What are Some of the Complications of Short Bowel Syndrome?

Patient Presentation
A 6-year-old female came to clinic for her health maintenance visit. She was excited about starting first grade as she had liked kindergarten. Her mother was concerned about the increased academic challenges of first grade, but said, “Last year she started to have an aide in the classroom and that will continue this year. Plus we have met the teacher who seems to understand her medical needs too.”

The past medical history showed that the girl had been born at 27 weeks gestation and had had necrotizing enterocolitis that required surgery and subsequent short bowel syndrome. She had 60 cm of bowel remaining after the surgery and retained her ileocecal valve. She had had an intestinal stricture and 2 surgical explorations for potential bowel obstruction. She had been on parenteral nutrition until she was 4.5 years of age but now was eating orally but still required speech therapy. She was known to have mild intellectual disability and was still receiving occupational therapy and physical therapy. Her main medical issues were managed by a gastroenterologist as she had fewer problems or complications at this time.

The pertinent physical exam revealed weight and length at the 5th percentile but tracking. Mild dolicochephaly could be appreciated. Her heart and lungs were normal. Her abdomen had multiple surgical scars. Neurologically she was a pleasant female who acting younger than her age. She had some mild hypertonia in her lower extremities.

The diagnosis of a well 6 year old with a history of prematurity, necrotizing enterocolitis with short bowel syndrome, and mild intellectual disability who was making good progress despite her past medical history. The pediatrician reviewed her multispecialty followup care which was decreasing in frequency overall, and provided her regular preventative health care including seasonal influenza vaccine. “Remember that I can try to help you with the school issues too if things come up. Dr. Rodriguez is really good with her medicine and eating, but I’m probably better with the school and therapies,” the pediatrician reminded the mother.

Necrotizing enterocolitis (NEC) is one of the most common gastrointestinal emergencies in neonates. Mortality rates are from 0-45% depending on infant weight and gestation with more premature and smaller infants having greater mortality. NEC usually occurs in premature infants but it also occurs in term infants. The etiology is unknown but is probably multifactorial with ischemia and/or reperfusion playing some role. There are ‘outbreaks’ of NEC but no causative organism has been identified. Regardless of the originating cause, inflammation of the intestine and release of inflammatory mediators causes various degrees of damage to the intestine. Patients who had a history of surgically treated NEC have an increased risk of neurodevelopmental disabilities such as the patient above. Treatment includes stopping gastric feeding, antibiotics, possible surgery and other supportive measures such as treatment for hypotension and respiratory failure.

Presenting signs of NEC can be subtle but can include:

  • Feeding intolerance
  • Delayed gastric emptying
  • Apnea
  • Abdominal distention and/or tenderness
  • Bleeding diathesis
  • Blood in the stool – obvious or occult
  • Decreased bowel sounds – i.e. ileus
  • Erythema of the abdominal wall
  • Lethargy
  • Shock and/or poor perfusion
  • Abnormal laboratory testing can include metabolic acidosis, hyponatremia, leukocytosis or leukopenia or thrombocytopenia.

Intestinal failure is a broad term that includes short bowel syndrome (SBS – 80% of cases) but also congenital enterocyte disorders and motility disorders.

Short bowel syndrome (is the loss of bowel (congenital or acquired) that results in inadequate ability to meet the patient’s nutritional needs without supplemental nutrition that is enteral or parenteral. “SBS is associated with excessive fluid and electrolyte losses and results in significant malabsorption of macronutrients, vitamins and minerals. This ultimately affects the ability to gain weight, grow, develop normally and is uniformly fatal if untreated.“ SBS causes malnutrition, failure to thrive, and recurrent infections. A clinical definition is a need for parenteral nutrition more than 60 days after bowel resection or a bowel length less than 25% of expected.

Common causes of SBS are necrotizing enterocolitis (~30% of cases) gastroschisis, Hirschsprung disease with proximal extension, intestinal atresia, and malrotation with midgut volvulus. Crohn’s disease is also a problem but more common in the adult population due to multiple intestinal resections.

The ultimate goal of SBS treatment is to restore enteral autonomy by increasing the absorptive ability of the remaining intestine. Supportive treatment and problem management is the mainstay as the intestine adapts to its own new reality. This adaption occurs mainly in the first 2 years after surgery but can continue up to 5 years.

At end of the second trimester of gestation, the bowel length is ~120 cm versus ~250 cm at term gestation. A general rule is 40 cm needs to remain for autonomous enteral function but patients with less may have enteral function and those with more may not. Improved risk factors include increased bowel length, site of remaining bowel (proximal is better), ileocecal value remaining intact, and presence of the colon. The ileocecal valve slows intestinal transit time and helps to limit bacterial translocation of colonic contents. The ileum also is an important area for fluid and electrolyte absorption and also bile acid and vitamin B12 absorption. Therefore retaining the ileocecal value and the area as much as possible is important.

Premature infants have increased risk of SBS because they have more risk of NEC, have shorter bowel segments to begin with, and are at risk for multiple of health problems which may complicate SBS management.

Learning Point
Treatment of patients is multimodal and treatment with one entity may help or hinder another potential problem.
Complications of SBS include:

  • Bile acid malabsorption – treated with bile acid binding resin
  • Electrolyte management – because of increased transit and decreased absorption, output including electrolytes must be monitored closely. This includes especially sodium but also magnesium
  • Gastric acid hypersecretion – treated with H2 blockers and proton pump inhibitors
  • Intestinal transit, increased – treated with anti-motility agents, soluble fiber, creation of intestinal valves
  • Intestinal absorption, decreased – treated with glucagon-like peptide analogue
  • **Nutritional support – parenteral (PN) or enteral nutrition. The preferred choice of enteral feeding is human milk or if not available then amino acid-based formulas for infants. The best chance of long term success is to institute enteral feedings as soon as possible. PN also has its own potential problems including catheter associated infections, vascular thrombosis and hepatic toxicity.
  • **Nutritional supplementation – fat soluble vitamins (e.g. A, D, E, and K) and trace metals (i.e. copper, manganese, selenium). Iron is also important especially with PN. Infection management – small bowel overgrowth, catheter-related, body space related
  • Surgical complications – surgical tenants in general are to preserve/salvage as much intestine as possible, restore bowel continuity as soon as possible, use measures to prevent abdominal compartment syndrome, removal of PN access lines as soon as possible. Additional surgical measures may include various lengthening or tapering procedures, creation of intestinal valves, and bowel and/or liver transplantation. Other surgical problems can include intestinal stricture or adhesion. Transplantation also comes with its own set of surgical and medical problems especially acute and chronic rejection.

** cornerstones of management

Questions for Further Discussion
1. How common is pneumatosis with necrotizing enterocolitis? A review can be found here
2. What information should be in a school health plan for a child with special needs? A review can be found here
3. What are some complications of prematurity?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Malabsorption Syndromes and Small Intestine Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Rich BS, Dolgin SE. Necrotizing Enterocolitis. Pediatr Rev. 2017;38(12):552-559. doi:10.1542/pir.2017-0002

Jaksic T. Short bowel syndrome (by Tom Jaksic and Biren Modi). Semin Pediatr Surg. 2018;27(4):207-208. doi:10.1053/j.sempedsurg.2018.07.010

Chandra R, Kesavan A. Current treatment paradigms in pediatric short bowel syndrome. Clin J Gastroenterol. 2018;11(2):103-112. doi:10.1007/s12328-017-0811-7

Federici S, De Biagi L. Long Term Outcome of Infants with NEC. Curr Pediatr Rev. 2019;15(2):111-114. doi:10.2174/1573396315666181130144925

Bazacliu C, Neu J. Necrotizing Enterocolitis: Long Term Complications. Curr Pediatr Rev. 2019;15(2):115-124. doi:10.2174/1573396315666190312093119

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa