilatation of stomach, loss of contractility and accumulation of undigested food contents
Physical Examination
In the late stages of GOO, patients may develop signs of malnutrition and incomplete obstruction.
- Weight loss
- Signs of chronic dehydration
- Malnutrition: more pronounced in patients with malignancy
- Abdominal distension
- Features of incomplete obstruction
- Aspiration pneumonia
- Abdominal examination:
- Abdominal mass may be present
- Location: Epigastrium, Left upper quadrant of the abdomen
- Palpation: Fullness of epigastrium
- Percussion: Tympanitic mass
Laboratory Findings
- Characteristic features due to vomiting:
- Complete Blood Count (CBC): may show anemia
- Electrolyte panel
- Liver function tests: in case of malignancy
- Test for H pylori for diagnosis of PUD
Imaging Findings
Imaging studies such as plain radiographs, contrast upper gastrointestinal (GI) studies and Computed Tomography (CT) with oral contrast may be used for evaluating patients with symptoms of GOO.
Plain radiographs
- Obstruction series includes:
- This helps in the determination of the presence of gastric dilatation.
Contrast upper gastrointestinal (GI) studies (Gastrografin or barium)
- Barium upper GI studies:
- Helps in the determination of site of obstruction
- Helps in the visualization of the gastric silhouette:
- Helps note the following:
- Nuclear gastric emptying study:
- Radionuclide is given orally and its passage is measured over a certain duration.
Computed tomography (CT) with oral contrast
- CT with oral contrast may also be of use in suspected cases with equivocal findings on X Ray and Barium Upper GI studies. CT-guided biopsy may be especially useful in cases of pancreatic cancer.
Other Diagnostic Studies
Endoscopy
- Upper endoscopy may help with:
- Visualization of the gastric outlet
- Biopsy sampling in case of intraluminal pathology
- Endoscopic biopsy helps rule out the presence of malignancy in patients with symptoms of Peptic Ulcer Disease (PUD)
Sodium chloride load test
- Procedure: Patient is infused with 750 mL of sodium chloride solution into the stomach via a nasogastric tube (NGT).
- In case > 400 mL is left in the stomach after half an hour, the diagnosis of GOO may be made.
Needle-guided biopsy
- Helps in the evaluation of patients for metastasis