Short bowel syndrome
Short bowel syndrome is malabsorption from insufficient functional small intestine, usually after massive resection for Crohn disease, mesenteric ischemia, or tumor. Diagnosis rests on residual bowel length and colon continuity; first-line treatment sequences diet, high-dose loperamide, and antisecretory therapy, escalating to parenteral nutrition and teduglutide.
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What this article covers
- Overview
Short bowel syndrome (SBS) is malabsorption of fluid, electrolytes, and nutrients from loss of functional small bowel, most often after extensive surgical resection, leaving absorptive surface area below what oral intake alone can offset.
- Epidemiology
The typical adult patient has had one or more major small bowel resections for Crohn disease, mesenteric vascular ischemia, or an abdominal tumor, the most common adult causes.
- Risk factors
Crohn disease with recurrent stricturing or fistulizing disease: repeated resections for obstruction, fistula, or abscess cumulatively shorten the small bowel.
- Pathophysiology
Absorptive capacity is lost roughly in proportion to the length and location of bowel removed.
- Clinical features
High-volume diarrhea or ostomy output: watery output that worsens with oral intake, the presenting complaint in most patients.
- Differential diagnosis
Small intestinal bacterial overgrowth (SIBO): causes bloating and diarrhea from proximal bacterial overgrowth, but bowel length is normal and diagnosis is confirmed by a breath test or jejunal…
- Diagnosis
The diagnosis is established by correlating a history of extensive small bowel resection, or extensive Crohn disease, mesenteric infarction, or NEC, with objective fluid, electrolyte, or nutrient…
- Management
First, optimize diet and oral intake: small, frequent, hyperphagic meals and a glucose-electrolyte oral rehydration solution rather than plain water or hypotonic drinks, which add to net fluid losses.
- Complications
Intestinal failure-associated liver disease (IFALD): progressive cholestasis and steatosis over months to years of PN dependence.
- Prognosis
Weaning from PN correlates directly with residual anatomy: more than 100 cm of small bowel with the colon in continuity is usually sufficient to avoid permanent PN dependence, while fewer than 100 cm…
- Prevention
Preserve bowel length and anatomy at index surgery: when feasible, preserving small bowel length and the ileocecal valve or colon limits the risk of severe SBS.
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Related articles
- Crohn disease
Crohn disease is a chronic transmural inflammatory bowel disease that can affect any segment from mouth to anus in skip lesions, most classically the terminal ileum, and is confirmed by ileocolonoscopy showing cobblestoning, skip areas, and non-caseating granulomas on biopsy. Management follows an ordered sequence of glucocorticoid or budesonide induction followed by immunomodulator or biologic maintenance, with surgery reserved for fixed complications rather than cure.
- Chronic mesenteric ischemia
Chronic mesenteric ischemia, or intestinal angina, is atherosclerotic stenosis of at least two of the three splanchnic vessels producing postprandial epigastric pain, food fear, and weight loss. Diagnosis rests on CT or magnetic resonance angiography showing severe stenosis after alternative causes are excluded, and treatment is revascularization, preferably endovascular stenting, with aggressive atherosclerotic risk-factor control.
- Small intestinal bacterial overgrowth
Small intestinal bacterial overgrowth is excessive bacterial colonization of the proximal small bowel, driven by stasis from strictures, blind loops, or dysmotility, or by loss of gastric-acid and immune defenses, producing bloating, diarrhea, and fat and B12 malabsorption. Diagnosis rests on a carbohydrate breath test or jejunal aspirate culture, and treatment corrects the underlying cause while a course of rifaximin or another antibiotic reduces the bacterial burden.
- Celiac disease
Celiac disease is an immune-mediated small-intestinal enteropathy triggered by dietary gluten in genetically predisposed individuals, presenting with malabsorptive diarrhea, iron-deficiency anemia, or dermatitis herpetiformis. Diagnosis requires IgA tissue transglutaminase serology with a total IgA level while the patient still eats gluten, confirmed by duodenal biopsy showing villous atrophy, and the only treatment is a strict lifelong gluten-free diet.
- Diarrhea
Diarrhea is three or more unformed stools daily, split by duration into acute (under 14 days, usually infectious), persistent (14 to 30 days, often parasitic), and chronic (over 30 days, usually noninfectious), and by mechanism into osmotic, secretory, inflammatory, malabsorptive, and motility diarrhea. Acute diarrhea is managed with rehydration and tested only when red-flag features are present, while chronic diarrhea is worked up by mechanism using stool studies, celiac serology, fecal calprotectin, and endoscopy.
- Nephrolithiasis
Nephrolithiasis affects 7-11% of the US population, most often as calcium oxalate stones, and presents as colicky flank pain radiating to the groin with hematuria. Noncontrast CT confirms the diagnosis and stone size drives management: hydration, NSAID/opioid analgesia, and alpha-blocker expulsive therapy for stones under 10 mm, urologic intervention for larger, infected, or obstructing stones.
- Refeeding syndrome
Refeeding syndrome is a potentially fatal shift of phosphate, potassium, and magnesium into cells when nutrition is reintroduced too quickly to a malnourished patient, driven by an insulin surge that also causes fluid retention and thiamine depletion. Prevention rests on identifying at-risk patients before feeding, starting calories low, giving thiamine first, and repleting electrolytes proactively rather than reactively.
- Acid suppression therapy (PPIs, H2 blockers, antacids)
Acid suppression therapy spans proton pump inhibitors (PPIs), histamine-2 receptor antagonists (H2RAs), and antacids, used to treat and prevent reflux, peptic ulcer disease, and bleeding. A once-daily PPI, such as omeprazole 20 mg before breakfast, is first-line for most indications; H2RAs and antacids serve milder or adjunctive roles.