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]

Large bowel obstruction is a common symptom of colorectal cancer, with an incidence range of 15% to 29%.[3] Colonic malignancy is the most common cause of large bowel obstruction in adults.[4] Approximately 30% of colorectal cancer patients initially present to an emergency care setting.[2] See our topic Colorectal cancer.

Risk factors

Patients with colorectal adenomas or polyps may go on to develop colorectal cancer.[9]

This could include an abdominal or gynaecological malignancy.

Ask about any signs and symptoms of an undiagnosed malignancy, such as rectal bleeding, recent weight loss, or a change in bowel habit.

Patients with inflammatory bowel disease have a 70% higher risk of developing colorectal cancer than the general population.[9] The risk increases with the duration and extent of the disease.[9] 

May be a cause of strictures.

May be a cause of strictures.

A rare cause of large bowel obstruction.

Examine hernial orifices to detect an obstruction secondary to an irreducible hernia; most commonly seen in small bowel obstruction. See our topic Small bowel obstruction.

Previous benign or malignant masses; pelvic abscess. 

Endometriosis is a rare cause of bowel obstruction.

Diabetes is associated with a 30% higher risk of colorectal cancer.[9] 

May predispose the patient to colonic volvulus or pseudo-obstruction.

Gut motility is altered in diabetes and is associated with autonomic dysfunction.

May predispose the patient to colonic volvulus.

May indicate an ischaemic colonic stricture.

In particular, a previous colorectal resection has a low risk of anastomotic stricture, a rare cause of large bowel obstruction.

May be a cause of strictures.

Some bowel cancers are known to have specific genetic predisposition.[9] 

For colorectal cancer, age-specific incidence rates increase steeply after age 50 years, with the highest rates above age 85 years.[9]

Men are at greater risk than women of developing colorectal cancer.[9] 

Approximately 13% of bowel cancers in the UK have been linked to obesity.[9] 

Megacolon from any cause may predispose the patient to colonic volvulus owing to the elongation of the colon on its mesentery.

Any condition that results in an elongated colon predisposes the patient to the development of colonic volvulus.

Typically these patients are constipated and may have abused laxatives in an attempt to improve their symptoms.

Consumption of red meat and processed meat has been associated with colorectal cancer.[9]

Approximately 11% of bowel cancers in the UK have been linked to excessive alcohol consumption.[9]

Approximately 8% of bowel cancers in the UK have been linked to tobacco smoking.[9]

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