The length of the small intestine can vary greatly, from as<unk>  as to as long as . On average it is about . Due to this variation it is recommended that following surgery the amount of<unk>  remaining be specified rather than the amount removed.<unk>  usually develops when there is less than 2 meters (6.6 feet) of the small intestine left to absorb sufficient nutrients. The resection of specific areas of the small<unk>  can lead to distinct symptoms in<unk> . 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 absorption Osteoporosis is a very common comorbidity in people with<unk>  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.
Short bowel syndrome
Gay bowel syndrome
Distal intestinal obstruction syndrome
Ileus
Intestinal pseudo-obstruction
Functional constipation
Wilderness-acquired diarrhea
Fecal impaction