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Gastric Outlet Obstruction, Emergency Medicine

Basics

Description

- Any process impeding the passage of gastric contents into the duodenum - Causes not limited to gastric pathology and may be duodenal or extraluminal in origin - Benign and malignant causes, including: - Neoplasms (most common cause in adults), intrinsic or extrinsic neoplasms (pancreatic, gastric lymphoma, duodenal, gallbladder). Extrinsic masses may cause compression at pylorus or proximal duodenum - Peptic ulcer disease (PUD), no longer most common cause in adults, with treatment of Helicobacter pylori and use of H2 blockers - Pyloric stenosis (most common pediatric cause): Incidence 2-5/1,000 - Postoperative complications, especially from gastric surgeries (e.g., edema, scarring, stricture, or hyperplasia of pylorus or duodenum) - Mechanical causes: Gastric volvulus, polyps, bezoars, duplication cysts - Edema, scarring, strictures/webs, or hyperplasia of pylorus or duodenum from various causes (e.g., caustic injury, chronic pancreatitis)

- Regardless of exact cause, gastric outlet obstruction characteristically leads to nausea and nonbilious vomiting - Persistent vomiting may lead to dehydration, electrolyte and acid-base derangements - Chronic symptoms may lead to weight loss, malnutrition, failure to thrive - Hypokalemic, hypochloremic metabolic alkalosis is classic finding

- Abdominal exam: - Variable amount of epigastric/abdominal distention - Tympanitic to auscultation - Succession splash >4 hr after eating - Digital rectal exam: Evaluate for occult blood

- Electrolytes, BUN/creatinine, glucose: - Hypokalemia - Hypochloremic metabolic alkalosis - Hypoglycemia - Prerenal azotemia

- Plain abdominal radiographs (obstructive series): - Often nondiagnostic - Dilated stomach or absence of air in bowel distally may be suggestive

- Abdominal US in pediatric patients: - No ionizing radiation - Elongated hypertrophic pyloric sphincter

  • Any process impeding the passage of gastric contents into the duodenum
  • Causes not limited to gastric pathology and may be duodenal or extraluminal in origin
  • Benign and malignant causes, including:Neoplasms (most common cause in adults), intrinsic or extrinsic neoplasms (pancreatic, gastric lymphoma, duodenal, gallbladder). Extrinsic masses may cause compression at pylorus or proximal duodenumPeptic ulcer disease (PUD), no longer most common cause in adults, with treatment of Helicobacter pylori and use of H2 blockersPyloric stenosis (most common pediatric cause): Incidence 2-5/1,000Postoperative complications, especially from gastric surgeries (e.g., edema, scarring, stricture, or hyperplasia of pylorus or duodenum)Mechanical causes: Gastric volvulus, polyps, bezoars, duplication cystsEdema, scarring, strictures/webs, or hyperplasia of pylorus or duodenum from various causes (e.g., caustic injury, chronic pancreatitis)

Etiology

  • Regardless of exact cause, gastric outlet obstruction characteristically leads to nausea and nonbilious vomiting
  • Persistent vomiting may lead to dehydration, electrolyte and acid-base derangementsChronic symptoms may lead to weight loss, malnutrition, failure to thriveHypokalemic, hypochloremic metabolic alkalosis is classic finding

Diagnosis

Signs and Symptoms

History

  • Symptoms may be intermittent until obstruction becomes complete
  • Nausea and vomiting, usually nonbilious
  • Abdominal pain, variable in character and often vague
  • Early satiety and epigastric fullness
  • Epigastric discomfort relieved with emesis
  • Weight loss, failure to thrive

Physical Exam

  • Vital signs:May be normalTachycardia, hypotension if volume depletion is significant
  • Abdominal exam:Variable amount of epigastric/abdominal distentionTympanitic to auscultationSuccession splash >4 hr after eatingDigital rectal exam: Evaluate for occult blood
  • Signs of dehydration in eyes, oral pharynx, mucous membranes, skin turgor
  • Signs of malnutrition in chronic or late obstruction
  • Weight loss when chronic and with malignancy
  • Abdominal pain, nausea/vomiting: GI symptoms may be more vague/subtle in elderly patients
  • If appropriate, consider other causes of symptoms (cardiac causes, neurologic causes)
  • Idiopathic hypertrophic pyloric stenosis:Most common cause in pediatric population"Typical"¯ patient is male (Caucasian and US-born Asians more common)Usually 2-8 wk old but may be diagnosed as early as 1st wk and up to 3 mo of ageInitially intermittent, nonprojectile, postprandial vomiting, which progresses to projectile, nonbilious vomitingA midepigastric peristaltic wave occurring prior to vomiting may be visible on examEpigastric "olive"¯ mass may be palpable in 80-90% of patients

Essential Workup

Careful history and physical exam

Diagnosis Tests & Interpretation

Lab

  • CBC:Anemia if malignancy or GI blood lossHigh hematocrit indicating hemoconcentration
  • Electrolytes, BUN/creatinine, glucose:HypokalemiaHypochloremic metabolic alkalosisHypoglycemiaPrerenal azotemia
  • Urinalysis
  • Amylase/lipase
  • Liver profile, if malignancy suspected
  • H. pylori, if PUD suspected

Imaging

  • Plain abdominal radiographs (obstructive series):Often nondiagnosticDilated stomach or absence of air in bowel distally may be suggestive
  • Abdominal US in pediatric patients:No ionizing radiationElongated hypertrophic pyloric sphincter
  • Abdominal CTs are often very helpful for detecting neoplastic, intraluminal, and extraluminal causes of obstruction.Likely to be most commonly used modality in adultsRadiation load is especially undesirable in pediatric population; ultrasound and fluoroscopic UGI series are preferred initial approaches

Diagnostic Procedures/Surgery

  • Upper GI series:To demonstrate site and character of obstruction"String sign,"¯ "double track sign,"¯ "beak sign,"¯ "shoulder sign"¯ are characteristic findings in pyloric stenosis
  • Upper endoscopy:To visualize gastric interior, gastric outlet, proximal duodenum

Differential Diagnosis

  • Proximal bowel obstruction
  • Exacerbation of PUD
  • Gastroenteritis
  • Cholelithiasis
  • Cholecystitis
  • Acute pancreatitis
  • Diabetic gastroparesis
  • Psychogenic vomiting

Treatment

Pre-Hospital

  • Vital signs, airway stabilization, oxygen administration, IV access
  • Fluid resuscitation if dehydrated, vomiting

Initial Stabilization/Therapy

  • 0.9% NS IV fluid resuscitation significant volume losses:Adults: 1 L bolusPeds: 20 mL/kg bolus
  • Correction of electrolyte abnormalities, especially hypokalemia

Ed Treatment/Procedures

  • Nasogastric tube (NGT)
  • Foley catheter to monitor urine output
  • Surgical consultation/intervention:Endoscopic balloon dilatation of benign stricturesEnteral stent placement (malignant causes)Gastrojejunostomy (malignant causes)Vagotomy and antrectomy or pyloroplasty or gastrojejunostomy or other variation (benign causes)

Medication

  • Famotidine: Adults: 20 mg (peds: 0.6-0.8 mg/kg/24 h div. q6-8h) IV q12h or
  • Ranitidine: 50 mg (peds: 2-4 mg/kg/24 h div. q6-8h) IV q8h
  • Pantoprazole: Adults: 40 mg IV (also H. pylori treatment as needed)

Follow-Up

Disposition

Admission Criteria

Most patients with gastric outlet obstruction will be admitted for fluid resuscitation, electrolyte repletion, gastroenterologic, and surgical evaluation.

Discharge Criteria

Rarely, patients may be considered for discharge if:

  • Symptoms of abdominal pain, vomiting have resolved
  • Evaluated and cleared by surgeon or gastroenterologist during presentation
  • Lab parameters, imaging, and patients volume status are normal

Issues for Referral

Surgical and gastroenterology consultations

Followup Recommendations

Any discharged patient should follow up with surgeon and/or gastroenterologist:

  • Specific instructions to return if symptoms recur

Pearls and Pitfalls

  • Misdiagnosing symptoms of gastric outlet obstruction as gastroenteritis
  • Failure to appreciate limitations of plain radiographs in diagnosing this condition
  • Failure to consider gastric outlet obstruction and malignancy in patient with epigastric pain and vomiting
  • Failure to adequately fluid resuscitation of patients, especially elderly or pediatric patients

Additional Reading

  • Dada SA, Fuhrman GM. Miscellaneous Disorders and their management in gastric surgery: Volvulus, carcinoid, lymphoma, gastric varices, and gastric outlet obstruction. Surg Clin North Am. 2011;91:1123-1130.
  • Kim JH, Shin JH, Song HY. Benign strictures of the esophagus and gastric outlet: Interventional management. Korean J Radiol. 2010;11(5);497-506.
  • Otjen JP, Iyer RS, Phillips GS, et al. Usual and unusual causes of pediatric gastric outlet obstruction. Pediatr Radiol. 2012;42:728-737.
  • Shone DN, Nikoomanesh P, Smith-Meek MM, et al. Malignancy is the most common cause of gastric outlet obstruction in the era of H2 blockers. Am J Gastroenterol. 1995;90:1769-1770.

See Also (Topic, Algorithm, Electronic Media Element)

  • Abdominal Pain
  • Bowel Obstruction
  • Pyloric Stenosis
  • Vomiting

Codes

ICD9

537.0 Acquired hypertrophic pyloric stenosis

ICD10

K31.1 Adult hypertrophic pyloric stenosis

SNOMED

  • 13483000 Acquired hypertrophic pyloric stenosis
  • 367403001 Pyloric stenosis (disorder)