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==Overview==
==Overview==
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 (ileus present for > 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 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]] pathways that travel to the [[Brain stem|brainstem]]. In turn, the [[brainstem]] sends increased [[autonomic]] output to the [[sympathetic]] [[neurons]] resulting in increased secretion of [[adrenergic]] [[neurotransmitters]] and decreased [[intestinal]] [[motility]]. Commonly used [[pain medications]] such as [[opiates]] and intraoperative [[anesthesia]] may also aggravate the development of ileus. Conditions commonly associated with ileus include [[diabetes mellitus]], [[hypothyroidism]], and [[hypoparathyroidism]]. On [[gross pathology]] findings of ileus include [[bowel]] contortion with 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]].
[[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 (ileus present for > 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 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]] pathways that travel to the [[Brain stem|brainstem]]. In turn, the [[brainstem]] sends increased [[autonomic]] output to the [[sympathetic]] [[neurons]] resulting in increased secretion of [[adrenergic]] [[neurotransmitters]] and decreased [[intestinal]] [[motility]]. Commonly used [[pain medications]] such as [[opiates]] and intraoperative [[anesthesia]] may also aggravate the development of ileus. Conditions commonly associated with ileus include [[diabetes mellitus]], [[hypothyroidism]], and [[hypoparathyroidism]]. On [[gross pathology]] findings of ileus include [[bowel]] contortion with 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]].
 
==Pathophysiology==
==Pathophysiology==
Ileus is defined as temporary cessation of [[intestinal]] [[peristalsis]] in the absence of mechanical obstruction. The [[pathogenesis]] of ileus is based on its multifactorial [[etiology]]. [[Intestinal]] [[peristalsis]] is primarily regulated by [[enteric nervous system]], [[autonomic nervous system]] and their interactions with [[central nervous system]] ([[CNS]]). However, certain [[medications]] and [[metabolic]] products may also alter the normal [[intestinal]] [[equilibrium]] leading to temporary [[dysfunction]] in [[intestinal]] movements. With increasing time, [[intestinal]] aperistalsis results in accumulation of air and fluid in the [[bowel]] [[lumen]].
 
===Normal physiology===
===Physiology===
*The [[gastrointestinal tract]] is regulated by the [[enteric nervous system]], [[autonomic nervous system]] and interactions with [[central nervous system]].
*The [[gastrointestinal tract]] is regulated by the [[enteric nervous system]], [[autonomic nervous system]] and interactions with [[central nervous system]].
*The [[enteric nervous system]] (ENS) is also known as intrinsic neural network and consists of [[neurons]] located in the walls of [[GI tract]].  
*The [[enteric nervous system]] ([[enteric nervous system|ENS]]) is also known as intrinsic [[Nervous system|neural network]] and consists of [[Neuron|neurons]] located in the walls of [[Gastrointestinal tract]].  
**ENS includes [[myenteric plexus]] ([[Auerbach's plexus|Auerbach's]]) and [[Meissner's plexus|submucosal (Meissner's]]) plexuses.  
**[[Enteric nervous system]] ([[enteric nervous system|ENS]]) includes [[Auerbach's plexus|myenteric plexus]] ([[Auerbach's plexus]]) and [[Meissner's plexus|submucosal plexuses]] ([[Meissner's plexus]]).  
**The [[myenteric plexus]] is located in the [[muscular]] layer and is also known as [[Auerbach's plexus]].  
**The [[Auerbach's plexus|myenteric plexus]] is located in the [[Muscle|muscular layer]] and is also known as [[Auerbach's plexus]].  
**The [[submucosal plexus]] is located in the [[submucosal]] layer and is also known as [[Meissner's plexus]].
**The [[Meissner's plexus|submucosal plexuses]] is located in the [[Submucosa|submucosal layer]] and is also known as [[Meissner's plexus]].
*The [[autonomic nervous system]] (ANS) is also known as extrinsic nervous system.  
*The [[autonomic nervous system]] ([[autonomic nervous system|ANS]]) is also known as extrinsic [[nervous system]].  
**The ANS consists of [[Sympathetic nervous system|sympathetic]] and [[parasympathetic nervous system]] which control [[GI]] function.  
**The [[autonomic nervous system]] ([[autonomic nervous system|ANS]]) consists of [[Sympathetic nervous system|sympathetic]] and [[parasympathetic nervous system]] which control [[Gastrointestinal tract]] function.  
**The [[sympathetic nervous system]] is [[inhibitory]] to [[visceral]] [[smooth muscle]] activity and decreases [[peristalsis]] and [[GI]] motility.
**The [[sympathetic nervous system]] is [[Inhibitory postsynaptic potential|inhibitory]] to [[Viscus|visceral]] [[smooth muscle]] activity and decreases [[peristalsis]] and [[Gastrointestinal tract]] motility.
**The [[parasympathetic nervous system]] is stimulatory to [[visceral]] [[smooth muscle]] activity and increases [[peristalsis]] and [[GI]] motility.
**The [[parasympathetic nervous system]] is stimulatory to [[Viscus|visceral]] [[smooth muscle]] activity and increases [[peristalsis]] and [[Gastrointestinal tract]] motility.
**The [[visceral]] sensory [[afferents]] of [[GI tract]] are located in the [[Parasympathetic nervous system|parasympathetic ANS]], while the [[visceral]] motor efferents are located in both [[Sympathetic nervous system|sympathetic]] and [[Parasympathetic nervous system|parasympathetic]] [[Autonomic nervous system|ANS]].  
**The [[Afferent nerve|afferent]] [[Viscus|visceral]] [[sensory system]] of [[Gastrointestinal tract|GI tract]] is part of the [[parasympathetic nervous system]], while the [[Efferent nerve|efferent]] [[Viscus|visceral]] motor system are located in both [[Sympathetic nervous system|sympathetic]] and [[Parasympathetic nervous system|parasympathetic]] [[autonomic nervous system]].  
**In addition, the extrinsic nervous system synapse with [[enteric nervous system]] and relay information to the [[central nervous system]].
**In addition, the extrinsic [[nervous system]] [[Chemical synapse|synapse]] with [[enteric nervous system]] and relay information to the [[central nervous system]].


[[File:Neural control gut.png|center|300px|frame|Neural control of gut.(By Boumphreyfr (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons)]]
[[File:Neural control gut.png|center|300px|frame|Neural control of gut.(By Boumphreyfr (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons)]]


===Pathophysiology===
===Pathogenesis===
*The most common cause of ileus is [[abdominal surgery]].<ref name="pmid9833803">{{cite journal |vauthors=Kalff JC, Schraut WH, Simmons RL, Bauer AJ |title=Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus |journal=Ann. Surg. |volume=228 |issue=5 |pages=652–63 |year=1998 |pmid=9833803 |pmc=1191570 |doi= |url=}}</ref><ref name="pmid7540700">{{cite journal |vauthors=Espat NJ, Cheng G, Kelley MC, Vogel SB, Sninsky CA, Hocking MP |title=Vasoactive intestinal peptide and substance P receptor antagonists improve postoperative ileus |journal=J. Surg. Res. |volume=58 |issue=6 |pages=719–23 |year=1995 |pmid=7540700 |doi=10.1006/jsre.1995.1113 |url=}}</ref><ref name="pmid10648460">{{cite journal |vauthors=Kalff JC, Schraut WH, Billiar TR, Simmons RL, Bauer AJ |title=Role of inducible nitric oxide synthase in postoperative intestinal smooth muscle dysfunction in rodents |journal=Gastroenterology |volume=118 |issue=2 |pages=316–27 |year=2000 |pmid=10648460 |doi= |url=}}</ref>
*[[Ileus]] is defined as temporary cessation of [[intestinal]] [[peristalsis]] in the absence of [[bowel obstruction|mechanical obstruction]]. The [[pathogenesis]] of [[ileus]] is based on its multifactorial [[etiology]].<ref name="pmid9833803">{{cite journal |vauthors=Kalff JC, Schraut WH, Simmons RL, Bauer AJ |title=Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus |journal=Ann. Surg. |volume=228 |issue=5 |pages=652–63 |year=1998 |pmid=9833803 |pmc=1191570 |doi= |url=}}</ref><ref name="pmid7540700">{{cite journal |vauthors=Espat NJ, Cheng G, Kelley MC, Vogel SB, Sninsky CA, Hocking MP |title=Vasoactive intestinal peptide and substance P receptor antagonists improve postoperative ileus |journal=J. Surg. Res. |volume=58 |issue=6 |pages=719–23 |year=1995 |pmid=7540700 |doi=10.1006/jsre.1995.1113 |url=}}</ref><ref name="pmid10648460">{{cite journal |vauthors=Kalff JC, Schraut WH, Billiar TR, Simmons RL, Bauer AJ |title=Role of inducible nitric oxide synthase in postoperative intestinal smooth muscle dysfunction in rodents |journal=Gastroenterology |volume=118 |issue=2 |pages=316–27 |year=2000 |pmid=10648460 |doi= |url=}}</ref>
**The risk of postoperative ileus depends upon the type of [[surgery]]; [[Laparoscopic surgery|laparoscopic]] procedures have lower risk as compared to open [[laparotomy]] which have the highest risk.
*[[Intestinal]] [[peristalsis]] is primarily regulated by [[enteric nervous system]], [[autonomic nervous system]] and their interactions with [[central nervous system]] ([[central nervous system|CNS]]). However, certain [[medications]] and [[metabolic]] products may also alter the normal [[intestine|intestinal]] [[Chemical equilibrium|equilibrium]] leading to temporary dysfunction in [[intestine|intestinal]] movements. Prolonged [[intestinal]] [[peristalsis|aperistalsis]] results in accumulation of air and fluid in the [[intestine|intestinal]] [[lumen]].
**The highest risk for postoperative ileus has been observed with [[colorectal]] [[surgery]].
*The most common cause of [[ileus]] is [[abdominal surgery]].<ref name="pmid9833803">{{cite journal |vauthors=Kalff JC, Schraut WH, Simmons RL, Bauer AJ |title=Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus |journal=Ann. Surg. |volume=228 |issue=5 |pages=652–63 |year=1998 |pmid=9833803 |pmc=1191570 |doi= |url=}}</ref><ref name="pmid7540700">{{cite journal |vauthors=Espat NJ, Cheng G, Kelley MC, Vogel SB, Sninsky CA, Hocking MP |title=Vasoactive intestinal peptide and substance P receptor antagonists improve postoperative ileus |journal=J. Surg. Res. |volume=58 |issue=6 |pages=719–23 |year=1995 |pmid=7540700 |doi=10.1006/jsre.1995.1113 |url=}}</ref><ref name="pmid10648460">{{cite journal |vauthors=Kalff JC, Schraut WH, Billiar TR, Simmons RL, Bauer AJ |title=Role of inducible nitric oxide synthase in postoperative intestinal smooth muscle dysfunction in rodents |journal=Gastroenterology |volume=118 |issue=2 |pages=316–27 |year=2000 |pmid=10648460 |doi= |url=}}</ref>
**In fact, postoperative ileus (due to any [[surgery]]) is so common that it is sometimes regarded as a normal [[sequelae]] of [[surgery]].  
**The risk of [[ileus|postoperative ileus]] depends upon the type of [[surgery]]; [[Laparoscopic surgery|laparoscopic]] procedures have lower risk, compared to [[laparotomy]] which have the highest [[Risk factor|risk]].
**Postoperative ileus that lasts longer than 3 days is termed as paralytic ileus or adynamic ileus.
**The highest [[Risk factor|risk]] for [[ileus|postoperative ileus]] has been observed with [[Colon (anatomy)|colorectal]] [[surgery|surgeries]].
**When a patient undergoes a [[surgical procedure]], it often puts the body under significant [[stress]].  
**In fact, [[ileus|postoperative ileus]] (due to any [[surgery]]) is so common that it is sometimes regarded as a normal [[sequelae]] of [[surgery]].  
***This [[Surgery|surgical]] [[stress]] may lead to release of [[inflammatory]] and [[neuroendocrine]] mediators (such as [[nitric oxide]], [[VIP]] and [[substance P]]) that may result in inhibition of [[intestinal]] motility and development of ileus.<ref name="pmid19580945">{{cite journal |vauthors=Doherty TJ |title=Postoperative ileus: pathogenesis and treatment |journal=Vet. Clin. North Am. Equine Pract. |volume=25 |issue=2 |pages=351–62 |year=2009 |pmid=19580945 |doi=10.1016/j.cveq.2009.04.011 |url=}}</ref>
**[[ileus|Postoperative ileus]] that lasts longer than 3 days is termed as [[ileus|paralytic ileus]] or [[ileus|adynamic ileus]].
***[[Stress]] inducing conditions may lead to increased recruitment of [[dendritic cells]], [[natural killer cells]], [[monocytes]], [[T cells]], [[macrophages]], and [[mast cells]]. The [[macrophages]] and [[mast cells]] are considered the key [[Cells (biology)|cells]] leading to the initiation and maintenance of the [[inflammatory]] process and release of chemical mediators.
**When a [[patient]] undergoes a [[surgery|surgical procedure]], it often puts the body under significant [[Stress (medicine)|stress]].  
***This [[Surgery|surgical]] [[Stress (medicine)|stress]] may lead to release of [[inflammatory]] and [[neuroendocrine]] mediators (such as [[nitric oxide]], [[VIP]] and [[substance P]]) that may result in inhibition of [[intestine|intestinal]] motility and development of [[ileus]].<ref name="pmid19580945">{{cite journal |vauthors=Doherty TJ |title=Postoperative ileus: pathogenesis and treatment |journal=Vet. Clin. North Am. Equine Pract. |volume=25 |issue=2 |pages=351–62 |year=2009 |pmid=19580945 |doi=10.1016/j.cveq.2009.04.011 |url=}}</ref>
***[[Stress (medicine)|Stress]] inducing conditions may lead to increased recruitment of [[dendritic cells]], [[natural killer cells]], [[monocytes]], [[T cells]], [[macrophages]], and [[mast cells]]. The [[macrophages]] and [[mast cells]] are considered the key [[Cells (biology)|cells]] leading to the initiation and maintenance of the [[inflammatory]] process and release of chemical mediators.
***Recent research has shown that inhibition of [[inflammatory]] mediators (such as [[nitric oxide]] & [[Vasoactive intestinal peptide|VIP]]) may lead to improved [[gastrointestinal]] [[peristalsis]] and function.  
***Recent research has shown that inhibition of [[inflammatory]] mediators (such as [[nitric oxide]] & [[Vasoactive intestinal peptide|VIP]]) may lead to improved [[gastrointestinal]] [[peristalsis]] and function.  
***The site of the [[surgery]] is the most commonly affected part of the [[Gastrointestinal tract|GI tract]]. However, recent research has shown that [[inflammation]] of the [[intestinal]] [[muscle]] may extend from site of [[surgery]] to other parts of the [[intestinal tract]].<ref name="pmid11740765">{{cite journal |vauthors=Bederman SS, Betsy M, Winiarsky R, Seldes RM, Sharrock NE, Sculco TP |title=Postoperative ileus in the lower extremity arthroplasty patient |journal=J Arthroplasty |volume=16 |issue=8 |pages=1066–70 |year=2001 |pmid=11740765 |doi=10.1054/arth.2001.27675 |url=}}</ref>
***The site of the [[surgery]] is the most common affected part of the [[Gastrointestinal tract|GI tract]]. However, recent research has shown that [[inflammation]] of the [[intestine|intestinal]] [[muscle]] may extend from site of [[surgery]] to other parts of the [[Gastrointestinal tract|intestinal tract]].<ref name="pmid11740765">{{cite journal |vauthors=Bederman SS, Betsy M, Winiarsky R, Seldes RM, Sharrock NE, Sculco TP |title=Postoperative ileus in the lower extremity arthroplasty patient |journal=J Arthroplasty |volume=16 |issue=8 |pages=1066–70 |year=2001 |pmid=11740765 |doi=10.1054/arth.2001.27675 |url=}}</ref>
***Moreover, [[intestinal]] distention as seen in ileus also contributes to [[Serosa|serosal]] injury and may aggravate [[intestinal]] [[ischemia]].  
***Moreover, [[intestine|intestinal]] distention seen in [[ileus]] is contributed to [[Serosa|serosal]] [[injury]] and may aggravate [[intestine|intestinal]] [[ischemia]].  
***Prolonged ileus leads to increased contact between various segments of [[intestine]] which predispose to [[fibrous]] [[adhesion]] formation, thereby further contributing to the severity of ileus. <ref>Lundin C, Sullins KE, White NA and al. Induction of peritoneal adhesions with small intestinal ischaemia and distention in the foal. ''Equine Vet J'' 21: 451, 1989</ref><ref>Vachon AM, Fisher AT. Small intestinal herniation through the epiploic foramen: 53 cases (1987-1993). ''Equine Vet J'' 27: 373, 1995</ref>
***Prolonged [[ileus]] leads to increased contact between various segments of [[intestine]] which predispose to [[fibrosis|fibrous]] adhesion formation, thereby further contributing to the severity of [[ileus]]. <ref>Lundin C, Sullins KE, White NA and al. Induction of peritoneal adhesions with small intestinal ischaemia and distention in the foal. ''Equine Vet J'' 21: 451, 1989</ref><ref>Vachon AM, Fisher AT. Small intestinal herniation through the epiploic foramen: 53 cases (1987-1993). ''Equine Vet J'' 27: 373, 1995</ref>
***[[Abdominal]] conditions such as [[gastroenteritis]] and [[peritonitis]] may also affect the [[intestinal]] [[motility]] leading to ileus.
***[[Abdomen|Abdominal]] conditions such as [[gastroenteritis]] and [[peritonitis]] may also affect the [[intestinal]] [[motility]] leading to [[ileus]].
**Abdominal [[incision]] leads to activation of [[inhibitory]] [[spinal reflex]] which results in decreased movements of [[intestine]], as a regulatory mechanism.<ref name="pmid8967419">{{cite journal |vauthors=Barquist E, Bonaz B, Martinez V, Rivier J, Zinner MJ, Taché Y |title=Neuronal pathways involved in abdominal surgery-induced gastric ileus in rats |journal=Am. J. Physiol. |volume=270 |issue=4 Pt 2 |pages=R888–94 |year=1996 |pmid=8967419 |doi=10.1152/ajpregu.1996.270.4.R888 |url=}}</ref>
**Abdominal [[incision]] leads to activation of [[inhibitory]] [[spinal cord|spinal]] [[reflex]] which results in decreased movements of [[intestine]], as a regulatory mechanism.<ref name="pmid8967419">{{cite journal |vauthors=Barquist E, Bonaz B, Martinez V, Rivier J, Zinner MJ, Taché Y |title=Neuronal pathways involved in abdominal surgery-induced gastric ileus in rats |journal=Am. J. Physiol. |volume=270 |issue=4 Pt 2 |pages=R888–94 |year=1996 |pmid=8967419 |doi=10.1152/ajpregu.1996.270.4.R888 |url=}}</ref>
***The [[painful]] stimuli stimulates the spinal [[afferents]] that [[synapse]] in the [[spinal cord]]. In the [[spinal cord]], the prevertebral adrenergic neurons are activated which leads to [[inhibition]] of [[intestinal]] [[motility]] via [[efferent]] nerves [[Sympathetic nervous system|(sympathetic ANS]]).
***The [[pain|painful]] stimuli stimulates the [[spinal cord|spinal]] [[Afferent nerve|afferents]] that [[synapse]] in the [[spinal cord]]. The [[Prevertebral ganglia|prevertebral adrenergic neurons]] in the [[spinal cord]] activate and inhibit [[intestine|intestinal]] [[motility]] via [[Efferent nerve|efferent nerves]] ([[Sympathetic nervous system|sympathetic ANS]]).
***Additionally, manipulation of [[intestine]] leads to activation of [[afferent]] pathways that travel to the [[Brain stem|brainstem]]. In turn, the [[brainstem]] sends increased [[autonomic]] output to the [[sympathetic]] [[neurons]] located in the inter-medio-lateral column of the thoracic cord. An increased activity of [[sympathetic]] [[neurons]] results in increased secretion of [[adrenergic]] output and decreased [[intestinal]] [[motility]].
***Additionally, manipulation of [[intestine]] leads to activation of [[Afferent nerve|afferent]] pathways that travel to [[brain stem]]. In turn, [[brain stem]] increases [[autonomic]] output to the [[sympathetic]] [[neurons]] located in the inter-medio-lateral column of the [[spinal cord|thoracic cord]]. The increased activity of [[sympathetic]] [[neurons]] results in increased [[secretion]] of [[adrenergic]] output and subsequent decreased [[intestinal]] [[motility]].
*Another [[chronic]] and a more severe form of [[ileus]] is known as chronic intestinal pseudo-obstruction (CIPO).<ref name="Di NardoDi Lorenzo2017">{{cite journal|last1=Di Nardo|first1=G.|last2=Di Lorenzo|first2=C.|last3=Lauro|first3=A.|last4=Stanghellini|first4=V.|last5=Thapar|first5=N.|last6=Karunaratne|first6=T. B.|last7=Volta|first7=U.|last8=De Giorgio|first8=R.|title=Chronic intestinal pseudo-obstruction in children and adults: diagnosis and therapeutic options|journal=Neurogastroenterology & Motility|volume=29|issue=1|year=2017|pages=e12945|issn=13501925|doi=10.1111/nmo.12945}}</ref><ref name="pmid23831693">{{cite journal |vauthors=Iida H, Ohkubo H, Inamori M, Nakajima A, Sato H |title=Epidemiology and clinical experience of chronic intestinal pseudo-obstruction in Japan: a nationwide epidemiologic survey |journal=J Epidemiol |volume=23 |issue=4 |pages=288–94 |year=2013 |pmid=23831693 |pmc=3709546 |doi= |url=}}</ref><ref name="pmid23108319">{{cite journal |vauthors=Yeung AK, Di Lorenzo C |title=Primary gastrointestinal motility disorders in childhood |journal=Minerva Pediatr. |volume=64 |issue=6 |pages=567–84 |year=2012 |pmid=23108319 |doi= |url=}}</ref>
*There is a [[chronic]] and severe form of [[ileus]], known as [[Intestinal pseudoobstruction|chronic intestinal pseudo-obstruction]] ([[Intestinal pseudoobstruction|CIPO]]).<ref name="Di NardoDi Lorenzo2017">{{cite journal|last1=Di Nardo|first1=G.|last2=Di Lorenzo|first2=C.|last3=Lauro|first3=A.|last4=Stanghellini|first4=V.|last5=Thapar|first5=N.|last6=Karunaratne|first6=T. B.|last7=Volta|first7=U.|last8=De Giorgio|first8=R.|title=Chronic intestinal pseudo-obstruction in children and adults: diagnosis and therapeutic options|journal=Neurogastroenterology & Motility|volume=29|issue=1|year=2017|pages=e12945|issn=13501925|doi=10.1111/nmo.12945}}</ref><ref name="pmid23831693">{{cite journal |vauthors=Iida H, Ohkubo H, Inamori M, Nakajima A, Sato H |title=Epidemiology and clinical experience of chronic intestinal pseudo-obstruction in Japan: a nationwide epidemiologic survey |journal=J Epidemiol |volume=23 |issue=4 |pages=288–94 |year=2013 |pmid=23831693 |pmc=3709546 |doi= |url=}}</ref><ref name="pmid23108319">{{cite journal |vauthors=Yeung AK, Di Lorenzo C |title=Primary gastrointestinal motility disorders in childhood |journal=Minerva Pediatr. |volume=64 |issue=6 |pages=567–84 |year=2012 |pmid=23108319 |doi= |url=}}</ref>
**CIPO is a more severe form of [[ileus]] resulting from disturbances in [[enteric nervous system]], [[autonomic nervous system]] and [[Smooth muscle|smooth muscle cell]] function.   
**[[Intestinal pseudoobstruction|CIPO]] is a severe form of [[ileus]] resulting from disturbances in [[enteric nervous system]], [[autonomic nervous system]] and [[Smooth muscle|smooth muscle cell]] function.   
**The cause of CIPO can be [[idiopathic]], sporadic, or secondary to [[metabolic]], [[connective tissue]], [[Endocrinology|endocrinological]], [[Neurology|neurological]], and [[Paraneoplastic syndrome|paraneoplastic disorders]].<ref name="pmid15880314">{{cite journal |vauthors=Stanghellini V, Cogliandro RF, De Giorgio R, Barbara G, Morselli-Labate AM, Cogliandro L, Corinaldesi R |title=Natural history of chronic idiopathic intestinal pseudo-obstruction in adults: a single center study |journal=Clin. Gastroenterol. Hepatol. |volume=3 |issue=5 |pages=449–58 |year=2005 |pmid=15880314 |doi= |url=}}</ref>
**The cause of [[Intestinal pseudoobstruction|CIPO]] can be [[idiopathic]], sporadic, or secondary to [[matabolism|metabolic]], [[connective tissue]], [[Endocrinology|endocrinologic]], [[Neurology|neurologic]], and [[Paraneoplastic syndrome|paraneoplastic disorders]].<ref name="pmid15880314">{{cite journal |vauthors=Stanghellini V, Cogliandro RF, De Giorgio R, Barbara G, Morselli-Labate AM, Cogliandro L, Corinaldesi R |title=Natural history of chronic idiopathic intestinal pseudo-obstruction in adults: a single center study |journal=Clin. Gastroenterol. Hepatol. |volume=3 |issue=5 |pages=449–58 |year=2005 |pmid=15880314 |doi= |url=}}</ref>
**CIPO is often due to [[dysfunction]] in the [[innervation]] of [[smooth muscle]] by the [[interstitial cells of Cajal]] resulting in partial or complete ineffective [[intestinal]] propulsion. However, any condition affecting the [[enteric nervous system]], [[autonomic nervous system]], [[smooth muscle cells]] and [[neuromuscular junction]] may lead to development of CIPO.
**[[Intestinal pseudoobstruction|CIPO]] is often due to dysfunction in [[Nerve|innervation]] of [[smooth muscle]] by the [[interstitial cells of Cajal]] resulting in partial or complete ineffective [[intestine|intestinal]] propulsion. However, any condition affecting the [[enteric nervous system]], [[autonomic nervous system]], [[smooth muscle cells]] and [[neuromuscular junction]] may lead to development of [[Intestinal pseudoobstruction|CIPO]].
**The lack of propulsive [[intestinal]] movements may lead to increased intra-[[bowel]] pressure.  
**The lack of propulsive [[intestine|intestinal]] movements may lead to increased intra-[[lumen|luminal]] [[pressure]].  
**The enhanced intra-[[bowel]] pressure leads to [[malabsorption]] and [[bacterial]] [[translocation]]. Over time, it can progress to present with [[malnutrition]] and [[sepsis]].
**The enhanced intra-[[lumen|luminal]] [[pressure]] leads to [[malabsorption]] and [[Small intestinal bacterial overgrowth syndrome|bacterial overgrowth]]. Over time, it can progress to present with [[malnutrition]] and [[sepsis]].
 
*The other common cause of [[ileus]] are the [[drugs]] that affect [[intestinal]] [[motility]] and [[Electrolyte disturbance|alteration in electrolyte levels]].
*The other common cause of [[ileus]] are the [[drugs]] that affect [[intestinal]] [[motility]] and [[Electrolyte disturbance|alteration in electrolyte levels]].
**Drugs affecting [[intestinal]] [[motility]] primarily includes antimotility agents and [[anesthetics]].
**Drugs affecting [[intestinal]] [[motility]] primarily includes antimotility agents and [[Anesthesia|anesthetics]].
***Anesthetic drugs: [[Anesthetic agents]] have a direct [[inhibitory]] effect on the [[intestinal]] [[motility]]. Long acting [[anesthetic agents]] such as [[bupivacaine]] are more frequently associated with postopertaive [[ileus]] as compared to short acting agents such as [[propofol]].
***[[Anesthesia|Anesthetic drugs]]: [[Anesthesia|Anesthetic agents]] have a direct [[inhibitory]] effect on the [[intestine|intestinal]] [[motility]]. Long acting [[Anesthesia|anesthetic agents]] such as [[bupivacaine]] are more frequently associated with [[ileus|postopertaive ileus]] as compared to short acting agents such as [[propofol]].
***[[Opiates]]: The use of [[opiates]] for [[pain]] alleviation is not without [[side effects]]. In fact [[opioid]] use has been associated with significant increase in the occurrence of postoperative ileus. [[Opioid]] medications that activate the µ (mu) receptors have been associated with decreased release of [[acetylcholine]] from [[cholinergic]] [[neurons]], resulting in delayed [[intestinal]] [[motility]]. The most common [[opioid]] pain medication, [[morphine]] initially activates the [[migrating myoelectric complex]] and later on results in [[atony]] resulting in [[inhibition]] of propulsion and delay in [[intestinal]] transit.
***[[Opiates]]: The use of [[opiates]] for [[pain]] alleviation is not without [[side effects]]. In fact [[opioid]] use has been associated with significant increase in the occurrence of [[ilues|postoperative ileus]]. [[Opioid]] [[medications]] that activate the µ (mu) [[Receptor (biochemistry)|receptors]] have been associated with decreased release of [[acetylcholine]] from [[cholinergic]] [[neurons]], resulting in delayed [[intestinal]] [[motility]]. The most common [[opioid]] [[pain]] [[medication]], [[morphine]] initially activates the [[migrating myoelectric complex]] and later on results in [[atony]] resulting in [[inhibition]] of propulsion and delay in [[intestinal]] transit.
**[[Electrolyte abnormalities]] such as [[hypokalemia]], [[hyponatremia]], [[hypocalcemia]], [[hypomagnesemia]], and [[metabolic acidosis]] may also lead to the development of intestinal ileus.
**[[Electrolyte abnormalities]] such as [[hypokalemia]], [[hyponatremia]], [[hypocalcemia]], [[hypomagnesemia]], and [[metabolic acidosis]] may also lead to the development of [[intestine|intestinal]] [[ileus]].


==Genetics==
There is no detected [[genetic disorder]] related to [[ileus]], nevertheless some cases of [[Intestinal pseudoobstruction|CIPO]] are related to alteration in [[FLNA]] and [[ACTG2]] [[genes]].
==Associated Conditions==
==Associated Conditions==
*[[Diabetes mellitus]]<ref name="pmid7208886">{{cite journal |vauthors=Hoeffel JC, Senot P, Champigneulle B, Drouin P |title=Gastric retention and gastric ileus in diabetes mellitus |journal=Radiologe |volume=20 |issue=11 |pages=540–2 |date=November 1980 |pmid=7208886 |doi= |url=}}</ref>
*[[Diabetes mellitus]]<ref name="pmid7208886">{{cite journal |vauthors=Hoeffel JC, Senot P, Champigneulle B, Drouin P |title=Gastric retention and gastric ileus in diabetes mellitus |journal=Radiologe |volume=20 |issue=11 |pages=540–2 |date=November 1980 |pmid=7208886 |doi= |url=}}</ref>
Line 64: Line 69:


==Gross Pathology==
==Gross Pathology==
On [[Gross pathology|gross patholog]]<nowiki/>y, findings of ileus include:<ref name="pmid18387380">{{cite journal |vauthors=Batke M, Cappell MS |title=Adynamic ileus and acute colonic pseudo-obstruction |journal=Med. Clin. North Am. |volume=92 |issue=3 |pages=649–70, ix |year=2008 |pmid=18387380 |doi=10.1016/j.mcna.2008.01.002 |url=}}</ref>
[[Gross pathology|gross pathologic]]<nowiki/>y, findings of [[ileus]] include:<ref name="pmid18387380">{{cite journal |vauthors=Batke M, Cappell MS |title=Adynamic ileus and acute colonic pseudo-obstruction |journal=Med. Clin. North Am. |volume=92 |issue=3 |pages=649–70, ix |year=2008 |pmid=18387380 |doi=10.1016/j.mcna.2008.01.002 |url=}}</ref>
*[[Bowel]] contortion
*[[Bowel]] contortion
*Distended [[Small intestine|small]] and [[large intestine]]
*Distended [[Small intestine|small]] and [[large intestine]]


==Microscopic Features==
==Microscopic Features==
On [[Microscopic examination|microscopic]] [[histopathological]] analysis, findings of ileus include [[inflammatory cells]] predominantly [[macrophage]] and [[mast cells]].
On [[Microscopic examination|microscopic]] [[histopathological]] [[analysis]], findings of [[ileus]] include [[inflammatory cells]] predominantly [[macrophage]] and [[mast cells]].


==References==
==References==

Revision as of 20:11, 6 October 2020

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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 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 (ileus present for > 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 surgical stress induced 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 pathways that travel to the brainstem. In turn, the brainstem sends increased autonomic output to the sympathetic neurons resulting in increased secretion of adrenergic neurotransmitters and decreased intestinal motility. Commonly used pain medications such as opiates and intraoperative anesthesia may also aggravate the development of ileus. Conditions commonly associated with ileus include diabetes mellitus, hypothyroidism, and hypoparathyroidism. On gross pathology findings of ileus include bowel contortion with distended small and large intestine. On microscopic histopathological analysis, findings of ileus include inflammatory cells predominantly macrophages and mast cells.

Pathophysiology

Physiology

Neural control of gut.(By Boumphreyfr (Own work) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons)

Pathogenesis

Genetics

There is no detected genetic disorder related to ileus, nevertheless some cases of CIPO are related to alteration in FLNA and ACTG2 genes.

Associated Conditions

Gross Pathology

gross pathologicy, findings of ileus include:[23]

Microscopic Features

On microscopic histopathological analysis, findings of ileus include inflammatory cells predominantly macrophage and mast cells.

References

  1. ↑ 1.0 1.1 Kalff JC, Schraut WH, Simmons RL, Bauer AJ (1998). "Surgical manipulation of the gut elicits an intestinal muscularis inflammatory response resulting in postsurgical ileus". Ann. Surg. 228 (5): 652–63. PMC 1191570. PMID 9833803.
  2. ↑ 2.0 2.1 Espat NJ, Cheng G, Kelley MC, Vogel SB, Sninsky CA, Hocking MP (1995). "Vasoactive intestinal peptide and substance P receptor antagonists improve postoperative ileus". J. Surg. Res. 58 (6): 719–23. doi:10.1006/jsre.1995.1113. PMID 7540700.
  3. ↑ 3.0 3.1 Kalff JC, Schraut WH, Billiar TR, Simmons RL, Bauer AJ (2000). "Role of inducible nitric oxide synthase in postoperative intestinal smooth muscle dysfunction in rodents". Gastroenterology. 118 (2): 316–27. PMID 10648460.
  4. ↑ Doherty TJ (2009). "Postoperative ileus: pathogenesis and treatment". Vet. Clin. North Am. Equine Pract. 25 (2): 351–62. doi:10.1016/j.cveq.2009.04.011. PMID 19580945.
  5. ↑ Bederman SS, Betsy M, Winiarsky R, Seldes RM, Sharrock NE, Sculco TP (2001). "Postoperative ileus in the lower extremity arthroplasty patient". J Arthroplasty. 16 (8): 1066–70. doi:10.1054/arth.2001.27675. PMID 11740765.
  6. ↑ Lundin C, Sullins KE, White NA and al. Induction of peritoneal adhesions with small intestinal ischaemia and distention in the foal. Equine Vet J 21: 451, 1989
  7. ↑ Vachon AM, Fisher AT. Small intestinal herniation through the epiploic foramen: 53 cases (1987-1993). Equine Vet J 27: 373, 1995
  8. ↑ Barquist E, Bonaz B, Martinez V, Rivier J, Zinner MJ, Taché Y (1996). "Neuronal pathways involved in abdominal surgery-induced gastric ileus in rats". Am. J. Physiol. 270 (4 Pt 2): R888–94. doi:10.1152/ajpregu.1996.270.4.R888. PMID 8967419.
  9. ↑ Di Nardo, G.; Di Lorenzo, C.; Lauro, A.; Stanghellini, V.; Thapar, N.; Karunaratne, T. B.; Volta, U.; De Giorgio, R. (2017). "Chronic intestinal pseudo-obstruction in children and adults: diagnosis and therapeutic options". Neurogastroenterology & Motility. 29 (1): e12945. doi:10.1111/nmo.12945. ISSN 1350-1925.
  10. ↑ Iida H, Ohkubo H, Inamori M, Nakajima A, Sato H (2013). "Epidemiology and clinical experience of chronic intestinal pseudo-obstruction in Japan: a nationwide epidemiologic survey". J Epidemiol. 23 (4): 288–94. PMC 3709546. PMID 23831693.
  11. ↑ Yeung AK, Di Lorenzo C (2012). "Primary gastrointestinal motility disorders in childhood". Minerva Pediatr. 64 (6): 567–84. PMID 23108319.
  12. ↑ Stanghellini V, Cogliandro RF, De Giorgio R, Barbara G, Morselli-Labate AM, Cogliandro L, Corinaldesi R (2005). "Natural history of chronic idiopathic intestinal pseudo-obstruction in adults: a single center study". Clin. Gastroenterol. Hepatol. 3 (5): 449–58. PMID 15880314.
  13. ↑ Hoeffel JC, Senot P, Champigneulle B, Drouin P (November 1980). "Gastric retention and gastric ileus in diabetes mellitus". Radiologe. 20 (11): 540–2. PMID 7208886.
  14. ↑ Rodrigo C, Gamakaranage CS, Epa DS, Gnanathasan A, Rajapakse S (February 2011). "Hypothyroidism causing paralytic ileus and acute kidney injury - case report". Thyroid Res. 4 (1): 7. doi:10.1186/1756-6614-4-7. PMC 3041782. PMID 21303532.
  15. ↑ Lord, Reginald V. N.; Sillin, Lelan F. (2010). "Motility Disorders of the Small Bowel": 17–26. doi:10.1007/978-1-84996-372-5_2.
  16. ↑ Kubota A, Imura K, Yagi M, Kawahara H, Mushiake S, Nakayama M, Kamata S, Okada A (December 1999). "Functional ileus in neonates: Hirschsprung's disease-allied disorders versus meconium-related ileus". Eur J Pediatr Surg. 9 (6): 392–5. doi:10.1055/s-2008-1072290. PMID 10661850.
  17. ↑ EHRENPREIS T (May 1951). "Meconium ileus and Hirschsprung's disease". Acta Paediatr. 40 (3): 227–32. PMID 14837740.
  18. ↑ Izumi Y, Masuda T, Horimasu Y, Nakashima T, Miyamoto S, Iwamoto H, Fujitaka K, Hamada H, Hattori N (October 2017). "Chronic Intestinal Pseudo-obstruction and Orthostatic Hypotension Associated with Small Cell Lung Cancer that Improved with Tumor Reduction after Chemoradiotherapy". Intern. Med. 56 (19): 2627–2631. doi:10.2169/internalmedicine.8574-16. PMC 5658530. PMID 28883237.
  19. ↑ Stengel A, Taché Y (December 2014). "Brain peptides and the modulation of postoperative gastric ileus". Curr Opin Pharmacol. 19: 31–7. doi:10.1016/j.coph.2014.06.006. PMC 4254047. PMID 24999843.
  20. ↑ Deck KB, Silverman H (July 1979). "Leiomyosarcomas of the small intestine". Cancer. 44 (1): 323–5. PMID 455259.
  21. ↑ Moeschl P, Miholic J (January 1989). "[Ileus following radiotherapy: importance and therapeutic aspects of surgery for late radiation injuries of the intestine]". Wien. Klin. Wochenschr. (in German). 101 (2): 84–7. PMID 2916344.
  22. ↑ Ferreira JA, Giani CA, Buiatti JB (October 1965). "[Megacolon. Complications]". Prensa Med Argent (in Spanish; Castilian). 52 (36): 2069–71. PMID 5879587.
  23. ↑ Batke M, Cappell MS (2008). "Adynamic ileus and acute colonic pseudo-obstruction". Med. Clin. North Am. 92 (3): 649–70, ix. doi:10.1016/j.mcna.2008.01.002. PMID 18387380.

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