Short Bowel Syndrome Definition and Management

Definition and Diagnostic Criteria

Short bowel syndrome (SBS) is a clinical pathological syndrome resulting from the loss of intestinal length due to disease or surgical resection, generally defined as a residual small intestinal length of 200 cm or less, according to the American Gastroenterological Association 1, 2
SBS occurs when, after surgery or congenitally, a patient is left with insufficient functional small intestine, leading to malabsorption of nutrients, fluids, and electrolytes, as reported by the American Gastroenterological Association 3
The measurement of bowel length should be taken from the duodenojejunal flexure to the ileocecal junction, the site of any small bowel-colon anastomosis, or to the end-ostomy, as recommended by the European Society for Clinical Nutrition and Metabolism 2, 4
Normal human small intestinal length varies from approximately 275 cm to 850 cm, and tends to be shorter in women, according to the European Society for Clinical Nutrition and Metabolism 4

General consequences include diarrhea, dehydration, electrolyte abnormalities, and weight loss due to loss of digestive and absorptive surface area, as reported by the American Gastroenterological Association 1
Terminal ileum loss can lead to vitamin B12 deficiency and bile acid-induced diarrhea, according to the American Gastroenterological Association 1
Colon loss can result in increased fluid and electrolyte losses, as reported by the European Society for Clinical Nutrition and Metabolism 4
Patients at greatest nutritional risk generally have duodenostomy or jejunoileal anastomosis with ≤35 cm of residual small intestine, jejunocolic or ileocolic anastomosis with ≤60 cm of residual small intestine, or end jejunostomy with ≤115 cm of residual small intestine, as identified by the American Gastroenterological Association 3

While SBS and intestinal failure (IF) are often used interchangeably, they represent distinct concepts, according to the American Gastroenterological Association 1, 2
IF is defined as the reduction of gut function below the minimum necessary for absorption of macronutrients or water and electrolytes, requiring intravenous supplementation, as defined by the European Society for Clinical Nutrition and Metabolism 1, 4
SBS is the most common cause of IF, but IF can also result from other disorders like chronic intestinal pseudo-obstruction, as reported by the American Gastroenterological Association 1, 2
IF severity is classified as severe (requiring parenteral nutrition), moderate (requiring enteral nutrition), or mild (requiring oral nutritional supplements), according to the European Society for Clinical Nutrition and Metabolism 4

Presence of the ileocecal valve and functional colon significantly improves prognosis, as reported by the European Society for Clinical Nutrition and Metabolism 4, 5
Patients with jejunum-colon anatomy may need parenteral nutrition if less than 50 cm small intestine remains, according to the European Society for Clinical Nutrition and Metabolism 4, 6
Patients with jejunostomy may need parenteral saline if less than 100 cm of jejunum remains, or parenteral nutrition and saline if less than 75 cm remains, as reported by the European Society for Clinical Nutrition and Metabolism 4, 6

Fluid and electrolyte imbalances, particularly hypomagnesemia, can occur, as reported by the European Society for Clinical Nutrition and Metabolism 4, 5
D-lactic acidosis from bacterial fermentation of unabsorbed carbohydrates is a potential complication, according to the European Society for Clinical Nutrition and Metabolism 5
Renal oxalate stones (25% risk in patients with preserved colon) and gallstone formation (45% in short bowel patients) are possible complications, as reported by the European Society for Clinical Nutrition and Metabolism 5
Small intestinal bacterial overgrowth, especially when the ileocecal valve has been resected, can occur, according to the European Society for Clinical Nutrition and Metabolism 5