Evaluation of Short Bowel Syndrome

Initial Anatomic Assessment

The American Gastroenterological Association recommends accurate bowel length measurement from the duodenojejunal flexure along the antimesenteric border of unstretched bowel to the ileocecal junction, any small bowel-colon anastomosis, or end-ostomy 3
If surgical measurement is unavailable, an opisometer can be used to trace the long axis of bowel on contrast studies showing all remaining small bowel 4
Patients can be classified into three anatomic groups: Group 1 (end-jejunostomy), Group 2 (jejunocolonic anastomosis), or Group 3 (jejuno-ileo-colic with intact ileocecal valve) 2, 3
Group 1 represents the most severe phenotype with worst prognosis, while Group 3 is most favorable 2

The European Society for Clinical Nutrition and Metabolism recommends initial comprehensive nutritional assessment by an experienced dietitian, with specific laboratory monitoring focused on electrolytes, micronutrients, and metabolic complications 1, 5
Core laboratory panel should include electrolytes (sodium, potassium, magnesium, calcium, phosphorus), liver function (bilirubin, alkaline phosphatase), pancreatic enzymes (lipase and amylase), and renal function (creatinine, estimated glomerular filtration rate) 1, 5, 6
Micronutrient assessment should include fat-soluble vitamins (serum retinol, 25-hydroxyvitamin D, alpha-tocopherol), vitamin B12 and methylmalonic acid, folate, iron studies, trace elements (zinc, selenium, chromium, copper), and manganese (in patients on home parenteral nutrition) 1, 5

The American College of Gastroenterology recommends baseline gastrointestinal malignancy screening before initiating treatment, with different approaches for adults versus pediatric patients 1
Adult patients should undergo colonoscopy with polypectomy and upper GI endoscopy with removal of any polyps within 6 months prior to starting treatment 1
Pediatric patients should undergo fecal occult blood testing within 6 months prior to starting treatment, and colonoscopy/sigmoidoscopy and upper GI endoscopy if new or unexplained blood in stool is detected 1

The Clinical Nutrition Society recommends monitoring of the renin-aldosterone axis effects in patients with short bowel syndrome, particularly those with jejunostomy 6
Specific labs to assess aldosterone effects include 24-hour urine magnesium, 24-hour urine potassium, serum potassium, serum magnesium, and serum sodium 6
Correction of hypokalemia in patients with high-output stoma requires first correcting sodium/water depletion to suppress hyperaldosteronism, and serum magnesium must be brought into normal range before potassium supplementation will be effective 6

Jejunostomy patients (Group 1) require daily measurement of jejunal output volume, and may need long-term parenteral saline or nutrition if <100 cm jejunum remains 4, 7
Jejunum-colon patients (Group 2) may need parenteral nutrition if <50 cm small intestine remains, and should be monitored for hyperoxaluria and oxalate stone formation 4, 7
Jejuno-ileo-colic patients (Group 3) have the most favorable prognosis, and rarely need long-term parenteral nutrition if ileum and colon are intact 2, 4, 7