From the University of Texas Southwestern, Department of Internal Medicine, Dallas, TX.
- Objective: To define intestinal failure and associated diseases that often lead to diarrhea and high-output states, and to provide a literature review on the current evidence and practice guidelines for the management of these conditions in the context of a clinical case.
- Methods: Database search on dietary and medical interventions as well as major societal guidelines for the management of intestinal failure and associated conditions.
- Results: Although major societal guidelines exist, the guidelines vary greatly amongst various specialties and are not supported by strong evidence from large randomized controlled trials. The majority of the guidelines recommend consideration of several drug classes, but do not specify medications within the drug class, optimal dose, frequency, mode of administration, and how long to trial a regimen before considering it a failure and adding additional medical therapies.
- Conclusions: Intestinal failure and high-output states affect a very heterogenous population with high morbidity and mortality. This subset of patients should be managed using a multidisciplinary approach involving surgery, gastroenterology, dietetics, internal medicine and ancillary services that include but are not limited to ostomy nurses and home health care. Implementation of a standardized protocol in the electronic medical record including both medical and nutritional therapies may be useful to help optimize efficacy of medications, aid in nutrient absorption, decrease cost, reduce hospital length of stay, and decrease hospital readmissions.
Key words: short bowel syndrome; high-output ostomy; entero-cutaneous fistula; diarrhea; malnutrition.
Intestinal failure includes but is not limited to short bowel syndrome (SBS), high-output enterostomy, and high-output related to entero-cutaneous fistulas (ECF). These conditions are unfortunate complications after major abdominal surgery requiring extensive intestinal resection leading to structural SBS. Absorption of macronutrients and micronutrients is most dependent on the length and specific segment of remaining intact small intestine . The normal small intestine length varies greatly but ranges from 300 to 800 cm, while in those with structural SBS the typical length is 200 cm or less [2,3]. Certain malabsorptive enteropathies and severe intestinal dysmotility conditions may manifest as functional SBS as well. Factors that influence whether an individual will develop functional SBS despite having sufficient small intestinal absorptive area include the degree of jejunal absorptive efficacy and the ability to overcompensate with enough oral caloric intake despite high fecal energy losses, also known as hyperphagia .
Maintenance of normal bodily functions and homeostasis is dependent on sufficient intestinal absorption of essential macronutrients, micronutrients, and fluids. The hallmark of intestinal failure is based on the presence of decreased small bowel absorptive surface area and subsequent increased losses of key solutes and fluids . Intestinal failure is a broad term that is comprised of 3 distinct phenotypes. The 3 functional classifications of intestinal failure include the following:
- Type 1. Acute intestinal failure is generally self-limiting, occurs after abdominal surgery, and typically lasts less than 28 days.
- Type 2. Subacute intestinal failure frequently occurs in septic, stressed, or metabolically unstable patients and may last up to several months.
- Type 3. Chronic intestinal failure occurs due to a chronic condition that generally requires indefinite parenteral nutrition (PN) [1,3,4].
SBS and enterostomy formation are often associated with excessive diarrhea, such that it is the most common etiology for postoperative readmissions. The definition of “high-output” varies amongst studies, but output is generally considered to be abnormally high if it is greater than 500 mL per 24 hours in ECFs and greater than 1500 mL per 24 hours for enterostomies. There is significant variability from patient to patient, as output largely depends on length of remaining bowel [2,4].
SBS, high-output enterostomy, and high-output from ECFs comprise a wide spectrum of underlying disease states, including but not limited to inflammatory bowel disease, post-surgical fistula formation, intestinal ischemia, intestinal atresia, radiation enteritis, abdominal trauma, and intussusception . Due to the absence of a United States registry of patients with intestinal failure, the prevalence of these conditions is difficult to ascertain. Most estimations are made using registries for patients on total parenteral nutrition (TPN). The Crohns and Colitis Foundation of America estimates 10,000 to 20,000 people suffer from SBS in the United States. This heterogenous patient population has significant morbidity and mortality for dehydration related to these high-output states. While these conditions are considered rare, they are relatively costly to the health care system. These patients are commonly managed by numerous medical and surgical services, including internal medicine, gastroenterology, surgery, dietitians, wound care nurses, and home health agencies. Management strategies differ amongst these specialties and between professional societies, which makes treatment strategies highly variable and perplexing to providers taking care of this patient population. Furthermore, most of the published guidelines are based on expert opinion and lack high-quality clinical evidence from randomized controlled trials (RCTs). Effectively treating SBS and reducing excess enterostomy output leads to reduced rates of dehydration, electrolyte imbalances, initiation of PN, weight loss and ultimately a reduction in malnutrition. Developing hospital-wide management protocols in the electronic medical record for this heterogenous condition may lead to less complications, fewer hospitalizations, and an improved quality of life for these patients.