Gastric Outlet Obstruction: Symptoms, Causes, Diagnosis, and Treatment
Clinical Presentation
Gastric outlet obstruction presents with a characteristic triad: postprandial vomiting, epigastric pain, and early satiety, often accompanied by progressive weight loss. 1, 2
Key symptoms to identify:
- Postprandial vomiting (often containing undigested food from meals eaten hours earlier) 2
- Epigastric abdominal pain and distension 2, 3
- Early satiety and inability to tolerate oral intake 1
- Progressive weight loss (particularly suggestive of malignancy) 4, 1
Physical examination findings include:
- Visible epigastric distension (progressive in malignant cases) 3
- Palpable epigastric mass (indicates possible gastric malignancy) 3
- Signs of dehydration (dry mucous membranes, poor skin turgor, sunken eyes) 3
- Succussion splash on auscultation 3
Causes: The Paradigm Shift
Malignancy now accounts for approximately 60% of gastric outlet obstruction cases in adults, representing a dramatic shift from the historical predominance of peptic ulcer disease. 4
Malignant Causes (Most Common)
- Gastric adenocarcinoma (particularly antral tumors) - accounts for ~15% of all cases 1
- Pancreatic cancer (head of pancreas causing duodenal compression or invasion) - one of the two most frequent malignant causes 1, 5
- Peritoneal carcinomatosis from various primary malignancies 4
- Gastric lymphoma (requires tissue diagnosis to differentiate from adenocarcinoma) 4, 1
- Duodenal or ampullary neoplasms 4, 1
Benign Causes (Now Less Common)
- Peptic ulcer disease with cicatrizing chronic duodenal ulcer - historically the most common cause but dramatically decreased with widespread H2 blocker and proton pump inhibitor use 4, 2
- Crohn's disease with stricture formation 4
- Corrosive ingestion 6
Critical Differential: Functional vs. Mechanical
Gastroparesis and adynamic ileus must be excluded as they mimic mechanical obstruction but require entirely different management. 4
Diagnostic Workup
Initial Laboratory Assessment
- Complete blood count (assess for anemia and leukocytosis) 1
- Comprehensive metabolic panel (electrolyte abnormalities, particularly hypochloremic hypokalemic metabolic alkalosis from vomiting, and renal function) 1
- Serum bicarbonate, arterial pH, and lactate (to exclude intestinal ischemia) 1
Imaging: CT Scan is Essential
CT abdomen and pelvis with IV contrast and neutral oral contrast has >90% diagnostic accuracy and is the primary imaging modality. 3, 1
CT scan determines:
- Location and extent of obstruction 1
- Underlying cause (mass, stricture, extrinsic compression) 1
- Presence of metastatic disease 1
- Assessment of resectability 1
Endoscopy is Mandatory
Upper endoscopy must be performed to visualize the obstruction, obtain tissue diagnosis via multiple biopsies, and assess feasibility of endoscopic intervention. 1, 7
Treatment Algorithm Based on Etiology and Prognosis
For Resectable Malignant Disease
Surgical resection is the treatment of choice when curative resection is feasible, with neoadjuvant chemotherapy considered for locally advanced but potentially resectable disease. 1
For Unresectable/Metastatic Malignant Disease
Treatment selection depends critically on life expectancy and surgical fitness:
Life Expectancy >2 Months AND Surgically Fit
Surgical gastrojejunostomy (preferably laparoscopic) provides more durable palliation than stenting. 1, 5
- Laparoscopic gastrojejunostomy with or without jejunostomy tube is preferred 5
- Provides sustained symptom relief for patients with longer prognosis 5
- In pancreatic cancer patients found unresectable at laparotomy, prophylactic gastrojejunostomy significantly decreases late obstruction (only 20% develop obstruction without prophylactic bypass) 5
Life Expectancy <2 Months OR Poor Surgical Candidates
Endoscopic self-expanding metal stent (SEMS) placement allows faster resumption of oral intake and shorter hospital stays. 1, 5, 8
- Stent placement is safe, effective, and minimally invasive 5
- Particularly appropriate for patients with limited life expectancy or poor performance status 5
Contraindications to stenting include multiple luminal obstructions or severely impaired gastric motility - consider venting gastrostomy instead. 1, 5
For Benign Disease (Peptic Ulcer)
Endoscopic balloon dilation combined with aggressive acid suppression and H. pylori eradication provides sustained relief in ~65% of patients. 7, 2
- Multiple dilation sessions may be required 7
- Surgery reserved only for endoscopic treatment failures due to significant morbidity and mortality 7
- Proton pump inhibitors and H. pylori eradication are essential adjuncts 2
Critical Management Pitfalls
Severe uncontrolled pain after gastric stent placement requires immediate endoscopic stent removal. 5, 1
Drain ascites before venting gastrostomy placement to reduce infectious complications. 1
Poor nutritional status, ascites, and poor functional status predict surgical gastrojejunostomy failure. 1
Do not use prokinetic antiemetics (like metoclopramide) in complete obstruction - they increase gastrointestinal motility and worsen symptoms; however, they may benefit incomplete obstruction. 5
Pharmacologic Symptom Management for Non-Surgical Candidates
When invasive procedures are not options or as adjuncts 5:
- Octreotide 150-300 mcg subcutaneously twice daily (high efficacy and tolerability, consider early) 5
- Corticosteroids (dexamethasone up to 60 mg/day; discontinue if no improvement in 3-5 days) 5
- Anticholinergics (scopolamine, hyoscyamine, glycopyrrolate) 5
- Opioids for pain control 5
- Intravenous or subcutaneous fluids if evidence of dehydration 5
Nasogastric tube drainage should be considered only on a limited trial basis if other measures fail, as it is uncomfortable and increases aspiration risk. 5