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Short-Bowel Syndrome

Updated : May 24, 2024





Background

In adults, the typical length of the small bowel, starting from the duodenojejunal flexure, spans approximately 275 to 850 centimeters. Approximately 9 liters of fluid traverse the small bowel daily, comprising oral fluids, saliva, biliary, gastric, and pancreatic secretions. On average, around 7 liters of these fluids are absorbed within the small bowel, with an additional 2 liters absorbed in the large bowel.

A healthy large bowel can absorb approximately 150 kilocalories per day, but in cases of malabsorption, this capacity can extend to as much as 1000 kilocalories per day. The primary site for nutrient absorption is within the initial 100 centimeters of the jejunum. Vitamin B12 and bile salts find absorption in the final 100 centimeters of the ileum, while magnesium is taken up in the terminal ileum and proximal colon. Water and sodium absorption is distributed throughout the entire length of the bowel.

Short bowel syndrome (SBS) among adults is defined as having less than 180 to 200 centimeters of remaining small bowel, necessitating nutritional and fluid supplements. Although there is no universally accepted definition for SBS in children, it has been suggested that intravenous supplementation may be necessary when a child has less than 25% of the expected small bowel length for their gestational age.

Epidemiology

SBS is most commonly seen in individuals with extensive surgical small intestine resection. This can occur due to Crohn’s disease, mesenteric ischemia, traumatic injury, or surgical complications. SBS’s exact incidence and prevalence can vary widely depending on the underlying causes and the population studied.

SBS can affect individuals of all ages, from newborns to the elderly, but the underlying causes may differ by age group. In children, congenital or neonatal conditions are more common, whereas surgical resection due to disease is a leading cause in adults. SBS does not show a strong gender preference and can affect males and females equally.

The prevalence of SBS may vary by region, depending on factors such as the incidence of underlying conditions like Crohn’s disease and access to healthcare and surgical interventions. The underlying cause can influence mortality rates in SBS, the extent of bowel resection, and the availability of medical interventions. The mortality rate has decreased in recent years with advancements in medical care and nutrition support.

Anatomy

Pathophysiology

Short Bowel Syndrome (SBS) can be categorized based on anatomical, pathophysiological, and postoperative factors. Anatomically, there are three main types of SBS:

  • End-Jejunostomy: This type involves the surgical creation of an opening (stoma) at the end of the jejunum, leading to the need for altered digestion and absorption.
  • Jejunocolonic Anastomosis: In this type, the jejunum is surgically connected to the left colon, commonly resulting in SBS. This connection affects the normal digestive process.
  • Jejunoileal Anastomosis: This type involves the surgical connection between the jejunum and the ileum, impacting the digestive and absorptive functions of the small intestine.

From a pathophysiological perspective, SBS can be further divided based on whether the colon remains in continuity with the digestive process.

The primary pathophysiological mechanism behind chronic intestinal failure in SBS is intestinal malabsorption. This occurs due to the reduction in the absorptive surface area of the intestine, as well as an increased rate of intestinal transit.

The successful management of SBS depends on addressing three distinct phases:

  • Acute Phase: This initial phase typically lasts 3 to 4 weeks and is characterized by metabolic disturbances, significant intestinal losses, and heightened gastric secretion. In the absence of inhibitory hormones normally released from the terminal ileum, gastric hypersecretion can occur. Proper management in a hospital setting is crucial during this phase to prevent complications such as dehydration leading to acute kidney failure, acid-base imbalances, and electrolyte deficiencies.

The acute phase requires close monitoring to stabilize the patient’s condition and mitigate potential complications associated with the sudden loss of significant portions of the small intestine.

  • The adaptation phase in Short Bowel Syndrome lasts 1 to 2 years, during which the remaining small bowel undergoes adaptive changes. These changes aim to increase the surface area available for nutrient absorption, slow down intestinal transit to maximize absorption time, and induce adaptive hyperphagia. These adaptive processes are stimulated by the presence of nutrients in the bowel and biliary and pancreatic secretions and hormones released by the ileum and colon.

The third and final phase of SBS is known as the maintenance phase. During this phase, management typically involves specialized diets, oral or intramuscular nutrient supplementation, and pharmacological treatments. Given the altered anatomy and function of the remaining intestine, this phase aims to sustain the patient’s nutritional status and overall health. The specific approach to management may vary from patient to patient and requires ongoing monitoring and adjustment as needed.

Etiology

Short Bowel Syndrome can arise from either extensive surgical removal of the small intestine or congenital intestinal disorders.

In adults, the primary underlying conditions that often lead to SBS include Crohn’s disease, mesenteric ischemia, radiation-induced enteritis, post-surgical adhesions, and complications following surgical procedures.

On the other hand, in children, the most frequently encountered conditions contributing to SBS are volvulus (intestinal twisting), congenital intestinal malformations, and necrotizing enterocolitis.

Genetics

Prognostic Factors

Clinical History

Chronic, watery diarrhea is one of the hallmark symptoms of SBS. The small intestine plays a crucial role in absorbing nutrients and fluids, so when it is compromised, it results in diarrhea. SBS can lead to malnutrition due to inadequate nutrients, vitamins, and minerals absorption. This can result in weight loss, muscle wasting, and nutritional deficiencies.

Diarrhea and malabsorption of fluids can lead to dehydration, which may cause symptoms such as thirst, dry mouth, and low urine output. Patients with SBS may experience abdominal discomfort, cramping, and bloating, often due to altered digestive processes. Malnutrition and nutrient deficiencies can lead to fatigue and weakness.

Frequent diarrhea can result in electrolyte imbalances, which may cause symptoms like muscle cramps, irregular heartbeats, and weakness. SBS can be congenital or acquired. Congenital SBS is present from birth, while acquired SBS typically results from surgical removal of a significant portion of the small intestine. The timing of surgery and the extent of intestinal resection can influence the onset and severity of symptoms.

Physical Examination

Most individuals with SBS experience weight loss due to malnutrition and malabsorption of nutrients. A healthcare provider may note evidence of muscle wasting and reduced subcutaneous fat. Signs of dehydration, such as dry mucous membranes, sunken eyes, and decreased skin turgor (skin elasticity), may be evident.

Abdominal examination may reveal abdominal distention, which results from impaired digestion and the accumulation of gas and fluid in the intestines. Auscultation of the abdomen may reveal increased bowel sounds (borborygmi), which can result from the intestine’s hyperactivity in response to the reduced absorptive surface area. If the patient is on TPN, signs of central line infections, such as redness, swelling, or tenderness at the catheter insertion site, may be noted.

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Differential Diagnoses

Atrophic Gastritis

Gastrinoma

Renal Failure

Short Gut Syndrome

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Surgical intervention is a crucial treatment avenue for individuals with short bowel syndrome (SBS). For patients relying on parenteral nutrition who experience rapid transit issues, there may be benefits in procedures like inverting intestinal segments or incorporating segments of the colon into the small intestine.

Patients with less than 60 centimeters of functional small bowel and experience complications linked to parenteral nutrition may qualify as candidates for intestinal transplantation. Potential solutions for patients with bowel dilation due to obstruction include intestinal tapering or strictureplasty.

The choice between these approaches depends on the length of the remaining bowel: intestinal tapering for remnants greater than 120 centimeters or tapering with extending for remnants less than 90 centimeters in adults or less than 30 centimeters in children.

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

Lifestyle Modifications

Lifestyle Modifications

The comprehensive approach involves lifestyle modifications, dietary adjustments, treatment of underlying conditions, optimization of vitamin D status, and, when necessary, bisphosphonates.

Phases of Management

Acute phase of management

The initial approach to managing short bowel syndrome focuses on preserving optimal nutritional health, optimizing the functional capacity of the remaining intestinal tissue, and pre-empting potential complications.

This entails the early implementation of parenteral nutrition shortly after surgery and the introduction of enteral nutrition once the patient’s ileus has resolved. This strategy encourages the process of intestinal adaptation, leading to enhanced nutrient absorption capabilities over time.

Chronic Phase of Management

Dehydration, chronic renal failure, hyponatremia, and nephrolithiasis resulting from short bowel syndrome are addressed through intravenous fluids to uphold proper hydration and urinary flow. Specifically, managing dehydration and hyponatremia in SBS patients aims to maintain adequate hydration, ensuring a daily urine output of 800 milliliters or more and a urine sodium level exceeding 20 millimoles/liter.

Hypomagnesemia, often stemming from magnesium malabsorption due to the loss of the distal ileum and right colon, as well as chelation with fatty acids, is managed by proper hydration as previously mentioned, along with magnesium supplementation to reach a level surpassing 1.5 milligrams/deciliter.

Medication

 

somatropin 

Zorbtive :

0.1 mg/kg/day subcutaneously (SC) for 4 weeks; may increase up to 8 mg/day



 
 

Media Gallary

References

Short-Bowel Syndrome

Updated : May 24, 2024




In adults, the typical length of the small bowel, starting from the duodenojejunal flexure, spans approximately 275 to 850 centimeters. Approximately 9 liters of fluid traverse the small bowel daily, comprising oral fluids, saliva, biliary, gastric, and pancreatic secretions. On average, around 7 liters of these fluids are absorbed within the small bowel, with an additional 2 liters absorbed in the large bowel.

A healthy large bowel can absorb approximately 150 kilocalories per day, but in cases of malabsorption, this capacity can extend to as much as 1000 kilocalories per day. The primary site for nutrient absorption is within the initial 100 centimeters of the jejunum. Vitamin B12 and bile salts find absorption in the final 100 centimeters of the ileum, while magnesium is taken up in the terminal ileum and proximal colon. Water and sodium absorption is distributed throughout the entire length of the bowel.

Short bowel syndrome (SBS) among adults is defined as having less than 180 to 200 centimeters of remaining small bowel, necessitating nutritional and fluid supplements. Although there is no universally accepted definition for SBS in children, it has been suggested that intravenous supplementation may be necessary when a child has less than 25% of the expected small bowel length for their gestational age.

SBS is most commonly seen in individuals with extensive surgical small intestine resection. This can occur due to Crohn’s disease, mesenteric ischemia, traumatic injury, or surgical complications. SBS’s exact incidence and prevalence can vary widely depending on the underlying causes and the population studied.

SBS can affect individuals of all ages, from newborns to the elderly, but the underlying causes may differ by age group. In children, congenital or neonatal conditions are more common, whereas surgical resection due to disease is a leading cause in adults. SBS does not show a strong gender preference and can affect males and females equally.

The prevalence of SBS may vary by region, depending on factors such as the incidence of underlying conditions like Crohn’s disease and access to healthcare and surgical interventions. The underlying cause can influence mortality rates in SBS, the extent of bowel resection, and the availability of medical interventions. The mortality rate has decreased in recent years with advancements in medical care and nutrition support.

Short Bowel Syndrome (SBS) can be categorized based on anatomical, pathophysiological, and postoperative factors. Anatomically, there are three main types of SBS:

  • End-Jejunostomy: This type involves the surgical creation of an opening (stoma) at the end of the jejunum, leading to the need for altered digestion and absorption.
  • Jejunocolonic Anastomosis: In this type, the jejunum is surgically connected to the left colon, commonly resulting in SBS. This connection affects the normal digestive process.
  • Jejunoileal Anastomosis: This type involves the surgical connection between the jejunum and the ileum, impacting the digestive and absorptive functions of the small intestine.

From a pathophysiological perspective, SBS can be further divided based on whether the colon remains in continuity with the digestive process.

The primary pathophysiological mechanism behind chronic intestinal failure in SBS is intestinal malabsorption. This occurs due to the reduction in the absorptive surface area of the intestine, as well as an increased rate of intestinal transit.

The successful management of SBS depends on addressing three distinct phases:

  • Acute Phase: This initial phase typically lasts 3 to 4 weeks and is characterized by metabolic disturbances, significant intestinal losses, and heightened gastric secretion. In the absence of inhibitory hormones normally released from the terminal ileum, gastric hypersecretion can occur. Proper management in a hospital setting is crucial during this phase to prevent complications such as dehydration leading to acute kidney failure, acid-base imbalances, and electrolyte deficiencies.

The acute phase requires close monitoring to stabilize the patient’s condition and mitigate potential complications associated with the sudden loss of significant portions of the small intestine.

  • The adaptation phase in Short Bowel Syndrome lasts 1 to 2 years, during which the remaining small bowel undergoes adaptive changes. These changes aim to increase the surface area available for nutrient absorption, slow down intestinal transit to maximize absorption time, and induce adaptive hyperphagia. These adaptive processes are stimulated by the presence of nutrients in the bowel and biliary and pancreatic secretions and hormones released by the ileum and colon.

The third and final phase of SBS is known as the maintenance phase. During this phase, management typically involves specialized diets, oral or intramuscular nutrient supplementation, and pharmacological treatments. Given the altered anatomy and function of the remaining intestine, this phase aims to sustain the patient’s nutritional status and overall health. The specific approach to management may vary from patient to patient and requires ongoing monitoring and adjustment as needed.

Short Bowel Syndrome can arise from either extensive surgical removal of the small intestine or congenital intestinal disorders.

In adults, the primary underlying conditions that often lead to SBS include Crohn’s disease, mesenteric ischemia, radiation-induced enteritis, post-surgical adhesions, and complications following surgical procedures.

On the other hand, in children, the most frequently encountered conditions contributing to SBS are volvulus (intestinal twisting), congenital intestinal malformations, and necrotizing enterocolitis.

Chronic, watery diarrhea is one of the hallmark symptoms of SBS. The small intestine plays a crucial role in absorbing nutrients and fluids, so when it is compromised, it results in diarrhea. SBS can lead to malnutrition due to inadequate nutrients, vitamins, and minerals absorption. This can result in weight loss, muscle wasting, and nutritional deficiencies.

Diarrhea and malabsorption of fluids can lead to dehydration, which may cause symptoms such as thirst, dry mouth, and low urine output. Patients with SBS may experience abdominal discomfort, cramping, and bloating, often due to altered digestive processes. Malnutrition and nutrient deficiencies can lead to fatigue and weakness.

Frequent diarrhea can result in electrolyte imbalances, which may cause symptoms like muscle cramps, irregular heartbeats, and weakness. SBS can be congenital or acquired. Congenital SBS is present from birth, while acquired SBS typically results from surgical removal of a significant portion of the small intestine. The timing of surgery and the extent of intestinal resection can influence the onset and severity of symptoms.

Most individuals with SBS experience weight loss due to malnutrition and malabsorption of nutrients. A healthcare provider may note evidence of muscle wasting and reduced subcutaneous fat. Signs of dehydration, such as dry mucous membranes, sunken eyes, and decreased skin turgor (skin elasticity), may be evident.

Abdominal examination may reveal abdominal distention, which results from impaired digestion and the accumulation of gas and fluid in the intestines. Auscultation of the abdomen may reveal increased bowel sounds (borborygmi), which can result from the intestine’s hyperactivity in response to the reduced absorptive surface area. If the patient is on TPN, signs of central line infections, such as redness, swelling, or tenderness at the catheter insertion site, may be noted.

Atrophic Gastritis

Gastrinoma

Renal Failure

Short Gut Syndrome

Surgical intervention is a crucial treatment avenue for individuals with short bowel syndrome (SBS). For patients relying on parenteral nutrition who experience rapid transit issues, there may be benefits in procedures like inverting intestinal segments or incorporating segments of the colon into the small intestine.

Patients with less than 60 centimeters of functional small bowel and experience complications linked to parenteral nutrition may qualify as candidates for intestinal transplantation. Potential solutions for patients with bowel dilation due to obstruction include intestinal tapering or strictureplasty.

The choice between these approaches depends on the length of the remaining bowel: intestinal tapering for remnants greater than 120 centimeters or tapering with extending for remnants less than 90 centimeters in adults or less than 30 centimeters in children.

Lifestyle Modifications

The comprehensive approach involves lifestyle modifications, dietary adjustments, treatment of underlying conditions, optimization of vitamin D status, and, when necessary, bisphosphonates.

Acute phase of management

The initial approach to managing short bowel syndrome focuses on preserving optimal nutritional health, optimizing the functional capacity of the remaining intestinal tissue, and pre-empting potential complications.

This entails the early implementation of parenteral nutrition shortly after surgery and the introduction of enteral nutrition once the patient’s ileus has resolved. This strategy encourages the process of intestinal adaptation, leading to enhanced nutrient absorption capabilities over time.

Chronic Phase of Management

Dehydration, chronic renal failure, hyponatremia, and nephrolithiasis resulting from short bowel syndrome are addressed through intravenous fluids to uphold proper hydration and urinary flow. Specifically, managing dehydration and hyponatremia in SBS patients aims to maintain adequate hydration, ensuring a daily urine output of 800 milliliters or more and a urine sodium level exceeding 20 millimoles/liter.

Hypomagnesemia, often stemming from magnesium malabsorption due to the loss of the distal ileum and right colon, as well as chelation with fatty acids, is managed by proper hydration as previously mentioned, along with magnesium supplementation to reach a level surpassing 1.5 milligrams/deciliter.

somatropin 

Zorbtive :

0.1 mg/kg/day subcutaneously (SC) for 4 weeks; may increase up to 8 mg/day