Short Bowel Syndrome

Short bowel syndrome (SBS) is a serious and chronic malabsorption disorder.1,2,3

SBS results from physical loss and functional deficiency of the intestine, primarily due to surgical resection.1,2 Depending on remnant bowel anatomy and its residual function, patients with SBS may not be able to absorb sufficient nutrients through diet alone.3

Short bowel syndrome illustration

Epidemiology

The exact prevalence of SBS is not known due to under-reporting and the lack of reliable patient databases.1 It is estimated that 10,000 to 20,000 people in the U.S. have this condition.4 These figures may underestimate true prevalence since they are based on the number of patients receiving long-term parenteral nutrition and/or intravenous fluid support and do not include patients with well-tolerated resections who do not require this therapy.1,5

There are several indications for resection that may lead to SBS in adults and children.2,3,6,7,8 SBS may arise from congenital malformations or from physiologic or surgical causes, such as Crohn’s disease and trauma. (Note that many of these causes will be the indication for resection that led to SBS). Patients with SBS are a heterogenous group due to large variations in intestinal function and remnant bowel anatomy.

Pathophysiology

Loss of the structure and function of certain portions of the bowel can impact the hormones (such as GLP-1 and GLP-2) and the surface area needed for absorption.2,8 SBS is not just characterized by the length of the remaining bowel, but the clinical features indicating the inability to maintain nutritional, fluid, and/or electrolyte homeostasis while consuming a normal, healthy diet.1

After bowel resection surgery, the lining of the remaining intestine may change to absorb more nutrients and fluid through a natural process called intestinal adaptation.2,9,10 This process is encouraged by the presence of nutrients in the gut lumen and the release of gut-related hormones—notably GLP-1, GLP-2 and growth hormone. Gastrointestinal adaptation facilitates weaning patients from parenteral nutrition and IV fluid support. However, this process is highly variable and dependent on a patient’s clinical status and remnant anatomy.

Navigating SBS

Complications in patients with SBS may relate directly to their disease, to consequences of fluid/electrolyte imbalance and malnutrition, and to complications associated with parenteral nutrition.2,11,12,13 Along with physical limitations, many patients may be unable to work — especially those on home parenteral nutrition. Whatever the cause, SBS and the use of parenteral nutrition are associated with significant morbidity.