Zespół samotnego owrzodzenia odbytnicy – Patofizjologia i mechanizm

Zespół samotnego owrzodzenia odbytnicy
Patofizjologia i mechanizm

Zespół samotnego owrzodzenia odbytnicy (ZSOO) to schorzenie o złożonej, wieloczynnikowej patogenezie, w której kluczową rolę odgrywa niedokrwienie błony śluzowej odbytnicy. Główne mechanizmy patogenetyczne obejmują wypadanie odbytnicy (w tym wewnętrzne wgłobienie stwierdzane u 94% pacjentów), paradoksalny skurcz mięśnia łonowo-odbytniczego, uraz bezpośredni błony śluzowej związany z przewlekłym parciem lub manipulacją oraz dyssynergię defekacyjną. U pacjentów z ZSOO obserwuje się podwyższone ciśnienie wewnątrzodbytnicze podczas parcia, a także wzrost ciśnienia spoczynkowego i podczas zaciskania zwieraczy, co prowadzi do przekrwienia żylnego, obrzęku i owrzodzeń śluzówki. Badania histopatologiczne wykazują włóknienie, obliterację blaszki właściwej, przerost mięśniówki oraz zniekształcenie krypt, a także potencjalne ryzyko progresji nowotworowej, co podkreśla kliniczne znaczenie dokładnej diagnostyki.

Patogeneza zespołu samotnego owrzodzenia odbytnicy

Podstawowe mechanizmy patogenetyczne
Rola wypadania odbytnicy i wgłobienia
Dyssynergia defekacyjna i nadmierne parcie
Rola urazu bezpośredniego
Zmiany histopatologiczne
Inne czynniki patogenetyczne
Podsumowanie mechanizmów patogenetycznych
Kolejne rozdziały

Patogeneza zespołu samotnego owrzodzenia odbytnicy

Zespół samotnego owrzodzenia odbytnicy (ZSOO) to rzadkie, łagodne schorzenie odbytnicy, które pomimo swojej nazwy nie zawsze objawia się pojedynczym owrzodzeniem oraz może dotyczyć różnych części odbytnicy, a nawet innych odcinków przewodu pokarmowego. Charakteryzuje się obecnością owrzodzeń, zmian polipowatych lub płaskich w błonie śluzowej odbytnicy.¹² Patogeneza ZSOO nie jest w pełni poznana i wydaje się mieć złożony, wieloczynnikowy charakter.

Podstawowe mechanizmy patogenetyczne

Obecnie uważa się, że główne mechanizmy patogenetyczne w ZSOO obejmują:

Przewlekłe uszkodzenie błony śluzowej odbytnicy
Niedokrwienie śluzówki odbytnicy
Paradoksalny skurcz mięśnia łonowo-odbytniczego
Wypadanie odbytnicy (zewnętrzne lub wewnętrzne)

³⁴⁵

Występowanie tych czynników prowadzi do upośledzenia przepływu krwi, co skutkuje niedokrwieniem błony śluzowej i jej owrzodzeniem. Warto podkreślić, że u różnych pacjentów mogą dominować różne mechanizmy patogenetyczne, co prawdopodobnie tłumaczy różnorodność obrazu klinicznego ZSOO.⁶⁷

Rola wypadania odbytnicy i wgłobienia

Wypadanie odbytnicy (jawne lub utajone) jest najczęstszym mechanizmem patogenetycznym w ZSOO. U 94% pacjentów z ZSOO można wykazać wewnętrzne wgłobienie (intussuscepcję) odbytnicy.⁸ Proces ten prowadzi do przekrwienia żylnego, pogorszenia przepływu krwi i obrzęku błony śluzowej odbytnicy, co skutkuje zmianami niedokrwiennymi z następczym owrzodzeniem.⁹ Nawet początkowe, niewielkie obszary wgłobienia mogą powodować uszkodzenie naczyń i dalsze upośledzenie ukrwienia śluzówki, co jest ostatnim etapem w procesie powstawania i rozwoju owrzodzenia.¹⁰

Badania wykazały, że pacjenci z ZSOO częściej wykazują wzrost ciśnienia w odbycie podczas parcia, paradoksalny skurcz mięśnia łonowo-odbytniczego oraz wypadanie wewnętrznej warstwy okrężnej mięśni gładkich odbytnicy. Ponadto, rzadziej obserwuje się u nich całkowite opróżnianie odbytnicy w porównaniu z grupą kontrolną.¹¹

Dyssynergia defekacyjna i nadmierne parcie

Dyssynergia defekacyjna, czyli brak koordynacji pomiędzy rozluźnieniem zwieraczy odbytu a napięciem tłoczni brzusznej podczas defekacji, jest często obserwowana u pacjentów z ZSOO. Badania wykazały, że 25-82% pacjentów z ZSOO może wykazywać dyssynergię z paradoksalnym skurczem odbytu.¹² Ten brak koordynacji mięśniowej powoduje zwiększone ciśnienie w obszarze odbytniczo-odbytowym, co prowadzi do urazowego ucisku ściany odbytnicy na kanał odbytu.¹³

Podczas prawidłowej defekacji krocze obniża się, aby wyprostować kanał odbytu. Nieprawidłowy skurcz mięśnia łonowo-odbytniczego podczas tego procesu lub defekacja w pozycji kucznej prowadzi do urazowego ucisku ściany odbytnicy. Z drugiej strony, przeciwstawna siła tego paradoksalnego ruchu powoduje niedokrwienie śluzówki i sprawia, że obszar ten staje się bardziej podatny na urazowe uszkodzenia i owrzodzenia.¹⁴

Nadmierne parcie podczas defekacji, często związane z przewlekłymi zaparciami, jest kolejnym istotnym czynnikiem w patogenezie ZSOO. Badania potwierdziły, że nieskoordynowana defekacja z nadmiernym parciem z czasem odgrywa kluczową rolę w ZSOO.¹⁵ Pacjenci z ZSOO wykazują wyższe ciśnienie wewnątrzodbytnicze podczas parcia niż zdrowe osoby z grupy kontrolnej.¹⁶

Rola urazu bezpośredniego

Uraz bezpośredni błony śluzowej odbytnicy jest często wymieniany jako czynnik przyczyniający się do rozwoju ZSOO. Może on wynikać z:

Przewlekłego parcia podczas defekacji
Samodzielnej manipulacji palcem w celu usunięcia zalegających mas kałowych
Stosowania czopków lub innych instrumentów

¹⁷¹⁸

Długotrwałe parcie podczas defekacji, szczególnie u pacjentów z zaparciami lub anomaliami anatomicznymi, może prowadzić do bezpośredniego urazu wrażliwej błony śluzowej odbytnicy. Pacjenci z owrzodzeniami odbytnicy częściej mają zwiększone ciśnienie spoczynkowe i podczas zaciskania w porównaniu ze zdrowymi osobami. Może to prowadzić do większego ogólnego obciążenia ciśnieniowego błony śluzowej odbytnicy i wyższego ryzyka urazowych uszkodzeń.¹⁹

Zmiany histopatologiczne

Badanie histopatologiczne jest „złotym standardem” w diagnostyce ZSOO. Charakterystyczne cechy histologiczne obejmują:

Włóknienie i obliterację blaszki właściwej błony śluzowej
Przerost i dezorganizację błony mięśniowej śluzówki
Zniekształcenie architektury gruczołów (krypt)
Zastąpienie blaszki właściwej przez tkankę mięśniową gładką i kolagen

²⁰²¹²²

W badaniach histopatologicznych wykazano również, że ZSOO może wiązać się z głębszym, ukrytym procesem nowotworowym. Zaobserwowano utratę ekspresji genu hMLH1 w kilku przypadkach ZSOO, co wskazuje na możliwość progresji nowotworowej. Opisano także przypadek dobrze zróżnicowanego gruczolakoraka naciekającego w ognisku ZSOO, a autorzy spekulowali, że istnieje możliwość rozwoju gruczolakoraka z błony śluzowej objętej ZSOO.²³

Inne czynniki patogenetyczne

Poza głównymi mechanizmami, w patogenezie ZSOO mogą odgrywać rolę również inne czynniki:

Zaburzenia naczyń krwionośnych

Sugeruje się, że zmiany miażdżycowe mogą wpływać na niedokrwienie śluzówki, podobnie jak zaburzenia w sygnalizacji cholinergicznej, które mogą być związane z polineuropatią cukrzycową. W obrazie histologicznym można wykazać zwiększenie ilości tkanki łącznej, co potwierdza hipotezę o zaburzeniach małych naczyń.²⁴²⁵

Czynniki psychologiczne

Uważa się, że czynniki psychologiczne mogą również odgrywać rolę w patogenezie ZSOO, ponieważ pacjenci z tym schorzeniem czasami cierpią na zaburzenia psychiczne, takie jak zaburzenie obsesyjno-kompulsyjne. Zaburzenie zachowań związanych z wypróżnianiem jako wyraz problemów psychologicznych wydaje się być istotnym czynnikiem patogenetycznym u niektórych pacjentów.²⁶²⁷

Zaburzenia przepływowości

Badania anorektalnej fizjologii wykazały, że pacjenci z ZSOO mają wyższe ciśnienie spoczynkowe i ciśnienie zaciskania niż osoby zdrowe. Nadaktywność zwieracza odbytu została uznana za istotny czynnik patofizjologiczny, który przyczynia się do zwiększonego ciśnienia wewnątrzodbytniczego, podwyższonego gradientu przezmurowego i zwiększonego ciśnienia opróżniania, co ostatecznie prowadzi do przekrwienia żylnego i owrzodzenia.²⁸²⁹

Podsumowanie mechanizmów patogenetycznych

Patogeneza ZSOO jest złożona i prawdopodobnie wieloczynnikowa. Główne mechanizmy obejmują niedokrwienie śluzówki odbytnicy spowodowane przez:

Wypadanie odbytnicy lub jej wgłobienie
Paradoksalny skurcz mięśnia łonowo-odbytniczego
Uraz bezpośredni związany z parciem lub manipulacją
Zaburzenia koordynacji mięśniowej podczas defekacji

³⁰³¹³²

Przewlekłe uszkodzenie śluzówki i uraz niedokrwienny są uważane za główne mechanizmy, chociaż dalsze badania mogą rzucić więcej światła na ten proces.³³ Warto podkreślić, że różne mechanizmy mogą dominować u różnych pacjentów, co tłumaczyłoby różnorodność obrazu klinicznego i endoskopowego ZSOO.³⁴

Zrozumienie złożonej patogenezy ZSOO jest kluczowe dla właściwego diagnozowania i leczenia tego rzadkiego, ale istotnego klinicznie schorzenia. Pomimo intensywnych badań, patogeneza ZSOO nie jest w pełni poznana, co wskazuje na potrzebę dalszych badań w tym obszarze.³⁵³⁶

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Materiały źródłowe

#1 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Solitary rectal ulcer syndrome is a multifactorial pathology, which entails a variety of clinical, histologic and endoscopic aspects that needs step-wise logical approach for management especially in relapsing refractory cases. […] The underlying mechanisms leading to SRUS are not certainly recognized. However, various factors are considered to have a role. Here we propose four main categories known to be involved. First, prolonged straining during defecation, which might end in direct trauma to the vulnerable rectal mucosa. Patients who have constipation or anatomical anomalies are more prone to suffer from straining and at higher risk for developing rectal ulcers. It is also reported that patients with solitary rectal ulcers are more likely to have increased resting and squeezing pressure than normal individuals. This may end in higher overall pressure burden bearded upon rectal mucosa and higher risk of traumatic injuries.
#2 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#3 Solitary rectal ulcer syndrome – UpToDate
https://www.uptodate.com/contents/solitary-rectal-ulcer-syndrome
Solitary rectal ulcer syndrome is an uncommon rectal disorder that can present with rectal bleeding, straining during defecation, and a sense of incomplete evacuation. […] The pathogenesis of the solitary rectal ulcer is incompletely understood. However, a number of factors appear to have a causative role in individual reports. It is possible that different etiologies may contribute to the development of solitary rectal ulcer syndrome. […] A common observation in a number of reports is rectal prolapse or rectal intussusception and paradoxical contraction of the puborectalis muscle. […] Patients with solitary rectal ulcer syndrome more frequently had increasing anal pressure at straining, paradoxical puborectalis contraction, and prolapse of the inner circular smooth muscle of the rectum and less frequently had complete rectal emptying compared with controls. […] Rectal prolapse and paradoxical contraction of the puborectalis muscle can result in rectal trauma by two different mechanisms.
#4 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Solitary rectal ulcer syndrome is a multifactorial pathology, which entails a variety of clinical, histologic and endoscopic aspects that needs step-wise logical approach for management especially in relapsing refractory cases. […] The underlying mechanisms leading to SRUS are not certainly recognized. However, various factors are considered to have a role. Here we propose four main categories known to be involved. First, prolonged straining during defecation, which might end in direct trauma to the vulnerable rectal mucosa. Patients who have constipation or anatomical anomalies are more prone to suffer from straining and at higher risk for developing rectal ulcers. It is also reported that patients with solitary rectal ulcers are more likely to have increased resting and squeezing pressure than normal individuals. This may end in higher overall pressure burden bearded upon rectal mucosa and higher risk of traumatic injuries.
#5 Solitary Rectal Ulcer Syndrome in Children: A Report of Six Cases
https://www.gutnliver.org/journal/view.html?volume=7&number=6&spage=752
Solitary rectal ulcer syndrome (SRUS) is a rare, benign disorder in children that usually presents with rectal bleeding, constipation, mucous discharge, prolonged straining, tenesmus, lower abdominal pain, and localized pain in the perineal area. The underlying etiology is not well understood, but it is secondary to ischemic changes and trauma in the rectum associated with paradoxical contraction of the pelvic floor and the external anal sphincter muscles; rectal prolapse has also been implicated in the pathogenesis. […] The underlying etiology is not well-understood but secondary to ischemic changes and trauma in the rectum associated with paradoxical contraction of the pelvic floor and external anal sphincter muscles and with rectal prolapse have been implicated in the pathogenesis. […] The pathophysiology of SRUS is incompletely understood. It is supposed to be due to secondary to ischemia and trauma to the rectal mucosa and paradoxical contraction of pelvic floor. The excessive straining generates a high intrarectal pressure which pushes the anterior rectal mucosa into the contracting puborectalis muscle resulting in pressure necrosis of rectal mucosa and the anterior rectal mucosa is frequently forced into the closed anal canal causing congestion, edema, and ulceration.
#6 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Disorganized contraction of puborectalis muscle in response to attempt on defecation is a well-proposed etiology, which result in higher pressures in anorectal area. During defecation, the perineum would descend to straighten the canal. Inappropriate puborectalis contraction during this process or defecation in squatting position will lead to traumatic compression of rectal wall against anal canal. On the other hand, the contradictory force of this paradoxical movement causes mucosal ischemia and renders the area more susceptible to traumatic injury and ulceration. […] The excessive pressure generated as the aggregate result of constipation, straining and puborectalis aberrant contraction may end in rectal prolapse and intussusception in the long run. Even the first tiny areas of intussusception can cause vascular injury and further compromise blood supply of the mucosa, which is the last part of ulcer formation and development. […] Overall, it seems that chronic mucosal injury and ischemic trauma are the main mechanisms though further studies may shed more light on the process.
#7 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#8 Solitary rectal ulcer syndrome – wikidoc
https://www.wikidoc.org/index.php/Solitary_rectal_ulcer_syndrome
Solitary rectal ulcer syndrome (SRUS, SRU), is a disorder of the rectum and anal canal, caused by straining and increased pressure during defecation. This increased pressure causes the anterior portion of the rectal lining to be forced into the anal canal (an internal rectal intussusception). The lining of the rectum is repeatedly damaged by this friction, resulting in ulceration. SRUS can therefore considered to be a consequence of internal intussusception (a sub type of rectal prolapse), which can be demonstrated in 94% of cases. […] The essential cause of SRUS is thought to be related to too much straining during defecation. […] Overactivity of the anal sphincter during defecation causes the patient to require more effort to expel stool. This pressure is produced by the modified valsalva manovoure (attempted forced exhalation against a closed glottis, resulting in increased abdominal and intra-rectal pressure). Patiest with SRUS were shown to have higher intra-rectal pressures when straining than healthy controls.
#9 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#10 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Disorganized contraction of puborectalis muscle in response to attempt on defecation is a well-proposed etiology, which result in higher pressures in anorectal area. During defecation, the perineum would descend to straighten the canal. Inappropriate puborectalis contraction during this process or defecation in squatting position will lead to traumatic compression of rectal wall against anal canal. On the other hand, the contradictory force of this paradoxical movement causes mucosal ischemia and renders the area more susceptible to traumatic injury and ulceration. […] The excessive pressure generated as the aggregate result of constipation, straining and puborectalis aberrant contraction may end in rectal prolapse and intussusception in the long run. Even the first tiny areas of intussusception can cause vascular injury and further compromise blood supply of the mucosa, which is the last part of ulcer formation and development. […] Overall, it seems that chronic mucosal injury and ischemic trauma are the main mechanisms though further studies may shed more light on the process.
#11 Solitary rectal ulcer syndrome – UpToDate
https://www.uptodate.com/contents/solitary-rectal-ulcer-syndrome
Solitary rectal ulcer syndrome is an uncommon rectal disorder that can present with rectal bleeding, straining during defecation, and a sense of incomplete evacuation. […] The pathogenesis of the solitary rectal ulcer is incompletely understood. However, a number of factors appear to have a causative role in individual reports. It is possible that different etiologies may contribute to the development of solitary rectal ulcer syndrome. […] A common observation in a number of reports is rectal prolapse or rectal intussusception and paradoxical contraction of the puborectalis muscle. […] Patients with solitary rectal ulcer syndrome more frequently had increasing anal pressure at straining, paradoxical puborectalis contraction, and prolapse of the inner circular smooth muscle of the rectum and less frequently had complete rectal emptying compared with controls. […] Rectal prolapse and paradoxical contraction of the puborectalis muscle can result in rectal trauma by two different mechanisms.
#12 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#13 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Disorganized contraction of puborectalis muscle in response to attempt on defecation is a well-proposed etiology, which result in higher pressures in anorectal area. During defecation, the perineum would descend to straighten the canal. Inappropriate puborectalis contraction during this process or defecation in squatting position will lead to traumatic compression of rectal wall against anal canal. On the other hand, the contradictory force of this paradoxical movement causes mucosal ischemia and renders the area more susceptible to traumatic injury and ulceration. […] The excessive pressure generated as the aggregate result of constipation, straining and puborectalis aberrant contraction may end in rectal prolapse and intussusception in the long run. Even the first tiny areas of intussusception can cause vascular injury and further compromise blood supply of the mucosa, which is the last part of ulcer formation and development. […] Overall, it seems that chronic mucosal injury and ischemic trauma are the main mechanisms though further studies may shed more light on the process.
#14 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Disorganized contraction of puborectalis muscle in response to attempt on defecation is a well-proposed etiology, which result in higher pressures in anorectal area. During defecation, the perineum would descend to straighten the canal. Inappropriate puborectalis contraction during this process or defecation in squatting position will lead to traumatic compression of rectal wall against anal canal. On the other hand, the contradictory force of this paradoxical movement causes mucosal ischemia and renders the area more susceptible to traumatic injury and ulceration. […] The excessive pressure generated as the aggregate result of constipation, straining and puborectalis aberrant contraction may end in rectal prolapse and intussusception in the long run. Even the first tiny areas of intussusception can cause vascular injury and further compromise blood supply of the mucosa, which is the last part of ulcer formation and development. […] Overall, it seems that chronic mucosal injury and ischemic trauma are the main mechanisms though further studies may shed more light on the process.
#15 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#16 Solitary rectal ulcer syndrome – wikidoc
https://www.wikidoc.org/index.php/Solitary_rectal_ulcer_syndrome
Solitary rectal ulcer syndrome (SRUS, SRU), is a disorder of the rectum and anal canal, caused by straining and increased pressure during defecation. This increased pressure causes the anterior portion of the rectal lining to be forced into the anal canal (an internal rectal intussusception). The lining of the rectum is repeatedly damaged by this friction, resulting in ulceration. SRUS can therefore considered to be a consequence of internal intussusception (a sub type of rectal prolapse), which can be demonstrated in 94% of cases. […] The essential cause of SRUS is thought to be related to too much straining during defecation. […] Overactivity of the anal sphincter during defecation causes the patient to require more effort to expel stool. This pressure is produced by the modified valsalva manovoure (attempted forced exhalation against a closed glottis, resulting in increased abdominal and intra-rectal pressure). Patiest with SRUS were shown to have higher intra-rectal pressures when straining than healthy controls.
#17
https://journals.lww.com/md-journal/fulltext/2018/05040/solitary_rectal_ulcer_syndrome__a_systematic.18.aspx
Straining: Lengthened straining during bowel movements in the patient who suffers from constipation may result in a direct trauma to the mucosa. […] Self-induced trauma: self-instrumentation can be occurred when individuals attempt to remove impacted stool by rectal digitation. […] Paradoxical contraction of puborectalis muscle: Uncoordinated muscle contraction in the puborectalis muscle has been indicated to be associated with increased intrarectum pressure and anal canal, resulting in ischemic production and ulceration. […] Rectal prolapse and intussusception: Rectal intussusception can lead to localized vascular trauma and consequently the onset of solitary local ulceration. […] The pathogenesis of SRUS is not adequately described, but various factors can be involved.
#18 Solitary Rectal Ulcer Syndrome and Stercoral Ulcers | Abdominal Key
https://abdominalkey.com/solitary-rectal-ulcer-syndrome-and-stercoral-ulcers/
Solitary rectal ulcer syndrome (SRUS), as the name implies, consists of several different clinical pathologic processes. […] These processes, however, end in a mutual common pathway that is associated with reduced blood perfusion of the rectal mucosa, leading to local ischemia and ulceration. […] As mentioned earlier, the underlying cause for this type of ulceration is chronic local ischemia of the colonic wall. […] Rectal intussusception, which may lead to full-thickness rectal prolapse, results in localized vascular trauma and ischemia, initiating solitary local ulceration. […] This uncoordinated sequence of muscle contraction and relaxation required for the defecation process, also called puborectalis syndrome or pelvic outlet obstruction, causes increased pressure inside the rectum and anal canal, generating ischemia and ulceration.
#19 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Solitary rectal ulcer syndrome is a multifactorial pathology, which entails a variety of clinical, histologic and endoscopic aspects that needs step-wise logical approach for management especially in relapsing refractory cases. […] The underlying mechanisms leading to SRUS are not certainly recognized. However, various factors are considered to have a role. Here we propose four main categories known to be involved. First, prolonged straining during defecation, which might end in direct trauma to the vulnerable rectal mucosa. Patients who have constipation or anatomical anomalies are more prone to suffer from straining and at higher risk for developing rectal ulcers. It is also reported that patients with solitary rectal ulcers are more likely to have increased resting and squeezing pressure than normal individuals. This may end in higher overall pressure burden bearded upon rectal mucosa and higher risk of traumatic injuries.
#20 Solitary Rectal Ulcer Syndrome in Children: A Report of Six Cases
https://www.gutnliver.org/journal/view.html?volume=7&number=6&spage=752
Histological examination is the gold standard for establishing the diagnosis of SRUS. The histological criteria for diagnosis include a thickened mucosal layer with distortion of the crypt architecture and fibromuscular obliteration which means that the lamina propria is replaced with smooth muscle and collagen leading to hypertrophy and disorganisation of the muscularis mucosa.
#21 The clinical, endoscopic and histological spectrum of the solitary rectal ulcer syndrome: a single-center experience of 116 cases | BMC Gastroenterology | Full Text
https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-12-72
Key histological features encompass fibromuscular obliteration of the lamina propria with splaying of muscularis mucosae upward between the crypts, thickened mucosa and glandular distortion. […] Studies emphasize that histopathology of SRUS may be associated with a deeper concealed malignancy. […] Another study reemphasizes this aspect by demonstrating loss of hMLH1 gene expression in several cases of SRUS indicating the possibility of neoplastic progression. […] A case of well differentiated infiltrating adenocarcinoma in the focus of SRUS has also been reported and the authors speculated that there is a chance of adenocarcinoma originating from SRUS mucosa. […] Inconsistency in morphologic appearances of associated lesions increases the likelihood of delayed or erroneous diagnosis of SRUS. […] A high index of suspicion is therefore required to diagnose potentially serious disease by repeated examinations and biopsies for histopathology.
#22 Coexistence of Solitary Rectal Ulcer Syndrome and Ulcerative Colitis: A Case Report and Literature Review
https://www.irjournal.org/journal/view.php?number=54
Solitary rectal ulcer syndrome (SRUS) is an uncommon benign disease that is misdiagnosed as malignancy or inflammatory bowel disease because of similarities in clinical and endoscopic manifestations. […] Its pathogenesis is probably multifactorial, and most accepted causes implicate direct trauma by repetitive self-digitation and ischemic injury to the rectal mucosa. […] SRUS is diagnosed by a combination of clinical aspects, endoscopic presentations, and histologic findings. […] The histologic findings of SRUS are characterized by fibromuscular obliteration of the lamina propria, thickened muscularis mucosa, and distortion of crypt architecture. […] SRUS accompanied by IBD is extremely rare, and an accurate differential diagnosis is difficult to achieve. […] The characteristic histological findings in all three cases were fibromuscular obliteration of the lamina propria, thickening of the muscularis mucosa, and elongation and distortion of the crypt.
#23 The clinical, endoscopic and histological spectrum of the solitary rectal ulcer syndrome: a single-center experience of 116 cases | BMC Gastroenterology | Full Text
https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-12-72
Key histological features encompass fibromuscular obliteration of the lamina propria with splaying of muscularis mucosae upward between the crypts, thickened mucosa and glandular distortion. […] Studies emphasize that histopathology of SRUS may be associated with a deeper concealed malignancy. […] Another study reemphasizes this aspect by demonstrating loss of hMLH1 gene expression in several cases of SRUS indicating the possibility of neoplastic progression. […] A case of well differentiated infiltrating adenocarcinoma in the focus of SRUS has also been reported and the authors speculated that there is a chance of adenocarcinoma originating from SRUS mucosa. […] Inconsistency in morphologic appearances of associated lesions increases the likelihood of delayed or erroneous diagnosis of SRUS. […] A high index of suspicion is therefore required to diagnose potentially serious disease by repeated examinations and biopsies for histopathology.
#24 Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation
https://www.termedia.pl/Effective-treatment-of-solitary-rectal-ulcer-syndrome-using-argon-plasma-coagulation,41,23487,1,1.html
The influence of atherosclerotic changes on mucosal ischaemia is also suggested, as well as disorders in cholinergic synapses of the autonomous nervous system, which can be related to diabetic polyneuropathy. […] It is also suspected that SRUS can be an innate malformation of the hamartoma type. […] The coexistence of several factors in SRUS pathogenesis is also possible. […] The therapy initially consists of conservative methods and is usually the end of therapy if there is some improvement or if patients are asymptomatic. […] The final SRUS diagnosis is established on the basis of histopathological criteria. […] A study of samples taken at endoscopy shows changes in all the layers of the rectal wall: muscular, submucosal and mucous. […] The APC was effective in stopping the bleeding in our case and other authors’ cases. It seems to be effective also in healing solitary rectal ulcer syndrome. […] The APC therapy in treating SRUS without rectum prolapse could become a crucial method of bleeding treatment in solitary ulcers and an important method (basic and complementary) among the means of SRUS treatment.
#25 Solitary Rectal Ulcer syndrome – WikiLectures
https://www.wikilectures.eu/w/Solitary_Rectal_Ulcer_syndrome
Humoral regulation may also be involved in pathogenesis. In patients, blood flow through the rectal mucosa is reduced, which is similar to a flow disorder in impaired cholinergic signaling. Another possible explanation for the worse flow is the hypothesis of a small vessel disorder; in the histological picture, an increase in the ligament can be demonstrated. […] Patients with solitary rectal ulcers have also been shown to have higher anal pressure, puborectal dyssynergia, and rectal hypersensitivity. […] All of the above factors, and possibly some others, appear to play a different role in the development of a solitary rectal ulcer.
#26 Solitary rectal ulcer syndrome – Wikipedia
https://en.wikipedia.org/wiki/Solitary_rectal_ulcer_syndrome
The excessive pressure caused by straining (i.e. dyssynergic defecation and constipation) may in the long term lead to development of the spectrum of rectal prolapse conditions (mucosal versus full-thickness prolapse, internal versus external rectal prolapse). […] Chronic vascular trauma (ischemia or hypoperfusion) in the rectal mucosa, which predisposes it to ulceration, and pressure necrosis. […] Psychological factors are also thought to be involved, since patients with SRUS sometimes have psychological disorders such as obsessive-compulsive disorder.
#27 Solitary rectal ulcer syndrome and enterocele in a 13-year-old boy
https://www.termedia.pl/Solitary-rectal-ulcer-syndrome-and-enterocele-in-a-13-year-old-boy,41,21157,1,1.html
Occult or overt rectal prolapse and paradoxical contraction of the pelvic floor muscles are the most commonly attributed factors involved in development of SRUS. […] In the present case chronically increased intra-abdominal pressure associated with straining and relaxation of the levator ani may have caused the small bowel to be forced into the rectal wall, as a consequence causing rectal wall congestion, edema and ulceration. […] A disturbance of toileting behavior as an expression of psychological problems appears to be an important pathogenic factor in some patients.
#28 Clinical and laboratory characteristics of solitary rectal ulcer syndrome: a retrospective analysis of 36 case | Scientific Reports
https://www.nature.com/articles/s41598-025-86324-0
The pathogenesis of SRUS is multifactorial, with key contributing factors, including rectal prolapse, paradoxical contraction of the puborectalis muscle, and direct trauma from straining or digital manipulation. […] A key histological feature that distinguishes SRUS from these other conditions is the obliteration of fibromuscular tissue in the lamina propria, which serves as a highly sensitive marker. Overactivity of the anal sphincter has been recognized as a significant pathophysiological factor that contributes to increased intrarectal pressure, elevated transmural gradient, and heightened voiding pressure, ultimately resulting in venous congestion and ulceration. […] The variation in biopsy results across different symptom groups suggests that the clinical presentation of SRUS is heterogeneous and may influence the histopathological findings.
#29 Fecal Evacuation Disorder Among Patients With Solitary Rectal Ulcer Syndrome: A Case-control Study
https://www.jnmjournal.org/journal/view.html?volume=20&number=4&spage=531
Solitary rectal ulcer syndrome (SRUS) is a disorder affecting all ages and presents with rectal bleeding, mucorrhea, tenesmus and feeling of incomplete evacuation. Pathogenesis of SRUS is not known. Mucosal ischemia was proposed to be an etiological factor in the past. Recently, fecal evacuation disorder (FED; also known as functional defecation disorder) has been proposed to be an important factor in the pathogenesis of SRU in a few uncontrolled studies on small number of patients. […] Pathogenesis of SRUS is largely unknown. Mucosal ischemia was proposed to be one of the mechanisms in the past. A few recent uncontrolled studies on small number of patients suggested a role of FED in the pathogenesis of SRUS. […] We found that a large proportion of patients with SRU had underlying FED and those with FED had thicker IAS. However, whether FED and increased IAS thickness are causes or effects of SRUS is not known.
#30 Solitary rectal ulcer syndrome – UpToDate
https://www.uptodate.com/contents/solitary-rectal-ulcer-syndrome
Solitary rectal ulcer syndrome is an uncommon rectal disorder that can present with rectal bleeding, straining during defecation, and a sense of incomplete evacuation. […] The pathogenesis of the solitary rectal ulcer is incompletely understood. However, a number of factors appear to have a causative role in individual reports. It is possible that different etiologies may contribute to the development of solitary rectal ulcer syndrome. […] A common observation in a number of reports is rectal prolapse or rectal intussusception and paradoxical contraction of the puborectalis muscle. […] Patients with solitary rectal ulcer syndrome more frequently had increasing anal pressure at straining, paradoxical puborectalis contraction, and prolapse of the inner circular smooth muscle of the rectum and less frequently had complete rectal emptying compared with controls. […] Rectal prolapse and paradoxical contraction of the puborectalis muscle can result in rectal trauma by two different mechanisms.
#31 Solitary rectal ulcer syndrome: Clinical features, pathophysiology, diagnosis and treatment strategies
https://www.wjgnet.com/1007-9327/full/v20/i3/738.htm
Solitary rectal ulcer syndrome (SRUS) is a rare benign disorder characterized by a combination of symptoms, endoscopic findings, and histological abnormalities. […] The underlying etiology and pathogenesis are not fully understood but multiple factors may be involved. The most accepted theories are related to direct trauma or local ischemia as causes. […] Mucosal prolapse, overt or occult, is the most common underlying pathogenetic mechanism in SRUS. This may lead to venous congestion, poor blood flow, and edema in the mucosal lining of the rectum and ischemic changes with resultant ulceration. […] The cause of ischemia may also be related to fibroblasts replacing blood vessels, and pressure by the anal sphincter. […] Anorectal physiology studies have shown that 25%-82% of patients with SRUS may have dyssynergia with paradoxical anal contraction. […] Studies have confirmed that uncoordinated defecation with excessive straining over time play a key role in SRUS. […] The pathogenesis of SRUS is not well understood, but may be multifactorial.
#32 Solitary Rectal Ulcer Syndrome in Children: A Report of Six Cases
https://www.gutnliver.org/journal/view.html?volume=7&number=6&spage=752
Solitary rectal ulcer syndrome (SRUS) is a rare, benign disorder in children that usually presents with rectal bleeding, constipation, mucous discharge, prolonged straining, tenesmus, lower abdominal pain, and localized pain in the perineal area. The underlying etiology is not well understood, but it is secondary to ischemic changes and trauma in the rectum associated with paradoxical contraction of the pelvic floor and the external anal sphincter muscles; rectal prolapse has also been implicated in the pathogenesis. […] The underlying etiology is not well-understood but secondary to ischemic changes and trauma in the rectum associated with paradoxical contraction of the pelvic floor and external anal sphincter muscles and with rectal prolapse have been implicated in the pathogenesis. […] The pathophysiology of SRUS is incompletely understood. It is supposed to be due to secondary to ischemia and trauma to the rectal mucosa and paradoxical contraction of pelvic floor. The excessive straining generates a high intrarectal pressure which pushes the anterior rectal mucosa into the contracting puborectalis muscle resulting in pressure necrosis of rectal mucosa and the anterior rectal mucosa is frequently forced into the closed anal canal causing congestion, edema, and ulceration.
#33 Solitary Rectal Ulcer Syndrome: A Narrative Review
https://pmc.ncbi.nlm.nih.gov/articles/PMC6819965/
Disorganized contraction of puborectalis muscle in response to attempt on defecation is a well-proposed etiology, which result in higher pressures in anorectal area. During defecation, the perineum would descend to straighten the canal. Inappropriate puborectalis contraction during this process or defecation in squatting position will lead to traumatic compression of rectal wall against anal canal. On the other hand, the contradictory force of this paradoxical movement causes mucosal ischemia and renders the area more susceptible to traumatic injury and ulceration. […] The excessive pressure generated as the aggregate result of constipation, straining and puborectalis aberrant contraction may end in rectal prolapse and intussusception in the long run. Even the first tiny areas of intussusception can cause vascular injury and further compromise blood supply of the mucosa, which is the last part of ulcer formation and development. […] Overall, it seems that chronic mucosal injury and ischemic trauma are the main mechanisms though further studies may shed more light on the process.
#34 Solitary Rectal Ulcer syndrome – WikiLectures
https://www.wikilectures.eu/w/Solitary_Rectal_Ulcer_syndrome
Humoral regulation may also be involved in pathogenesis. In patients, blood flow through the rectal mucosa is reduced, which is similar to a flow disorder in impaired cholinergic signaling. Another possible explanation for the worse flow is the hypothesis of a small vessel disorder; in the histological picture, an increase in the ligament can be demonstrated. […] Patients with solitary rectal ulcers have also been shown to have higher anal pressure, puborectal dyssynergia, and rectal hypersensitivity. […] All of the above factors, and possibly some others, appear to play a different role in the development of a solitary rectal ulcer.
#35 Coexistence of Solitary Rectal Ulcer Syndrome and Ulcerative Colitis: A Case Report and Literature Review
https://www.irjournal.org/journal/view.php?number=54
However, the development of the solitary rectal ulcer near the UC lesion indicates a possible sequential relationship between SRUS and UC. […] Additional studies are warranted to clarify the relationship between SRUS and UC, including underlying mechanisms responsible for their development and predisposing factors.
#36 Effective treatment of solitary rectal ulcer syndrome using argon plasma coagulation
https://www.termedia.pl/Effective-treatment-of-solitary-rectal-ulcer-syndrome-using-argon-plasma-coagulation,41,23487,1,1.html
The influence of atherosclerotic changes on mucosal ischaemia is also suggested, as well as disorders in cholinergic synapses of the autonomous nervous system, which can be related to diabetic polyneuropathy. […] It is also suspected that SRUS can be an innate malformation of the hamartoma type. […] The coexistence of several factors in SRUS pathogenesis is also possible. […] The therapy initially consists of conservative methods and is usually the end of therapy if there is some improvement or if patients are asymptomatic. […] The final SRUS diagnosis is established on the basis of histopathological criteria. […] A study of samples taken at endoscopy shows changes in all the layers of the rectal wall: muscular, submucosal and mucous. […] The APC was effective in stopping the bleeding in our case and other authors’ cases. It seems to be effective also in healing solitary rectal ulcer syndrome. […] The APC therapy in treating SRUS without rectum prolapse could become a crucial method of bleeding treatment in solitary ulcers and an important method (basic and complementary) among the means of SRUS treatment.