Gastric outlet obstruction
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
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
Benign causes
- Acute- edema and inflammation
- Chronic- due to intrinsic obstruction as a result of fibrosis and scar formation
- PUD: 5% cases (most commonly affecting pylorus and initial part of the duodenum)
- Gastric polyps
- Caustic ingestion
- Obstruction by gallstones (Bouveret syndrome)
- Complication of acute pancreatitis: pancreatic pseudocyst formation
- Bezoars
Congenital:[1]
- Pyloric stenosis:
- most common cause in children
- more common in boys>girls
- due to hypertrophy of pyloric circular smooth muscles
- Congenital duodenal webs
- Annular pancreas
Malignant causes
- Malignancies involving neighboring structures:[2][3][4][5][6][7][5]
- Pancreas: Pancreatic cancer
- Most common malignancy leading to extrinsic obstruction of the pylorus
- Occurence in one fifth of patients
- Stomach: Gastric cancer
- Duodenum: Duodenal cancer, ampullary cancer
- Bile duct: Cholangiocarcinoma
- Secondary metastasis to the gastric outlet by other primaries
- Pancreas: Pancreatic cancer
Differentiating Gastric outlet obstruction from Other Diseases
Epidemiology and Demographics
- 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.
- The incidence of GOO in cases with pancreatic cancer is approximately 20%.
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:[8][9]
- 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:
- 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
- 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:[14]
- 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:[15][16]
- 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
Treatment
Medical Therapy
Surgery
Prevention
References
- ↑ Kreel L, Ellis H (1965). "Pyloric stenosis in adults: A clinical and radiological study of 100 consecutive patients". Gut. 6 (3): 253–61. PMC 1552275. PMID 18668780.
- ↑ Johnson CD (1995). "Gastric outlet obstruction malignant until proved otherwise". Am. J. Gastroenterol. 90 (10): 1740. PMID 7572886.
- ↑ 3.0 3.1 Shone DN, Nikoomanesh P, Smith-Meek MM, Bender JS (1995). "Malignancy is the most common cause of gastric outlet obstruction in the era of H2 blockers". Am. J. Gastroenterol. 90 (10): 1769–70. PMID 7572891.
- ↑ 4.0 4.1 Johnson CD, Ellis H (1990). "Gastric outlet obstruction now predicts malignancy". Br J Surg. 77 (9): 1023–4. PMID 2207566.
- ↑ 5.0 5.1 Tendler DA (2002). "Malignant gastric outlet obstruction: bridging another divide". Am. J. Gastroenterol. 97 (1): 4–6. doi:10.1111/j.1572-0241.2002.05391.x. PMID 11808968.
- ↑ Jeong HY, Yang HW, Seo SW, Seong JK, Na BK, Lee BS, Song GS, Park HS, Lee HY (2002). "Adenocarcinoma arising from an ectopic pancreas in the stomach". Endoscopy. 34 (12): 1014–7. doi:10.1055/s-2002-35836. PMID 12471549.
- ↑ Emerson L, Layfield LJ, Rohr LR, Dayton MT (2004). "Adenocarcinoma arising in association with gastric heterotopic pancreas: A case report and review of the literature". J Surg Oncol. 87 (1): 53–7. doi:10.1002/jso.20087. PMID 15221920.
- ↑ Green ST, Drury JK, McCallion J, Erwin L (1987). "Carcinoid tumour presenting as recurrent gastric outlet obstruction: a case of long-term survival". Scott Med J. 32 (2): 54–5. doi:10.1177/003693308703200212. PMID 3602991.
- ↑ Chowdhury A, Dhali GK, Banerjee PK (1996). "Etiology of gastric outlet obstruction". Am. J. Gastroenterol. 91 (8): 1679. PMID 8759707.
- ↑ Urayama S, Kozarek R, Ball T, Brandabur J, Traverso L, Ryan J, Wechter D (1995). "Presentation and treatment of annular pancreas in an adult population". Am. J. Gastroenterol. 90 (6): 995–9. PMID 7771437.
- ↑ Miner PB, Harri JE, McPhee MS (1982). "Intermittent gastric outlet obstruction from a pedunculated gastric polyp". Gastrointest. Endosc. 28 (3): 219–20. PMID 7129059.
- ↑ Cappell MS, Davis M (2006). "Characterization of Bouveret's syndrome: a comprehensive review of 128 cases". Am. J. Gastroenterol. 101 (9): 2139–46. doi:10.1111/j.1572-0241.2006.00645.x. PMID 16817848.
- ↑ Dubois A, Price SF, Castell DO (1978). "Gastric retention in peptic ulcer disease. A reappraisal". Am J Dig Dis. 23 (11): 993–7. PMID 717362.
- ↑ Hangen D, Maltz GS, Anderson JE, Knauer CM (1989). "Marked hypergastrinemia in gastric outlet obstruction". J. Clin. Gastroenterol. 11 (4): 442–4. PMID 2760432.
- ↑ Lau JY, Chung SC, Sung JJ, Chan AC, Ng EK, Suen RC, Li AK (1996). "Through-the-scope balloon dilation for pyloric stenosis: long-term results". Gastrointest. Endosc. 43 (2 Pt 1): 98–101. PMID 8635729.
- ↑ Awan A, Johnston DE, Jamal MM (1998). "Gastric outlet obstruction with benign endoscopic biopsy should be further explored for malignancy". Gastrointest. Endosc. 48 (5): 497–500. PMID 9831838.