Ileus overview: Difference between revisions
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==Overview== | ==Overview== | ||
[[Ileus]] is defined as temporary cessation of [[intestinal]] [[peristalsis]] in the absence of [[bowel obstruction|mechanical obstruction]]. The word [[ileus]] | [[Ileus]] is defined as the temporary cessation of [[intestinal]] [[peristalsis]] in the absence of [[bowel obstruction|mechanical obstruction]]. The word [[ileus]] is derived from the Greek word "είλειν" which means to twist. There is no specific system for classification of [[ileus|postoperative ileus]]. However, based on [[etiology]], [[ileus|postoperative ileus]] may be classified into [[drug]] induced [[ileus]], [[ileus]] secondary to [[metabolic]] and [[electrolyte disturbances]] and [[ileus]] due to some [[systemic]] disorders. The [[pathogenesis]] of [[ileus]] is based on its multifactorial [[etiology]]. [[Ileus]] is most commonly seen during the [[surgery|postoperative]] period (usually 3 days after [[surgery]]). Commonly used [[analgesics]] such as [[opiates]] and [[anesthesia]] may also aggravate the development of [[ileus]]. [[Enteric nervous system|Enteric]] and [[autonomic nervous system]] disturbances can cause a severe variety of [[ileus]], named [[Intestinal pseudoobstruction|chronic intestinal pseudo-obstruction]] ([[Intestinal pseudoobstruction|CIPO]]), which may be related to some altered [[genes]]. Conditions commonly associated with [[ileus]] include [[diabetes mellitus]], [[hypothyroidism]], and [[hypoparathyroidism]]. The [[incidence]] and [[prevalence]] of [[ileus]] varies with the type of [[surgery]] performed. The [[incidence]] of [[ileus]] in [[patient|patients]] undergoing [[laparotomy]] is approximately 9,000 per 100,000 cases worldwide, which is more common compared to other [[surgery|surgeries]]. Common [[risk factors]] in the development of [[ileus]] include [[Aging|older age]], [[electrolyte abnormalities]], previous history of [[abdominal surgery]], postoperative [[Deep vein thrombosis|deep venous thrombosis]], [[diabetic ketoacidosis]], history of chronic [[opiates]] use and [[hypothyroidism]]. [[patient|Patients]] with [[ileus]] are usually presented with [[abdominal pain]], [[abdominal distention]], [[nausea and vomiting]] with [[postprandial]] discomfort, [[constipation]] or obstination and loss of appetite. Common [[Complication (medicine)|complications]] of [[ileus]] include [[Electrolyte imbalance|electrolyte imbalance]], [[dehydration]], [[intestinal perforation]], [[sepsis]], [[jaundice]], [[intestine|Intestinal]] strangulation and [[pulmonary]] [[Complication (medicine)|complications]]. There are no [[diagnostic]] laboratory findings associated with [[ileus]]. However, laboratory evaluations must be done to identify the severity and presence of other [[Complication (medicine)|complications]] of [[ileus]] such as [[electrolyte abnormalities]] and [[hypovolemia]]. Findings on an [[x-ray]] suggestive of [[ileus]] include multiple air–fluid levels throughout the [[abdomen]], elevated [[diaphragm]] with [[Dilatation of large intestine|dilatation of both large]] and [[small intestine]], slow movement of [[barium]] with a [[patent]] [[intestinal]] [[lumen]]. An [[abdomen]] and [[pelvis]] [[Computed tomography|CT scan]] (with [[intravenous]] [[Contrast medium|contrast]] and [[Contrast medium|oral water soluble contrast]]) can also distinguish early [[ileus|postoperative ileus]] from [[bowel obstruction|mechanical obstruction]]. In addition, a [[Computed tomography|CT scan]] can also identify other [[Complication (medicine)|complications]] seen in the post[[surgery|operative]] period or [[ileus]] related [[Complication (medicine)|complications]], such as [[Gastrointestinal perforation|perforation]], strangulation and [[necrosis]]. [[Intravenous]] [[Fluid replacement|hydration]] is advised with appropriate rapid supplementation for [[Electrolyte abnormalities|electrolyte abnormalities.]] [[NSAID]]<nowiki/>s are used as baseline [[analgesic]] [[medication|medications]]. [[patient|Patients]] are put on [[NPO]] and [[nasogastric tube]] is advised to relieve recurrent [[vomiting]] or [[Abdominal distension|abdominal distention]] associated with [[pain]]. [[Surgery operation|Surgical]] intervention is not routinely recommended for the management of [[ileus]]. However, [[patient|patients]] with prolonged [[ileus]], [[radiology|radiologic]] or clinical findings indicating development of [[ileus]] [[Complication (medicine)|complication]], such as [[intestinal perforation]], strangulation or [[necrosis]] and worsening of clinical or [[laboratory]] conditions of [[patient|patients]] may require urgent [[Surgery|surgical]] intervention to identify and alleviate [[Complication (medicine)|complications]] of [[ileus]]. | ||
==Historical Perspective== | ==Historical Perspective== | ||
The word [[ileus]] | The word [[ileus]] is derived from the Greek word "είλειν" which means to twist. [[Gallstone ileus]] was first described by Thomas Bartholin in 1654. The effect of [[splanchnic nerve|splanchnic nerves]] on [[intestine|intestinal]] [[peristalsis]] was discovered by Bayliss and Starling in 1899. Later in 1958, Robertson, Eddy and Vosseler delineated a case of [[ileus]], [[Complication (medicine)|complicated]] by [[Cecum|cecal]] [[Gastrointestinal perforation|perforation]]. | ||
==Classification== | ==Classification== | ||
There is no specific system for classification of [[ileus|postoperative ileus]]. However based on [[etiology]], [[ileus|postoperative ileus]] may be classified into [[drug]] induced [[ileus]], [[ileus]] secondary to [[metabolic]] and [[electrolyte disturbances]] and [[ileus]] due to some [[systemic]] disorders. | There is no specific system for classification of [[ileus|postoperative ileus]]. However, based on [[etiology]], [[ileus|postoperative ileus]] may be classified into [[drug]] induced [[ileus]], [[ileus]] secondary to [[metabolic]] and [[electrolyte disturbances]] and [[ileus]] due to some [[systemic]] disorders. | ||
==Pathophysiology== | ==Pathophysiology== | ||
[[Ileus]] is defined as a temporary cessation of [[intestinal]] [[peristalsis]] in the absence of [[bowel obstruction|mechanical obstruction]]. The [[pathogenesis]] of [[ileus]] is based on its multifactorial [[etiology]]. [[Ileus]] is most commonly seen during the [[surgery|postoperative]] period (usually 3 days after [[surgery]]). When a [[patient]] undergoes a [[surgical procedure]], it often puts the body under significant [[stress]]. It is thought that [[ileus]] is the result of [[surgery|surgical]] [[stress]] induced [[Inflammation|inflammatory]] process, that leads to release of [[inflammatory]] and [[neuroendocrine]] mediators (such as [[nitric oxide]], [[VIP]] and [[substance P]]). Additionally, manipulation of the [[intestine]] leads to activation of [[afferent nerve|afferent]] pathways that travel to [[Brain stem]], which leads to increased [[autonomic]] output to the [[sympathetic]] [[neurons]] and increased secretion of [[adrenergic]] [[neurotransmitters]] and subsequent decreased [[intestinal]] [[motility]]. Commonly used [[analgesics]] such as [[opiates]] and [[anesthesia]] may also | [[Ileus]] is defined as a temporary cessation of [[intestinal]] [[peristalsis]] in the absence of [[bowel obstruction|mechanical obstruction]]. The [[pathogenesis]] of [[ileus]] is based on its multifactorial [[etiology]]. [[Ileus]] is most commonly seen during the [[surgery|postoperative]] period (usually 3 days after [[surgery]]). When a [[patient]] undergoes a [[surgical procedure]], it often puts the body under significant [[stress]]. It is thought that [[ileus]] is the result of a [[surgery|surgical]] [[stress]]-induced [[Inflammation|inflammatory]] process, that leads to the release of [[inflammatory]] and [[neuroendocrine]] mediators (such as [[nitric oxide]], [[VIP]] and [[substance P]]). Additionally, manipulation of the [[intestine]] leads to activation of [[afferent nerve|afferent]] pathways that travel to the[[Brain stem]], which leads to increased [[autonomic]] output to the [[sympathetic]] [[neurons]] and increased secretion of [[adrenergic]] [[neurotransmitters]] and subsequent decreased [[intestinal]] [[motility]]. Commonly used [[analgesics]] such as [[opiates]] and [[anesthesia]] may also increase the development of [[ileus]]. [[Enteric nervous system|Enteric]] and [[autonomic nervous system]] disturbances can cause a severe form of [[ileus]], named [[Intestinal pseudoobstruction|chronic intestinal pseudo-obstruction]] ([[Intestinal pseudoobstruction|CIPO]]) which may be related to some altered [[genes]]. Conditions commonly associated with [[ileus]] include [[diabetes mellitus]], [[hypothyroidism]], and [[hypoparathyroidism]]. On [[gross pathology]] findings of [[ileus]] include [[bowel]] contortion with a distended [[Small intestine|small]] and [[large intestine]]. On [[Microscopic examination|microscopic]] [[histopathological]] [[analysis]], findings of [[ileus]] include [[inflammatory cells]] predominantly [[macrophage|macrophages]] and [[mast cells]]. | ||
==Causes== | ==Causes== | ||
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==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
[[Ileus]] is most commonly seen in [[patient|patients]] undergoing [[Surgery|surgical treatment]]. The [[incidence]] and [[prevalence]] of [[ileus]] varies with the type of [[surgery]] performed. [[patient|Patients]] with large incisions are at a relatively higher risk of developing [[ileus]] as compared to [[patient|patients]] undergoing minor [[Surgery|surgical procedures]] with small incisions. The [[incidence]] of [[ileus]] in [[patient|patients]] undergoing [[laparotomy]] is approximately | [[Ileus]] is most commonly seen in [[patient|patients]] undergoing [[Surgery|surgical treatment]]. The [[incidence]] and [[prevalence]] of [[ileus]] varies with the type of [[surgery]] performed. [[patient|Patients]] with large incisions are at a relatively higher risk of developing [[ileus]] as compared to [[patient|patients]] undergoing minor [[Surgery|surgical procedures]] with small incisions. The [[incidence]] of [[ileus]] in [[patient|patients]] undergoing [[laparotomy]] is approximately 9,000 per 100,000 cases worldwide, which is more common compared to other [[surgery|surgeries]]. The [[prevalence]] of [[ileus]] is not precisely known. However, it is estimated that that around 10 percent (10,000 per 100,000) of the people undergoing [[surgery|surgical procedures]] develop [[ileus]] that lasts longer than three days. [[ileus|Postoperative ileus]] has been present in 15% of [[patient|patients]] who had partial [[intestine|bowel]] [[resection]], based on one study. [[patient|Patients]] of all age groups may develop [[ileus]] but it is more commonly seen in the [[elderly]] due to underlying [[Comorbidity|comorbidities]]. There is no racial predisposition for [[ileus]] and men and women are affected equally. | ||
==Risk Factors== | ==Risk Factors== | ||
Common [[risk factors]] in the development of [[ileus]] include [[Ageing|older age]], [[electrolyte abnormalities]], previous history of [[abdominal surgery]], prolonged [[abdominal]] or [[pelvic]] [[surgery]], [[laparotomy]], lower [[Gastrointestinal tract]] procedures, delayed postoperative [[Enteral feeding|enteral nutrition]], use of preoperative [[albumin]], postoperative [[Deep vein thrombosis|deep venous thrombosis]], [[diabetic ketoacidosis]], history of | Common [[risk factors]] in the development of [[ileus]] include [[Ageing|older age]], [[electrolyte abnormalities]], previous history of [[abdominal surgery]], prolonged [[abdominal]] or [[pelvic]] [[surgery]], [[laparotomy]], lower [[Gastrointestinal tract]] procedures, delayed postoperative [[Enteral feeding|enteral nutrition]], use of preoperative [[albumin]], postoperative [[Deep vein thrombosis|deep venous thrombosis]], [[diabetic ketoacidosis]], history of chronic [[opiates]] use and [[hypothyroidism]]. Less common [[risk factors]] include [[spinal cord injury]] (specifically [[thoracic]] cord), Severe [[illnesses|illness]] like [[sepsis]], [[obesity]], [[peripheral vascular disease]] and development of some postoperative [[Complication (medicine)|complications]]. | ||
==Screening== | ==Screening== | ||
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==Natural History, Complications, and Prognosis== | ==Natural History, Complications, and Prognosis== | ||
[[patient|Patients]] with [[ileus]] are usually presented with [[abdominal pain]], [[abdominal distention]], [[abdomen|abdominal]] [[cramp|cramping]], [[nausea and vomiting]] with [[postprandial]] discomfort, [[constipation]] or obstination and loss of appetite. Common [[Complication (medicine)|complications]] of [[ileus]] include [[Electrolyte imbalance|electrolyte imbalance]], [[malabsorption]], [[dehydration]], [[intestinal perforation]], [[Renal insufficiency|renal failure]], [[ascites]], [[sepsis]], [[jaundice]], [[intestine|Intestinal]] strangulation and [[pulmonary]] [[Complication (medicine)|complications]]. Depending on the duration of the [[ileus|postoperative ileus]] at the time of [[diagnosis]], the [[prognosis]] may vary. However, the [[prognosis]] is generally regarded as good. Most cases of [[ileus|postoperative ileus]] resolve spontaneously and do not require | [[patient|Patients]] with [[ileus]] are usually presented with [[abdominal pain]], [[abdominal distention]], [[abdomen|abdominal]] [[cramp|cramping]], [[nausea and vomiting]] with [[postprandial]] discomfort, [[constipation]] or obstination and loss of appetite. Common [[Complication (medicine)|complications]] of [[ileus]] include [[Electrolyte imbalance|electrolyte imbalance]], [[malabsorption]], [[dehydration]], [[intestinal perforation]], [[Renal insufficiency|renal failure]], [[ascites]], [[sepsis]], [[jaundice]], [[intestine|Intestinal]] strangulation and [[pulmonary]] [[Complication (medicine)|complications]]. Depending on the duration of the [[ileus|postoperative ileus]] at the time of [[diagnosis]], the [[prognosis]] may vary. However, the [[prognosis]] is generally regarded as good. Most cases of [[ileus|postoperative ileus]] resolve spontaneously and do not require further [[treatment]]. | ||
==Diagnosis== | ==Diagnosis== | ||
===Diagnostic Study of Choice=== | ===Diagnostic Study of Choice=== | ||
The [[diagnosis]] of [[ileus]] is made in the presence of positive history and [[Physical examination|physical exam findings]] with [[Medical sign|signs]] of [[intestine|intestinal]] aperistalsis on an [[x-ray]]. In [[patient|patients]] where findings of [[x ray]] are equivocal, [[CT scan]] of the [[abdomen]] should be done to rule out underlying [[bowel obstruction|mechanical obstruction]] as a cause of delayed [[intestinal]] [[motility]]. | The [[diagnosis]] of [[ileus]] is made in the presence of positive history and [[Physical examination|physical exam findings]] with [[Medical sign|signs]] of [[intestine|intestinal]] aperistalsis on an [[x-ray]]. In [[patient|patients]] where findings of an [[x-ray]] are equivocal, a [[CT scan]] of the [[abdomen]] should be done to rule out underlying [[bowel obstruction|mechanical obstruction]] as a cause of delayed [[intestinal]] [[motility]]. | ||
===History and Symptoms=== | ===History and Symptoms=== | ||
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===Laboratory Findings=== | ===Laboratory Findings=== | ||
There are no [[diagnostic]] laboratory findings associated with [[ileus]]. However, laboratory evaluations must be done to identify the severity and presence of other [[Complication (medicine)|complications]] of [[ileus]] such as [[electrolyte abnormalities]] and [[hypovolemia]]. Common laboratory | There are no [[diagnostic]] laboratory findings associated with [[ileus]]. However, laboratory evaluations must be done to identify the severity and presence of other [[Complication (medicine)|complications]] of [[ileus]] such as [[electrolyte abnormalities]] and [[hypovolemia]]. Common laboratory tests include [[complete blood count]], [[Liver function test|liver function test]], [[renal function test]], [[Electrolyte|serum electrolytes]], serum [[lipase]] and [[amylase]], [[arterial blood gas]], [[Lactic acid|lactate level]], serum [[albumin]] and measurement of [[inflammatory]] markers. | ||
===X-ray=== | ===X-ray=== | ||
An [[abdomen|abdominal]] [[x-ray]] with [[barium meal]] ([[small bowel series]]) may be helpful in the [[diagnosis]] of [[ileus]]. Findings on an [[x-ray]] suggestive of [[ileus]] include multiple air–fluid levels throughout the [[abdomen]], elevated [[diaphragm]] with [[Dilatation of large intestine|dilatation of both large]] and [[small intestine]], slow movement of [[barium]] with a [[patent]] [[intestinal]] [[lumen]]. Serial [[X-rays|x rays]] may also differentiate [[ileus|paralytic ileus]] from [[bowel obstruction|mechanical intestinal obstruction]]. | An [[abdomen|abdominal]] [[x-ray]] with [[barium meal]] ([[small bowel series]]) may be helpful in the [[diagnosis]] of [[ileus]]. Findings on an [[x-ray]] suggestive of [[ileus]] include multiple air–fluid levels throughout the [[abdomen]], elevated [[diaphragm]] with [[Dilatation of large intestine|dilatation of both the large]] and [[small intestine]], slow movement of [[barium]] with a [[patent]] [[intestinal]] [[lumen]]. Serial [[X-rays|x-rays]] may also differentiate [[ileus|paralytic ileus]] from [[bowel obstruction|mechanical intestinal obstruction]]. | ||
===CT=== | ===CT=== | ||
An [[abdomen|abdominal]] and [[pelvis|pelvic]] [[Computed tomography|CT scan]] is used to confirm the [[diagnosis]] of [[ileus|postoperative ileus]] only in cases when [[X-rays|x ray]] is not [[diagnosis|diagnostic]]. [[ | An [[abdomen|abdominal]] and [[pelvis|pelvic]] [[Computed tomography|CT scan]] is used to confirm the [[diagnosis]] of [[ileus|postoperative ileus]] only in cases when an [[X-rays|x-ray]] is not [[diagnosis|diagnostic]]. An [[abdomen]] and [[pelvis]] [[Computed tomography|CT scan]] (with [[intravenous]] [[Contrast medium|contrast]] and [[Contrast medium|oral water soluble contrast]]) can also distinguish early [[ileus|postoperative ileus]] from [[bowel obstruction|mechanical obstruction]]. In addition, a [[Computed tomography|CT scan]] can also identify other [[Complication (medicine)|complications]] seen in post-[[surgery|operative]] period or [[ileus]] related [[Complication (medicine)|complications]], such as [[Gastrointestinal perforation|perforation]], strangulation and [[necrosis]]. Findings on a [[Computed tomography|CT scan]] [[diagnosis|diagnostic]] of [[ileus|postoperative ileus]] include multiple air–fluid levels throughout the [[abdomen]], an elevated [[diaphragm]], [[dilation]] of both the [[Large intestine|large]] and [[small intestine]] with no evidence of [[bowel obstruction|mechanical obstruction]]. | ||
===MRI=== | ===MRI=== | ||
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===Other Diagnostic Studies=== | ===Other Diagnostic Studies=== | ||
Other [[diagnosis|diagnostic studies]] for [[ileus]] include [[enteroclysis]]. An [[enteroclysis]] is done when [[abdomen|abdominal]] [[x ray]] and [[Computed tomography|CT scan]] are inconclusive but [[patient]] is still suspected of [[ileus]]. In [[enteroclysis]], [[Contrast medium|water-soluble radio-opaque contrast medium]] such as [[gastrografin]] is used to observe the movements of [[intestine]]. [[Enteroclysis]] can also help in differentiating [[ileus]] from [[small bowel obstruction]]. | Other [[diagnosis|diagnostic studies]] for [[ileus]] include [[enteroclysis]]. An [[enteroclysis]] is done when an [[abdomen|abdominal]] [[x-ray]] and [[Computed tomography|CT scan]] are inconclusive but the [[patient]] is still suspected of [[ileus]]. In [[enteroclysis]], [[Contrast medium|water-soluble radio-opaque contrast medium]] such as [[gastrografin]] is used to observe the movements of [[intestine]]. [[Enteroclysis]] can also help in differentiating [[ileus]] from [[small bowel obstruction]]. | ||
==Treatment== | ==Treatment== | ||
===Medical Therapy=== | ===Medical Therapy=== | ||
The majority of cases of [[ileus]] are resolved with correction of underlying [[Electrolyte abnormalities|electrolyte disorder]] and only require supportive care. [[Intravenous]] [[Fluid replacement|hydration]] is advised with appropriate rapid supplementation for [[Electrolyte abnormalities|electrolyte abnormalities.]] [[NSAID]]<nowiki/>s are used as baseline [[analgesic]] [[medication|medications]]. In contrast, [[opiates]] and antimotility drugs (such as [[Vagus nerve|vagolytic]] agents) should be avoided generally, although [[opiates]] are sometimes used in case of severe intractable [[pain]]. [[patient|Patients]] are put on [[NPO]] and [[nasogastric tube]] | The majority of cases of [[ileus]] are resolved with correction of underlying [[Electrolyte abnormalities|electrolyte disorder]] and only require supportive care. [[Intravenous]] [[Fluid replacement|hydration]] is advised with appropriate rapid supplementation for [[Electrolyte abnormalities|electrolyte abnormalities.]] [[NSAID]]<nowiki/>s are used as baseline [[analgesic]] [[medication|medications]]. In contrast, [[opiates]] and antimotility drugs (such as [[Vagus nerve|vagolytic]] agents) should be avoided generally, although [[opiates]] are sometimes used in case of severe intractable [[pain]]. [[patient|Patients]] are put on a [[NPO]] and [[nasogastric tube]] to relieve recurrent [[vomiting]] or [[Abdominal distension|abdominal distention]] associated with the [[pain]]. [[Prokinetic|Prokinetic agents]] such as [[erythromycin]] are not routinely recommended. In [[ileus|paralytic ileus]] certain [[medication|medications]] such as [[hyoscyamine]], [[methscopolamine bromide]], [[oxycodone]], [[polyethylene glycol-electrolyte solution]] ([[polyethylene glycol-electrolyte solution|PEG-ES]]) are [[Contraindication|contraindicated]]. | ||
===Surgery=== | ===Surgery=== | ||
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[[Category:Medicine]] | [[Category:Medicine]] | ||
[[Category:Gastroenterology]] | [[Category:Gastroenterology]] | ||
[[Category:Up-To-Date]] | |||
[[Category:Up-To-Date]] | [[Category:Up-To-Date]] | ||
Latest revision as of 13:17, 14 April 2021
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Akshun Kalia M.B.B.S.[2]
Overview
Ileus is defined as the temporary cessation of intestinal peristalsis in the absence of mechanical obstruction. The word ileus is derived from the Greek word "είλειν" which means to twist. There is no specific system for classification of postoperative ileus. However, based on etiology, postoperative ileus may be classified into drug induced ileus, ileus secondary to metabolic and electrolyte disturbances and ileus due to some systemic disorders. The pathogenesis of ileus is based on its multifactorial etiology. Ileus is most commonly seen during the postoperative period (usually 3 days after surgery). Commonly used analgesics such as opiates and anesthesia may also aggravate the development of ileus. Enteric and autonomic nervous system disturbances can cause a severe variety of ileus, named chronic intestinal pseudo-obstruction (CIPO), which may be related to some altered genes. Conditions commonly associated with ileus include diabetes mellitus, hypothyroidism, and hypoparathyroidism. The incidence and prevalence of ileus varies with the type of surgery performed. The incidence of ileus in patients undergoing laparotomy is approximately 9,000 per 100,000 cases worldwide, which is more common compared to other surgeries. Common risk factors in the development of ileus include older age, electrolyte abnormalities, previous history of abdominal surgery, postoperative deep venous thrombosis, diabetic ketoacidosis, history of chronic opiates use and hypothyroidism. Patients with ileus are usually presented with abdominal pain, abdominal distention, nausea and vomiting with postprandial discomfort, constipation or obstination and loss of appetite. Common complications of ileus include electrolyte imbalance, dehydration, intestinal perforation, sepsis, jaundice, Intestinal strangulation and pulmonary complications. There are no diagnostic laboratory findings associated with ileus. However, laboratory evaluations must be done to identify the severity and presence of other complications of ileus such as electrolyte abnormalities and hypovolemia. Findings on an x-ray suggestive of ileus include multiple air–fluid levels throughout the abdomen, elevated diaphragm with dilatation of both large and small intestine, slow movement of barium with a patent intestinal lumen. An abdomen and pelvis CT scan (with intravenous contrast and oral water soluble contrast) can also distinguish early postoperative ileus from mechanical obstruction. In addition, a CT scan can also identify other complications seen in the postoperative period or ileus related complications, such as perforation, strangulation and necrosis. Intravenous hydration is advised with appropriate rapid supplementation for electrolyte abnormalities. NSAIDs are used as baseline analgesic medications. Patients are put on NPO and nasogastric tube is advised to relieve recurrent vomiting or abdominal distention associated with pain. Surgical intervention is not routinely recommended for the management of ileus. However, patients with prolonged ileus, radiologic or clinical findings indicating development of ileus complication, such as intestinal perforation, strangulation or necrosis and worsening of clinical or laboratory conditions of patients may require urgent surgical intervention to identify and alleviate complications of ileus.
Historical Perspective
The word ileus is derived from the Greek word "είλειν" which means to twist. Gallstone ileus was first described by Thomas Bartholin in 1654. The effect of splanchnic nerves on intestinal peristalsis was discovered by Bayliss and Starling in 1899. Later in 1958, Robertson, Eddy and Vosseler delineated a case of ileus, complicated by cecal perforation.
Classification
There is no specific system for classification of postoperative ileus. However, based on etiology, postoperative ileus may be classified into drug induced ileus, ileus secondary to metabolic and electrolyte disturbances and ileus due to some systemic disorders.
Pathophysiology
Ileus is defined as a temporary cessation of intestinal peristalsis in the absence of mechanical obstruction. The pathogenesis of ileus is based on its multifactorial etiology. Ileus is most commonly seen during the postoperative period (usually 3 days after surgery). When a patient undergoes a surgical procedure, it often puts the body under significant stress. It is thought that ileus is the result of a surgical stress-induced inflammatory process, that leads to the release of inflammatory and neuroendocrine mediators (such as nitric oxide, VIP and substance P). Additionally, manipulation of the intestine leads to activation of afferent pathways that travel to theBrain stem, which leads to increased autonomic output to the sympathetic neurons and increased secretion of adrenergic neurotransmitters and subsequent decreased intestinal motility. Commonly used analgesics such as opiates and anesthesia may also increase the development of ileus. Enteric and autonomic nervous system disturbances can cause a severe form of ileus, named chronic intestinal pseudo-obstruction (CIPO) which may be related to some altered genes. Conditions commonly associated with ileus include diabetes mellitus, hypothyroidism, and hypoparathyroidism. On gross pathology findings of ileus include bowel contortion with a distended small and large intestine. On microscopic histopathological analysis, findings of ileus include inflammatory cells predominantly macrophages and mast cells.
Causes
Common causes of ileus include surgery (major abdominal & non-abdominal surgeries), metabolic and electrolyte disturbances (such as hyponatremia, hypokalemia, hypocalcemia and hypomagnesemia), Endocrine disorders (such as diabetes, hypoparathyroidism, hypothyroidism, and adrenal insufficiency), systemic disorders (such as myocardial infarction, pneumonia, renal failure), trauma, sepsis, and drugs (such as opiates, anticholinergic agents, autonomic blockers, tricyclic antidepressants and general anesthesia).
Differentiating Ileus overview from Other Diseases
Ileus must be differentiated from other diseases that cause abdominal pain, constipation, nausea and vomiting such as small bowel obstruction, gastric outlet obstruction, gastroparesis, gastrointestinal perforation, acute cholecystitis, acute pancreatitis, chronic pancreatitis, liver abscess and spontaneous bacterial peritonitis.
Epidemiology and Demographics
Ileus is most commonly seen in patients undergoing surgical treatment. The incidence and prevalence of ileus varies with the type of surgery performed. Patients with large incisions are at a relatively higher risk of developing ileus as compared to patients undergoing minor surgical procedures with small incisions. The incidence of ileus in patients undergoing laparotomy is approximately 9,000 per 100,000 cases worldwide, which is more common compared to other surgeries. The prevalence of ileus is not precisely known. However, it is estimated that that around 10 percent (10,000 per 100,000) of the people undergoing surgical procedures develop ileus that lasts longer than three days. Postoperative ileus has been present in 15% of patients who had partial bowel resection, based on one study. Patients of all age groups may develop ileus but it is more commonly seen in the elderly due to underlying comorbidities. There is no racial predisposition for ileus and men and women are affected equally.
Risk Factors
Common risk factors in the development of ileus include older age, electrolyte abnormalities, previous history of abdominal surgery, prolonged abdominal or pelvic surgery, laparotomy, lower Gastrointestinal tract procedures, delayed postoperative enteral nutrition, use of preoperative albumin, postoperative deep venous thrombosis, diabetic ketoacidosis, history of chronic opiates use and hypothyroidism. Less common risk factors include spinal cord injury (specifically thoracic cord), Severe illness like sepsis, obesity, peripheral vascular disease and development of some postoperative complications.
Screening
There is insufficient evidence to recommend routine screening for ileus.
Natural History, Complications, and Prognosis
Patients with ileus are usually presented with abdominal pain, abdominal distention, abdominal cramping, nausea and vomiting with postprandial discomfort, constipation or obstination and loss of appetite. Common complications of ileus include electrolyte imbalance, malabsorption, dehydration, intestinal perforation, renal failure, ascites, sepsis, jaundice, Intestinal strangulation and pulmonary complications. Depending on the duration of the postoperative ileus at the time of diagnosis, the prognosis may vary. However, the prognosis is generally regarded as good. Most cases of postoperative ileus resolve spontaneously and do not require further treatment.
Diagnosis
Diagnostic Study of Choice
The diagnosis of ileus is made in the presence of positive history and physical exam findings with signs of intestinal aperistalsis on an x-ray. In patients where findings of an x-ray are equivocal, a CT scan of the abdomen should be done to rule out underlying mechanical obstruction as a cause of delayed intestinal motility.
History and Symptoms
Obtaining a history gives important information in making a diagnosis of ileus. The areas of focus should be on onset, duration, and progression of symptoms with special focus on past medical history and current medications. Previous history of surgery, constipation, hypothyroidism, diabetes and renal failure may predispose an individual to developing ileus. Common symptoms of ileus include postprandial abdominal pain, abdominal discomfort, abdominal distension, nausea and vomiting, feeding intolerance, constipation, flatulence, and belching. Less common symptoms include wound dehiscence and impaired wound healing.
Physical Examination
Physical examination of patients with ileus is usually remarkable for abdominal distension, abdominal tenderness, and minimal or absent bowel sounds. Hypotension, fever and tachycardia are possible findings, especially in complicated ileus. Patients with ileus usually appear fatigued and in discomfort. Patients with prolonged ileus may progress to develop peritoneal signs such as rigidity, guarding and rebound tenderness.
Laboratory Findings
There are no diagnostic laboratory findings associated with ileus. However, laboratory evaluations must be done to identify the severity and presence of other complications of ileus such as electrolyte abnormalities and hypovolemia. Common laboratory tests include complete blood count, liver function test, renal function test, serum electrolytes, serum lipase and amylase, arterial blood gas, lactate level, serum albumin and measurement of inflammatory markers.
X-ray
An abdominal x-ray with barium meal (small bowel series) may be helpful in the diagnosis of ileus. Findings on an x-ray suggestive of ileus include multiple air–fluid levels throughout the abdomen, elevated diaphragm with dilatation of both the large and small intestine, slow movement of barium with a patent intestinal lumen. Serial x-rays may also differentiate paralytic ileus from mechanical intestinal obstruction.
CT
An abdominal and pelvic CT scan is used to confirm the diagnosis of postoperative ileus only in cases when an x-ray is not diagnostic. An abdomen and pelvis CT scan (with intravenous contrast and oral water soluble contrast) can also distinguish early postoperative ileus from mechanical obstruction. In addition, a CT scan can also identify other complications seen in post-operative period or ileus related complications, such as perforation, strangulation and necrosis. Findings on a CT scan diagnostic of postoperative ileus include multiple air–fluid levels throughout the abdomen, an elevated diaphragm, dilation of both the large and small intestine with no evidence of mechanical obstruction.
MRI
There are no MRI findings associated with ileus.
Ultrasound
There are no specific ultrasound findings associated with ileus. However, patients with ileus for more than seven days (prolonged ileus) may be evaluated with an abdomen and pelvic ultrasound to determine the underlying cause. Prolonged ileus is generally due to mechanical obstruction and an ultrasound can be done to determine the etiology, such as abscess, strangulated hernia and necrotic bowel.
Other Imaging Findings
There are no other imaging findings associated with ileus.
Other Diagnostic Studies
Other diagnostic studies for ileus include enteroclysis. An enteroclysis is done when an abdominal x-ray and CT scan are inconclusive but the patient is still suspected of ileus. In enteroclysis, water-soluble radio-opaque contrast medium such as gastrografin is used to observe the movements of intestine. Enteroclysis can also help in differentiating ileus from small bowel obstruction.
Treatment
Medical Therapy
The majority of cases of ileus are resolved with correction of underlying electrolyte disorder and only require supportive care. Intravenous hydration is advised with appropriate rapid supplementation for electrolyte abnormalities. NSAIDs are used as baseline analgesic medications. In contrast, opiates and antimotility drugs (such as vagolytic agents) should be avoided generally, although opiates are sometimes used in case of severe intractable pain. Patients are put on a NPO and nasogastric tube to relieve recurrent vomiting or abdominal distention associated with the pain. Prokinetic agents such as erythromycin are not routinely recommended. In paralytic ileus certain medications such as hyoscyamine, methscopolamine bromide, oxycodone, polyethylene glycol-electrolyte solution (PEG-ES) are contraindicated.
Surgery
Surgical intervention is not routinely recommended for the management of ileus. However, patients with prolonged ileus, radiologic or clinical findings indicating development of ileus complication, such as intestinal perforation, strangulation or necrosis and worsening of clinical or laboratory conditions of patients may require urgent surgical intervention to identify and alleviate complications of ileus.
Primary Prevention
Effective measures for the primary prevention of ileus include early mobilization, avoidance of Ryle's tube (nasogastric tube), prior oral feeding with high carbohydrate solid or liquid solution, limiting parenteral fluids, avoidance of pain medications such as opiates, utilizing a minimally invasive surgical method and use of epidural anesthesia for postoperative analgesia.
Secondary Prevention
Effective measures for the secondary prevention of ileus include use of local spinal anesthesia via epidural approach and intravenous (IV) ketorolac as a baseline analgesic for postoperative pain seen in patients of ileus. Ileus associated nausea and vomiting should be treated with serotonin receptor antagonist. Other measures include early mobilization and ambulation, removal of urinary catheter within 24 to 48 hours of surgery with avoidance of routine nasogastric tubes and abdominal drains.
References