Short Bowel Syndrome

Background

  • Poor absorption of macronutrients and micronutrients in children who have had part of their intestines removed or damaged
  • Risk of developing SBS with an intestinal length <75 cm
    • For reference, the average neonate at the beginning of the third trimester has an intestinal length of 125 cm and 250 cm at term

 

Epidemiology

  • 0.02-0.1% of live births
  • 2% of neonatal intensive care unit (NICU) admissions

 

Causes

  • Sequela of a diverse set of diseases that either lead to resection of part of the intestines or functional malabsorption
  • Necrotising enterocolitis (35% of all SBS)
  • Complicated meconium ileus or volvulus (20% of all SBS)
  • Abdominal wall defects (e.g. gastroschisis, 12.5% of all SBS)
  • Intestinal atresia
  • Later in childhood
    • Crohn's disease
    • Trauma
    • Malignancy
    • Radiation

 

General Signs and Symptoms

  • Abdominal pain
  • Diarrhea
  • Steatorrhea
  • Dehydration
  • Weight Loss
  • Fatigue
  • Anemia
  • Vitamin Deficiency (A, D, E, K, B9, B12, Ca, Mg, Fe, Zn)

 

Anatomy and Problems

  • The problems associated with SBS heavily depend on the region of the GI tract that is affected
  • Jejunum:
    • Digestive and absorptive site of most nutrients with digestive enzymes and nutrient transport proteins
    • Deficit leads to reduction in absorption of most nutrients
  • Ileum:
    • Site of B12, bile acid, and small amount of nutrient digestion/absorption
    • B12 deficiency, decreased bile acid reabsorption, fat soluble vitamin deficiency, diarrhea, hyperoxaluria, and kidney stones, electrolyte absorption abnormalities
  • Ileocecal Valve:
    • Barrier to colonic reflux
    • Damage leads to decreased small intestine transit time, bacterial overgrowth
  • Colon:
    • Electrolyte, water, and short-chain fatty acid absorption
    • Damage leads to fluid/electrolyte abnormalities with short-chain fatty acid absorption deficits

 

Adaptation

  • The GI tract in infants is resilient and will begin to adapt to the malabsorption of SBS
    • For example, the ileum can change to function like jejunum if jejunum is resected by altering the enzymes it expresses and increasing the number of villi
  • Some data shows that certain nutrients can stimulate this gut adaptation when given through total parenteral nutrition (TPN)
    • Arginine, citrulline, glutamine, triglycerides, GLP-2, and omega-3 fatty acids
      • In general, diets higher in fat and protein lead to enhanced intestinal adaptation
      • Except for patients with retained colons which can benefit from high carb diets

Treatment/monitoring

  • The goal of SBS treatment is to assist in transitioning to full enteral feedings through a slow weaning process and gut adaptation
  • Treatment success is dependent on which segment of the GI tract has been removed/damaged, presence/absece of ileocecal valve, the rate of intestinal adaptation, and length of small bowel remaining
  • Feeding
    • Start with TPN
    • Slowly introduce enteral feedings
      • Start with continuous enteral feeding via nasogastric or gastric-tube with about 5% of daily nutrition
      • Continue to transition to full enteral nutrition with early introduction of oral feeding as oral aversion can develop
    • Managing complications
      • Diarrhea
        • Anti-motility agents
        • Cholestyramine
      • Gastric acid hypersecretion/peptic ulcers
        • Proton pump inhibitor (PPI)
      • Bacterial overgrowth
        • Monitor D-lactate level
        • Treat with low-dose antibiotic
      • Kidney stones from enteric hyperoxaluria
        • Low-oxalate diet
        • Increased fluid intake
        • Cholestyramine
      • Vitamin and mineral deficiencies
        • Supplement accordingly
    • Surgical procedures can be considered
      • Serial transverse enteroplasty (STEP procedure) is done to maximize the length of bowel
  • Small bowel/liver transplat is indicated in some patients due to cholestatic liver failure secondary to long-term TPN use

 

References

Cuffari, C. “Pediatric Short Bowel Syndrome”. Aug 27, 2014. Medscape. Accessed 26 Mar 2016.

O’Keefe, SJ, et al. "Short bowel syndrome and intestinal failure: consensus definitions and overview." Clinical Gastroenterology and Hepatology 4.1 (2006): 6-10

Olieman, JF, et al. "Enteral nutrition in children with short-bowel syndrome: current evidence and recommendations for the clinician."Journal of the American Dietetic Association 110.3 (2010): 420-426. 

Pauley-Hunter RJ, Vanderhoof JA. “Pathophysiology of Short Bowel Syndrome”. Sep 15, 2014. UpToDate. Accessed 26 Mar 2016.

“Surgical Options” University of Michigan Children’s Intestinal Rehabilitation Program. Available at: http://surgery.med.umich.edu/pediatric/chirp/clinical/mm/surgopt.shtml. Accessed March 27, 2016.4 

Thompson, JS., et al. "Current management of the short bowel syndrome." Surgical Clinics of North America 91.3 (2011): 493-510. 

Vanderhoof JA, Pauley-Hunter RJ. “Management of Short Bowel Syndrome in Children”.  Feb 9, 2015. UpToDate. Accessed 26 Mar 2016. 

Wales, PW., et al. "Neonatal short bowel syndrome: population-based estimates of incidence and mortality rates." Journal of pediatric surgery 39.5 (2004): 690-695 

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