This disorder often occurs after a large part of the small intestine (usually more than two thirds of its length) is removed.
Diarrhea is the main symptom.
After surgery, people are given food and fluids by vein (intravenously).
Some people must continue the intravenous feedings for life.
Drugs such as loperamide and cholestyramine can help reduce diarrhea.
Common reasons for removing a large portion of small intestine are Crohn disease Crohn Disease Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more , a blockage of an artery that supplies blood to a large part of the intestine (mesenteric infarction Acute Mesenteric Ischemia Acute mesenteric ischemia is sudden blockage of blood flow to part of the intestines, which may lead to gangrene and perforation (puncture). Severe abdominal pain develops suddenly. Angiography... read more ), inflammation of the intestine caused by radiation (radiation enteritis), cancer, a twisted loop of intestine (volvulus Intestinal Obstruction An obstruction of the intestine is a blockage that completely stops or seriously impairs the passage of food, fluid, digestive secretions, and gas through the intestines. The most common causes... read more ), and birth defects Overview of Digestive Tract Birth Defects The digestive organs may be incompletely developed or abnormally positioned, causing blockages, or the muscles or nerves of the digestive tract may be defective. Symptoms depend on the location... read more .
Most digestion and absorption of food takes place in the small intestine. The consequences of removing a portion of the small intestine depend on how much is removed and its location. The small intestine is about 12 to 21 feet (about 4 meters) in length. If the middle part (jejunum) is removed, sometimes the last part (ileum) can adapt and absorb more nutrients. If more than about 3 feet (about 1 meter) of ileum is removed, the remaining small intestine usually cannot adapt. Before adaptation occurs, or if it does not, the intestines have difficulty absorbing many nutrients, including fats, proteins, and vitamins. If the end of the ileum has been removed, the intestines also cannot absorb bile acids secreted by the liver, which aid digestion and cannot absorb vitamin B12.
Malabsorption causes diarrhea, typically beginning immediately after the surgery. Later, people develop undernutrition and vitamin deficiencies, such as B12 deficiency Vitamin B12 Deficiency Vitamin B12 deficiency can occur in vegans who do not take supplements or as a result of an absorption disorder. Anemia develops, causing paleness, weakness, fatigue, and, if severe, shortness... read more .
The diagnosis of short bowel syndrome is based on the results of a doctor's evaluation of the person’s prior surgery, symptoms, and results of an examination.
Immediately after surgery, when diarrhea is typically severe, doctors give intravenous fluids to replace fluid and electrolyte losses and usually also give intravenous feedings. These feedings, called total parenteral nutrition Intravenous Feeding Intravenous feeding is used when the digestive tract cannot adequately absorb nutrients, as occurs in severe malabsorption disorders. It is also used when the digestive tract must be temporarily... read more (TPN), contain all necessary nutrients, including proteins, fats, carbohydrates, vitamins, and minerals. As people recover and their stool output lessens, they are slowly given fluids by mouth.
People who have had a large amount of small intestine removed (such as those with less than 3 feet [about 1 meter] of remaining jejunum) and those who continue to have excessive fluid and other nutrient losses require TPN for life. Other people eventually tolerate food by mouth. The recommended diet usually has more fat and protein than carbohydrate. Small, frequent meals are better than fewer, large ones.
People who need TPN may be given injections of a drug called teduglutide. This drug may help reduce the amount of TPN people need.
People who have diarrhea after meals should take antidiarrheal drugs such as loperamide 1 hour before eating. Cholestyramine can be taken with meals to reduce diarrhea caused by malabsorption of bile acid. Most people should take supplemental vitamins, calcium, and magnesium. Because people with short bowel syndrome often have excess stomach acid, most people also take an acid-blocking drug, such as a proton pump inhibitor. Some people require monthly injections of vitamin B12.
Small intestine transplantation Small Intestine Transplantation Small intestine transplantation is the removal of the small intestine from a recently decreased person and then the transfer of the small intestine, sometimes with other organs, into a person... read more is an alternative for people who do not adapt to their short bowel and who cannot tolerate long-term TPN.