How do you differentiate between gastric and duodenal perforation?

Differentiating Gastric from Duodenal Perforation

The key differences between gastric and duodenal perforation are primarily based on anatomical location, clinical presentation, imaging findings, and intraoperative characteristics, with duodenal perforations typically presenting with more severe pain radiating to the back and having a higher likelihood of retroperitoneal air on imaging.

Clinical Presentation Differences

• Pain characteristics:

  • Gastric perforation: Epigastric pain that may radiate to the left upper quadrant
  • Duodenal perforation: Severe epigastric pain often radiating to the back or right upper quadrant 1

• Timing of symptoms:

  • Gastric perforation: Often occurs in patients with known gastric ulcers or risk factors like NSAIDs or steroid use
  • Duodenal perforation: Frequently associated with a history of duodenal ulceration, with symptoms potentially worsening after meals 2

Imaging Findings

• CT scan findings (preferred first-line imaging for suspected perforation):

  • Gastric perforation: Free air predominantly in the left upper quadrant and anterior to the stomach
  • Duodenal perforation: Retroperitoneal air, especially around the right kidney and posterior to the duodenum 3, 4

• Plain radiography differences:

  • Gastric perforation: Larger volume of free air under the diaphragm
  • Duodenal perforation: May show free air under the right hemidiaphragm, but can be subtle or absent in up to 24.6% of cases 3

Laboratory Findings

• Both conditions may show:
  • Leukocytosis
  • Elevated inflammatory markers
  • Metabolic acidosis on arterial blood gas (more common in duodenal perforation due to delayed diagnosis) 1

Intraoperative Findings

• Location:

  • Gastric perforation: Located in the stomach, commonly along the lesser curvature or anterior wall
  • Duodenal perforation: Located in the duodenum, most commonly in the first part (anterior wall) 2

• Surrounding inflammation:

  • Gastric perforation: Generally less surrounding inflammation
  • Duodenal perforation: Often has more surrounding inflammation and may involve the pancreas in severe cases 2

Management Considerations

• Both types require:

  • Urgent surgical consultation even if endoscopic repair is considered 2
  • IV fluids, nothing by mouth, broad-spectrum antibiotics, and nasogastric tube placement 2

• Specific management differences:

  • Gastric perforations: Can be managed with TTSCs or OTSCs for perforations <2 cm and endoscopic suturing or combination of TTSCs and endoloop for perforations >2 cm 2
  • Duodenal perforations: Large type 1 duodenal perforations (lateral duodenal wall tear >3 cm) are difficult to close endoscopically and often require urgent surgical intervention 2, 5

Pitfalls and Caveats

• Duodenal perforations can be easily missed due to their retroperitoneal location, leading to delayed diagnosis and increased morbidity 2
• Gastric perforations may be misdiagnosed as cardiac issues due to referred pain patterns
• Free peritoneal air may not be evident in up to 12% of gastroduodenal perforations, making diagnosis challenging 3
• In bariatric surgery patients, perforations in the excluded segment require thorough exploration of the jejuno-jejunostomy and gastric remnant 2

Diagnostic Algorithm

1. Obtain CT scan with IV and oral contrast (most valuable imaging technique) 5
2. If CT unavailable, perform chest/abdominal X-ray to detect free air
3. Assess for retroperitoneal air (suggests duodenal perforation)
4. Evaluate pain radiation pattern (back pain suggests duodenal)
5. Consider endoscopy if diagnosis remains unclear and patient is stable
6. Surgical exploration may be necessary for definitive diagnosis in unclear cases 5

Remember that both conditions represent surgical emergencies requiring prompt diagnosis and management to reduce morbidity and mortality.