Large Bowel Obstruction Causes and Management

Etiology of Large Bowel Obstruction

Colorectal cancer is the most common cause of large bowel obstruction, accounting for approximately 60% of all cases, according to the World Journal of Emergency Surgery 1, 2, 3
Volvulus is the second most common cause, particularly sigmoid volvulus, accounting for 15-20% of cases 1, 3
Diverticular disease is the third most common cause, usually due to stricture formation following repeated episodes of diverticulitis, accounting for 10% of cases 1
Other causes, including carcinomatosis, endometriosis, inflammatory bowel disease stenosis, ischemic strictures, radiation stenosis, and post-anastomotic stenosis, account for 10-15% of cases 1, 5

The sigmoid colon is the most common site for malignant large bowel obstruction, with approximately 75% of obstructing colorectal cancers occurring distal to the splenic flexure 4, 3
Approximately 20% of patients diagnosed with colorectal cancer will present with left-sided large bowel obstruction as their initial presentation 4, 6
Large bowel obstruction represents almost 80% of emergencies related to colorectal cancer 2, 3

CT scan is the most accurate diagnostic tool with approximately 90% accuracy for identifying the site, severity, and etiology of large bowel obstruction 7

For obstructing right-sided colon cancers, primary resection and ileocolic anastomosis is generally the treatment of choice 4, 3
For left-sided malignant large bowel obstruction, management options include primary resection with or without anastomosis 4, subtotal colectomy with or without anastomosis 6, defunctioning stoma with interval resection 4, and self-expanding colonic stents as a bridge to surgery 4, 2
Self-expanding colonic stents have been successfully used as a non-invasive technique to relieve left-sided malignant bowel obstruction, allowing surgical resection to be performed electively rather than emergently 4, 6
Emergency surgery for large bowel obstruction is associated with high morbidity and mortality rates, almost three times that of elective resections 4

Colonic pseudo-obstruction can mimic mechanical large bowel obstruction and must be distinguished as it typically does not require surgical intervention 1
Diverticulitis with stricture formation can mimic malignant large bowel obstruction 1
Inflammatory bowel disease can also mimic malignant large bowel obstruction 1