What can cause a small intestine perforation?

Causes of Small Intestine Perforation

Small bowel perforation is primarily caused by intestinal ischemia, inflammatory bowel disease (particularly Crohn's disease), and trauma in Western countries, while infectious causes like typhoid fever predominate in developing regions. 1

Common Causes by Geographic Region

Western Countries

• Intestinal ischemia - Unrecognized mesenteric ischemia leading to bowel wall necrosis
• Inflammatory bowel disease - Particularly complicated Crohn's disease
• Trauma - Both blunt and penetrating abdominal trauma
• Medication-induced - NSAIDs, potassium chloride, steroids 1
• Medical treatments - Cancer chemotherapy and radiotherapy 1
• Peptic ulcer disease - Particularly in the duodenum, often related to H. pylori infection or NSAID use 2

Developing Countries

• Typhoid fever - Causes ileal perforation with high mortality rates up to 60% 1
• Tuberculosis - Commonly affects the ileocecal region and terminal ileum 1
• Other infectious causes - Particularly in immunocompromised patients:
  • Amoebic infection
  • Clostridium difficile
  • Cytomegalovirus
  • Histoplasmosis 1

Pathophysiological Mechanisms

Infectious Causes

• Typhoid perforation - Typically occurs in the third week of disease, presenting with abdominal pain and fever 1
• Tuberculosis - Most commonly affects the ileocecal region, causing strictures that may lead to perforation in ulcerative forms 1

Non-infectious Causes

• Ischemia - Inadequate blood supply leading to bowel wall necrosis
• Inflammatory - Transmural inflammation in Crohn's disease weakens the intestinal wall
• Obstructive - Increased intraluminal pressure proximal to an obstruction
• Neoplastic - Primary or metastatic tumors eroding through the bowel wall 3

Clinical Presentation and Diagnosis

• Symptoms - Abdominal pain, fever, peritoneal signs
• Imaging - CT is the first-line investigation for suspected perforation 3
• CT findings - Free intraperitoneal air, localized extraluminal air bubbles adjacent to the bowel wall, oral contrast extravasation, bowel wall thickening, and surrounding fat stranding 4

Management Considerations

Surgical Approach

1. Class A patients (stable, minimal contamination):

   • Open or laparoscopic resection with primary anastomosis
   • Primary repair for small, single perforations with minimal contamination
   • 3-5 days of antibiotics plus specific treatment for underlying cause 1

2. Class B and C patients (unstable or significant contamination):

   • Urgent surgical exploration
   • Consider delayed bowel anastomosis
   • Stoma creation or exteriorization of perforation (if distal to Treitz ligament)
   • Continue antibiotics until infection signs resolve 1

3. Severe hemodynamic instability:

   • Damage control surgery regardless of patient class
   • Focus on physiological restoration 1

Specific Management for Different Causes

• Typhoid perforation - Resection of unhealthy tissue with primary anastomosis of healthy edges (10 cm on each side) is recommended 1
• Tubercular perforation - Resection and anastomosis rather than primary closure 1
• Crohn's disease perforation - Resection, lavage, and stoma creation in stable patients 1

Complications and Outcomes

• Morbidity - Wound infection (46.8%), wound dehiscence (31.3%), enterocutaneous fistula (11.5%) 5
• Mortality - Overall mortality rate around 16.6%, higher in developing countries 5
• Prognostic factors - Multiple perforations, severe peritoneal contamination, and delayed presentation worsen outcomes 1

Prevention Strategies

• H. pylori eradication - For peptic ulcer disease 2
• Careful NSAID use - Particularly in high-risk patients 2
• Early diagnosis and treatment of conditions that can lead to perforation (IBD, tuberculosis)
• Prompt surgical intervention when perforation is suspected

Understanding the specific cause of small bowel perforation is crucial for appropriate management, as treatment strategies may differ significantly based on etiology.