Short Bowel Syndrome

Question 1

How is short bowel syndrome defined?

Answer 1

Short bowl is defined as residual short bowel length of <200cm.

Question 2

How does the jejunum affect absorption?

Answer 2

The jejunum is the primary site of macronutrient absorption (aa, fa, and monosaccharides), and therefore, the shorter the jejunum, the more aggressive the nutrition support needed.

Question 3

What are the 5 classifications of intestinal failure outlined in the ESPEN 2016 guidelines?

Answer 3

Short bowel, intestinal dysmotility, intestinal fistula, mechanical obstruction and extensive mucosal disease, such as that associated with inflammatory bowel disease.

Question 4

What does the Nightingale 1993 paper recommend? (3)

Answer 4

• Parenteral nutrition, alongside IV fluids and electrolytes is only required for a jejunum length of <75cm.
• Any more of which may be managed with long term IV fluid +/- e- only, with or without PN, alongside long term nutritional support tailored to the anatomical changes.

However, monitoring is important since there can be intestinal adaptation not accounted for in short bowel studies since they’re very small patient numbers, and mainly single centred.

Question 5

What are the principles of dietary management in jejunostomy patients? (5)

Answer 5

1. A jejunostomy is the complete resection of the ileum and colon.
2. 85cm of jejunum is preserved and represents the terminal intestine.
3. The loss of the ileum results in malabsorption of B12 and bile salts along with micronutrients Mg and Ca.
4. Loss of the colon results in high water and Na losses an there is increased transit time in the absence of the ileocecal valve.
5. Importantly, the remnant may be able to adapt to increase its absorptive capacity over a period of up to 2 years, however, this means immediately post operatively, this group are at high risk of dehydration and e- imbalances.

Question 6

What are the principles of dietary management in patients with a jejuno colonic resection/jejunocolonic anastomosis? (4)

Answer 6

1. A JCA is the partial resection of the ileum, while the colon is preserved.
2. 85cm jejunum and a section of the ileum is attached to the colon but the ileocecal valve is lost.
3. The partial loss of the ileum means there is still risk of malabsorption of micronutrients, B12 and bile salts.
4. The presence of the colon means water, sodium and micronutrient absorption can take place and there is a slower transit time.

Question 7

How does SBS affect energy requirements?

Answer 7

reduced bowel length is associated with malabsorption. Therefore, requirements are higher because of increased losses.

Question 8

What three studies have macronutrient absorption in patients with short bowel syndrome at varying lengths?

Answer 8

• Woolf 1987
• Messing 1999
• Crenn 2004

Limited evidence from old studies with small cohorts

Question 9

What do the three studies on malabsorption in SBS suggest?

Answer 9

These studies suggest that patient with SBS absorb about two thirds energy and protein intake, and they recommend a hyperphagia diet of high energy 30 - 60kcal/kg/day and high protein 1.25-1.5g protein /kg in order for dietary intake to corresponds to metabolisable energy

Question 10

What are the differences in carbohydrate requirements for jejunostomy and JCA?

Answer 10

• JCA patients –> 50-60% of total energy from carbs
• jejunostomy patients –? low to moderate carb of 40-50% and low fibre

Question 11

Outline the Noordgaard 1994 study (5)

Answer 11

• small cohort RCT
• allocated 8 JCA and and 6 jejunostomy patients to iso-caloric diets but with either a 60:20% or 20:60% carbohydrate:fat ratio and compared composition of faecal losses.
• jejunostomies excreted equal amount of calories irrelevant of the dietary composition.
• However, JCA patients saw an increase in energy absorption from 49% to 69% on the high carbohydrate diet.
• This is explained by the presence of a colon and the ability of the gut microflora to ferment polysaccharides, producing SCFA which contribute to energy balance in this group.
• Colonic fermentation provided an additional 1000kcal in those with JCA on high a carbohydrate diet

Question 12

What is the evidence base for low fibre diets in jejunostomy patients?

Answer 12

• No studies analysing low fibre diets in jejunostomy patients.
• Anecdotal evidence is used in practise based on expert opinion which explains that low fibre decreases intestinal transit time, which theoretically should decrease stoma output but there are no robust studies to support this.

Question 13

What are the dietary fat recommendations for jejunostomy and JCA patients?

Answer 13

• high fat diet is recommended for jejunostomy patients with the aim of 30-40% total energy
• JCA patients tolerate this less well and in fact, are recommended 20-30% total energy from fat with 50% of this being from MCT sources.

Question 14

What were the findings of the Crenn 2004 paper?

Answer 14

• strong correlation between dietary fat ingestion and intestinal fat absorption, analysed by faecal fat output, in patients with jejunostomies.
• In contrast increased fat intake was not as strongly associated with fat absorption in jejuno-ileo-colic and jejunocolic patients.
• Concluding that fat is better tolerated and provides a better source of energy for those without a colon.

Question 15

How does fat in the colon impact on electrolyte levels?

Answer 15

due to colonic continuity, where unabsorbed fat can move into the colon and contribute to increased diarrhoea –> exacerbates calcium and magnesium losses and increases the absorption of oxalates

Question 16

Why are JCA patients recommended a low oxalate diet?

Answer 16

25% of JCA patients develop renal stones, low oxalate and increased calcium is advised.

Question 17

What did the Jeppesen and Mortensen 1998 paper find?

Answer 17

substituting long chain triglycerides for MCT more than doubled the amount of fat absorbed, reducing the amount of unabsorbed in the gut and aiding in oxalate excretion, leading to the recommendation of MCT fat in the JCA diet.

Question 18

What are the recommendations for lactose? Include citations. (4)

Answer 18

• Exclusion of lactose often recommended due to the hypothesis that there is decrease lactase production in short bowel
• 2 RCTS have refuted this
• Marteau et al 1997 found lactose absorption was 61% in JCA and 53% in jejunostomy. Therefore there is no evidence to suggest the need for the exclusion of lactose.
• ## This is important as not only is it a good source of energy to meet the requirements of a hyperphagic diet, but for JCA patients, many diary products also provide the much needed calcium for the prevention of kidney stones.

Question 19

What are the fluid recommendations for jejunostomy patients? (3)

Answer 19

• hypotonic drinks should be avoided in this group since fluids providing <90mmol Na/L will result in Na secretion into the intestinal lumen, leading to increased fluid losses.
• high salt intake is recommended because of these high Na losses and these patients will also benefit from oral rehydration solution with minimum 90mmol Na/L to promote hydration status.

In practise, some patients take sodium chloride capsules up to 7g/24h.

Question 20

What are the fluid requirements for JCA patients?

Answer 20

in the presence of a functioning colon, fluid and sodium absorption can occur, indicating nil need for fluid restrictions or salt additions in those with a JCA.

Question 21

What are the nutritional support recommendations for SBS? (4)

Answer 21

• whole protein ons/en are recommended for both jejunostomy and JCA patients.
• Elemental or peptide based supplements and EN often have a higher osmolality, and similar to hypotonic solutions, can contribute to increased fluid into the intestinal lumen, contributing to increased stoma output and dehydration.
• Additionally, higher volumes are often needed to meet requirements, and since many jejunostomy patients are on a fluid restriction of 500-1000ml, this is not appropriate.
• For jejunostomy patients, modular products may be helpful to meet the recommended 30-40% dietary fat per day.