You are the gastroenterology registrar and have been referred a neonate from the NICU. He was born at 30 weeks gestation but unfortunately developed fulminant sepsis secondary to necrotising enterocolitis. He underwent a laparotomy and had 15 cm of dead gut removed. He is now being referred to you for long term management of short bowel syndrome.
- Short bowel syndrome is the malabsorptive state which occurs due to congenital disease or when a significant portion of the small bowel is removed due to surgery
- The amount and anatomy of the remaining gut determines outcome of enteral and parenteral nutrition
- Intestinal failure is when a child is dependant on parenteral nutrition
- Structural and functional adaptation occurs with the remaining small bowel
- Management requires a multidisciplinary team approach
- Complications include: growth failure, parenteral nutrition associated liver disease, small bowel bacterial overgrowth, sepsis and nutritional deficiencies
What is short bowel syndrome or short gut?
This is the malabsorptive state which occurs due to surgical resection or congenital disease of a significant portion of the small intestine. The amount and anatomy of the remaining bowel influences the tolerance for enteral nutrition (EN) and the need for parenteral nutrition (PN).
What are the common causes of short gut?
Children who have undergone procedures for necrotising enterocolitis, volvulus, atresias, gastroschisis.
This makes ex premature babies, and children with chromosomal anomalies, one of the larger cohorts presenting with short gut – something to keep in mind during clinical examinations!
What is intestinal failure?
Intestinal failure (IF) in a child with short gut is defined as a dependence on parenteral nutrition to maintain minimal energy and fluid requirement for growth.
What is intestinal adaptation?
Intestinal adaptation is the process by which the remaining bowel attempts to increase fluid and nutrient absorption. Structural adaptation involves an increase in the size of the intestinal villi and absorptive area while functional adaptation refers to the slowing of the transit time of the bowel thus increasing the time for nutrient reabsorption.
How does the remaining anatomy influence outcome?
The jejunum is the primary absorptive site for most nutrients. Jejunal resection thus leads to a deficiency of nutrients at least in the short term. Adaptation here is primarily functional.
The ileum is the primary site for B12 and bile acid absorption, and so resection here may lead to B12 and fat malabsorption.
Loss of the ileocecal valve has been associated with the need for longer term PN.
How is it managed?
Management requires a multidisciplinary team approach.
This focuses on the provision and monitoring of calories, micronutrients, fluids and electrolytes and growth. This is often provided for by a combination or parenteral (PN) and/or enteral nutrition. Although patients often require PN and home PN of some form for a long time, the ultimate goal is the successful weaning of PN to complete enteral nutrition, with sustained growth and maintenance of normal nutrition.
To normalise life for the child, parents and caregivers of children on PN are often trained in hospital to administer PN at home. PN bags are premixed and delivered weekly to their home. Home PN training is managed by a dedicated nursing team and delivery of the PN is coordinated by the pharmacist. Growth velocity and weight are reviewed by the dietician.
The medical team monitor nutrient levels and treat any complications which arise, as well as review the ratio of enteral nutrition to parenteral nutrition according to the child’s progress.
Some hospitals have special nutrition teams comprising nurses, pharmacists, dietician and doctors to ensure the child achieves his or her growth potential.
Long term parenteral nutrition is administered through central venous catheters which are placed by surgeons. Complications central venous catheters include line sepsis, thrombosis and migration.
Surgical intervention is also required for placement of feeding stomas such as a gastrostomy or jejunostomy. These feeding tubes allow for the administration of enteral feeds, either continually or in boluses.
1. Growth failure
2. Parenteral nutrition associated liver disease (PNALD)
Long term use of parenteral nutrition results in liver disease, which occurs in 40-60% of infants on PN. PNALD comprises of changes in liver histology including fibrosis and eventually cirrhosis and failure.
Strategies to prevent PNALD include early introduction and grading up of enteral feeds, cycling of PN and prevention of infection. Fish oil based lipid emulsion has been shown to reverse PNALD when compared to standard soybean based lipid emulsions. Oral ursodeoxycholic acid may also improve cholestasis.
3. Small bowel bacterial overgrowth (SBBO)
This occurs due to impaired motility of the bowel and bacterial reflux from the colon (with ileocecal valve resection or incompetence).
The loss of the terminal ileum is also a risk factor for bacterial overgrowth. SBBO can result in further malabsorption with failure to thrive, bacterial translocation causing sepsis, and D lactic acidosis, which occurs when the GI tract is colonised by D lactate producing organisms causing toxic blood levels, ataxia and delirium. Symptoms include abdominal pain, cramps, distension and diarrhoea. SBBO may also cause deficiency of fat soluble vitamins and B12.
Treatment may include cycling antibiotics such as metronidazole, trimethoprim plus sulphamethoxazole or rifaximin.
This is ether due to bacterial translocation from the bowel or catheter related infections. It is for the latter reason that home PN training to caregivers emphasises strict aseptic techniques. Some centres have begun trialling ethanol locks for tunnelled catheters to reduce the incidence of catheter related blood stream infections.
5. Micronutrient deficiencies
Patients are particularly susceptible to deficiencies in fat soluble vitamins and zinc, calcium, selenium, copper and magnesium.
When would we consider intestinal transplantation?
Indications for intestinal transplantation include:
- Impending and overt liver failure due to PNALD
- Thrombosis of 2 or more central veins
- 2 or more episodes per year of catheter related sepsis requiring hospitalization
- Line related fungaemia, septic shock or ARDS
- Frequent episodes of dehydration despite optimal fluid supplementation
Uko V, Radhakrishnan K, Alkhouri N. Short bowel syndrome in children: Current and potential therapies. Pediatr Drugs 2012;14(3):179–188.
Duro D, Kammin D, Duggan C. Overview of Pediatric Short Bowel Syndrome. JPGN 2008 47:S33–S36.