Introduction
Short bowel syndrome (SBS) is a form of intestinal failure that most often results from surgical resection related to Crohn disease, mesenteric infarction, radiation enteritis, or surgery for recurrent bowel obstructions. It is characterized by the inability to absorb protein/energy requirements or to maintain fluid, electrolyte, or micronutrient balance when consuming a normal diet. After surgical resection, the remaining small intestine undergoes structural and functional adaptation over 1 to 2 years that gradually improves absorption. Successful medical management of SBS is dependent on a combination of diet, medications, oral or tube enteral supplements, parenteral nutrition (PN), and intestinotrophic hormones ( Fig. 72-1 ).
Anatomy of Short Bowel Syndrome
A thorough evaluation of the patient’s remaining gastrointestinal tract is the basis for making therapeutic recommendations. Operative reports should have antimesenteric measurements of residual bowel, its location, and any gross pathologic changes. In addition, the extent and location of bypassed segments should be noted as an aid to potential reconstruction in the future. An upper gastrointestinal barium radiograph with small bowel follow-through or computed tomography (CT) scan enterography provide an estimate of the length of the remaining small bowel. Three anatomic configurations of SBS that have management and outcomes implications have been described. Type 1 is an end jejunostomy with most of the small intestine and all of the colon either resected or out of continuity. A minimum of 100 cm of intestine is needed to avoid permanent PN. Type 2 is a remnant small bowel anastomosed to part of the colon. In this configuration, at least 60 cm of residual small intestine is required to avoid permanent PN. Type 3 anatomy is a jejunoileal colonic anastomosis with the entire colon intact, in which case at least 30 cm of small intestinal length is required to avoid permanent PN. Table 72-1 summarizes the anatomic factors favoring enteral autonomy and anatomic configurations that make permanent PN dependence likely. Plasma citrulline levels lower than 20 μmol/L in adults and 15 μmol/L in pediatric patients also have been associated with permanent dependence on PN. Citrulline is produced mainly by small intestinal enterocytes, and its level correlates with residual small intestine length and functional enterocyte mass.
| Factors Favoring Enteral Autonomy | Factors Associated with Parenteral Nutrition Dependence |
|---|---|
| Length of remaining bowel >30 cm of small bowel with colon >100 cm of small bowel alone Jejunum resection Preserved ileocecal valve Presence of colon Absence of mucosal disease Normal hepatic and pancreatic function | Jejunoileal anastomosis and remaining small bowel length <35 cm Jejunocolic anastomosis and remaining small bowel length <60 cm Large ileal resection Patients with end jejunostomy and remaining small bowel length <115 cm |
Dietary Management of Short Bowel Syndrome
Patients should follow strict dietary guidelines established by a dietitian with expertise in the management of SBS. These guidelines include eating frequent meals and the avoidance of simple carbohydrates (foods with sugar) in favor of complex carbohydrates (e.g., pasta). See Table 72-2 for diet guidelines based on the patient’s anatomy. Patients should be encouraged to avoid drinking hyperosmolar beverages such as fruit juices and hypo-osmolar beverages like water, which increase gastrointestinal fluid output in persons with SBS. Sipping of an isotonic oral rehydration solution (ORS) throughout the day should be encouraged to maximize intestinal fluid reabsorption. ORS is a glucose–electrolyte solution that promotes water reabsorption by way of the sodium–glucose cotransport mechanism and is used to treat cholera-associated diarrhea. ORS recipes are shown in Table 72-3 . After large resections, oral multivitamins should be given twice daily and fat-soluble vitamins (A, D, E, and K) and trace element levels should be monitored. Table 72-4 shows deficiency manifestations and repletion doses for common vitamins and trace elements. Magnesium and potassium deficiencies are also very common and require careful monitoring with oral or intermittent intravenous (IV) repletion.
| Physiology of Macronutrient Absorption | Diet with Colon | Diet without Colon |
|---|---|---|
| CHO will reduce osmotic load and delay intestinal transit | Complex CHO (50%-60%) | Complex CHO (40%-50%) |
| Simple sugars have a greater osmolality resulting in increased intestinal losses | Low simple sugar | Low simple sugar |
| Protein is generally well tolerated | Protein (20%-30%) | Protein (20%-30%) |
| High fat intake may worsen malabsorption in patients with a colon by inducing choleraic diarrhea, whereas fat intake can be used as a source of additional calories for weight gain in patients without a colon | Low fat (20%-30%) | Moderate fat (30%-40% or more) |
| To maximize absorption, patients should be encouraged to eat small frequent meals or snacks throughout the day and to limit the amount of fluid consumed with food | Small frequent meals | Small frequent meals |
| Homemade ORS | Gatorade ORS | Gatorade G2 ORS |
|---|---|---|
| 1 L water 2/3 tsp salt 2 Tbsp sugar Sugar-free flavoring to taste | 2 cups Gatorade 2 cups water ½ tsp salt | 4 cups Gatorade G2 ½ tsp salt |
| Vitamin | Clinical Manifestations | Repletion Dose |
|---|---|---|
| Vitamin A | Night blindness, dry skin, decreased saliva, diarrhea, headache, vomiting, hair loss, liver damage | 5000-50,000 IU/day |
| Vitamin B6 | Dermatitis, glossitis, anemia, seizures, peripheral neuropathy | 50-150 mg/day |
| Vitamin B12 | Macrocytic anemia, fatigue, paresthesia of hands or feet, dementia, glossitis | 1000 mcg IM 1-4×/month |
| Vitamin D 25-hydroxy | Rickets, osteomalacia, reduced serum calcium, muscle twitching | 1000-50,000 IU/day |
| Vitamin E | RBC hemolysis, edema, skin lesions, anemia, neurologic symptoms | 150-450 IU/day |
| Copper | General weakness, skin sores, bone disease, vomiting, diarrhea, anemia, peripheral neuropathy | 4-6 mg/day |
| Zinc sulfate | Diarrhea, anorexia, prolonged wound healing, skin disorders, muscle pain | 50-150 mg elemental/day |
| Selenium | Nausea, vomiting, abdominal pain, hair and nail changes, nerve damage, fatigue | 200 mcg/day |
Dietary Management of Short Bowel Syndrome
Patients should follow strict dietary guidelines established by a dietitian with expertise in the management of SBS. These guidelines include eating frequent meals and the avoidance of simple carbohydrates (foods with sugar) in favor of complex carbohydrates (e.g., pasta). See Table 72-2 for diet guidelines based on the patient’s anatomy. Patients should be encouraged to avoid drinking hyperosmolar beverages such as fruit juices and hypo-osmolar beverages like water, which increase gastrointestinal fluid output in persons with SBS. Sipping of an isotonic oral rehydration solution (ORS) throughout the day should be encouraged to maximize intestinal fluid reabsorption. ORS is a glucose–electrolyte solution that promotes water reabsorption by way of the sodium–glucose cotransport mechanism and is used to treat cholera-associated diarrhea. ORS recipes are shown in Table 72-3 . After large resections, oral multivitamins should be given twice daily and fat-soluble vitamins (A, D, E, and K) and trace element levels should be monitored. Table 72-4 shows deficiency manifestations and repletion doses for common vitamins and trace elements. Magnesium and potassium deficiencies are also very common and require careful monitoring with oral or intermittent intravenous (IV) repletion.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
