Intestinal resection

Intestinal resection is usually well tolerated, but massive resection is followed by the short-gut syndrome.

The effects of resection depend on the extent and the areas involved.

Because the gut is long, a 30-50% resection can usually be tolerated without undue problems.

Ileal resection:

The ileum has specific receptors for the absorption of bile salts and vitamin B₁₂. Therefore, relatively small resections will lead to malabsorption of these substances.

Removal of the ileocaecal valve increases the incidence of diarrhoea.

The following occur in ileal resection:

Bile salts and fatty acids enter the colon and interfere with water and electrolyte absorption, causing diarrhoea.

Increased bile salt synthesis can compensate for loss of ~ 1/3 of the bile salts in the faeces. Greater loss than this results in decreased micellar formation and steatorrhoea.

Increased oxalate absorption is caused by the presence of bile salts in the colon. This gives rise to renal oxalate stones.

There is a low serum B₁₂ and macrocytosis.

Jejunal resection:

The ileum can take over the jejunal absorptive function

Jejunal resection may lead to gastric hypersecretion with high gastrin levels (unclear mechanism)

Intestinal adaptation takes place, with an increase in the absorption per unit length of bowel

Massive resection (short-gut syndrome):

This occurs following resection in:

Crohn’s disease

Mesenteric occlusion

Trauma

Severe symptoms occur when there is less than 90-100cm of small bowel remaining.

Diarrhoea (with severe water and electrolyte loss)

Malnutrition

Parenteral nutrition (sometimes long-term) is necessary.

With intestinal adaptation most will eventually recover, although they continue to have diarrhoea and little functional reserve should another GI problem occur.