Short bowel syndrome: pathophysiological and clinical aspects

Short bowel syndrome (SBS) is characterized by maldigestion and malabsorption after extensive loss of the small bowel. Intraluminal nutrients, gastrointestinal secretions and enterohormones stimulate a process of adaptation which consists of a gradual increase in intestinal length and width, villus height, crypt depth, and absorptive capacity. Duration of treatment, incidence of complications, and overall prognosis for an individual patient depends on his age, the amount of resected bowel, which parts of the small intestine are preserved, and whether the ileocecal valve and the colon have remained intact. Dysmotility is a common symptom despite an apparently short transit time. Long-term parenteral nutrition is mandatory, until the adaptation process allows an entirely enteral nutrition, and careful monitoring and possibly continued supplementation of vitamins will be necessary even thereafter. How far the intestinal adaptation can be enhanced by additional pharmacological therapy has not yet been clarified. Surgical procedures aim at slowing down intestinal transit, increasing absorptive surface area, and/or refashioning dilated intestinal loops in order to improve peristalsis. SBS patients frequently suffer acute and chronic complications such as central venous catheter infections, chronic cholestasis and hepatic failure, bacterial overgrowth with subsequent d-lactic acidosis, and translocation of bacteria and endotoxin. Without the option of transplantation, survival rates currently reach 80%. Small bowel transplantation—isolated or in combination with other organs—is in constant evolution and may offer new hope for patients with an extremely short bowel.