Short bowel syndrome overview: Difference between revisions

Jump to navigation Jump to search
m (Bot: Removing from Primary care)
 
(9 intermediate revisions by 2 users not shown)
Line 4: Line 4:


==Overview==
==Overview==
'''Short bowel syndrome''' is a [[malabsorption]] disorder caused by the [[surgery|surgical]] removal of the [[small intestine]], or rarely due to the complete dysfunction of a large segment of bowel. Most cases are acquired, although some children are born with a congenital short bowel. It does usually not develop unless a person has lost more than two-thirds of their small intestine.
Short bowel syndrome is a [[malabsorption]] disorder caused by the [[surgery|surgical]] removal of the [[small intestine]]. Most cases are acquired, although some children are born with a [[Congenital disorder|congenital]] short bowel. It does usually not develop unless a person has lost more than two-thirds of their [[small intestine]]. [[Intestine]] has the ability to adapt following [[resection]]. [[Adaptation]] depends on multiple factors including individual, [[Intestine|intestinal]] and [[Therapy|therapeutic]] measurements. Successful [[adaptation]] depends on the length of remaining [[intestine]], portion of the resected [[intestine]], and early introduction of [[nutrition]] therapy. Total [[Intestine|intestinal]] [[adaptation]] defines as when patient is [[Weaning|weaned]] from [[Total parenteral nutrition|parenteral nutrition]]. The hallmark of short bowel syndrome is [[diarrhea]]. Complications might happen due to [[malnutrition]], [[surgery]] and [[Total parenteral nutrition|parenteral nutrition]]. Management of short bowel syndrome consists of medical and surgical therapy. Medical therapy consists of [[Nutrition|nutritional]] therapy and [[pharmacotherapy]]. Patients who have severe or worsened [[malabsorption]] might require [[surgery]] including [[Intestine|intestinal]] [[Organ transplant|transplant]]. Effective measures must be adopted for [[secondary prevention]] of complications following [[total parenteral nutrition]] including [[liver disease]], [[Gallstone disease|cholelithiasis]], [[kidney stone]], [[Small bowel bacterial overgrowth syndrome|small bowel bacterial overgrowth]], [[lactic acidosis]], [[lactic acidosis]].  


==Historical Perspective==
==Historical Perspective==
Line 10: Line 10:


==Classification==
==Classification==
Based on the length of the remaining [[Intestine|bowel]], short bowel syndrome may be divided into three types such as end-jejunostomy, jejunocolonic [[anastomosis]], ileocolonic [[anastomosis]]. They have different progress from mild to severe dysfunction. All of them require home [[Total parenteral nutrition|parenteral nutrition]] except ileocolonic [[anastomosis]] which has excellent prognosis and rarely needs [[Total parenteral nutrition|parenteral nutrition]]. Based on the etiology, short bowel syndrome may be divided into three categories such as [[vascular]] abnormalities, [[Mucous membrane|mucosal]] disease of [[intestine]] and causes without preexisting [[Intestine|intestinal disease]].
Based on the length of the remaining [[Intestine|bowel]], short bowel syndrome may be divided into end-jejunostomy, jejunocolonic [[anastomosis]], ileocolonic [[anastomosis]]. Severity varies from mild to severe. All of them require home [[Total parenteral nutrition|parenteral nutrition]] except ileocolonic [[anastomosis]] which has excellent [[prognosis]] and rarely needs [[Total parenteral nutrition|parenteral nutrition]]. Based on the [[etiology]], short bowel syndrome may be divided into three categories such as [[vascular]] abnormalities, [[Mucous membrane|mucosal]] disease of [[intestine]] and causes without preexisting [[Intestine|intestinal disease]].


==Pathophysiology==
==Pathophysiology==
Short bowel syndrome occurrs as a result of [[bowel resection]] following various diseases of the gut such as [[Crohn's disease]], [[Cancer|malignancies]], [[ischemia]], and [[Physical trauma|trauma]]. Short bowel syndrome occurs when the length of the [[small intestine]] is less than 2 meters and requires [[Nutrition|nutritional]] therapy to prevent [[malnutrition]]. Post [[bowel resection]], adaptation might occur which includes structural, motility and functional changes in the remaining [[intestine]]. Changes usually start in the first 24 hours following [[bowel resection]] and last for about two years. [[Adaptation]] depends upon multiple factors including individual, [[Intestine|intestinal]] and [[Therapy|therapeutic]] measurements. Following [[bowel resection]], [[adaptation]] occurs in three phases including acute, adaptive, and maintenance phases. Successful [[adaptation]] depends on the length of remaining [[intestine]], portion of the resected [[intestine]], and early introduction of [[nutrition]] therapy. The term total [[Intestine|intestinal]] [[adaptation]] is used when the patient is weaned from [[Total parenteral nutrition|parenteral nutrition]]. The main reason for [[malabsorption]] following [[bowel resection]] is reduced [[Absorptive state|absorptive]] capacity of the [[small intestine]] due to loss of surface area. On [[Gross examination|gross]] and [[microscopic]] examination, the resected [[Intestine|bowel]] segment may show the underlying causes including [[Crohn's disease]], [[Cancer|malignancies]] or [[ischemia]].


==Causes==
==Causes==
Short bowel syndrome in adults is usually caused by surgical removal of the [[intestine]] due to different diseases including [[Crohn's disease]], [[mesenteric ischemia]], [[Cancer|malignancies]] or [[Radiation enteropathy|radiation enteritis]]. Less common causes include [[Physical trauma|trauma]], [[volvulus]], [[adhesion]] and [[Iatrogenesis|iatrogenic]] [[surgery]] on [[Gastrointestinal tract|gastrointestinal]] system.
Short bowel syndrome in adults is usually caused by [[Surgery|surgical]] removal of the [[intestine]] due to different diseases including [[Crohn's disease]], [[mesenteric ischemia]], [[Cancer|malignancies]] or [[Radiation enteropathy|radiation enteritis]]. Less common causes include [[Physical trauma|trauma]], [[volvulus]], [[adhesion]] and [[Iatrogenesis|iatrogenic]] [[surgery]] on [[Gastrointestinal tract|gastrointestinal]] system.


==Differentiating short bowel syndrome from Other Diseases==
==Differentiating short bowel syndrome from Other Diseases==


==Epidemiology and Demographics==
==Epidemiology and Demographics==
The [[incidence]] and [[prevalence]] of short bowel syndrome is difficult to estimate. All the data is derived from patients receiving home [[parenteral nutrition]]. Therefore, there are different distributions around the world. The [[incidence]] of short bowel syndrome was estimated to be 1-2 cases per 100,000 individuals worldwide per year. The [[prevalence]] of short bowel syndrome is approximately 0.3-0.4 per 100,000 individuals in the USA to 0.1-4 per 100,000 individuals in Europe. It affects all age groups. There is no racial predilection to short bowel syndrome and is reported worldwide. Short bowel syndrome affects men and women equally.
The [[incidence]] and [[prevalence]] of short bowel syndrome is difficult to estimate. All the data is derived from patients receiving home [[parenteral nutrition]]. Therefore, there are different distributions around the world. The [[incidence]] of short bowel syndrome was estimated to be 1-2 cases per 100,000 individuals worldwide per year. The [[prevalence]] of short bowel syndrome is approximately 0.3-4 per 100,000 individuals in the USA to 0.1-4 per 100,000 individuals in Europe. It affects all age groups. There is no racial predilection to short bowel syndrome and is reported worldwide. Short bowel syndrome affects men and women equally.


==Risk Factors==
==Risk Factors==
Common risk factor in the development of short bowel syndrome may be [[Iatrogenesis|iatrogenic]] including any operation on the [[gastrointestinal]] system.
Common [[risk factor]] for the development of short bowel syndrome may be [[Iatrogenesis|iatrogenic]] including any operation on the [[gastrointestinal]] system.


==Screening==
==Screening==
There is insufficient evidence to recommend routine screening for short bowel syndrome.
There is insufficient evidence to recommend routine [[Screening (medicine)|screening]] for short bowel syndrome.


==Natural History, Complications, and Prognosis==
==Natural History, Complications, and Prognosis==


The symptoms of short bowel syndrome usually develop immediately following [[bowel resection]]. [[Diarrhea]] may cause massive [[fluid]] and [[Electrolyte disturbance|electrolyte loss]]. Immediately after surgery, [[Intestine|intestinal]] [[adaptation]] develops in three phases, including [[Acute (medicine)|acute]], adaptive and maintenance phase. During the [[adaptation]], structural, motility and functional changes happen. Patients need [[hydration]] and [[Nutrition|nutritional]] support via [[Route of administration|parenteral]], [[Feeding tube|enteral]] and [[Mouth|oral]] routes. Length of remaining small bowel is the most important prognostic factor. patients with more than 200 cm length of small bowel, usually does not need parenteral nutrition. Patients with shorter small bowel may not weaned off from parenteral nutrition support. Complications might happen due to [[malnutrition]], [[surgery]] and [[Total parenteral nutrition|parenteral nutrition]]. Malnutrition presents with [[vitamin]], [[mineral]] and [[Essential fatty acid|essential fatty acids]] deficiencies. Complications related to [[surgery]] including [[thrombosis]], [[infection]], [[Bleeding|hemorrhage]], [[atelectasis]] and [[anastomosis]] disruption might occur. [[Small intestinal bacterial overgrowth]] due to [[Stasis (medicine)|stasis]] and obstruction might happen. [[Chronic liver disease]] following [[Total parenteral nutrition|parenteral nutrition]] is a common complication in short bowel syndrome. There is no definite cure for short bowel syndrome. However, [[Medication|medications]] and [[Nutrition|nutritional]] therapy significantly improve the quality of life and survival of the patients. Prognosis of short bowel syndrome depends on the location and size of the [[bowel resection]], underlying [[pathology]], [[nutrition]] support, [[pharmacotherapy]], and extent of [[Intestine|intestinal]] [[adaptation]]. The 2 and 5-year [[survival rate]] of patients with short bowel syndrome are approximately 80% and 70%, respectively.
The [[symptoms]] of short bowel syndrome usually develop immediately following [[bowel resection]]. [[Diarrhea]] may cause massive [[fluid]] and [[Electrolyte disturbance|electrolyte loss]]. Immediately after surgery, [[Intestine|intestinal]] [[adaptation]] develops in three phases, including [[Acute (medicine)|acute]], adaptive and maintenance phase. During the [[adaptation]], structural, motility and functional changes occur. Patients need [[hydration]] and [[Nutrition|nutritional]] support via [[Route of administration|parenteral]], [[Feeding tube|enteral]] and [[Mouth|oral]] routes. Length of remaining [[small bowel]] is the most important [[Prognosis|prognostic factor]]. Patients with more than 200 cm length of [[small bowel]], usually do not need [[parenteral nutrition]]. Patients with shorter [[small bowel]] may not wean off from [[parenteral nutrition]] support. Complications might occur due to [[malnutrition]], [[surgery]] and [[Total parenteral nutrition|parenteral nutrition]]. [[Malnutrition]] presents with [[vitamin]], [[mineral]] and [[Essential fatty acid|essential fatty acids]] deficiencies. Complications related to [[surgery]] including [[thrombosis]], [[infection]], [[Bleeding|hemorrhage]], [[atelectasis]] and [[anastomosis]] disruption might occur. [[Small intestinal bacterial overgrowth]] due to [[Stasis (medicine)|stasis]] and obstruction might also occur. [[Chronic liver disease]] following [[Total parenteral nutrition|parenteral nutrition]] is a common complication in short bowel syndrome. There is no definite cure for short bowel syndrome. However, [[Medication|medications]] and [[Nutrition|nutritional]] therapy significantly improve the quality of life and survival of the patients. [[Prognosis]] of short bowel syndrome depends on the location and size of the [[bowel resection]], underlying [[pathology]], [[nutrition]] support, [[pharmacotherapy]], and extent of [[Intestine|intestinal]] [[adaptation]]. The 2 and 5-year [[survival rate]] of patients with short bowel syndrome are approximately 80% and 70%, respectively.
==Diagnosis==
==Diagnosis==
===Diagnostic Criteria===
===Diagnostic Criteria===
Short bowel syndrome is mainly diagnosed based on clinical presentation. There are no established criteria for the diagnosis of Short bowel syndrome. History of [[bowel resection]]<nowiki/>and clinical manifestation including [[diarrhea]] and [[malnutrition]] would confirm the diagnosis.
Short bowel syndrome is mainly diagnosed based on clinical presentation. There are no established criteria for the diagnosis of short bowel syndrome. History of [[bowel resection]] <nowiki/>and clinical manifestation including [[diarrhea]] and [[malnutrition]] would confirm the [[diagnosis]].


===History and Symptoms===
===History and Symptoms===
Line 39: Line 40:


===Physical Examination===
===Physical Examination===
Patients with short bowel syndrome usually appear weak and tired. Physical examination of patients with short bowel syndrome is usually remarkable for signs of [[malabsorption]], [[dehydration]] and [[Tenderness (medicine)|abdominal tenderness]].
Patients with short bowel syndrome usually appear weak and tired. [[Physical examination]] of patients with short bowel syndrome is usually remarkable for signs of [[malabsorption]], [[dehydration]] and [[Tenderness (medicine)|abdominal tenderness]].


===Laboratory Findings===
===Laboratory Findings===
Laboratory findings consistent with the diagnosis of short bowel syndrome include [[anemia]], [[hypoalbuminemia]], low level of [[Vitamin|vitamins]], [[Mineral|minerals]], and [[Dietary mineral|micronutrients]]. Level of [[Acute phase protein|acute phase reactants]] is high. Abnormal [[liver function tests]] including elevated [[Liver function tests|liver enzymes]] and [[bilirubin]] might be seen. [[Fluid]] and [[Electrolyte disturbance|electrolyte imbalance]] might be present. [[Fecal fat]]<nowiki/>test is usually positive.
Laboratory findings consistent with the [[diagnosis]] of short bowel syndrome include [[anemia]], [[hypoalbuminemia]], low level of [[Vitamin|vitamins]], [[Mineral|minerals]], and [[Dietary mineral|micronutrients]]. Level of [[Acute phase protein|acute phase reactants]] is high. Abnormal [[liver function tests]] including elevated [[Liver function tests|liver enzymes]] and [[bilirubin]] might be seen. [[Fluid]] and [[Electrolyte disturbance|electrolyte imbalance]] might be present. [[Fecal fat]] <nowiki/>test is usually positive.


===Electrocardiogram===
===Electrocardiogram===
There are no [[The electrocardiogram|ECG]] findings associated with short bowel syndrome. In case of [[malnutrition]] and [[Electrolyte disturbance|electrolyte imbalance]], an [[The electrocardiogram|ECG]] may be helpful. [[Hypokalemia]] might present with [[Cardiac arrhythmia|arrhythmia]], [[ST segment depression]], low [[T wave]], prominent [[U waves]] and QRS prolongation. [[Hypocalcemia]] might present with [[QT prolongation|QT interval prolongation]]. Hypomagnesemia might present with [[QT prolongation|QT interval prolongation]] and [[Ventricle (heart)|ventricular]] and [[Supraventricular tachycardia|supraventricular arrhythmia]].
There are no [[The electrocardiogram|ECG]] findings associated with short bowel syndrome. In case of [[malnutrition]] and [[Electrolyte disturbance|electrolyte imbalance]], an [[The electrocardiogram|ECG]] may be helpful. [[Hypokalemia]] might present with [[Cardiac arrhythmia|arrhythmia]], [[ST segment depression]], low [[T wave]], prominent [[U waves]] and [[QRS complex|QRS]] prolongation. [[Hypocalcemia]] might present with [[QT prolongation|QT interval prolongation]]. [[Hypomagnesemia]] might present with [[QT prolongation|QT interval prolongation]] and [[Ventricle (heart)|ventricular]] and [[Supraventricular tachycardia|supraventricular arrhythmia]].


===X-ray===
===X-ray===
An [[abdominal x-ray]] may be helpful in the diagnosis of short bowel syndrome. [[Abdominal x-ray]] helps to rule out [[ileus]] or [[Bowel obstruction|intestinal obstruction]]. [[Upper gastrointestinal series]] might demonstrate [[Stenosis|strictures]] and [[dilation]] of the [[Intestine|bowel]].
An [[abdominal x-ray]] may be helpful in the [[diagnosis]] of short bowel syndrome. [[Abdominal x-ray]] helps to rule out [[ileus]] or [[Bowel obstruction|intestinal obstruction]]. [[Upper gastrointestinal series]] might demonstrate [[Stenosis|strictures]] and [[dilation]] of the [[Intestine|bowel]].


===Ultrasound===
===Ultrasound===
There are no echocardiography findings associated with short bowel syndrome. [[Ultrasound]] may be helpful in the diagnosis of complications of short bowel syndrome including [[Gallstone disease|gallstones]] and [[Hepato-biliary diseases|liver diseases]]. [[Medical ultrasonography|Doppler ultrasound]] might be used to diagnose [[Venous thromboembolism|venous thrombosis]].
There are no abnormal [[echocardiographic]] findings associated with short bowel syndrome. [[Ultrasound]] may be helpful in the [[diagnosis]] of complications of short bowel syndrome including [[Gallstone disease|gallstones]] and [[Hepato-biliary diseases|liver diseases]]. [[Medical ultrasonography|Doppler ultrasound]] might be used to diagnose [[Venous thromboembolism|venous thrombosis]].


===CT scan===
===CT scan===
[[Computed tomography|Abdominal CT scan]] with [[Contrast medium|contrast]] may be helpful in the diagnosis of short bowel syndrome complications including [[dilation]], [[obstruction]] of the [[Intestine|bowel]] and signs of [[Hepato-biliary diseases|liver diseases]].
[[Computed tomography|Abdominal CT scan]] with [[Contrast medium|contrast]] may be helpful in the [[diagnosis]] of short bowel syndrome complications including [[dilation]], [[obstruction]] of the [[Intestine|bowel]] and signs of [[Hepato-biliary diseases|liver diseases]].


===MRI===
===MRI===
There are no MRI findings associated with short bowel syndrome.
There are no [[Magnetic resonance imaging|MRI]] findings associated with short bowel syndrome.


===Other Imaging Findings===
===Other Imaging Findings===
Line 67: Line 68:
==Treatment==
==Treatment==
===Medical Therapy===
===Medical Therapy===
Management of short bowel syndrome is complicated and requires close collaboration of all medical team members including the physician, nutritionist, and nurse with the patient and their families. Medical therapy consists of [[Nutrition|nutritional]] therapy and [[pharmacotherapy]]. [[Nutrition|Nutritional]] therapy is essential for short bowel syndrome and to restore the [[Intestine|intestinal]] [[adaptation]]. It could be provided through [[Mouth|oral]], [[Feeding tube|enteral]] and [[Route of administration|parenteral]] routes. The ultimate goal is to provide necessary [[Nutrient|nutrients]] via [[Route of administration|oral route]] other than [[Route of administration|parenteral]] or [[Feeding tube|enteral]] routes. All patients require enough [[fluid]], [[Electrolyte|electrolytes]], [[Dietary supplement|supplements]] and [[Calorie|calories]]. Medications are used to control [[symptoms]] of short bowel syndrome include antimotility agents, antisecretory agents, and [[Tropic hormone|trophic agents]]. Lifelong follow-up is usually needed.


===Surgery===
===Surgery===
[[Surgery]] is not the first-line treatment option for patients with short bowel syndrome. [[Surgery]] is usually reserved for patients with the goal to wean them off [[Total parenteral nutrition|parenteral nutrition]]. Patients who have severe or worsened [[malabsorption]] might require [[surgery]] including [[Intestine|intestinal]] [[Organ transplant|transplant]]. [[Organ transplant|Transplant]] is [[contraindicated]] in patients with active [[infection]] or [[Cancer|malignancies]]. Approximately half of the patients with short bowel syndrome will require [[surgery]]. Bianchi [[Surgery|procedure]] and serial transverse enteroplasty (STEP) are performed to lengthen dilated [[Intestine|bowel]]. Stricturoplasty might be necessary. [[Organ transplant|Intestinal transplant]] is reserved for patients who have life-threatening complications of [[Intestine|intestinal]] failure, irreversible permanent [[total parenteral nutrition]] requirement and episodes of [[sepsis]] or loss of [[Vein|venous]] access.


===Primary Prevention===
===Primary Prevention===
There are no established measures for the [[primary prevention]] of short bowel syndrome. However, treating underlying causes including [[Crohn's disease]] and [[Cancer|malignancies]] might prevent short bowel syndrome.


===Secondary Prevention===
===Secondary Prevention===
There are several ways to prevent complications of short bowel syndrome. Management strategies and regular follow-up are needed to find and treat complications accordingly. Effective measures must be done for secondary prevention of complications following total parenteral nutrition including liver disease, [[Gallstone disease|cholelithiasis]], [[kidney stone]], [[Small bowel bacterial overgrowth syndrome|small bowel bacterial overgrowth]], [[lactic acidosis]], [[lactic acidosis]]. [[Hydration]], consuming [[Dietary supplement|supplements]], [[Antibiotic|antibiotic therapy]], and regular monitoring with [[Blood test|blood tests]], [[ultrasound]] and [[Scan|scans]] are recommended.
There are several ways to [[Prevention (medical)|prevent]] complications of short bowel syndrome. Management strategies and regular follow-up are needed to find and treat complications accordingly. Effective measures must be done for [[secondary prevention]] of complications following [[total parenteral nutrition]] including [[liver disease]], [[Gallstone disease|cholelithiasis]], [[kidney stone]], [[Small bowel bacterial overgrowth syndrome|small bowel bacterial overgrowth]], [[lactic acidosis]], [[lactic acidosis]]. [[Hydration]], consuming [[Dietary supplement|supplements]], [[Antibiotic|antibiotic therapy]], and regular monitoring with [[Blood test|blood tests]], [[ultrasound]] and [[Scan|scans]] are recommended.


==References==
==References==
{{reflist|2}}
{{reflist|2}}
 
{{WikiDoc Help Menu}}
{{WikiDoc Help Menu}}
{{WikiDoc Sources}}
{{WikiDoc Sources}}
[[Category:Medicine]]
[[Category:Gastroenterology]]
[[Category:Surgery]]
[[Category:Up-To-Date]]

Latest revision as of 00:10, 30 July 2020

Short bowel syndrome Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Short bowel syndrome from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X-ray

Echocardiography and Ultrasound

CT scan

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Short bowel syndrome overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Short bowel syndrome overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Short bowel syndrome overview

CDC on Short bowel syndrome overview

Short bowel syndrome overview in the news

Blogs on Short bowel syndrome overview

Directions to Hospitals Treating Short bowel syndrome

Risk calculators and risk factors for Short bowel syndrome overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sadaf Sharfaei M.D.[2]

Overview

Short bowel syndrome is a malabsorption disorder caused by the surgical removal of the small intestine. Most cases are acquired, although some children are born with a congenital short bowel. It does usually not develop unless a person has lost more than two-thirds of their small intestine. Intestine has the ability to adapt following resection. Adaptation depends on multiple factors including individual, intestinal and therapeutic measurements. Successful adaptation depends on the length of remaining intestine, portion of the resected intestine, and early introduction of nutrition therapy. Total intestinal adaptation defines as when patient is weaned from parenteral nutrition. The hallmark of short bowel syndrome is diarrhea. Complications might happen due to malnutritionsurgery and parenteral nutrition. Management of short bowel syndrome consists of medical and surgical therapy. Medical therapy consists of nutritional therapy and pharmacotherapy. Patients who have severe or worsened malabsorption might require surgery including intestinal transplant. Effective measures must be adopted for secondary prevention of complications following total parenteral nutrition including liver diseasecholelithiasiskidney stonesmall bowel bacterial overgrowthlactic acidosislactic acidosis.

Historical Perspective

The first successful intestinal resection was performed in 1880. In 1935, Haymond following research on many patients with bowel resection, reported that 30 to 50% loss of bowel was well tolerated. Total parenteral nutrition (TPN) was introduced during 1960s which helped patients to survive following bowel resection.

Classification

Based on the length of the remaining bowel, short bowel syndrome may be divided into end-jejunostomy, jejunocolonic anastomosis, ileocolonic anastomosis. Severity varies from mild to severe. All of them require home parenteral nutrition except ileocolonic anastomosis which has excellent prognosis and rarely needs parenteral nutrition. Based on the etiology, short bowel syndrome may be divided into three categories such as vascular abnormalities, mucosal disease of intestine and causes without preexisting intestinal disease.

Pathophysiology

Short bowel syndrome occurrs as a result of bowel resection following various diseases of the gut such as Crohn's diseasemalignanciesischemia, and trauma. Short bowel syndrome occurs when the length of the small intestine is less than 2 meters and requires nutritional therapy to prevent malnutrition. Post bowel resection, adaptation might occur which includes structural, motility and functional changes in the remaining intestine. Changes usually start in the first 24 hours following bowel resection and last for about two years. Adaptation depends upon multiple factors including individual, intestinal and therapeutic measurements. Following bowel resectionadaptation occurs in three phases including acute, adaptive, and maintenance phases. Successful adaptation depends on the length of remaining intestine, portion of the resected intestine, and early introduction of nutrition therapy. The term total intestinal adaptation is used when the patient is weaned from parenteral nutrition. The main reason for malabsorption following bowel resection is reduced absorptive capacity of the small intestine due to loss of surface area. On gross and microscopic examination, the resected bowel segment may show the underlying causes including Crohn's diseasemalignancies or ischemia.

Causes

Short bowel syndrome in adults is usually caused by surgical removal of the intestine due to different diseases including Crohn's diseasemesenteric ischemiamalignancies or radiation enteritis. Less common causes include traumavolvulusadhesion and iatrogenic surgery on gastrointestinal system.

Differentiating short bowel syndrome from Other Diseases

Epidemiology and Demographics

The incidence and prevalence of short bowel syndrome is difficult to estimate. All the data is derived from patients receiving home parenteral nutrition. Therefore, there are different distributions around the world. The incidence of short bowel syndrome was estimated to be 1-2 cases per 100,000 individuals worldwide per year. The prevalence of short bowel syndrome is approximately 0.3-4 per 100,000 individuals in the USA to 0.1-4 per 100,000 individuals in Europe. It affects all age groups. There is no racial predilection to short bowel syndrome and is reported worldwide. Short bowel syndrome affects men and women equally.

Risk Factors

Common risk factor for the development of short bowel syndrome may be iatrogenic including any operation on the gastrointestinal system.

Screening

There is insufficient evidence to recommend routine screening for short bowel syndrome.

Natural History, Complications, and Prognosis

The symptoms of short bowel syndrome usually develop immediately following bowel resectionDiarrhea may cause massive fluid and electrolyte loss. Immediately after surgery, intestinal adaptation develops in three phases, including acute, adaptive and maintenance phase. During the adaptation, structural, motility and functional changes occur. Patients need hydration and nutritional support via parenteralenteral and oral routes. Length of remaining small bowel is the most important prognostic factor. Patients with more than 200 cm length of small bowel, usually do not need parenteral nutrition. Patients with shorter small bowel may not wean off from parenteral nutrition support. Complications might occur due to malnutritionsurgery and parenteral nutritionMalnutrition presents with vitaminmineral and essential fatty acids deficiencies. Complications related to surgery including thrombosisinfectionhemorrhageatelectasis and anastomosis disruption might occur. Small intestinal bacterial overgrowth due to stasis and obstruction might also occur. Chronic liver disease following parenteral nutrition is a common complication in short bowel syndrome. There is no definite cure for short bowel syndrome. However, medications and nutritional therapy significantly improve the quality of life and survival of the patients. Prognosis of short bowel syndrome depends on the location and size of the bowel resection, underlying pathologynutrition support, pharmacotherapy, and extent of intestinal adaptation. The 2 and 5-year survival rate of patients with short bowel syndrome are approximately 80% and 70%, respectively.

Diagnosis

Diagnostic Criteria

Short bowel syndrome is mainly diagnosed based on clinical presentation. There are no established criteria for the diagnosis of short bowel syndrome. History of bowel resection and clinical manifestation including diarrhea and malnutrition would confirm the diagnosis.

History and Symptoms

The hallmark of short bowel syndrome is diarrhea. A positive history of operation on gastrointestinal system and symptoms of malabsorption is suggestive of short bowel syndrome. The most common symptoms of short bowel syndrome include dehydrationabdominal pain, and fatigue.

Physical Examination

Patients with short bowel syndrome usually appear weak and tired. Physical examination of patients with short bowel syndrome is usually remarkable for signs of malabsorptiondehydration and abdominal tenderness.

Laboratory Findings

Laboratory findings consistent with the diagnosis of short bowel syndrome include anemiahypoalbuminemia, low level of vitaminsminerals, and micronutrients. Level of acute phase reactants is high. Abnormal liver function tests including elevated liver enzymes and bilirubin might be seen. Fluid and electrolyte imbalance might be present. Fecal fat test is usually positive.

Electrocardiogram

There are no ECG findings associated with short bowel syndrome. In case of malnutrition and electrolyte imbalance, an ECG may be helpful. Hypokalemia might present with arrhythmiaST segment depression, low T wave, prominent U waves and QRS prolongation. Hypocalcemia might present with QT interval prolongation. Hypomagnesemia might present with QT interval prolongation and ventricular and supraventricular arrhythmia.

X-ray

An abdominal x-ray may be helpful in the diagnosis of short bowel syndrome. Abdominal x-ray helps to rule out ileus or intestinal obstructionUpper gastrointestinal series might demonstrate strictures and dilation of the bowel.

Ultrasound

There are no abnormal echocardiographic findings associated with short bowel syndrome. Ultrasound may be helpful in the diagnosis of complications of short bowel syndrome including gallstones and liver diseasesDoppler ultrasound might be used to diagnose venous thrombosis.

CT scan

Abdominal CT scan with contrast may be helpful in the diagnosis of short bowel syndrome complications including dilationobstruction of the bowel and signs of liver diseases.

MRI

There are no MRI findings associated with short bowel syndrome.

Other Imaging Findings

There are no other imaging findings associated with short bowel syndrome.

Other Diagnostic Studies

There are no other diagnostic studies associated with short bowel syndrome.

Treatment

Medical Therapy

Management of short bowel syndrome is complicated and requires close collaboration of all medical team members including the physician, nutritionist, and nurse with the patient and their families. Medical therapy consists of nutritional therapy and pharmacotherapyNutritional therapy is essential for short bowel syndrome and to restore the intestinal adaptation. It could be provided through oralenteral and parenteral routes. The ultimate goal is to provide necessary nutrients via oral route other than parenteral or enteral routes. All patients require enough fluidelectrolytessupplements and calories. Medications are used to control symptoms of short bowel syndrome include antimotility agents, antisecretory agents, and trophic agents. Lifelong follow-up is usually needed.

Surgery

Surgery is not the first-line treatment option for patients with short bowel syndrome. Surgery is usually reserved for patients with the goal to wean them off parenteral nutrition. Patients who have severe or worsened malabsorption might require surgery including intestinal transplantTransplant is contraindicated in patients with active infection or malignancies. Approximately half of the patients with short bowel syndrome will require surgery. Bianchi procedure and serial transverse enteroplasty (STEP) are performed to lengthen dilated bowel. Stricturoplasty might be necessary. Intestinal transplant is reserved for patients who have life-threatening complications of intestinal failure, irreversible permanent total parenteral nutrition requirement and episodes of sepsis or loss of venous access.

Primary Prevention

There are no established measures for the primary prevention of short bowel syndrome. However, treating underlying causes including Crohn's disease and malignancies might prevent short bowel syndrome.

Secondary Prevention

There are several ways to prevent complications of short bowel syndrome. Management strategies and regular follow-up are needed to find and treat complications accordingly. Effective measures must be done for secondary prevention of complications following total parenteral nutrition including liver diseasecholelithiasiskidney stonesmall bowel bacterial overgrowthlactic acidosislactic acidosisHydration, consuming supplementsantibiotic therapy, and regular monitoring with blood testsultrasound and scans are recommended.

References

Template:WikiDoc Sources