Loss of segments of the bowel can lead to imbalances and symptoms related to gastric acid, bacterial overgrowth, and bile salt malabsorption.
Managing Gastric Acid Hypersecretion
Gastric hypersecretion happens when the stomach produces too much acid. It must be addressed after significant resection of the small bowel. It will increase the volume of secretions entering the small bowel and increase acid in the upper gut.
Loss of segments in the small bowel results in a change in the levels of hormones involved with digestion (cholecystokinin or CCK, secretin, and gastrin) that results in continued acid secretion. This increased acid load causes erosion of the gut lining and an increased stool volume contributing to diarrhea, and electrolyte losses. In addition it alters pancreatic enzymes, and compromises bile salt function making them less effective.
The treatment for gastric hypersecretion is acid suppression through H2 blockers, and proton pump inhibitors (PPIs).
Managing Bacterial Overgrowth
When the surgical resection results in loss of the ileocecal valve, bacteria from the colon can enter the small bowel. Small intestinal bacterial overgrowth (SIBO) occurs when there are too many bacteria in the small intestine.
Symptoms occur after eating because the bacteria in the intestine begin to consume the food in the small intestine before it can be absorbed. These bacteria give off hydrogen and other gases, which cause bloating and diarrhea. These bacteria can also contribute to malabsorption and loss of nutrients.
Here there is a treatment role for cycles of antibiotics, and a long-term maintenance approach with probiotics.
Managing Bile Salt Malabsorption
Bile is a fluid produced in the liver and stored in the gallbladder. It is released into the duodenum during a meal to help digest fats and is reabsorbed in the ileum. When part of the ileum is lost, it results in malabsorption of bile acids which can lead to diarrhea.
This may be treated by medications that bind bile, such as cholestyramine (Questran, Cholybar). However, when too much ileum is removed (greater than 100 cm/3.3 feet of the terminal ileum), more severe bile salt malabsorption may occur, and the liver is unable to compensate. When that happens cholestyramine may actually worsen steatorrhea, or undigested fat in the stools.
Current supportive medical treatments include the use of anti-motility agents that reduce fluid loss, and hence decrease diarrhea. Reducing motility slows transit time and increases intestinal absorption.
Examples of these agents include loperamide (Imodium), diphenoxylate with atropine (Lomotil), opium, and codeine.
Octreotide is another drug that may help increase absorption time and decrease diarrhea. It reduces bile and pancreatic secretions and gastric acid production, while inhibiting fluid and electrolyte secretion from the small bowel. In addition it slows stomach emptying allowing increased transit time.
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Adapted from IFFGD Publication #258 by Evelin Eichler, MS, RD, LD, Clinical Dietitian, University Medical Center, Gastrointestinal Motility Nutrition Specialist, Texas Tech University, Department of Internal Medicine, Texas Tech University Health Sciences Center, El Paso, TX; Richard McCallum MD, FACP, FRACP (AUST), FACG, Professor of Medicine and Founding Chair and Chief of Gastroenterology, Department of Internal Medicine, Texas Tech University Health Sciences Center, El Paso, TX; Susan S. Schneck, MA, International Foundation for Functional Gastrointestinal Disorders, Milwaukee, WI; and William F. Norton, Communications Director, International Foundation for Functional Gastrointestinal Disorders, Milwaukee, WI.