A 45-year-old woman with a history of peptic ulcer disease presents with acute severe epigastric pain and board-like abdominal rigidity. Plain abdominal radiograph is obtained. Which of the following radiographic findings is NOT expected in perforated peptic ulcer disease?

Explanation

## Radiographic Signs of Perforated Peptic Ulcer **Key Point:** Perforated peptic ulcer disease presents with characteristic pneumoperitoneum, but Rigler's triad is NOT associated with simple perforation — it is pathognomonic for **pneumatosis intestinalis with portal venous gas**, which indicates bowel ischemia and necrosis. ### Expected Findings in Perforated PUD **High-Yield:** The classic radiographic signs of perforated peptic ulcer are: 1. **Free air under the diaphragm** — visible on upright chest radiograph or left lateral decubitus abdominal film. This is the most common and specific sign. 2. **Falciform ligament sign** — air outlining the falciform ligament of the liver, creating a linear lucency. This is a sensitive sign of pneumoperitoneum. 3. **Mediastinal emphysema** — air tracking into the mediastinum through the diaphragmatic hiatus or via esophageal perforation (less common in PUD, more in esophageal rupture). 4. **Pneumoretroperitoneum** — air in the retroperitoneum if the perforation is posterior and sealed off. ### Why Rigler's Triad Is Wrong **Clinical Pearl:** Rigler's triad consists of: - Pneumatosis intestinalis (air in the bowel wall) - Portal venous gas (air in the portal vein branches) - Free intraperitoneal air **Warning:** Rigler's triad is NOT a sign of simple peptic ulcer perforation. It indicates **advanced intestinal ischemia and necrosis**, typically seen in: - Mesenteric ischemia (arterial or venous thrombosis) - Bowel infarction - Necrotizing enterocolitis (in neonates) - Advanced sepsis with bowel wall compromise In uncomplicated perforated PUD, the perforation is localized to the ulcer site, and there is no bowel wall necrosis or ischemia. Therefore, pneumatosis intestinalis and portal venous gas would NOT be expected. ### Comparison Table: Pneumoperitoneum vs. Ischemic Bowel Signs | Sign | Perforated PUD | Mesenteric Ischemia / Bowel Necrosis | | --- | --- | --- | | Free air under diaphragm | ✓ (common) | ✓ (late finding) | | Falciform ligament sign | ✓ (sensitive) | ✓ (if perforation occurs) | | Pneumatosis intestinalis | ✗ (not expected) | ✓ (pathognomonic) | | Portal venous gas | ✗ (not expected) | ✓ (ominous sign) | | Mediastinal emphysema | ± (rare, if air tracks cephalad) | ✗ (not typical) | | Prognosis | Good with early surgery | Poor (high mortality) | **Mnemonic:** **RIGLER** = **R**are **I**schemic **G**ut **L**esion **E**vidence **R**adiographically — this triad signals bowel death, not simple ulcer perforation. ### Clinical Correlation A 45-year-old with PUD presenting with acute epigastric pain and board-like rigidity has a perforated ulcer. The plain radiograph will show free air (pneumoperitoneum), and the falciform ligament sign may be visible. Mediastinal emphysema can occur if air tracks upward through the diaphragm. However, Rigler's triad would indicate that the patient has developed mesenteric ischemia or bowel necrosis — a much more serious condition with different etiology and prognosis.