Epidemiology
Intestinal obstruction is a common surgical emergency. It accounts for up to 20% of admissions with acute abdominal pain. Of these patients, around 20% will have large bowel obstruction.[1] Obstruction is also the most common indication for emergency surgery for colorectal cancer, comprising up to 80% of such emergencies.[5] Similarly, colonic malignancy is the most common cause of large bowel obstruction in adults; approximately 30% of patients with colorectal cancer initially present to an emergency care setting.[4][6][7] See Colorectal cancer.
Colonic volvulus leads to between 2 and 15% of all large bowel obstructions in the developed world but this incidence varies globally.[2][8] Africa, South America, Russia, Eastern Europe, the Middle East, India, and Brazil are referred to as the “volvulus belt”, as there is much higher incidence of colonic volvulus in these countries, where it represents 13% to 42% of all intestinal obstructions.[8][9][10][11]
Risk factors
Colorectal malignancy is the most common cause of large bowel obstruction in adults; approximately 30% of colorectal cancer patients initially present to an emergency care setting.[4][5][7] Risk factors for colorectal cancer include:[18]
Colorectal adenomas or polyps.
Inflammatory bowel disease. Patients with inflammatory bowel disease also have a 70% higher risk of developing colorectal cancer than the general population.[18] The risk of colorectal cancer increases with the duration and extent of the inflammatory bowel disease.
Diabetes. Diabetes is associated with a 30% higher risk of colorectal cancer.[18]
Family history of bowel cancer. Some bowel cancers are known to have specific genetic predisposition.[18]
Older age. For colorectal cancer, age-specific incidence rates increase steeply after age 50 years, with the highest rates above age 85 years.[18]
Obesity. Approximately 13% of bowel cancers in the UK have been linked to obesity.[18]
Alcohol excess. Approximately 11% of bowel cancers in the UK have been linked to excessive alcohol consumption.[18]
Smoking.
Diet high in red meat and processed meat. Consumption of red meat and processed meat has been associated with colorectal cancer.[18]
This could include an abdominal or gynecologic malignancy. Malignant bowel obstruction can be seen in advanced ovarian cancer, with an estimated incidence of up to 50%.[19][20]
Ask about any signs and symptoms of an undiagnosed malignancy, such as rectal bleeding, recent weight loss, or a change in bowel habit.
May be a cause of strictures.
Recurrent colonic or rectal Crohn disease or ulcerative colitis may produce large bowel obstruction.
A rare cause of large bowel obstruction.[22]
Examine hernial orifices to detect an obstruction secondary to an irreducible hernia; most commonly seen in small bowel obstruction. See Small bowel obstruction.
Endometriosis is a rare cause of bowel obstruction.[23]
May predispose patients to colonic volvulus: 30% to 80% of patients with cecal volvulus have a history of previous abdominal surgery.[24]
May indicate an ischemic colonic stricture.
In particular, a previous colorectal resection has a low risk of anastomotic stricture, a rare cause of large bowel obstruction.
Megacolon from any cause may predispose patients to colonic volvulus owing to the elongation of the colon on its mesentery.
May be a cause of strictures.
Digital rectal exam may identify a pelvic mass suggestive of a foreign body.
Patient may not report the ingestion or insertion of a foreign body.
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