13.09.12 Short bowel syndrome

Types

• Jejunoileal resection and a jejunocolic anastomosis (jejunum-colon)

• Predominantly jejunal resection with more than 10 cm of terminal ileum and the colon remaining (jejunum-ileum)

• Jejunoileal resection, colectomy, and formation of a stoma (jejunostomy)

Clinical pictures

• • Jejunum-ileum

  • Rarely need long term enteral or parenteral nutrition

  • Jejunum-colon

    • Gradual undernutrition dominates the clinical picture

  • Due to adaptation, nutritional requirements may reduce with time

  • May need parenteral nutrition if less than 50 cm small intestine remains

  • Need a high carbohydrate low oxalate diet

  • The volume of food may increase diarrhoea (grade A)

  • Jejunostomy

    • Fluid and electrolyte losses dominate the clinical picture

    • Adaptation does not occur so nutritional and fluid requirements do not reduce with time

  • If less than 200 cm of jejunum remains, oral hypotonic fluids may need to be restricted

    • A glucose-saline supplement (sodium concentration of about 100 mmol/l) is sipped to reduce stomal losses of sodium

    • Hypomagnesaemia is common and is treated by correcting sodium depletion, oral or intravenous magnesium supplements

    • And occasionally with oral 1 alpha hydroxycholecalciferol

  • Jejunal output may be further reduced by drugs that reduce motility (loperamide)

    • Or, if the bowel is very short (less than 100 cm), drugs that reduce gastric acid secretion (H2 antagonists, PPIs, or somatostatin analogues)

Common causes of a short bowel

• • Jejunum-colon

    • Crohn’s disease

    • Mesenteric ischaemia

    • Irradiation

    • Small bowel volvulus

    • Adhesions

  • Jejunostomy

  • Crohn’s disease

  • UC

  • Irradiation

    • Mesenteric ischaemia

    • Desmoid

Physiological consequences

• Gastrointestinal motility

  • Gastric emptying and small bowel transit for liquid is normal in jejunum-colon patients but fast in patients with a jejunostomy

    • Ileal and colonic braking mechanisms have been resected

  • May relate to circulating plasma levels of peptide YY and glucagon-like peptide 2 (GLP-2)

  • Gastrointestinal secretions

  • The majority of this fluid is reabsorbed in the upper jejunum

  • Jejunum-colon patients can reabsorb unabsorbed fluid in their colon but this is not the case for jejunostomy patients who lose much salt and water from their stoma

  • Jejunal mucosa is ‘‘leaky’’ and rapid sodium fluxes occur across it

    • If water or any solution with a sodium concentration of less than 90 mmol/l is drunk there is a net efflux of sodium from the plasma into the bowel lumen

  • Gastric acid hypersecretion may occur in the first two weeks after a small bowel resection

  • Absorptive functions

    • Vitamin B12 and fat malabsorption occurs when more than 60–100 cm of terminal ileum have been resected

  • Increased hepatic synthesis of bile salts cannot compensate for the loss of ileal surface area

    • Unabsorbed bile salts may contribute to colonic secretion in patients with a remaining colon

    • Magnesium deficiency occurs due to because of chelation with unabsorbed fatty acids and increased renal excretion (secondary hyperaldosteronism)

  • Hypomagnesaemia reduces the secretion and function of parathormone

Management of undernutrition

• 50% or more of the energy from the diet may be malabsorbed

• Parenteral nutrition should be avoided unless absolutely necessary

  • May only be needed for a few weeks or months before oral supplements are adequate

  • In the long term, parenteral nutrition is needed if a patient absorbs less than one third of the oral energy intake

• Unabsorbed long chain fatty acids in the colon (In jejunum-colon patients)

  • Reduce transit time and reduce water and sodium absorption so making diarrhoea worse

  • Toxic to bacteria and so reduce carbohydrate fermentation

  • Bind to calcium and magnesium, increasing stool losses

  • Increase oxalate absorption so predisposing to the formation of renal stones

• A low fat diet may increase calcium, magnesium, and zinc absorption but makes essential fatty acid deficiency more likely

  • Medium chain triglycerides are an alternative source of energy and are absorbed from the small and large bowel

• If a diet is high in monosaccharides D-lactic acidosis may occur

Vitamin and mineral deficiencies

• Most patients require long term B12 treatment

• Selenium deficiency is common and patients may need larger amounts than normal subjects

• Zinc deficiency is uncommon unless stool volumes are large

• Vitamins A, D, E, and K, and essential fatty acids may need to be replaced

Management of a patient with a jejunostomy

• Exclude/treat causes other than a short bowel

  • Infection (intra or extraluminal)

  • Partial obstruction

  • Abrupt stopping of drugs

• Correct dehydration with intravenous saline while the patient takes nothing by mouth for 24–48 hours

  • This stops thirst and thus the desire to drink

• Reduce oral hypotonic fluids to 500 ml/day

  • This is the most important measure

• Give glucose/saline solution to sip (sodium concentration at least 90 mmol/l)

  • Most stomal/fistula losses (except from the colon) have a sodium concentration of about 100 mmol/l

• Add sodium chloride to any liquid feeds to make the sodium concentration near to 100 mmol/l while keeping osmolality near 300 mosmol/kg

• Give drugs to reduce motility

  • Loperamide 2–8 mg (non-sedative and non-addictive) before food

  • Occasionally, addition of codeine phosphate further reduces stomal output

• If there is net ‘‘secretory’’ output (generally more than 3 l/24 hours), drugs that reduce gastric acid secretion can reduce stomal output by 1–2 l/24 hours

  • H2 antagonists or proton pump inhibitors

  • Octreotide if unable to absorb oral drugs, octreotide

• Other measures include:

  • Separating solids and liquids (that is, having no drink for half an hour before or after food)

  • Using salt capsules instead of glucose/saline solution

  • A trial of fludrocortisone if the ileum remains

• Correct hypomagnesaemia

  • Intravenous magnesium sulphate initially then oral magnesium oxide and/or 1-alpha cholecalciferol

Summary

Notes

• Bowel length measurements are from the duodenojejunal flexure

  • Can be made at surgery or with the use of an opisiometer tracing out the long axis of the bowel on a contrast study

  • Normal human small intestinal length varies from about 275 cm to 850 cm, and tends to be shorter in women

  • In general, nutritional/fluid supplements are likely to be needed if less than 200 cm of small bowel remains

• Daily gastrointestinal secretions:

  • 0.5 litre of saliva

  • 2.0 litres of gastric juice

  • 1.5 litres of pancreaticobiliary secretions plus passive jejunal secretions

  • Drug absorption may be impaired