What is short bowel syndrome?
Short bowel syndrome (SBS) or short gut syndrome, is a condition in which the body can’t absorb enough fluids and nutrients because part of the small intestine is missing or isn’t working properly. Short bowel syndrome can be congenital (present from birth), or conditions may develop in which a large section of the small intestine has to be removed by surgery.
What does the small intestine do?
The small intestine is a part of the digestive system. The small intestine has three sections:
- The duodenum, which is located next to the stomach (shortest section).
- The jejunum, which lies between the duodenum and the ileum.
- The ileum, which is the longest section and connects to the large intestine (colon).
The small intestine absorbs fluids, proteins, carbohydrates (starches and sugars), iron, fats, vitamins and minerals (such as calcium, sodium and potassium).
If the duodenum and a portion of the jejunum have been removed by surgery, the ileum can take on their role in absorbing nutrients. But if a substantial part of the jejunum or the ileum is removed, it’s hard to get adequate nutrition. In these cases, nutrients usually have to be provided in a form other than food.
Children need more calories than adults because they are still growing. If a child is born with portions of the small intestine missing, it can lead to serious problems.
Symptoms and Causes
What causes short bowel syndrome?
Short bowel syndrome can occur as a congenital (present at birth) condition. For example, the small intestine might be abnormally short at birth, a section of the bowel might be missing or the bowel does not form completely before birth (intestinal atresia).
In other cases, patients develop conditions in which a large section of the small intestine has to be removed by surgery. In newborns, especially premature infants, necrotizing enterocolitis (the inflammation and loss of blood flow to the intestine, leading to severe damage) is the most common cause of short bowel syndrome.
Other causes include:
- Crohn's disease (the intestine becomes inflamed and scarred); in this condition, SBS occurs primarily in patients who have undergone extensive surgery to the small bowel.
- Intussusception (part of the intestine is folded into another part and compromises the blood flow to the involved portion of the intestine).
- Injury to the intestine due to:
- Volvulus (twisting of the intestine).
- Trauma (injury).
- Gastroschisis (when the intestines develop outside the body prior to birth).
- Narrowing or obstruction of the intestines.
- Blood clots or abnormal blood flow (ischemia) affecting the circulation to the intestine.
What are the symptoms of short bowel syndrome?
Symptoms of short bowel syndrome include:
- Diarrhea. Watery diarrhea is the most common symptom of short bowel syndrome in infants and children.
- Excessive gas and/or foul-smelling stool.
- Poor appetite.
- Weight loss or inability to gain weight.
Other complications can occur as a result of short bowel syndrome, including:
Management and Treatment
How is short bowel syndrome in children treated?
A variety of treatments may be required in order to treat SBS in children:
To absorb nutrients correctly, changes need to be made to the diet. If surgery was done to remove part of the small intestine, patients need a normal balance of electrolytes, fluids and other nutrients to prevent dehydration, malnutrition and other problems.
Total parenteral nutrition (TPN)
The child may need total parenteral nutrition (TPN) after bowel surgery. TPN provides nourishment while bypassing the digestive system. TPN solutions contain a mixture of fluids and nutrients, such as protein, fats, sugars, and essential vitamins and minerals.
The solutions are given intravenously (through a large vein into which a catheter, a flexible plastic tube, has been inserted). TPN is given over 10 to 12 hours or sometimes longer; infants and children usually receive this type of solution while sleeping.
Some children must remain on TPN indefinitely. Serious complications can occur when this form of nutrition is used over the long term, such as infection at the site where the catheter is inserted, the formation of blood clots and liver damage.
Despite the risk of complications, TPN can be lifesaving in children and adults unable to take in appropriate nutrition through their gastrointestinal tract. In addition, recent changes in TPN regimens, when combined with starting feeds early on, may decrease the chance of developing a long-term liver injury.
Over time, enteral nutrition can replace TPN in some patients. Enteral feeding is given through a gastric tube (g-tube) inserted in the stomach via a surgical incision or placed using an endoscope. In some cases, a nasogastric (NG) tube that passes from the nose into the stomach might be used instead of the g-tube. In other patients, the use of a similar tube placed in the small intestine (jejunostomy tube or j-tube) is an alternative.
Some children may be able to receive small amounts of solid food and liquids in addition to enteral or parenteral (intravenous) feeding. This helps to allow babies and children to maintain the ability to chew and suck and helps them develop normal eating patterns in the future.
In some cases, patients who have had a part of their intestine removed by surgery undergo a process called intestinal adaptation. During intestinal adaptation, the intestine may grow in size after surgery. The surface area inside the intestine increases as the mucosa (lining of the intestine) becomes thicker. The villi (the lining of the intestine responsible for intestinal absorption) become longer and denser, helping to promote absorption of nutrients. The diameter of the intestine may also increase.
What medications are prescribed for short bowel syndrome?
Medications may be used to help slow the passage of food through the intestine. This allows more time for the nutrients to remain in contact with the cells lining the intestine, which improves absorption.
Anti-diarrhea drugs such as loperamide hydrochloride can be given to children, if recommended by their provider, with limited side effects. Since the stomach is likely to secrete greater amounts of acid during the recovery period, patients can take antacids or an anti-ulcer medication to treat or reduce the risk of stomach ulcers. Antibiotics may be prescribed on occasion to prevent or treat bacterial overgrowth.
Newer medications like teduglutide, a medication given via injection have been approved in adults with SBS but not in children by the FDA. These medications can help reduce TPN requirements in some SBS patients but will require study in children and have potential significant side effects.
When is surgery needed for short bowel syndrome?
In some cases, surgery for SBS can be done to improve the working length of the intestine by various procedures such as Bianchi procedure and serial transverse enteroplasty procedure (STEP). These procedures may also help decrease the chance of bacterial overgrowth by narrowing the diameter of the intestine which may be increased in cases of SBS.
The decision if surgery will help improve an individual patient’s functional status is made on a case-by-case basis. This often depends on the length of the small intestine that is present, as well as the underlying cause of the SBS.
Intestinal transplantation involves placing a donor small intestine into the patient. This may be considered for patients who cannot use their intestine to absorb food and fluids, are entirely dependent on TPN and are at risk of losing access sites for intravenous nutrition.
Liver transplantation may be required at the same time if patients develop irreversible liver disease from long-term TPN use. Since very few centers perform intestinal transplant, an early referral to a transplant center helps in planning the transplant prior to the development of major complications.
Outlook / Prognosis
What is the prognosis (outlook) for children who have short bowel syndrome?
The prognosis for infants and children who have short bowel syndrome can be good, depending on the residual length of the intestine. However, they will need lifelong follow-up care. Children need to be closely monitored for any nutritional deficiencies or other conditions that may result from continued use of enteral or parenteral nutrition. Overall, quality of life and chance of coming off TPN have improved with a better understanding of the problem and preventing complications.
The main causes of death among infants and children who receive parenteral nutrition are infections and disorders of the liver and biliary tract (the pathway by which bile flows from the liver to the small intestine). Infectious complications may become less frequent with recent advances in protocols for the care of central lines in children. Cholestasis (a condition where bile cannot flow from the liver to the duodenum) is a common complication following long-term use of total parenteral nutrition. Newer approaches to managing TPN have helped to decrease the chance of cholestasis and associated liver disease.
A team approach involving pediatric gastroenterologists, pediatric dietitians, pharmacists, pediatric surgeons and transplant surgeons, and social workers is vital in managing and improving outcomes in patients with short bowel syndrome.