What is the likely diagnosis and recommended management for a patient presenting with epigastric pain and a tense, tympanitic abdomen on percussion?

Perforated Peptic Ulcer Until Proven Otherwise

This clinical presentation—epigastric pain with a tense, tympanitic abdomen—is highly suspicious for perforated peptic ulcer with pneumoperitoneum, and you should immediately obtain a CT scan if available, or chest/abdominal X-ray if CT is not promptly accessible, while preparing for potential surgical intervention 1.

Why This Diagnosis is Most Likely

The tympanitic percussion finding indicates free intraperitoneal air, which is the hallmark of hollow viscus perforation. When combined with epigastric pain and abdominal rigidity (tense abdomen suggesting peritonitis), this triad strongly points to perforated peptic ulcer 1. Research confirms that pneumoperitoneum causes diagnostic changes in percussion sounds, with decreased resonant frequencies as air accumulates in the peritoneal cavity 2.

Immediate Diagnostic Workup

Imaging priority:

• First-line: CT scan - This is the gold standard with strong recommendation from WSES guidelines 1

  • CT has superior sensitivity for detecting free air (detects up to 88-100% of perforations)
  • Identifies perforation site, size, and excludes other causes
  • Shows unexplained intraperitoneal fluid, pneumoperitoneum, bowel wall thickening, and mesenteric fat streaking

• If CT unavailable: Erect chest/abdominal X-ray 1

  • Detects free air in 30-85% of cases (highly variable)
  • Left lateral decubitus views are better tolerated by patients with peritonitis
  • Critical caveat: Negative X-ray does NOT rule out perforation

• If imaging is negative but suspicion remains high: Water-soluble contrast via nasogastric tube 1

  • Up to 12% of perforations have normal CT scans
  • Contrast study can detect gastroduodenal perforation when other imaging is equivocal

Laboratory studies:

• Routine labs and arterial blood gas analysis (strong recommendation) 1
• Expect: leukocytosis, metabolic acidosis, possibly elevated serum amylase
• These are non-specific but support the diagnosis

Critical Management Considerations

Surgical preparation:

• If free air is visible on X-ray AND you have clear peritonitis on exam, this is sufficient to justify immediate surgical exploration without waiting for CT 1
• Physical examination may be equivocal in up to one-third of patients, particularly with contained/sealed perforations 1

Immediate interventions while awaiting imaging:

• NPO status
• IV fluid resuscitation
• Nasogastric tube decompression
• Broad-spectrum antibiotics (empiric coverage for perforated peptic ulcer)
• Surgical consultation

Common Pitfalls to Avoid

1. Don't be falsely reassured by minimal peritoneal signs - Up to one-third of perforated peptic ulcers present without obvious peritonitis 1

2. Don't delay CT for plain films if CT is readily available - CT should be your first imaging study when promptly accessible 1

3. Don't rule out perforation based on negative plain X-ray alone - Free air is only visible in 30-85% of cases on plain films 1

4. Don't forget cardiac causes - While this presentation is classic for perforation, always consider myocardial infarction in the differential of epigastric pain 3