Short Bowel Syndrome

AUTHOR: Fred F. Ferri, MD

Definition

Short bowel syndrome (SBS) is a malabsorption syndrome that results from extensive small intestinal resection or congenital causes (Table E1).

TABLE E1 Daily Stomal or Fecal Losses of Electrolytes, Minerals, and Trace Elements in Severe Short Bowel Syndrome ^∗

Component		Amount Lost
Sodium		90-100 mEq/L
Potassium		10-20 mEq/L
Calcium		772 (591-950) mg/day
Magnesium		328 (263-419) mg/day
Iron		11 (7-15) mg/day
Zinc		12 (10-14) mg/day
Copper		1.5 (0.5-2.3) mg/day

^∗For sodium and potassium, the average concentration per liter of stomal effluent is given. Values for minerals and trace elements are mean 24-h losses, with the range in parentheses.

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

Synonyms

Short bowel

SBS

ICD-10CM CODE
K91.2		Postsurgical malabsorption, not elsewhere classified

Epidemiology & Demographics

Parallels Crohn disease (see “Crohn Disease” in Section I), which is the most common cause of the syndrome in adults.
In children, two thirds of short bowels are related to congenital abnormalities (intestinal atresia, gastroschisis, volvulus, aganglionosis) and one third are related to necrotizing enterocolitis.
Prevalence: 10,000 to 20,000 cases are estimated to exist in the U.S.

Physical Findings & Clinical Presentation

Diarrhea and steatorrhea
Weight loss
Anemia related to iron or vitamin B₁₂ absorption
Bleeding diathesis related to vitamin K malabsorption
Osteoporosis/osteomalacia related to vitamin D and calcium malabsorption
Hyponatremia, hypokalemia
Hypovolemia
Other macronutrient or micronutrient deficiency states

Etiology

Extensive bowel resection for treatment of the conditions mentioned previously (see “Epidemiology”). SBS typically does not occur until less than 200 cm of healthy small intestine remains. Risk for SBS is decreased if colon is intact.
Congenital.
Box E1 summarizes causes of short bowel syndrome.

BOX E1 Causes of Short Bowel Syndrome (SBS) and Intestinal Failure in Adults and Children

Adults

Catastrophic vascular accidents:

Superior mesenteric arterial embolism
Superior mesenteric arterial thrombosis
Superior mesenteric venous thrombosis

Chronic intestinal pseudoobstruction

Intestinal resection for tumor or trauma

Midgut volvulus

Multiple intestinal resections for Crohn disease

Radiation enteritis

Refractory sprue

Scleroderma and mixed connective tissue disease

Children

Congenital villus atrophy

Extensive aganglionosis

Gastroschisis

Jejunal or ileal atresia

^∗Necrotizing enterocolitis

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

The human intestine is 3 to 8 m in length. Removal of up to half of the small intestine produces no disruption in nutrient absorption, and most patients can maintain nutritional balance on oral feeding if they have more than 100 cm (3 ft) of jejunum. Similarly, 100 cm of intact jejunum can maintain a normal water, sodium, and potassium balance under normal circumstances. The presence of an intact colon can compensate for some small intestine loss.

Site-specific functions (Fig. E1):

Calcium, magnesium, phosphorus, iron, and vitamins are absorbed in the duodenum and proximal jejunum.
Vitamin B₁₂ and bile acids are absorbed in the ileum. The resection of more than 60 cm of ileum results in vitamin B₁₂ malabsorption. The loss of more than 100 cm results in fat malabsorption (from the loss of bile acids).
The loss of gastrointestinal endocrine hormones can affect intestinal motility.
Intestinal bacterial overgrowth may also occur, especially if the ileocecal valve is lost.
Macronutrient requirements in patients with SBS are summarized in Table E2.

Figure E1 Specific Areas of Absorption of Dietary Constituents and Secretions in the Small Intestine and Colon

Macronutrients and micronutrients are absorbed predominantly in the proximal jejunum. Bile acids and vitamin B₁₂ (cobalamin) are absorbed only in the ileum. Electrolytes and water are absorbed in both the small and large intestine. Medium-chain triglycerides (MCTs), calcium, and some amino acids can be absorbed in the colon.

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

TABLE E2 Macronutrient Requirements in Patients With Short Bowel Syndrome

Colon Present		Colon Absent
Carbohydrate
Complex carbohydrates/starches		Variable types
30-35 kcal/kg per day		30-35 kcal/kg per day
Soluble fiber
Fat
MCT/LCT		LCT
20%-30% of caloric intake		20%-30% of caloric intake
Protein
Intact protein		Intact protein
1.0-1.5 g/kg per day		1.0-1.5 g/kg per day

LCT, Long-chain triglycerides; MCT, medium-chain triglycerides.

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

∗Functional SBS can also occur in conditions associated with severe malabsorption and intact bowel length.

Extensive small bowel resection with colectomy (<100 cm of jejunum):

Rx: Long-term total parenteral nutrition (TPN). Some patients can switch to oral intake after 1 to 2 yr of TPN. In jejunostomy patients, excessive fluid loss can be reduced with H₂ blockers, proton pump inhibitors, or octreotide. Micronutrients are supplemented.

Extensive small bowel resection with partial colectomy (usually patients with Crohn disease):

Rx: Oral intake alone is possible in all patients with >100 cm of jejunum. In addition to vitamin B₁₂ deficiency, these patients often have diarrhea. Consider lactose malabsorption and bacterial overgrowth treated, respectively, with lactose restriction and antibiotics (tetracycline 250 mg PO tid or metronidazole 500 mg PO tid for 2 wk). Nonspecific antidiarrheal agents may also be indicated (e.g., Imodium or codeine). The patient must be monitored for micronutrient losses.
Table E3 and Fig. E2 summarize management strategies for SBS. Intestinal transplantation is performed mostly in children at selective centers.
Therapeutic agents used to decrease intestinal transit and diarrheal volume are summarized in Table E4.
FDA-approved medications for SBS in patients receiving nutritional support are:
1. Recombinant growth hormone somatropin (Zorbtive): Effective in increasing weight and reducing parenteral nutrition volume. These effects do not persist when the drug is stopped.
2. Teduglutide (Gattex), a recombinant DNA analog of glucagon-like peptide-2. It promotes mucosal growth in the small bowel through stimulation of crypt cell proliferation and inhibition of enterocyte apoptosis. This drug may have to be continued indefinitely for effects to persist.

Figure E2 Algorithm for management of the patient with short bowel syndrome.

H2RA, Histamine 2 receptor antagonist; IV, intravenous; MCT, medium-chain triglycerides; PPI, proton pump inhibitor; TPN, total parenteral nutrition.

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

TABLE E3 Management Strategies for Short Bowel Syndrome

Acute phase
1. Treat postoperative complications
2. Maintain full support via the parenteral route
3. Initiate low-rate trophic enteral feeds
4. Document amount and site of remaining bowel and underlying disease
Early adaptation (up to 1 yr postsurgery)
1. Increase enteral nutrition to tolerance; supplement with glutamine
2. Achieve permanent parenteral access, if indicated
3. Maximize antiperistaltic agents
4. Octreotide for high-output ostomy or fistula
5. Dietary counseling
6. Clinical trials of trophic growth factors
Long-term adaptation (>1 yr postsurgery)
1. Recruit bypassed bowel
2. Bowel-lengthening procedure (Bianchi or STEP)
3. Monitor for development of TPN-associated complications, and refer for transplant before recurrent sepsis, thrombosis, or end-stage liver disease

STEP, Serial transverse enteroplasty; TPN, total parenteral nutrition.

From Cameron JL, Cameron AM: Current surgical therapy, ed 10, Philadelphia, 2011, Saunders.

TABLE E4 Therapeutic Agents Used to Decrease Intestinal Transit and Diarrheal Volume in Patients With Short Bowel Syndrome (SBS)

Agent		Dosage
Loperamide ^∗		4-6 mg 4× daily
Diphenoxylate-atropine ^∗		2.5-5 mg 4× daily
Codeine phosphate ^∗		15-60 mg 2-4× daily
Tincture of opium		0.6 ml (2.5 mg) 2-4× daily
Ranitidine ^†		300 mg twice daily
Omeprazole ^‡		40 mg twice daily
Octreotide		50-100 μg SC twice daily
Clonidine		0.3 mg transcutaneous patch once weekly

SC, Subcutaneously.

^∗The antidiarrheal agents loperamide, diphenoxylate-atropine, and codeine phosphate are given 1 h before meals and at bedtime. Dosages may be increased over those recommended because of incomplete absorption in patients with SBS.

^†Cimetidine, famotidine, and nizatidine are alternatives.

^‡Esomeprazole, lansoprazole, rabeprazole, and pantoprazole are alternatives.

From Feldman M et al: Sleisenger and Fordtran’s gastrointestinal and liver disease, ed 10, Philadelphia, 2016, Elsevier.

Complications

Oxalate kidney stones
Cholesterol gallstones
D-Lactic acidosis

Prognosis

Directly dependent on the extent of the bowel resection and in the case of Crohn disease by the underlying illness.
Whether the colon remains in continuity with the small bowel is an important factor in the patient’s ability to adapt after significant small bowel resection.

Related Content

Short Bowel Syndrome (Patient Information)

Malabsorption (Related Key Topic)

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Basic Information ⬇

Diagnosis ⬆ ⬇

Treatment ⬆