Perforated Bowel – Causes of Intestinal Tears and Ruptures
Bowel perforation is the opening of the wall of the small or large intestine thereby allowing the intestinal contents to spill into the peritoneal cavity. This can occur anywhere in the gastrointestinal tract, however, the intestines which compromise the majority of the length of the gut are more likely to be affected, especially in a case of trauma. A bowel perforation may be free or contained. With a free perforation the intestinal contents can spill and spread into the intraperitoneal cavity. In a contained perforation, the site of the perforation is walled off by surrounding gut structures and there is little or no spillage. Upper bowel perforation may be free or contained while lower bowel perforation is almost always free.
Bowel perforation may arise with trauma, iatrogenically or as a complication of an underlying bowel condition which is usually chronic in nature. Although uncommon, bowel perforation is a medical emergency and the mortality rate is high (20 to 40%). When the intestinal contents spill into the peritoneal cavity it causes inflammation known as peritonitis. This may be as a result of chemicals like digestive enzymes and stomach acid (chemical peritonitis) or bacteria from the gut (bacterial peritonitis). Chemical peritonitis is more likely to occur with stomach or duodenal perforation, due to the presence of gastric acid and proteases within the pancreatic juices, but is followed by bacterial peritonitis. A perforation lower down the small intestine (jejunum and ileum) and the colon.
Causes of a Perforated Bowel
The most common cause of a perforated duodenum arises as a complication of a duodenal ulcer (perforated ulcer). However, a perforation is a rare complication. The entire list of causes of a bowel perforation includes :
Trauma
Sharp force or blunt force trauma to the abdomen can cause a bowel perforation. With a penetrating injury like a knife stabbing, the small bowel is more likely to be perforated as it occupies most of the peritoneal cavity. Blunt force injuries leading to bowel perforation are seen more frequently in children but occurs in less than 10% of severe abdominal injuries. In adults it is more likely to be associated with car accident injuries, sporting injuries and severe assault.
Foreign bodies, especially sharp objects, may also cause a perforation of the bowels if it can bypass the esophagus and stomach with causing any tears or becoming lodged in the wall. Consuming caustic substances can cause chemical trauma and lead to a perforation but is more likely to affect the upper gut – esophagus, stomach and duodenum.
Iatrogenic
A perforation may occur with investigative procedures like an upper GI endoscopy, ERCP (endoscopic retrograde cholangiopancreatography) or colonoscopy. However, this is rare. It may also occur with surgical procedures like a laparoscopy, especially in obese or pregnant patients, those with bowel inflammation or obstruction. Bowel perforation may also arise as a complication of the following :
- cholecystectomy (gallbladder removal)
- kidney transplantation
- radiation therapy for abdominopelvic malignancies
It is often associated with bowel obstruction (iatrogenic) – read more on blocked bowel and blocked colon. Certain drugs like aspirin, NSAIDs and corticosteroids can cause a perforation if there is underlying duodenal ulcers or diverticular disease and is more likely to occur in elderly patients.
Bowel Inflammation
Bowel perforation may arise as a complication in a number of inflammatory bowel conditions (acute and chronic) like :
- Inflammatory bowel disease – Crohn’s disease, ulcerative colitis
- Appendicitis
- Diverticulitis
- Infectious and ischemic colitis
- Necrotizing vasculitis
Tumors
Any intra-abdominal malignancy (cancer) can cause a perforated bowel. This may also be seen with a lymphoma or renal carcinoma. Benign tumors are less likely to cause a perforation but it may be seen in certain cases, such as a desmoid tumor.
Other Causes
Most of the conditions are uncommon causes of a perforated bowel.
- Fecal impaction and other causes of an impacted bowel
- Cholecystitis (acute)
- Bowel strangulation (non-surgical like a hernia)
- Megacolon
- Spontaneous perforation (very rare)
References
- Intestinal Perforation. Emedicine Medscape
