Perforation

Perforation (Latin: perforatio, “to bore through”) is a pathological condition in which a full-thickness defect develops in the wall of a hollow organ. This defect creates a direct communication between the organ lumen and adjacent anatomical spaces, most commonly the peritoneal cavity, but also the pleural cavity or the mediastinum. Less commonly, it communicates with the external environment.

This is a life-threatening surgical emergency. When irritating luminal contents, such as gastric fluid, intestinal contents, bile, urine, or pus, spill into normally sterile body cavities, they trigger severe inflammation. Depending on the site, this may result in peritonitis, mediastinitis, or pleurisy, and, without urgent treatment, may rapidly progress to sepsis and multiple organ failure.

Aetiology and Pathophysiology

Perforation typically results from necrosis of the organ wall, followed by breakdown of all layers and loss of integrity. The underlying causes are diverse.

Main etiologic groups:

• Inflammatory conditions leading to perforation: The most common group.
  • Peptic ulcer disease (gastric or duodenal): perforation of a chronic ulcer.
  • Acute appendicitis, acute cholecystitis, diverticulitis: gangrene of the wall with subsequent rupture.
  • Inflammatory bowel disease (Crohn’s disease, ulcerative colitis): transmural inflammation or severe ulceration may lead to perforation.
  • Acute suppurative otitis media: perforation of the tympanic membrane. Purulent otorrhea (discharge into the external auditory canal) may occur.
• Tumors: necrosis of a malignant tumor invading the organ wall.
• Trauma:
  • Penetrating trauma: stab wounds or gunshot injuries to the abdomen or chest.
  • Blunt trauma: rupture due to direct impact.
• Iatrogenic injury: perforation as a complication of endoscopic procedures (e.g., upper endoscopy, colonoscopy) or surgery.
• Ischemia: bowel wall necrosis due to strangulating obstruction or acute mesenteric ischemia (e.g., mesenteric arterial/venous thrombosis).

Clinical significance

When a hollow viscus perforates into the peritoneal cavity, the presentation is classically an acute abdomen, with abrupt onset and rapid progression. Definitive management requires emergency surgical intervention.

Classic features (example: perforated peptic ulcer):

• Pain: sudden, severe “knife-like” epigastric pain that quickly becomes generalized.
• Guarding/rigidity: a board-like, rigid abdomen with reduced movement during respiration.
• Peritoneal signs: severe pain on palpation with rebound tenderness (Blumberg sign).
• Systemic deterioration: pallor, diaphoresis, tachycardia, hypotension.

The diagnostic “gold standard” is a plain upright (erect) abdominal radiograph. It may demonstrate free air beneath the diaphragm (pneumoperitoneum), typically as a crescent-shaped lucency (the crescent sign). If the diagnosis remains uncertain, CT is more sensitive. Ultrasound may also be used in selected cases.

Differential Diagnosis

Perforation should be distinguished from other causes of an acute abdomen. These include acute pancreatitis, which may also present with severe pain and peritoneal signs. Additional differentials include acute bowel obstruction, acute mesenteric ischemia, and renal colic. In women, urgent gynecologic conditions such as ruptured ovarian cyst or ovarian apoplexy should also be considered. The key imaging finding supporting perforation is free intraperitoneal air, which is uncommon in most alternative diagnoses.