The resection of the ileum leads to a malabsorption of vitamin B12, bile acids and the fat soluble vitamins A, D, E and K. Loss of the distal ileum also leads to loss of inhibitory hormones; leading to gastric hypersecretion, intestinal hypermotility (decreases in the intestinal transit time) leading to secretory diarrhea and macronutrient, micronutrient, vitamin and mineral deficiencies. Loss of the ileocecal valve leads to small intestinal bacterial overgrowth(SIBO) as bacterial flora normally found in the large intestines migrate proximally and colonize the small intestines leading to further malabsorption. SIBO leads to malabsorption as the bacteria colonizing the small intestine metabolize nutrients, directly competing with the intestinal absorption of nutrients. The bacteria colonizing the small intestines in SIBO may also cause bile acid deconjugation leading to malabsorption of lipids.In a process called intestinal adaptation, physiological changes to the remaining portion of the small intestine occur to increase its absorptive capacity. These changes usually take place over 1-2 years. These changes include:

Enlargement (increased diameter) and lengthening of the villi found in the lining
Increase in the diameter of the small intestine
Slow down in peristalsis or movement of food through the small intestine (an increase in the transit time) to increase the time available for nutrient absorptionOsteoporosis is a very common comorbidity in people with short bowel syndrome who are on parenteral nutrition, with an estimated prevalence of 57-67%. The contributing factors to the osteoporosis include malnutrition, vitamin D deficiency due to malabsorption and vitamin D deficiency due to scarce sunlight exposure due to chronic disability.
Diagnosis
Definition
Intestinal failure is decreased intestinal function such that nutrients, water, and electrolytes are not sufficiently absorbed. Short bowel syndrome is when there is less than 2 m (6.6 ft) of working bowel and is the most common cause of intestinal failure. Treatments
Symptoms of short bowel syndrome are usually addressed with medication. These include:
Anti-diarrheal medicine (e.g. loperamide, codeine)
Vitamin, mineral supplements and L-glutamine powder mixed with water
H2 blocker and proton pump inhibitors to reduce stomach acid
Lactase supplement (to improve the bloating and diarrhea associated with lactose intolerance)In 2004, the USFDA approved a therapy that reduces the frequency and volume of total parenteral nutrition (TPN), comprising:  NutreStore (oral solution of glutamine) and Zorbtive (growth hormone, of recombinant DNA origin, for injection) together with a specialized oral diet. After 24 weeks of successful Phase III patient treatment trials, Teduglutide was shown to be relatively safe and effective with varying degrees of benefits and adverse effects per patient. Adequate safety evaluations prove to be difficult due to a limited sample size available for study, however. In 2012, an advisory panel to the USFDA voted unanimously to approve for treatment of SBS the agent teduglutide, a glucagon-like peptide-2 analog developed by NPS Pharmaceuticals, who intend to market the agent in the United States under the brandname Gattex.