ABSTRACT
Malignancy is the commonest cause of large bowel obstruction, with colorectal cancer being the most frequent pathology. Rapid diagnosis, confirmed by appropriate investigations followed by resuscitation, is essential. Malignant large bowel obstruction may be caused by a variety of tumours, including gynaecological tumours such as advanced cervical and ovarian cancer. Mechanical obstruction of the colon by either an intrinsic or extrinsic malignancy results in dilatation of the colon proximal to the obstruction and a relative reduction in luminal diameter beyond. The increase in fluid and gas proximally results in increased colonic pressure and reduced mesenteric blood flow. The concept of ‘closed-loop’ obstruction is important when considering malignant large bowel obstruction as it impacts on the symptoms and signs of the patient, as well as affecting the urgency, with which surgical intervention is required. A plain abdominal X-ray is often the first diagnostic investigation that is undertaken in a patient with suspected malignant large bowel obstruction.
