What is short bowel syndrome?
It is a malabsorption syndrome from extensive intestinal resection.
Defined as when the small bowel is less than 200 cm in length.
Can lead to intestinal failure
What is the spectrum of short bowel syndrome?
Limited Ileocolonic resections–>jejunocolonic anastomosis–>end jejunostomy
Mild–>Severe
**End jejunostomy dependent on parenatal nutrition
What are the major causes of short bowel syndrome in adults?
Inflammatory Bowel Disease: Crohn’s & Ulcerative Colitis
Mesenteric Infarction
Radiation Injury
What are the major causes of short bowel syndrome in children?
usu congenital anomalies:
gastroschisis, intestinal atresia, malrotation, necrotizing enterocolitis
Other causes of short bowel?
volvulus
postsurgical complications
jejunoileal bypass
benign tumors
What are the symptoms/results of short bowel syndrome?
Diarrhea Steatorrhhea weight loss mineral/trace element deficiencies hypovolemia + hyponatremia OR hypokalemia
Why are serum citrulline concentrations a predictor of permanent or transient intestinal failure?
Citrulline is an amino acid that isn’t incorporated into proteins, but is a part of the urea cycle in the liver & kidneys.
It is produced by enterocytes in the small bowel & therefore the serum levels are indicative of how bad the damage is.
List the reasons for why Short Bowel Syndrome does what it does. Pathophysiology.
Loss of absorptive surface area
Loss of site-specific transport processes
Loss of site-specific endocrine cells & gastrointestinal hormones
Loss of ileocecal valve
Intestinal adaptation to resection
Where are GI hormones produced?
in the intestinal mucosa
Where are gastrin, CCK, secretin, GIP, motilin produced?
by endocrine cells in the proximal Gi tract
After intestinal resections, 1/2 the patients experience _______. People don’t know why. Perhaps loss of inhibitory signals.
hypergastrinemia
increased gastric acid secretions
Where are the GI hormones GLP1, GLP2, & PYY produced? What do they do?
in the ileum & proximal colon
- *they are released by intraluminal fat & carbs & cause a delay of gastric emptying
- inhibit gastric acid secretion
- promote intestinal growth
Where does most of the absorption in the SI take place?
in the proximal small bowel
Which part of the small intestine is perfect for absorption?
the jejunum b/c of the tall villi & deep crypts
What is better: to lose the jejunum or ileum?
Surprisingly, the jejunum. This is b/c the ileum is so good at adapting. It can make its crypts deeper & villi taller & increase its diameter & length. The ileum is what absorbs B12 & bile acids.
All areas do electrolytes & water.
When does bacterial overgrowth occur?
when you eat one simple carb that one type of bacteria eats…then that one will overgrow…need to even it out with the bacteria.
What’s the problem with losing your ileocecal valve?
This is what separates the ileal & colonic contents. It minimizes the bacterial colonization in the SI. It regulates the emptying of contents.
Removing it:
decreases intestinal transit time
increases risk of small bowel bacterial overgrowth
this overgrowth may worsen nutrient & cobalamin malabsorption
How long does it take the ileum to fully adapt if say the jejunum is fully resected?
1-2 years
What’s the problem with Mr. Short having a bunch of orange juice?
The sugar creates a hyper osmotic state, attracts water & worsens the diarrhea.
What’s the problem with Mr. Short having a bunch of mayo & butter?
It adds lipids, which are already hard to break down & worsens the steatorrhea.
Right after a bowel resection…how do you provide nutrition? What else do you do?
parenteral nutrition
H2 blocker/PPI to suppress gastric hypersecretion
What’s the problem w/ gastric hyper secretion?
It deactivates the pancreatic enzymes.
It reduces the optimal pH needed for fat absorption.
It increases intestinal fluid losses.
What’s the difference in how children v. adults handle the high carb enteral feeding formulas?
Children–have a problem
Adults–can ferment malabsorbed carbs into short chain fatty acids in the colon
This can generate 100 kcal/day
How is it best to do enteral feeding soon after bowel resection?
continuous feeding
this causes saturation of the carrier proteins & takes full advantage of the absorptive area that is available.
