Pediatrics

Pediatric Malnutrition Syndromes: Short bowel syndrome

OVERVIEW: What every practitioner needs to know

Are you sure your patient has Short Bowel syndrome? What are the typical findings for this disease?

Short Bowel syndrome is a complex condition due to an underlying congenital disease or a surgical resection resulting in a significant reduction in the length of small bowel.

Common causes include necrotizing enterocolitis (NEC), congential intestinal atresias, abdominal wall defects, and midgut volvulus. The bowel resection can lead to a malabsorptive state causing deficiency of nutrients and also a heightened susceptibility to serious and systemic infections.

The amount of bowel resected and the length of the remaining bowel determine the extent of the malabsorption, which, in turn, will also determine the need for specialized enteral or parenteral nutrition. With the advent of total parenteral nutrition (TPN), long term survival has steadily increased.

Short Bowel syndrome occurs following major bowel resection. Patients develop diarrhea and malabsorption of nutrients with large-volume, foul-smelling stools. The patient may develop vitamin and mineral deficiencies. Bacterial overgrowth within the remaining bowel may become an issue when enteral feeds are tolerated. Also, many patients undergoing bowel resection will need long term TPN, increasing their risk of catheter related infections and central line sepsis. Long term TPN use can also lead to cholestasis and liver disease.

What other disease/condition shares some of these symptoms?

Colitis

Severe malnutrition

Anastamotic ulcer

Chronic diarrhea

What caused this disease to develop at this time?

  • Occurs after a resection of a portion of small bowel. In a newborn, the main cause is necrotizing enterocolitis (NEC) leading to an ischemic portion of bowel that must be resected. This is more common in premature infants, as incidence decreases with increased gestational age.

  • Other causes of intestinal resection are intestinal atresias, abdominal wall defects (i.e. gastroschisis, omphalocele), midgut volvulus.

  • Rarely bowel resection for Hirschsprung disease will result in short gut due to the involvement of small bowel.

  • The resection leads to compromised intestinal function causing malabsorption of nutrients, fluids, and electrolytes.

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

  • CMP: monitor hydration status, electrolyte balances

  • CBC: monitor leukocytosis

  • Vitamin levels: to monitor deficiencies due to malabsorption

  • Stool studies: rule out infectious causes of diarrhea

Would imaging studies be helpful? If so, which ones?

Upper GI series: looks for variations in anatomy. This will also help to assess if dilatation of the small bowel is present. Can also picture narrowed segments caused by stricturing.

Barium enema: allows for the ability to look for strictures.

Liver ultrasound: Should obtain study with a doppler. The doppler allows you to assess the direction of portal flow. This study will also help to determine if ascites is present.

If you are able to confirm that the patient has Short Bowel syndrome, what treatment should be initiated?

Introducing early enteral therapy is actually beneficial when trying to rehabilitate the small intestine after resection. This allows the intestine to adapt accordingly with the hopes of eventually discontinuing parenteral nutrition. Enteral feeds should initially be given by gastrostomy tube at a continuous rate, as these feedings are better tolerated. Formula given should contain long chain fatty acids with a high protein content and low carbohydrate load. These elemental formulas allow those with short gut to take in already broken down proteins, which make it easier for digestion.

Start a multivitamin consisting of the fat soluble vitamins A, D, E, and K. These levels will be depleted secondary to the malabsorption.

Because of the increased amount of fluid losses due to malabsorption, patients often require IV fluids and TPN. Those patients on long term parenteral nutrition are susceptible to TPN induced cholestasis and can receive Ursodiol at a dose of 10mg/kg/dose twice a day. It is important to understand that this medication should only be given if the patient is receiving enteral feeds. It is also important to know that this medication can increase stool output.

Over time, patients will have dysmotility, which can impair advancements of enteral feeds. In these cases, promotility agents can be administered. Dysmotility can also lead to impaired flow of bowel contents. This impaired flow can harbor increased bacterial growth leading to bacterial overgrowth, which will worsen the stool frequency and the malabsorption. To treat overgrowth, start Bactrim 3 mg/kg/dose bid or Flagyl 10 mg/kg/dose bid. These medications should be cycled on a weekly to biweekly course.

In those patients with increased stool output, you can start Loperamide at 0.1 mg/kg/dose four times a day.

Increased gastric acid is encountered and the amount of acid secreted is usually increased with larger segmented resections. You can treat this with either a H-2 blocker (i.e. Ranitidine) or a proton pump inhibitor (PPI).

If there is dilatation of the small bowel, with impaired function, and the inability to advance enteral feeds, then consideration must be given to surgical lengthening. The most common operation is called a serial transverse enteroplasty (STEP) and it results in lengthening of the bowel. It also reduces the diameter of the bowel, which should reduce bacterial overgrowth.

What are the adverse effects associated with each treatment option?

When introducing enteral therapy, one must carefully monitor the patient's fluid and electrolyte balance. The increased amount of enteral nutrition can result in osmotic diarrhea. If the carbohydrate load is too large, the stool will be positive for reducing substances.

Those patients who require long term parenteral nutrition or IV hydration will require a centrally placed catheter. This catheter can be a set up for line sepsis and will result in treatment of IV antibiotics. Repeated infections can also lead to multiple line changes, which eventually can compromise the patient's vascular access. If multiple infections have occurred, an ethanol lock can be placed only when the patient is infection free. This lock administers a small amount of ethanol for a few hours three times per week. It is important to know that the patient is unable to receive Metronidazole for bacterial overgrowth if an ethanol lock has been placed.

Long term TPN can lead to significant damage to the liver resulting in cholestasis. To prevent cholestasis from occurring, it is important to establish lipid lowering methods, cycling, and/or lipid modification.

Though Loperamide is used to decrease intestinal motility, it can also increase the risk of bacterial overgrowth.

While Ursodiol can improve cholestasis by facilitating bile flow, it can also cause increased stool output.

Treating increased gastric acid secretion with an H-2 blocker or a PPI can alter the normal pH leading to increased bacterial overgrowth.

What are the possible outcomes of Short Bowel syndrome?

With the advent of parenteral nutrition, the long term survival has steadily increased. The eventual goal is to rehabilitate the intestine to have sole dependence on enteral nutrition and minimizing the complications of treatment.

In those patients who are dependent on TPN to maintain adequate nutrition, the most important risk is related to catheter related infections. With repeated infections, vascular access can be compromised. If intestinal rehabilitation is successful, TPN will be weaned. However, some may still require IV fluid supplementation to prevent dehydration.

While each therapeutic option can be of benefit, it is important to know the adverse effects of each treatment option. The key is to improve long term survival by preventing potential complications.

If the patient fails intestinal rehabilitation, intestinal transplantation can be an alternative. However, transplantation has its own complications including immunosuppression leading to post-transplantation lymphoproliferative disorder and rejection.

What causes this disease and how frequent is it?

Short bowel syndrome occurs after a significant resection of a portion of small bowel. In a newborn, the main causes are due to necrotizing enterocolitis (NEC) leading to an ischemic portion of bowel. This condition is more common in pediatric infants, as incidence decreases with increased gestational age.

Other causes of resection are due to intestinal atresias, abdominal wall defects (i.e. gastroschisis, omphalocele), midgut volvulus.

There have been cases of Hirschsprung disease resulting in short gut to the involvement of small bowel.

Overall incidence has been reported to be 1200 per 100,000 live births. However, the mortality rate of this condition is relatively high. Survival rates have been reported to be in the range of 73% - 89%.

How do these pathogens/genes/exposures cause the disease?

Other clinical manifestations that might help with diagnosis and management

In those patients who do not respond well to enteral feeds, it is important to obtain an upper GI series with small bowel follow through to look at the affected segment of bowel. If there is small bowel dilatation with impaired function, the patient may be a candidate for a surgical procedure to lengthen the bowel without losing any surface area.

What complications might you expect from the disease or treatment of the disease?

- osmotic diarrhea, especially when trying to advance enteral feeds

- catheter related infections (line sepsis)

- failure to thrive

- D lactic acidosis

- carbohydrate malabsorption

- TPN dependence and TPN induced cholestasis

- bacterial overgrowth

- dehydration

- malnutrition and vitamin deficiencies

- anastomotic strictures

Are additional laboratory studies available; even some that are not widely available?

How can Short Bowel syndrome be prevented?

What is the evidence?

Duro, D, Kamin, D, Duggan, C. "Overview of Pediatric Short Bowel Syndrome". J Pediatric Gastroenterol Nutri. vol. 47. 2008. pp. S33-S36.

Raphael, B, Nurko, S, Jian, H, Hart, K, Kamin, D, Jaksic, T, Duggan, C. "Cisapride Improves Enteral Tolerance in Pediatric Short Bowel Syndrome with Dysmotility". J Pediatr Gastroenterol Nurt. vol. 52. 2011 May. pp. 590-4.

Cserni, T, Takayasu, H, Muzsnay, Z, Varga, G, Murphy, F, Folaranmi, SE, Rakoczy, G. "New idea of intestinal lengthening and tailoring". Pediatr Surg Int. 2011 April 17.

Vanderhoof, JA, Walker, WA, Watkins, JB, Duggan, C. "Nutrition in Pediatrics". BC Decker. 2003.

Modi, B. "Improved Survival in a Multidisciplinary Short Bowel Syndrome Program". Journal of Pediatric Surgery. 2008. pp. 20-24.

Ongoing controversies regarding etiology, diagnosis, treatment

Studies regarding the use of Cisapride have been recently done to improve intestinal motility. The dose used is 0.1 - 0.2 mg/kg/dose three to four times per day. Unfortunately, the study quoted showed 20% of the cohort group had QT prolongation (Raphael B, et al. Cisapride Improves Enteral Tolerance in Pediatric Short Bowel Syndrome with Dysmotility. J Pediatr Gastroenterol Nurt. 2011).

Bianchi and STEP procedures have been performed to increase the intestinal length. The Bianchi is a challenging operation and only increases the diameter by half and double the length. The STEP is easier, but it actually changes the orientation of the muscle fibers. A new procedure called the SILT, of Spiral Intestinal Lengthening and Tailoring is being researched. This operation was performed only with a simulator and showed a lengthening of 60% and an increase in diameter by 33% (Cserni T, et al. New idea of intestinal lengthening and tailoring. Pediatr Surg Int. 2011 April 17).

There have been studies in regards to lipid limitation in parenteral nutrition with omega 3 fatty acids and Omegaven. These products have been studies to prevent TPN induced cholestasis and seem promising.

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