Bowel obstruction (or intestinal obstruction) is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion. It can occur at any level distal to the duodenum of the small intestine and is a medical emergency. The condition is often treated conservatively over a period of 2-5 days with the patient’s progress regularly monitored by an assigned physician. Surgical procedures are performed on occasion however in life-threatening cases, such as when the root cause is a fully lodged foreign object or malignant tumor.
Small bowel obstruction
Causes of small bowel obstruction include:
Adhesions from previous abdominal surgery
Hernias containing bowel
Crohn’s disease causing adhesions or inflammatory strictures
Neoplasms, benign or malignant
Intussusception in children
Superior mesenteric artery syndrome, a compression of the duodenum by the superior mesenteric artery and the abdominal aorta
Foreign bodies (e.g. gallstones in gallstone ileus, swallowed objects)
Carcinoid rare, preferred location: ileum
Large bowel obstruction
Causes of large bowel obstruction include:
Inflammatory bowel disease
Colonic volvulus (sigmoid, caecal, transverse colon)
Benign strictures (diverticular disease)
Differential diagnoses of bowel obstruction include:
Pseudo-obstruction or Ogilvie’s syndrome
Pneumonia or other systemic illness.
The main diagnostic tools are blood tests, X-rays of the abdomen, CT scanning and/or ultrasound. If a mass is identified, biopsy may determine the nature of the mass.
Radiological signs of bowel obstruction include bowel distension and the presence of multiple (more than six) gas-fluid levels on supine and erect abdominal radiographs.
Contrast enema or small bowel series or CT scan can be used to define the level of obstruction, whether the obstruction is partial or complete, and to help define the cause of the obstruction.
According to a meta-analysis of prospective studies by the Cochrane Collaboration, the appearance of water-soluble contrast in the cecum on an abdominal radiograph within 24 hours of oral administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 96% and specificity of 96%. PMID 15674958
Colonoscopy, small bowel investigation with ingested camera or push endoscopy, and laparoscopy are other diagnostic options.