Clinical features

Cardinal symptoms, common to most types of intestinal obstruction intestinal obstruction include:

• vomiting
• colic
• distension - visible peristalsis may be present
• absolute constipation

The presentation is dependent on the level of bowel obstruction, for example stomach, proximal or distal small bowel, large bowel, and the completeness of obstruction.

The most acute presentation of intestinal obstruction is due to obstruction of the upper small bowel - this is due to the large volume of biliary and pancreatic secretions that become obstructed.

Obstruction of the distal large bowel is, in general, a more chronic presentation. This is because of the large capacity of the colon and caecum and their absorptive activities. In about 50% of cases the ileo-caecal valve remains competent leading to progressive dilatation of the thin-walled caecum due to swallowed air and will, if not urgently treated, rupture. If the ileo-caecal valve does become incompetent then the small bowel is distended and this will delay further the onset of symptoms.

Findings on examination include:

• dehydration
• abdomen distention
• lack of localised abdominal tenderness unless strangulation has occurred
• on percussion: centre of the abdomen tends to be resonant and the periphery dull - collection of bowel gas at the most elevated point

If the obstruction is partial, then the clinical features are less clearly defined.