After the eggs have been initially deposited near the anus, they are readily transmitted to other surfaces through  contamination . [ 19 ]  The surface of the eggs is sticky when laid, [ 12 ] [ 11 ]  and the eggs are readily transmitted from their initial deposit near the anus to fingernails, hands, night-clothing and bed linen. [ 9 ]  From here, eggs are further transmitted to food, water, furniture, toys, bathroom  fixtures  and other objects. [ 12 ] [ 18 ] [ 19 ]  Household pets often carry the eggs in their fur, while not actually being infected. [ 21 ]  Dust containing eggs can become airborne and widely dispersed when dislodged from surfaces, for instance when shaking out bed clothes and linen. [ 11 ] [ 18 ] [ 21 ]  Consequently, the eggs can enter the mouth and nose through inhalation, and be swallowed later. [ 9 ] [ 11 ] [ 18 ] [ 19 ]  Although pinworms do not strictly multiply inside the body of their human host, [ 9 ]  some of the pinworm larvae may hatch on the anal  mucosa , and migrate up the  bowel  and back into the  gastrointestinal tract  of the original host. [ 9 ] [ 18 ]  This process is called  retroinfection . [ 11 ] [ 18 ]  According to Burkhart (2005), when this retroinfection occurs, it leads to a heavy  parasitic  load and ensures that the pinworm infestation continues. [ 18 ]  This statement is contradictory to a statement by Caldwell, who contends that retroinfection is rare and not clinically significant. [ 11 ]  Despite the limited, 13-week lifespan of individual pinworms, [ 12 ]   autoinfection  (infection from the original host to itself), either through the anus-to-mouth route or through retroinfection, causes the pinworms to inhabit the same host indefinitely. [ 18 ]


The life cycle begins with eggs being  ingested . [ 12 ]  The eggs hatch in the  duodenum  (first part of the  small intestine ). [ 19 ]  The emerging pinworm  larvae  grow rapidly to a size of 140 to 150 micrometres, [ 9 ]  and migrate through the small intestine towards the  colon . [ 12 ]  During this migration they  moult  twice and become adults. [ 12 ] [ 18 ]  Females survive for 5 to 13 weeks, and males about 7 weeks. [ 12 ]  The male and female pinworms mate in the  ileum  (last part of the small intestine), [ 12 ]  whereafter the male pinworms usually die, [ 19 ]  and are passed out with stool. [ 11 ]  The gravid female pinworms settle in the  ileum ,  caecum  (beginning of the  large intestine ),  appendix  and  ascending colon , [ 12 ]  where they attach themselves to the  mucosa [ 18 ]  and ingest colonic contents. [ 10 ]  Almost the entire body of a gravid female becomes filled with eggs. [ 19 ]  The estimations of the number of eggs in a gravid female pinworm ranges from about 11,000 [ 12 ]  to 16,000. [ 18 ]  The egg-laying process begins approximately five weeks after initial ingestion of pinworm eggs by the human host. [ 12 ]  The gravid female pinworms migrate through the  colon  towards the  rectum  at a rate of 12 to 14 centimetres per hour. [ 12 ]  They emerge from the  anus , and while moving on the skin near the anus, the female pinworms deposit eggs either through contracting and expelling the eggs, dying and then disintegrating, or bodily rupture due to the host scratching the worm. [ 19 ]  After depositing the eggs, the female becomes opaque and dies. [ 11 ]  The reason the female emerges from the anus is to obtain the oxygen necessary for the maturation of the eggs. [ 11 ]


Diagnosis relies on finding the eggs or the adult pinworms. [ 19 ]  Individual eggs are invisible to the naked eye, but they can be seen using a low-power  microscope . [ 21 ]  On the other hand, the light-yellowish thread-like adult pinworms are clearly visually detectable, usually during the night when they move near the anus, or on toilet paper. [ 8 ] [ 14 ] [ 21 ]  Shining a flashlight on the infected individual's anus about one hour after they fall asleep is one form of detection and may show worms crawling out of the anus. [ 22 ]  Another form of detection is the use of transparent  adhesive tape  (e.g.  Scotch Tape ) applied on the anal area which will pick up deposited eggs, and diagnosis can be made by examining the tape with a microscope. [ 16 ] [ 21 ]  This test is most successful if done every morning for several days, because the females do not lay eggs every day, and the number of eggs varies. [ 21 ]  A third method of diagnosis is examining a sample from under their fingernails under a microscope as itching around the anal area is common and therefore they may have collected some eggs under their nails as a result. [ 23 ]


Pinworms do not lay eggs in the  feces , [ 21 ]  but sometimes eggs are deposited in the intestine. [ 19 ]  As such, routine examination of fecal material gives a positive diagnosis in only 5 to 15% of infected subjects, [ 14 ]  and is therefore of little practical diagnostic use. [ 9 ]  In a heavy infection, female pinworms may adhere to  stools  that pass out through the anus, and they may thus be detected on the surface on the stool. [ 14 ] [ 19 ]  Adult pinworms are occasionally seen during  colonoscopy . [ 14 ]  On a microscopic level, pinworms have an identifying feature of  alae  (i.e., protruding ridges) running the length of the worm. [ 24 ]


Pinworm infection cannot be totally prevented under most circumstances. [ 25 ]  This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. [ 19 ]  Infection may occur in the highest strata of society, where hygiene and  nutritional  status are typically high. [ 26 ]  The stigma associated with pinworm infection is hence considered a possible over-emphasis. [ 26 ]   Counselling  is sometimes needed for upset parents who have discovered their children are infected, as they may not realize how prevalent the infection is. [ 19 ]


Preventive action revolves around  personal hygiene  and the cleanliness of the living quarters. [ 26 ]  The  rate  of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases. [ 21 ] [ 26 ]


The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after  defecation  and before meals. [ 26 ] [ 27 ]  Showering every morning is also highly recommended to wash off any eggs that may be still lying on the skin. [ 28 ]  Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily [ 26 ]  and clothes and linens should be washed in hot water and then be placed in a hot dryer in order to kill off any eggs. [ 28 ]  Children can wear gloves while asleep, and the bedroom floor should be kept clean. [ 26 ]  Regular disinfection of kitchen and bathroom surfaces will help to prevent spread as well. [ 29 ]  Food should be covered to limit contamination with dust-borne parasite eggs. [ 26 ]  It is not recommended to shake clothes and bed linen as the eggs may detach and spread [ 26 ]  or to share clothes and towels. Nail biting and sucking on fingers is also discouraged.


Medication  is the primary treatment for pinworm infection. [ 26 ]  However, reinfection is frequent regardless of the medication used. [ 8 ]  Total elimination of the parasite in a household may require repeated doses of medication for up to a year or more. [ 9 ]  Because the drugs kill the adult pinworms, but not the eggs, the first retreatment is recommended in two weeks. [ 21 ]  Also, if one household member spreads the eggs to another, it will be a matter of two or three weeks before those eggs become adult worms and thus amenable to treatment. [ 27 ]   Asymptomatic  infections, often in small children, can serve as reservoirs of infection, and therefore the entire household should be treated regardless of whether or not symptoms are present. [ 9 ] [ 26 ]


The  benzimidazole  compounds  albendazole  ( brand names  e.g.,  Albenza ,  Eskazole ,  Zentel  and  Andazol ) and  mebendazole  ( brand names  e.g.,  Ovex ,  Vermox ,  Antiox  and  Pripsen ) are the most effective. [ 26 ]  They work by inhibiting the  microtubule  function in the pinworm adults, causing  glycogen  depletion, [ 26 ]  thereby effectively starving the parasite. [ 27 ]  A single 100 milligram dose of  mebendazole  with one repetition after two weeks, is considered the safest, and is usually effective with cure rate of 96%. [ 8 ] [ 26 ]  Mebendazole has no serious  side effects , although  abdominal pain  and  diarrhea  have been reported. [ 26 ]   Pyrantel pamoate  (also called pyrantel embonate,  brand names  e.g.,  Reese's Pinworm Medicine ,  Pin-X ,  Combantrin ,  Anthel ,  Helmintox , and  Helmex ) kills adult pinworms through  neuromuscular blockade , [ 27 ]  and is considered as effective as the  benzimidazole  compounds and is used as a second-line medication. [ 9 ]  Pyrantel pamoate is available over the counter and does not require a prescription. Pinworms located in the  genitourinary system  (in this case, female genital area) may require other drug treatments. [ 8 ]


The available data on mebendazole, albendazole, and pyrantel pamoate use in pregnancy is limited and they are all assigned to  pregnancy category  level C. Treatment of a pinworm infection during pregnancy is only recommended for patients with significant symptoms that may be causing adverse effects to the pregnant woman such as loss of sleep and weight loss. [ 30 ] [ 31 ]  Pyrantel pamoate is the treatment of choice in pregnancy but should be used only after consultation with a health care practitioner rather than self-treatment. [ 30 ]  Treatment should be avoided in the first trimester, and if possible done in the third trimester. [ 32 ] [ 31 ]  If the pregnant woman is asymptomatic, then they should be treated after the baby is delivered. [ citation needed ]


Mebendazole has less than 10% of the oral dose absorbed into systemic circulation with a clinically insignificant amount of drug excreted in breastmilk, and therefore treatment should not be withheld during breastfeeding. [ 31 ]  There is limited data on the use of pyrantel pamoate and albendazole in breastfeeding but  WHO  also classifies them as compatible with breastfeeding. This is due to the drugs acting mainly in the intestinal system of the mother with only a very small amount of drug being absorbed into the systemic circulation. [ 31 ] [ 33 ]


Pinworm infection occurs worldwide, [ 10 ]  and is the most common  helminth  (i.e., parasitic worm) infection in the United States and Western Europe. [ 18 ]  In the United States, a study by the  Center of Disease Control  reported an overall  incidence rate  of 11.4% among people of all ages. [ 18 ]  Pinworms are particularly common in children with approximately 30% of children being infected and most commonly seen in children between 7 and 11 years old. [ 34 ]  The  prevalence rates  in children having been reported as high as 61% in India, 50% in England, 39% in Thailand, 37% in Sweden, and 29% in Denmark. [ 18 ]   Finger sucking  has been shown to increase both incidence and relapse rates, [ 18 ]  and  nail biting  has been similarly associated. [ 14 ]  Because it spreads from host to host through  contamination , enterobiasis is common among people living in close contact, and tends to occur in all people within a household. [ 10 ]  The prevalence of pinworms is not associated with gender, [ 10 ]  nor with any particular  social class ,  race , or culture. [ 18 ]  Pinworms are an exception to the tenet that intestinal parasites are uncommon in affluent communities. [ 18 ]


The earliest known instance of pinworms is evidenced by pinworm eggs found in  coprolite ,  carbon dated  to 7837 BC at western  Utah . [ 12 ]  Pinworm infection is not classified as a  neglected tropical disease  unlike many other parasitic worm infections. [ 35 ]


Garlic  has been used as a treatment in the ancient cultures of China, India, Egypt, and Greece. [ 36 ]   Hippocrates  mentioned garlic as a remedy against intestinal parasites. [ 37 ]  German botanist  Adam Lonicer  also recommended garlic against parasitic worms. [ 38 ]


Proctoscopy , or  rectoscopy , is a common medical procedure in which an instrument called a proctoscope (also known as a  rectoscope , although the latter may be a bit longer) is used to examine the  anal cavity ,  rectum , or  sigmoid colon . A proctoscope is a short, straight, rigid, hollow metal tube, and usually has a small light bulb mounted at the end. It is approximately 15 cm (5 inches) long, while a rectoscope is approximately 25 cm (10 inches) long. [ 1 ]  During proctoscopy, the proctoscope is lubricated and inserted into the  rectum , and then the  obturator  is removed, allowing an unobstructed view of the interior of the rectal cavity. This procedure is normally done to inspect for  hemorrhoids  or rectal  polyps  and might be mildly uncomfortable as the proctoscope is inserted further into the rectum. Modern  fibre-optic  proctoscopes allow more extensive observation with less discomfort.


A  proctoscope  is a hollow, tube-like  speculum  that is used for visual inspection of the rectum. [ 2 ] [ 3 ]  Both disposable and non-disposable proctoscopes are available for use. Out of these, the non-disposable Kelly's rectal speculum, [ 4 ]  named after the American gynecologist  Howard Atwood Kelly , is the most commonly used speculum for proctoscopy. Some proctoscopes have a light source for better visibility. The proctoscope is inserted into the  anal canal  with the patient in  Sims' position . Fibre optic proctoscopes are now available which cause less discomfort to the patient.
The proctoscope is used in the diagnosis of  hemorrhoids , carcinoma of anal canal or rectum and  rectal polyp . It is used therapeutically for  polypectomy  and rectal biopsy.


Disposable proctoscopes without light are also available.   The proctoscope also has a hollow channel through which other instruments may be inserted. For example, another instrument may be used to take a  biopsy  of a small amount of  tissue  for examination under a  microscope . Also, air may be injected through the proctoscope to help make viewing easier. Similar instruments, the  sigmoidoscope  and  colonoscope  may be used to visualize more proximal parts of the bowels.


Rectal discharge  is intermittent or continuous expression of liquid from the anus ( per rectum ). Normal rectal mucus is needed for proper excretion of waste. Otherwise, this is closely related to types of  fecal incontinence  (e.g., fecal leakage) but the term rectal discharge does not necessarily imply degrees of incontinence. Types of fecal incontinence that produce a liquid leakage could be thought of as a type of rectal discharge.


Different types of discharge are described. Generally "rectal discharge" refers to either a mucous or  purulent  discharge, but, depending upon what definition of rectal discharge is used, the following could be included:


There are many different types of rectal discharge, but the most common presentation of a discharge is passage of mucus or pus wrapped around an otherwise normal bowel movement. [ 10 ]


Rectal discharge has many causes, and may present with other symptoms: [ 10 ] [ 11 ]


Pus  usually indicates  infection . Frequently medical sources do not differentiate between the two types of discharge, instead using the general term  mucopurulent discharge , which, strictly speaking, should only be used to refer to a discharge that contains both mucus and pus. Purulent discharges may be blood-streaked. [ citation needed ]


Mucus  coats the walls of the  colon  in health, functioning as a protective barrier and also to aid  peristalsis  by  lubrication  of  stool . Mucous discharges can be thought of in three broad categories:


A mucous rectal discharge may be blood-streaked. With some conditions, the blood can be homogenously mixed with the mucus, creating a pink goo. An example of this could be the so-called "red currant jelly" stools in  intussusception . This appearance refers to the mixture of sloughed  mucosa , mucus, and blood. [ 12 ]


Note : "mucus" is a noun, used to name the substance itself, and "mucous" is an adjective, used to describe a discharge. "Mucoid" is also an adjective and means mucus-like. "Mucinous" strictly speaking refers to something having a  mucin -like attribute, but it often is used interchangeably with the word "mucous" (as mucus usually contains a high percentage of mucin).


The differential diagnosis of rectal discharge is extensive,  but the general  etiological  themes are  infection  and  inflammation . [ 11 ]   Some lesions can cause a discharge by mechanically interfering with, or preventing the complete closure of, the  anal canal . This type of lesion may not cause discharge intrinsically, but instead, allow transit of liquid stool components and mucus.


Perianal  Crohn's disease  is associated with fistulizing, fissuring and perianal abscess formation. [ 18 ]


After  colostomy , the distal section of bowel continues to produce mucus despite fecal diversion, often resulting in mucinous discharge. [ 19 ]


Occasionally,  intestinal parasitic  infection can present with discharge, for example  whipworm . [ 20 ]


Several pathologies can present with perianal discharge. Although not exactly the same as rectal discharge, perianal discharge can be misinterpreted as such, given the anatomical proximity. [ citation needed ]


Fistulae  draining into the perianal region, as well as  pilonidal diseases , are the main entities that fall within this category. Perianal tumours can also discharge when they fungate or otherwise become cystic or necrotic. [ citation needed ]


Proctitis is inflammation of the lining of the rectum [ 21 ]  including the  distal  15 cm (6 in) of the rectum. [ citation needed ]


Proctitis  has many causes. Common infection causes include: sexual intercourse with someone who has a sexually transmitted disease (STD), infection from a foodborne illness, and strep throat (in children). [ 22 ]   Proctitis may also be caused by some types of inflammatory bowel disease, radiation therapy, injury to the rectum or anus, or some types of antibiotic. [ 22 ] [ clarification needed ] [ citation needed ]


Tuberculosis  proctitis can create a mucous discharge. [ 23 ]


Anal warts are irregular, verrucous lesions caused by  human papilloma virus . Anal warts are usually transmitted by unprotected,  anoreceptive intercourse .  Anal warts may be asymptomatic, [ 24 ]  or may cause rectal discharge, anal wetness,  rectal bleeding , and  pruritus ani . [ 14 ]  Lesions can also occur within the anal canal, where they are more likely to create symptoms. [ citation needed ]


The bacterium  Chlamydia trachomatis  can cause 2 conditions in humans; viz.  trachoma  and  lymphogranuloma venereum . Trachoma can cause an asymptomatic  proctitis , but the symptoms of lymphogranuloma venereum are usually more severe, including  pruritus ani , purulent rectal
discharge,  hematochezia   rectal pain  and  diarrhea  or  constipation . [ 14 ] [ 24 ]  Lymphogranuloma venereum can cause  fistulas ,  strictures  and  anorectal abscesses  if left untreated. Hence, it can be confused with Crohn's disease. [ 25 ] [ 26 ]


Rectal gonorrhea is caused by  Neisseria gonorrhoeae . [ 24 ]  The condition is usually asymptomatic, but symptoms can include rectal discharge (which can be creamy, purulent or bloody),  pruritus ani ,  tenesmus , and possibly  constipation . When symptomatic, these usually appear 5–7 days post-exposure. [ 14 ]  Discharge is the most common symptom, and it is usually a brownish mucopurulent consistency. [ 27 ]


Anorectal syphilis is caused by  Treponema pallidum  and is contracted through anoreceptive intercourse. Symptoms are usually minimal, but mucous discharge, bleeding, and  tenesmus  may be present. [ 27 ]


When the fecal stream is diverted as part of a  colostomy , a condition called  diversion colitis  may develop in the section of bowel that no longer is in contact with stool. The mucosal lining is nourished by short-chain fatty acids, which are produced as a result of bacterial fermentation in the gut. Long-term lack of exposure to these nutrients can cause inflammation of the colon (colitis). [ 28 ]  Symptoms include  rectal bleeding , mucous discharge,  tenesmus , and  abdominal pain . [ 27 ]


Anal carcinoma is much less common than  colorectal cancer . The most common form is  squamous cell carcinoma , followed by  adenocarcinoma  and  melanoma . [ 29 ]  SCC usually occurs in the anal canal, and more rarely on the anal margin. Anal margin SCC presents as a lesion with rolled, everted edges and central ulceration. [ 27 ]  Symptoms include a painful lump, bleeding,  pruritus ani ,  tenesmus , discharge or possibly  fecal incontinence . SSC in the anal canal most commonly causes bleeding, but may also cause anal pain, a lump,  pruritus ani , discharge,  tenesmus , change in bowel habits and  fecal incontinence . Because these symptoms are so unspecific, and because symptoms of anal carcinoma may not always be typical, this can lead to delays in diagnosis. [ 30 ]


Rare neoplasms at this site that can give rise to discharge include Paget's disease (which is possibly a type of adenocarcinoma) and verrucous carcinoma. [ 27 ]


Adenoma  is the most common colorectal  polyp . Adenomas are not malignant, but rarely  adenocarcinoma  can develop from them. Large adenomas can cause  rectal bleeding , mucus discharge,  tenesmus , and a sensation of urgency. Mucus production may be so great that it can cause  electrolyte  disturbances in the blood. [ 27 ]


Juvenile polyps  may cause rectal discharge.


A  rectal prolapse  occurs when walls of the  rectum  have  prolapsed  to such a degree that they protrude out of the  anus  and are visible outside the body. [ 2 ]  However, most researchers agree that there are 3 to 5 different types of rectal prolapse, depending on whether the prolapsed section is visible externally, and whether the full or only partial thickness of the rectal wall is involved. [ 3 ] [ 4 ]


Rectal prolapse may occur without any symptoms, but depending upon the nature of the prolapse there may be  mucous discharge  (mucus coming from the anus),  rectal bleeding , degrees of  fecal incontinence , and  obstructed defecation  symptoms. [ 5 ]


Rectal prolapse is generally more common in elderly women, although it may occur at any age and in either sex. It is very rarely life-threatening, but the symptoms can be debilitating if left untreated. [ 5 ]  Most external prolapse cases can be treated successfully, often with a surgical procedure. Internal prolapses are traditionally harder to treat and surgery may not be suitable for many patients.


The different kinds of rectal prolapse can be difficult to grasp, as different definitions are used and some recognize some subtypes and others do not. Essentially, rectal prolapses may be: [ citation needed ]


External (complete) rectal prolapse  (rectal procidentia, full thickness rectal prolapse, overt rectal prolapse [ 6 ] ) is
a full thickness, circumferential, true intussusception of the rectal wall which protrudes from the anus and is visible externally. [ 7 ] [ 8 ]


Internal rectal intussusception  (occult rectal prolapse, internal procidentia) can be defined as a funnel shaped infolding of the upper rectal (or lower  sigmoid ) wall that can occur during  defecation . [ 9 ]  This infolding is perhaps best visualised as folding a sock inside out, [ 10 ]  creating "a tube within a tube". [ 11 ]  Another definition is "where the rectum collapses but does not exit the anus". [ 12 ]  Many sources differentiate between internal rectal intussusception and mucosal prolapse, implying that the former is a full thickness prolapse of rectal wall. However, a publication by the  American Society of Colon and Rectal Surgeons  stated that internal rectal intussusception involved the  mucosal  and  submucosal  layers separating from the underlying  muscularis mucosa  layer attachments, resulting in the separated portion of rectal lining "sliding" down. [ 5 ]  This may signify that authors use the terms internal rectal prolapse and internal mucosal prolapse to describe the same phenomena.


Mucosal prolapse  (partial rectal mucosal prolapse) [ 13 ]  refers to prolapse of the loosening of the submucosal attachments to the muscularis propria of the distal rectummucosal layer of the rectal wall. Most sources define mucosal prolapse as an external, segmental prolapse which is easily confused with prolapsed (3rd or 4th degree)  hemorrhoids  (piles). [ 10 ]  However, both internal mucosal prolapse (see below) and circumferential mucosal prolapse are described by some. [ 13 ]  Others do not consider mucosal prolapse a true form of rectal prolapse. [ 14 ]


Internal mucosal prolapse  (rectal internal mucosal prolapse, RIMP) refers to prolapse of the mucosal layer of the rectal wall which does not protrude externally. There is some controversy surrounding this condition as to its relationship with hemorrhoidal disease, or whether it is a separate entity. [ 15 ]  The term "mucosal hemorrhoidal prolapse" is also used. [ 16 ]


Solitary rectal ulcer syndrome  (SRUS, solitary rectal ulcer, SRU) occurs with internal rectal intussusception and is part of the spectrum of rectal prolapse conditions. [ 5 ]  It describes  ulceration  of the rectal lining caused by repeated frictional damage as the internal intussusception is forced into the anal canal during straining. SRUS can be considered a consequence of internal intussusception, which can be demonstrated in 94% of cases.


Mucosal prolapse syndrome  (MPS) is recognized by some. It includes solitary rectal ulcer syndrome, rectal prolapse, proctitis cystica profunda, and inflammatory polyps. [ 17 ] [ 18 ]  It is classified as a chronic benign inflammatory disorder.


Rectal prolapse and internal rectal intussusception has been classified according to the size of the prolapsed section of rectum, a function of rectal mobility from the sacrum and infolding of the rectum. This classification also takes into account sphincter relaxation: [ 19 ]


Rectal internal mucosal prolapse has been graded according to the level of descent of the intussusceptum, which was predictive of symptom severity: [ 20 ]


The most widely used classification of internal rectal prolapse is according to the height on the rectal/sigmoid wall from which they originate and by whether the intussusceptum remains within the rectum or extends into the  anal canal . The height of intussusception from the anal canal is usually estimated by  defecography . [ 11 ]


Recto-rectal (high) intussusception  (intra-rectal intussusception) is where the intussusception starts in the rectum, does not protrude into the anal canal, but stays within the rectum. (i.e. the intussusceptum originates in the rectum and does not extend into the anal canal. The intussuscipiens includes rectal lumen distal to the intussusceptum only). These are usually intussusceptions that originate in the upper rectum or lower  sigmoid . [ 11 ]


Recto-anal (low) intussusception  (intra-anal intussusception) is where the intussusception starts in the rectum and protrudes into the anal canal (i.e. the intussusceptum originates in the rectum, and the intussuscipiens includes part of the anal canal)


An Anatomico-Functional Classification of internal rectal intussusception has been described, [ 11 ]  with the argument that other factors apart from the height of intussusception above the anal canal appear to be important to predict symptomology. The parameters of this classification are anatomic descent, diameter of intussuscepted bowel, associated rectal hyposensitivity and associated delayed colonic transit:


Patients may have associated gynecological conditions which may require multidisciplinary management. [ 5 ]  History of  constipation  is important because some of the operations may worsen constipation. Fecal incontinence may also influence the choice of management.


Rectal prolapse may be confused easily with prolapsing hemorrhoids. [ 5 ]  Mucosal prolapse also differs from prolapsing (3rd or 4th degree) hemorrhoids, where there is a segmental prolapse of the hemorrhoidal tissues at the 3, 7 and 11 o'clock positions. [ 13 ]  Mucosal prolapse can be differentiated from a full thickness external rectal prolapse (a complete rectal prolapse) by the orientation of the folds (furrows) in the prolapsed section. In full thickness rectal prolapse, these folds run circumferential.  In mucosal prolapse, these folds are radially. [ 10 ]  The folds in mucosal prolapse are usually associated with internal hemorrhoids. Furthermore, in rectal prolapse, there is a sulcus present between the prolapsed bowel and the anal verge, whereas in hemorrhoidal disease there is no sulcus. [ 3 ]  Prolapsed, incarcerated hemorrhoids are extremely painful, whereas as long as a rectal prolapse is not strangulated, it gives little pain and is easy to reduce. [ 5 ]


The prolapse may be obvious, or it may require straining and squatting to produce it. [ 5 ]  The anus is usually patulous, (loose, open) and has reduced resting and squeeze pressures. [ 5 ]  Sometimes it is necessary to observe the patient while they strain on a toilet to see the prolapse happen [ 21 ]  (the perineum can be seen with a mirror or by placing an endoscope in the bowl of the toilet). [ 10 ]  A phosphate enema may need to be used to induce straining. [ 3 ]


The perianal skin may be macerated (softening and whitening of skin that is kept constantly wet) and show  excoriation . [ 10 ]


These may reveal congestion and  edema  (swelling) of the distal rectal mucosa, [ 21 ]  and in 10-15% of cases there may be a solitary rectal ulcer on the anterior rectal wall. [ 5 ]  Localized inflammation or ulceration can be biopsied and may lead to a diagnosis of SRUS or colitis cystica profunda. [ 5 ]  Rarely, a  neoplasm  (tumour) may form on the leading edge of the intussusceptum. In addition, patients are frequently elderly and therefore have increased incidence of  colorectal cancer . Full length colonoscopy is usually carried out in adults prior to any surgical intervention. [ 5 ]  These investigations may be used with contrast media ( barium enema ) which may show the associated mucosal abnormalities. [ 10 ]


This investigation is used to diagnose internal intussusception, or demonstrate a suspected external prolapse that could not be produced during the examination. [ 3 ]  It is usually not necessary with obvious external rectal prolapse. [ 10 ]   Defecography  may demonstrate associated conditions like  cystocele , vaginal vault prolapse or  enterocele . [ 5 ]


Colonic transit studies  may be used to rule out  colonic inertia  if there is a history of severe constipation. [ 3 ] [ 5 ]  Continent prolapse patients with slow transit constipation, and who are fit for surgery may benefit from subtotal colectomy with rectopexy. [ 5 ]


This investigation objectively documents the functional status of the sphincters. However, the clinical significance of the findings are disputed by some. [ 10 ]  It may be used to assess for pelvic floor dyssenergia, [ 5 ]  ( anismus  is a contraindication for certain surgeries, e.g. STARR), and these patients may benefit from post-operative  biofeedback  therapy. Decreased squeeze and resting pressures are usually the findings, and this may predate the development of the prolapse. [ 5 ]  Resting tone is usually preserved in patients with mucosal prolapse. [ 21 ]  In patients with reduced resting pressure, levatorplasty may be combined with prolapse repair to further improve continence. [ 10 ]


It may be used to evaluate incontinence, but there is disagreement about what relevance the results may show, as rarely do they mandate a change of surgical plan. [ 5 ]  There may be denervation of striated musculature on the electromyogram. [ 21 ]  Increased nerve conduction periods (nerve damage), this may be significant in predicting post-operative incontinence. [ 5 ]


Rectal prolapse is a "falling down" of the rectum so that it is visible externally. The appearance is of a reddened, proboscis-like object through the anal sphincters. Patients find the condition embarrassing. [ 10 ]  The symptoms can be socially debilitating without treatment, [ 5 ]  but it is rarely life-threatening. [ 10 ]


The true incidence of rectal prolapse is unknown, but it is thought to be uncommon. As most affected people are elderly, the condition is generally under-reported. [ 22 ]  It may occur at any age, even in children, [ 23 ]  but there is peak onset in the fourth and seventh decades. [ 3 ]  Women over 50 are six times more likely to develop rectal prolapse than men. It is rare in men over 45 and in women under 20. [ 21 ]  When males are affected, they tend to be young and report significant bowel function symptoms, especially  obstructed defecation , [ 5 ]  or have a predisposing disorder (e.g., congenital  anal atresia ). [ 10 ]  When children are affected, they are usually under the age of 3.


35% of women with rectal prolapse have never had children, [ 5 ]  suggesting that pregnancy and labor are not significant factors. Anatomical differences such as the wider pelvic outlet in females may explain the skewed gender distribution. [ 10 ]


Associated conditions, especially in younger patients include autism, developmental delay syndromes, and psychiatric conditions requiring several medications. [ 5 ]


Signs and symptoms include:


Initially, the mass may protrude through the anal canal only during defecation and straining, and spontaneously return afterwards. Later, the mass may have to be pushed back in following defecation. This may progress to a chronically prolapsed and severe condition, defined as spontaneous prolapse that is difficult to keep inside, and occurs with walking, prolonged standing, [ 5 ]  coughing or sneezing ( Valsalva  maneuvers). [ 3 ]  A chronically prolapsed rectal tissue may undergo pathological changes such as thickening, ulceration and bleeding. [ 5 ]


If the prolapse becomes trapped externally outside the anal sphincters, it may become strangulated and there is a risk of perforation. [ 21 ]   This may require an urgent surgical operation if the prolapse cannot be manually reduced. [ 5 ]  Applying granulated sugar on the exposed rectal tissue can reduce the  edema  (swelling) and facilitate this. [ 21 ]


The precise cause is unknown, [ 3 ] [ 10 ] [ 9 ]  and has been much debated. [ 5 ]  In 1912 Moschcowitz proposed that rectal prolapse was a sliding hernia through a pelvic  fascial  defect. [ 10 ]


This theory was based on the observation that rectal prolapse patients have a mobile and unsupported pelvic floor, and a hernia sac of peritoneum from the Pouch of Douglas and rectal wall can be seen. [ 5 ]   Other adjacent structures can sometimes be seen in addition to the rectal prolapse. [ 5 ]  Although a  pouch of Douglas   hernia , originating in the cul de sac of Douglas, may protrude from the anus (via the anterior rectal wall), [ 21 ]  this is a different situation from rectal prolapse.


Shortly after the invention of  defecography , In 1968 Broden and Snellman used  cinedefecography  to show that rectal prolapse begins as a circumferential intussusception of the rectum, [ 3 ] [ 10 ]  which slowly increases over time. [ 21 ]  The leading edge of the intussusceptum may be located at 6–8 cm or at 15–18 cm from the  anal verge . [ 21 ]  This proved an older theory from the 18th century by  John Hunter  and  Albrecht von Haller  that this condition is essentially a full-thickness rectal intussusception, beginning about 3 inches above the  dentate line  and protruding externally. [ 5 ]


Since most patients with rectal prolapse have a long history of constipation, [ 10 ]  it is thought that prolonged, excessive and repetitive straining during defecation may predispose to rectal prolapse. [ 3 ] [ 9 ] [ 21 ] [ 24 ] [ 25 ] [ 26 ]  Since rectal prolapse itself causes functional obstruction, more straining may result from a small prolapse, with increasing damage to the anatomy. [ 9 ]  This excessive straining may be due to predisposing pelvic floor dysfunction (e.g.  obstructed defecation ) and anatomical factors: [ 10 ] [ 21 ]


Some authors question whether these abnormalities are the cause, or secondary to the prolapse. [ 3 ]  Other predisposing factors/associated conditions include:


The association with uterine prolapse (10-25%) and cystocele (35%) may suggest that there is some underlying abnormality of the pelvic floor that affects multiple pelvic organs. [ 3 ]  Proximal bilateral pudendal neuropathy has been demonstrated in patients with rectal prolapse who have fecal incontinence. [ 5 ]  This finding was shown to be absent in healthy subjects, and may be the cause of denervation-related atrophy of the external anal sphincter. Some authors suggest that  pudendal nerve  damage is the cause for pelvic floor and anal sphincter weakening, and may be the underlying cause of a spectrum of pelvic floor disorders. [ 5 ]


Sphincter function in rectal prolapse is almost always reduced. [ 3 ]  This may be the result of direct sphincter injury by chronic stretching of the prolapsing rectum. Alternatively, the intussuscepting rectum may lead to chronic stimulation of the rectoanal inhibitory reflex (RAIR - contraction of the external anal sphincter in response to stool in the rectum). The RAIR was shown to be absent or blunted. Squeeze (maximum voluntary contraction) pressures may be affected as well as the resting tone. This is most likely a denervation injury to the external anal sphincter. [ 3 ]


The assumed mechanism of  fecal incontinence  in rectal prolapse is by the chronic stretch and trauma to the anal sphincters and the presence of a direct conduit (the intussusceptum) connecting rectum to the external environment which is not guarded by the sphincters. [ 5 ]


The assumed mechanism of obstructed defecation is by disruption to the rectum and anal canal's ability to contract and fully evacuate rectal contents. The intussusceptum itself may mechanically obstruct the rectoanal  lumen , creating a blockage that straining, anismus and colonic dysmotility exacerbate. [ 5 ]


Some believe that internal rectal intussusception represents the initial form of a progressive spectrum of disorders the extreme of which is external rectal prolapse. The intermediary stages would be gradually increasing sizes of intussusception. However, internal intussusception rarely progresses to external rectal prolapse. [ 30 ]  The factors that result in a patient progressing from internal intussusception to a full thickness rectal prolapse remain unknown. [ 5 ]  Defecography studies demonstrated that degrees of internal intussusception are present in 40% of asymptomatic subjects, raising the possibility that it represents a normal variant in some, and may predispose patients to develop symptoms, or exacerbate other problems. [ 31 ]


Surgery is thought to be the only option to potentially cure a complete rectal prolapse. [ 7 ]  For people with medical problems that make them unfit for surgery, and those who have minimal symptoms, conservative measures may be beneficial. Dietary adjustments, including increasing dietary fiber may be beneficial to reduce constipation, and thereby reduce straining. [ 7 ]  A bulk forming agent (e.g.  psyllium ) or stool softener can also reduce constipation. [ 7 ]


Surgery is often required to prevent further damage to the anal sphincters. The goals of surgery are to restore the normal anatomy and to minimize symptoms. There is no globally agreed consensus as to which procedures are more effective, [ 7 ]  and there have been over 50 different operations described. [ 5 ]


Surgical approaches in rectal prolapse can be either perineal or abdominal. A perineal approach (or trans-perineal) refers to surgical access to the rectum and sigmoid colon via an incision around the anus and  perineum  (the area between the genitals and the anus). [ 32 ]  Abdominal approach (trans-abdominal approach) involves the surgeon cutting into the  abdomen  and gaining surgical access to the  pelvic cavity . Procedures for rectal prolapse may involve fixation of the bowel (rectopexy), or resection (a portion removed), or both. [ 7 ]  Trans-anal (endo-anal) procedures are also described where access to the internal rectum is gained through the anus itself.


Abdominal procedures are associated with lower risk of postoperative recurrence of the prolapse, compared with perineal procedures (6.1% vs 16.3% in patients who are younger than 65 years of age at the time of surgery). [ 33 ]


The abdominal approach carries a small risk of impotence in males (e.g. 1-2% in abdominal rectopexy). [ 10 ]  Abdominal operations may be open or  laparoscopic  (keyhole surgery). [ 3 ]


Laparoscopic procedures
Recovery time following laparoscopic surgery is shorter and less painful than following traditional abdominal surgery. [ 32 ]  Instead of opening the pelvic cavity with a wide incision (laparotomy), a laparoscope (a thin, lighted tube) and surgical instruments are inserted into the pelvic cavity via small incisions. [ 32 ]  Rectopexy and anterior resection have been performed laparoscopically with good results.


The perineal approach generally results in less post-operative pain and complications, and a reduced length of hospital stay. These procedures generally carry a higher recurrence rate and poorer functional outcome. [ 5 ]  The perineal procedures include perineal rectosigmoidectomy and Delorme repair. [ 3 ]  Elderly, or other medically high-risk patients are usually treated by perineal procedures, [ 3 ]   as they can be performed under a  regional anesthetic , or even  local anesthetic  with  intravenous sedation , thus avoid the risks of a  general anesthetic . [ 10 ]  Alternatively, perineal procedures may be selected to reduce risk of nerve damage, for example in young male patients for whom sexual dysfunction may be a major concern. [ 5 ]


Perineal rectosigmoidectomy


The goal of Perineal rectosigmoidectomy is to resect or remove the redundant bowel. This is done through the perineum. The lower rectum is anchored to the sacrum through fibrosis in order to prevent future prolapse. [ 7 ]  The full thickness of the rectal wall is incised at a level just above the dentate line. Redundant rectal and sigmoid wall is removed and the new edge of colon is reconnected (anastomosed) with the anal canal with stitches or staples. [ 10 ]  This procedure may be combined with levatorplasty, to tighten the pelvic muscles. [ 7 ]  A combined a perineal proctosigmoidectomy with anterior levatorplasty is also called an Altemeier procedure. [ 3 ]  Levatorplasty is performed to correct levator diastasis which is commonly associated with rectal prolapse. [ 3 ]  Perineal rectosigmoidectomy was first introduced by Mikulicz in 1899, and it remained the preferred treatment in Europe for many years. [ 3 ]  It was Popularized by Altemeier. [ 10 ]  The procedure is simple, safe and effective. [ 3 ]  Continence levatorplasty may enhance restoration of continence (2/3 of patients). [ 3 ]  Complications occur in less than 10% of cases, and include pelvic bleeding, pelvic abscess and anastomotic dehiscence (splitting apart of the stitches inside), bleeding or leak at a dehiscence [ 3 ]  Mortality is low. [ 10 ]  Recurrence rates are higher than for abdominal repair, [ 3 ]  16-30%, but more recent studies give lower recurrence rates. [ 3 ]  Additional levatorplasty can reduce recurrence rates to 7%. [ 3 ]


Delorme Procedure


This is a modification of the perineal rectosigmoidectomy, differing in that only the mucosa and submucosa are excised from the prolapsed segment, rather than full thickness resection. [ 10 ]  The prolapse is exposed if it is not already present, and the mucosal and submucosal layers are stripped from the redundant length of bowel. The muscle layer that is left is plicated (folded) and placed as a buttress above the pelvic floor. [ 7 ]  The edges of the mucosal are then stitched back together. "Mucosal proctectomy" was first discussed by Delorme in 1900, [ 10 ]  now it is becoming more popular again as it has low morbidity and avoids an abdominal incision, while effectively repairing the prolapse. [ 3 ]  The procedure is ideally suited to those patients with full-thickness prolapse limited to partial circumference (e.g., anterior wall) or less-extensive prolapse (perineal rectosigmoidectomy may be difficult in this situation). [ 3 ] [ 10 ]  Fecal incontinence is improved following surgery (40%–75% of patients). [ 5 ] [ 10 ]  Post operatively, both mean resting and squeeze pressures were increased. [ 5 ]  Constipation is improved in 50% of cases, [ 5 ]  but often urgency and tenesmus are created. Complications, including infection, urinary retention, bleeding,  anastomotic  dehiscence (opening of the stitched edges inside),  rectal stricture  (narrowing of the gut lumen), diarrhea, and fecal impaction occur in 6-32% of cases. [ 5 ] [ 10 ]  Mortality occurs in 0–2.5% cases. [ 10 ]  There is a higher recurrence rate than abdominal approaches (7-26% cases). [ 5 ] [ 10 ]


Anal encirclement (Thirsch procedure)


This procedure can be carried out under  local anaesthetic . After reduction of the prolapse, a subcutaneous suture (a stitch under the skin) or other material is placed encircling the anus, which is then made taut to prevent further prolapse. [ 7 ]  Placing silver wire around the anus first described by Thiersch in 1891. [ 10 ]  Materials used include nylon, silk, silastic rods, silicone, Marlex mesh, Mersilene mesh, fascia, tendon, and Dacron. [ 10 ]  This operation does not correct the prolapse itself, it merely supplements the anal sphincter, narrowing the anal canal with the aim of preventing the prolapse from becoming external, meaning it remains in the rectum. [ 10 ]  This goal is achieved in 54-100% cases. Complications include breakage of the encirclement material, fecal impaction, sepsis, and erosion into the skin or anal canal. Recurrence rates are higher than the other perineal procedures. This procedure is most often used for people who have a severe condition or who have a high risk of adverse effects from general anesthetic, [ 7 ]  and who may not tolerate other perineal procedures.


Internal rectal intussusception  (rectal intussusception, internal intussusception, internal rectal prolapse, occult rectal prolapse, internal rectal  procidentia  and rectal invagination) is a medical condition defined as a funnel shaped infolding of the  rectal  wall that can occur during  defecation . [ 9 ]


This phenomenon was first described in the late 1960s when  defecography  was first developed and became widespread. [ 5 ]  Degrees of internal intussusception have been demonstrated in 40% of asymptomatic subjects, raising the possibility that it represents a normal variant in some, and may predispose patients to develop symptoms, or exacerbate other problems. [ 31 ]


Internal intussusception may be  asymptomatic , but common symptoms include: [ 3 ]


Recto-rectal  intussusceptions may be  asymptomatic , apart from mild obstructed defecation. "interrupted defaecation" in the morning is thought by some to be characteristic. [ 11 ]


Recto-anal  intussusceptions commonly give more severe symptoms of straining, incomplete evacuation, need for digital evacuation of stool, need for support of the  perineum  during defecation, urgency, frequency or intermittent  fecal incontinence . [ 11 ]


It has been observed that intussusceptions of thickness ≥3 mm, and those that appear to cause obstruction to rectal evacuation may give clinical symptoms. [ 36 ] [ 37 ]


There are two schools of thought regarding the nature of internal intussusception, viz: whether it is a primary phenomenon, or secondary to (a consequence of) another condition.


Some believe that it represents the initial form of a progressive spectrum of disorders the extreme of which is external rectal prolapse. The intermediary stages would be gradually increasing sizes of intussusception. The folding section of rectum can cause repeated trauma to the mucosa, and can cause  solitary rectal ulcer syndrome . [ 10 ]  However, internal intussusception rarely progress to external rectal prolapse. [ 30 ]


Others argue that the majority of patients appear to have rectal intussusception as a consequence of obstructed defecation rather than a cause, [ 38 ] [ 39 ]  possibly related to excessive straining in patients with obstructed defecation. [ 36 ]  Patients with other causes of obstructed defecation ( outlet obstruction ) like  anismus  also tend to have higher incidence of internal intussusception.  Enteroceles  are coexistent in 11% of patients with internal intussusception. [ 40 ]  Symptoms of internal intussusception overlap with those of  rectocele , indeed the 2 conditions can occur together. [ 41 ]


Patients with  solitary rectal ulcer syndrome  combined with internal intussusception (as 94% of SRUS patients have) were shown to have altered rectal wall biomechanics compared to patients with internal intussusception alone. [ 42 ]  The presumed mechanism of the  obstructed defecation  is by telescoping of the intussusceptum, occluding the rectal lumen during attempted defecation. [ 36 ]  One study analysed resected rectal wall specimens in patients with obstructed defecation associated with rectal intussusception undergoing  stapled trans-anal rectal resection . They reported abnormalities of the  enteric nervous system  and  estrogen receptors . [ 43 ]  One study concluded that intussusception of the  anterior  rectal wall shares the same cause as  rectocele , namely deficient recto-vaginal ligamentous support. [ 44 ]


The following conditions occur more commonly in patients with internal rectal intussusception than in the general population:


Unlike external rectal prolapse, internal rectal intussusception is not visible externally, but it may still be diagnosed by  digital rectal examination , while the patient strains as if to defecate. [ 11 ]  Imaging such as a  defecating proctogram [ 47 ]  or dynamic MRI defecography can demonstrate the abnormal folding of the rectal wall. Some have advocated the use of anorectal physiology testing ( anorectal manometry ). [ 5 ]


Nonsurgical measures to treat internal intussusception include pelvic floor retraining, [ 48 ]  a  bulking agent  (e.g.  psyllium ),  suppositories  or  enemas  to relieve constipation and straining. [ 21 ]  If there is  incontinence  ( fecal leakage  or more severe FI), or paradoxical contraction of the pelvic floor ( anismus ), then biofeedback retraining is indicated. [ 49 ]  Some researchers advise that internal intussusception be managed conservatively, compared to external rectal prolapse which usually requires surgery. [ 50 ]


As with external rectal prolapse, there are a great many different surgical interventions described. Generally, a section of rectal wall can be  resected  (removed), or the rectum can be fixed (rectopexy) to its original position against the  sacral vertebrae , or a combination of both methods. Surgery for internal rectal prolapse can be via the abdominal approach or the transanal approach. [ 51 ]


It is clear that there is a wide spectrum of symptom severity, meaning that some patients may benefit from surgery and others may not. Many procedures receive conflicting reports of success, leading to a lack of any consensus about the best way to manage this problem. [ 49 ]  Relapse of the intussusception after treatment is a problem. Two of the most commonly employed procedures are discussed below.


This procedure aims to "[correct] the descent of the posterior and middle pelvic compartments combined with reinforcement of the rectovaginal septum". [ 51 ]


Rectopexy has been shown to improve anal incontinence ( fecal leakage ) in patients with rectal intussusception. [ 52 ]  The operation has been shown to have low recurrence rate (around 5%). [ 53 ]  It also improves obstructed defecation symptoms. [ 54 ]


Complications include constipation, which is reduced if the technique does not use posterior rectal mobilization (freeing the rectum from its attached back surface). [ 55 ]


The advantage of the laparoscopic approach is decreased healing time and less complications. [ 53 ]


This operation aims to "remove the anorectal mucosa circumferentially and reinforce the anterior anorectal junction wall with the use of a circular stapler". [ 45 ] [ 46 ]  In contrast to other methods, STARR does not correct the descent of the rectum, it removes the redundant tissue. [ 51 ]  The technique was developed from a similar stapling procedure for prolapsing  hemorrhoids . Since, specialized circular staplers have been developed for use in external rectal prolapse and internal rectal intussusception. [ 56 ]


Complications, sometimes serious, have been reported following STARR, [ 57 ] [ 58 ] [ 59 ] [ 60 ] [ 61 ]   but the procedure is now considered safe and effective. [ 60 ]  STARR is   contraindicated  in patients with weak sphincters (fecal incontinence and urgency are a possible complication) and with  anismus  (paradoxical contraction of the pelvic floor during attempted defecation). [ 60 ]  The operation has been shown to improve rectal sensitivity and decrease rectal volume, the reason thought to create urgency. [ 51 ]  90% of patients do not report urgency 12 months after the operation. The anal sphincter may also be stretched during the operation. STARR was compared with biofeedback and found to be more effective at reducing symptoms and improving quality of life. [ 62 ]


Rectal mucosal prolapse  (mucosal prolapse, anal mucosal prolapse) is a sub-type of rectal prolapse, and refers to abnormal descent of the  rectal   mucosa  through the  anus . [ 21 ]  It is different to an internal intussusception (occult prolapse) or a complete rectal prolapse (external prolapse, procidentia) because these conditions involve the full thickness of the rectal wall, rather than only the mucosa (lining). [ 13 ]


Mucosal prolapse is a different condition to prolapsing (3rd or 4th degree)  hemorrhoids , [ 13 ]  although they may look similar.


Rectal mucosal prolapse can be a cause of  obstructed defecation  (outlet obstruction). [ 9 ]  and rectal malodor.


Symptom severity increases with the size of the prolapse, and whether it spontaneously reduces after defecation, requires manual reduction by the patient, or becomes irreducible. The symptoms are identical to advanced hemorrhoidal disease, [ 13 ]  and include:


The condition, along with complete rectal prolapse and  internal rectal intussusception , is thought to be related to chronic straining during  defecation  and  constipation .


Mucosal prolapse occurs when the results from loosening of the submucosal attachments (between the mucosal layer and the  muscularis propria ) of the  distal   rectum . [ 3 ]  The section of prolapsed rectal mucosa can become ulcerated, leading to bleeding.


Mucosal prolapse can be differentiated from a full thickness external rectal prolapse (a complete rectal prolapse) by the orientation of the folds (furrows) in the prolapsed section. In full thickness rectal prolapse, these folds run circumferential. In mucosal prolapse, these folds are radially. [ 10 ]  The folds in mucosal prolapse are usually associated with internal hemorrhoids. [ 21 ]


EUA  (examination under anesthesia) of anorectum and banding of the mucosa with rubber bands.


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 be considered to be a consequence of internal intussusception (a sub type of rectal prolapse), which can be demonstrated in 94% of cases. It may be  asymptomatic , but it can cause  rectal pain ,  rectal bleeding ,  rectal malodor , incomplete evacuation and  obstructed defecation  (rectal outlet obstruction).


Symptoms include: [ 18 ] [ 21 ] [ 63 ]


The condition is thought to be uncommon. It usually occurs in young adults, but children can be affected too. [ 64 ]


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. [ 65 ]  SRUS is also associated with prolonged and incomplete evacuation of stool. [ 66 ]


More effort is required because of concomitant  anismus , or non-relaxation/paradoxical contraction of  puborectalis  (which should normally relax during defecation). [ 67 ]  The increased pressure forces the anterior rectal lining against the contracted puborectalis and frequently the lining prolapses into the anal canal during straining and then returns to its normal position afterwards.


The repeated trapping of the lining can cause the tissue to become swollen and congested. Ulceration is thought to be caused by resulting poor blood supply ( ischemia ), combined with repeated frictional trauma from the prolapsing lining, and exposure to increased pressure are thought to cause ulceration. Trauma from hard stools may also contribute.


The site of the ulcer is typically on the  anterior  wall of the  rectal ampulla , about 7–10 cm from the anus. However, the area may of ulceration may be closer to the anus, deeper inside, or on the lateral or posterior rectal walls. The name "solitary" can be misleading since there may be more than one ulcer present. Furthermore, there is a "preulcerative phase" where there is no ulcer at all. [ 68 ]


Pathological specimens of sections of rectal wall taken from SRUS patients show thickening and replacement of muscle with fibrous tissue and excess collagen. [ 69 ]  Rarely, SRUS can present as polyps in the rectum. [ 70 ] [ 71 ]


SRUS is therefore associated and with internal, and more rarely, external rectal prolapse. [ 66 ]  Some believe that SRUS represents a spectrum of different diseases with different causes. [ 72 ]


Another condition associated with internal intussusception is  colitis cystica profunda  (also known as CCP, or proctitis cystica profunda), which is  cystica profunda  in the rectum. Cystica profunda is characterized by formation of  mucin   cysts  in the muscle layers of the gut lining, and it can occur anywhere along the gastrointestinal tract. When it occurs in the rectum, some believe to be an interchangeable diagnosis with SRUS since the  histologic  features of the conditions overlap. [ 73 ] [ 74 ]  Indeed, CCP is managed identically to SRUS. [ 75 ]


Electromyography may show  pudendal nerve  motor latency. [ 18 ]


Complications are uncommon, but include massive rectal bleeding, ulceration into the prostate gland or formation of a  stricture . [ 76 ] [ 77 ] [ 78 ]  Very rarely, cancer can arise on the section of prolapsed rectal lining. [ 17 ]


SRUS is commonly misdiagnosed, and the diagnosis is not made for 5–7 years. [ 64 ]  Clinicians may not be familiar with the condition, and treat for Inflammatory bowel disease, or simple constipation. [ 79 ] [ 80 ]


The thickened lining or ulceration can also be mistaken for types of cancer. [ 81 ] [ 82 ] [ 83 ] [ 84 ]


The differential diagnosis of SRUS (and CCP) includes: [ 10 ]


Defecography ,  sigmoidoscopy ,  transrectal  ultrasound , mucosal  biopsy , anorectal  manometry  and  electromyography  have all been used to diagnose and study SRUS. [ 18 ] [ 67 ]  Some recommend biopsy as essential for diagnosis since ulcerations may not always be present, and others state  defecography  as the investigation of choice to diagnose SRUS. [ 63 ] [ 74 ] [ 79 ]


Although SRUS is not a medically serious disease, it can be the cause of significantly reduced  quality of life  for patients. It is difficult to treat, and treatment is aimed at minimizing symptoms.


Stopping straining during bowel movements, by use of  correct posture ,  dietary fiber  intake (possibly included bulk forming  laxatives  such as  psyllium ), stool softeners (e.g.  polyethylene glycol , [ 85 ] [ 86 ]  and  biofeedback  retraining to coordinate pelvic floor during defecation. [ 87 ] [ 88 ]


Surgery may be considered, but only if non surgical treatment has failed and the symptoms are severe enough to warrant the intervention. Improvement with surgery is about 55-60%. [ 89 ]


Ulceration may persist even when symptoms resolve. [ 90 ]


A group of conditions known as  Mucosal prolapse syndrome  (MPS) has now been recognized. It includes SRUS, rectal prolapse, proctitis cystica profunda, and inflammatory polyps. [ 17 ] [ 18 ]  It is classified as a chronic benign inflammatory disorder. The unifying feature is varying degrees of rectal prolapse, whether internal intussusception (occult prolapse) or external prolapse.


Rectal prolapse affects less than 0.5% of the general population. [ 91 ]  It affects women more commonly, with a female to male ratio of 9:1. [ 91 ]


Rosebud pornography and prolapse pornography (or rosebudding or rectal prolapse pornography) is an anal sex practice that occurs in some extreme anal pornography wherein a pornographic actor or actress performs a rectal prolapse wherein the walls of the rectum slip out of the anus. Rectal prolapse is a serious medical condition that requires the attention of a medical professional. However, in rosebud pornography, it is performed deliberately. Michelle Lhooq, writing for VICE, argues that rosebudding is an example of producers making 'extreme' content due to the easy availability of free pornography on the internet. She also argues that rosebudding is a way for pornographic actors and actresses to distinguish themselves. [ 92 ]  Repeated rectal prolapses can cause bowel problems and anal leakage and therefore risk the health of pornographic actors or actresses who participate in them. [ 92 ]  Lhooq also argues that some who participate in this form of pornography are unaware of the consequences. [ 92 ]


Prolapse refers to "the falling down or slipping of a body part from its usual position or relations". It is derived from the Latin  pro-  - "forward" +  labi  - "to slide".  "Prolapse" .  Merriam-Webster.com Dictionary . Merriam-Webster.   Prolapse  can refer to many different medical conditions other than rectal prolapse.


procidentia has a similar meaning to prolapse, referring to "a sinking or prolapse of an organ or part". It is derived from the Latin  procidere  - "to fall forward". [ 93 ]   Procidentia  usually refers to  uterine prolapse , but rectal procidentia can also be a synonym for rectal prolapse.


Intussusception is defined as  invagination  (infolding), especially referring to "the slipping of a length of intestine into an adjacent portion". It is derived from the Latin  intus  - "within" and  susceptio  - "action of undertaking", from  suscipere  - "to take up".  "Intussusception" .  Merriam-Webster.com Dictionary . Merriam-Webster.  Rectal intussusception is not to be confused with other  intussusceptions  involving  colon  or  small intestine , which can sometimes be a medical emergency. Rectal intussusception by contrast is not life-threatening.


Intussusceptum refers to the  proximal  section of rectal wall, which telescopes into the  lumen  of the  distal  section of  rectum  (termed the intussuscipiens). [ 10 ]  What results is 3 layers of rectal wall overlaid. From the lumen outwards, the first layer is the proximal wall of the intussusceptum, the middle is the wall of the intussusceptum folded back on itself, and the outer is the distal rectal wall, the intussuscipiens. [ 10 ]


A  rectal stricture  ( rectal stenosis ) [ 1 ]  is a chronic and abnormal narrowing or constriction of the  lumen  of the  rectum  which presents a partial or complete obstruction to the movement of bowel contents. A rectal stricture is located deeper inside the body compared to an  anal stricture . Sometimes other terms with wider meaning are used, such as  anorectal stricture ,  colorectal stricture  or  rectosigmoid stricture .


Rectal stricture has been defined as the inability to pass a rigid  proctoscope  (12 mm diameter) or a rigid  sigmoidoscope  (19 mm diameter) through the affected cross-section of rectum. [ 1 ]  If the rectal stricture is accessible during digital rectal examination, a rectal stricture may be defined as narrowing to less than one-finger breadth. [ 2 ]


Anal strictures are usually located at the anal verge in a narrow band, but sometimes they involve the entire length of the anal canal. [ 1 ]  Surgeons and anatomists have different definitions of the anal canal. [ 3 ]  Surgically and clinically, the anal canal is usually defined as the zone from the anal verge to the anorectal ring (at the level of the external anal sphincter and the  puborectalis muscle ). The anorectal ring is easy to identify when patients are asked to squeeze during  digital rectal examination . [ 3 ]  Anatomically, the anal canal is defined as the zone from the anal verge to the dentate line ( pectinate line ). [ 3 ]  This is a line formed by the lower ends of the anal columns and represents the embryological junction between the  hindgut  and the  proctodeum . [ 3 ]


Both rectal stricture and  anal stricture  (anal stenosis) are types of colonic stricture. They both can also be more widely categorized as gastrointestinal strictures. However, rectal strictures behave differently to colonic strictures because of the proximity of the rectum to the anal canal and pelvic organs, and because of different blood supply. [ 2 ]


There may be no symptoms (clinically silent stricture), [ 4 ]  or only minor symptoms, but may get worse over time. [ 2 ]  On the other hand, acute  bowel obstruction  may develop as the first major sign of a stricture. This may be the case with malignant strictures, and the condition may be a medical emergency which requires urgent treatment in order to avoid serious complications such as  bowel perforation . [ 5 ]  When symptoms are caused, the term "clinically relevant rectal stricture" is used. [ 1 ]  Possible symptoms include:


The first step is exclusion of malignant causes. This may involve tissue  biopsy ,  endorectal ultrasound ,  computed tomography , and  magnetic resonance imaging . [ 1 ]  The next step is assessment of the stricture. The distance from the anal verge, the diameter of the narrowest point of the stricture, and the longitudinal length are ascertained. The degree of narrowing can be assessed with a water-soluble  contrast enema . [ 1 ]


Rectal strictures are usually classified as benign or malignant (associated with cancer).


Benign rectal strictures can be further subcategorized as primary (caused by diseases) and secondary (caused by complication of surgery). Secondary strictures very often occur at the site of a previous surgical anastomosis. Primary strictures have various causes, including different inflammatory disease processes. Causes of benign strictures include:


Acute bowel obstruction is a common presenting manifestation of colorectal cancer which is locally advanced. [ 5 ]  Malignant strictures may also develop in the context of inflammatory bowel disease. Treatment for malignant strictures is ideally resection (surgical removal) with or without radiotherapy. If resection is not possible or not sensible, symptoms of the stricture may be palliated with radiotherapy, stents, or debulking. [ 1 ]  Possible malignant processes which may cause rectal stricture include:


The narrowing may be because of an intrinsic process occurring within the lumen of the rectum (luminal), within the wall of the rectum (mural), or it can be due to an extrinsic process that is compressing the rectum from the outside (extramural). [ 1 ] [ 8 ]  In the case of external compression of the bowel, the term pseudostricture may be used. [ 9 ]


According to one review of a total of 730 cases, those which formed after anastomosis represented 74% of all reported benign rectal strictures. [ 2 ]  The next most common cause of benign rectal stricture was inflammatory bowel disease, accounting for 20% of all cases. [ 2 ]  This means all other causes of rectal stricture are, by comparison, rare.


Rectal stricture is reported to develop after colorectal resection at a rate of 3-30%. Such strictures mostly form after resection due to rectal cancer with colorectal or coloanal anastomosis. Stricture is also possible as a complication following resection because of diverticular disease. According to some reports, rectal strictures are more likely following stapled anastomosis compared to hand sutured anastomosis. [ 2 ]  However, a Cochrane review found no significant difference in the rate of rectal stricture between hand sewn and stapled  ileocolic anastomosis  (usually performed after right‐sided  colon cancer  and  Crohn's disease ). [ 10 ]


Inflammatory bowel diseases (IBD) include Crohn’s disease, which affects only the colon, and ulcerative colitis, which may affect any section of the gastrointestinal tract. The relapsing-remitting, chronic inflammation in the bowel wall non uncommonly leads to the development of colonic strictures, including rectal strictures. [ 6 ]  Rectal strictures are more common in Crohn's disease than in ulcerative colitis. [ 2 ]  There is a risk of malignancy developing at the site of stricture. Therefore, tissue biopsy of strictures is carried out in order to check for dysplasia or malignancy.


Stricture may occur following trauma such as caustic burns caused by chemical agents. [ 11 ] [ 12 ]  If they cause inflammation, chronic use of  suppositories  may cause rectal stricture, [ 2 ]  but overall this is a safe method of drug delivery. [ 13 ]


Thermal burns are possible if hot water enemas are attempted by patients or practitioners of alternative medicine in the belief that they will provide a stronger stimulus for evacuation of stool. [ 11 ]  The rectal mucosa is vulnerable to thermal burns in such cases because it is sensitive only to distension (stretching) and not to thermal stimuli. [ 11 ]  Usually a burn of the rectal wall heals after 2–3 weeks without permanent stricture. Such burns may be treated with bowel resting, antibiotics, stool softeners, liquid diet and steroid suppository to reduce inflammation. [ 11 ]  Sometimes thermal burns progress to chronic stricture. [ 11 ]


The rectum is very close to the prostate in males and the uterus and cervix in females, and therefore it frequently receives radiation during radiotherapy for cancers in the pelvic region.  Radiation proctitis  (chronic radiation enterocolitis) usually appears after several months of treatment, and is characterized by rectal bleeding or obstructed defecation secondary to the formation of strictures. [ 7 ]  Such rectal strictures are usually located in the proximal rectum, and are one of the most common features of late radiation damage. [ 14 ]  The mechanism of stricture formation is  obliterative endarteritis , lymphatic dilation, and tissue ischemia and necrosis. [ 7 ]  Then there is collagen deposition and fibrosis in the submucosal layer. [ 7 ]  They are often associated with a fistula. [ 14 ]  Post-irradiation strictures may cause symptoms such as diarrhea, tenesmus, narrow feces, abdominal pain, and vomiting. [ 7 ]  The risk of intestinal obstruction due to strictures in patients receiving radiotherapy in the pelvis is reported as 1–15%. [ 7 ]


Sexually transmitted infections  may sometimes cause rectal strictures in persons who engage in anoreceptive sex. [ 2 ]   Lymphogranuloma venereum  usually affects the genital mucosa. However, it may rarely present as the anorectal variant, termed "lymphogranuloma venereum proctitis". Lymph nodes are enlarged and suppurative (produce pus). The condition is similar to Crohn's disease with rectal stricture formation (eventually), bowel perforation and fistulae. [ 15 ]  In one report,  herpes simplex virus 2  was implicated as the cause of a rectal stricture. [ 2 ]  Rarely, rectal stricture may develop in  actinomycosis  infection. [ 2 ]


If a foreign body becomes stuck there is reactive inflammation and fibrosis, which eventually may lead to the formation of a stricture. [ 2 ]  In  endometriosis , if ectopic endometrial tissue is present in the rectal wall it may cause rectal stricture. [ 2 ]   Solitary rectal ulcer syndrome  may also sometimes be associated with rectal stricture. [ 2 ]


Rectal stricture may sometimes be a complication of surgical procedures other than anastomosis. For example, endoscopic submucosal dissection, which is a minimally invasive treatment for colorectal cancer, may rarely cause development of a rectal stricture. [ 2 ]  Other surgical procedures which may cause the development of a stricture include  ventral rectopexy , [ 8 ]   Delorme’s procedure , [ 16 ]  and  hemorrhoidectomy .


How a rectal stricture is treated depends on the exact cause, the distance from the anal verge, the degree of narrowing, the severity of symptoms, and the health of the patient. [ 1 ]  Short strictures are more responsive to dilation. Longer strictures may require more significant surgical procedures. [ 1 ]  Generally, benign rectal strictures may not require treatment if they do not cause symptoms. [ 1 ]  For example, a non symptomatic stricture may be detected as an incidental finding during colonoscopy for an unrelated reason. [ 1 ]  Treatment options fall into 3 main categories: dilatation, stenting, or surgery. [ 11 ]


The treatment depends on the cause. For example, strictures caused by infections may respond well to  antibiotics . [ 2 ]  Use of  stool softeners ,  laxatives  and high fiber diet is a general measure for most strictures, and is also sometimes advised for prevention of recurrence of stricture even after treatment. [ 2 ]  Non surgical treatment may be combined with other procedures such as dilation.  Steroids  may be injected into the stricture. It is unknown exactly how the steroid helps to prevent recurrence of the stricture, but it may involve inhibition of collagen formation and cross-linking, and increase of collagen breakdown. In combination, this reduces contraction of scar tissue. [ 7 ]   TNF inhibitors  such as  infliximab  have also been injected into strictures endoscopically. However, this is not a common treatment. [ 6 ]  Healing of rectal strictures in inflammatory bowel disease with TNF inhibitor occurs in 59% of cases. [ 2 ]   Mitomycin C  has been used as a topical application, in combination with manual dilation. [ 17 ]


For rectal strictures which are mild and close to the anal verge (<6 cm), digital dilation (with fingers) or dilation with instruments is possible. [ 1 ]  Such instruments include Hagar's dilators, esophageal dilators, St Marks anal dilators, and bougie dilators. [ 16 ] [ 1 ] [ 2 ]  Sometimes the patient can be shown how to perform this dilation at home, but this is may be difficult for them, and rarely gives good long term results. [ 16 ]  Dilation with instruments by the surgeon may be performed under sedation or under general aesthesia for moderate strictures. [ 16 ]  This treatment is often the first to be attempted, and is successful about 50% of the time. [ 2 ]  Hegar dilators come in multiple sizes with different diameters. This enables progressive dilation over time which reduces the risk of bowel perforation. [ 1 ]


Balloon dilation is the most common method of mechanical dilation, [ 11 ]  and is also often considered the first line treatment. [ 2 ]  This treatment is simple, but repeat procedures may be needed. [ 11 ]  Balloon dilation may be combined with intralesional steroid injection. [ 7 ]  Injection of steroid seems to increase the effectiveness of balloon dilation, and increases the length of time before relapse. [ 7 ]  The success rate of balloon dilation for benign rectal strictures overall is about 78%. [ 2 ]  In rectal strictures in the context of Crohn's disease, the long-term success rate of balloon dilation is about 80%. However, it may be ineffective for very tight, fibrotic strictures. [ 17 ]  Fluoroscopic guidance can be used during the procedure to improve visualization. [ 2 ]  The risk of bowel perforation is about 1%. [ 2 ]


Surgical procedures are indicated if multiple other treatments have failed, or if the stricture involves a long section of bowel. [ 11 ]  Surgical procedures may be carried out by the transanal approach or via the transabdominal approach. [ 11 ]  Debulking of malignant strictures may be carried out with laser ablation or with argon beam plasma coagulation. [ 1 ]  Various procedures and methods have been used to surgically treat strictures, including:


Self-expandable metallic stents  (SEMS) are sometimes used, but they are usually considered not suitable for very low rectal strictures. [ 14 ]  However, this view is now challenged. [ 18 ]  Stents may be used as the definitive treatment of a stricture, or as a temporary measure to stabilize a patient with acute obstruction before another procedure is carried out. [ 11 ]  Stents are not commonly used for benign rectal strictures. [ 11 ]  Sometimes they are used when strictures are associated with malignancy. In such cases, use of a stent may avoid or delay the need for  colostomy . [ 19 ]


A  rectovestibular fistula , also referred to simply as a  vestibular fistula , is an anorectal  congenital disorder  where an abnormal connection ( fistula ) exists between the  rectum  and the  vulval vestibule  of the female genitalia.


If the fistula occurs within the  hymen , it is known as a  rectovaginal fistula , a much rarer condition. [ 1 ]


If a colostomy is not performed immediately after birth, patients with rectovestibular fistulae may present later in life with complications including severe  constipation  and  megacolon  (abnormal dilation of the colon), requiring colostomy or further surgery. [ 2 ]


A rectovestibular fistula occurs when the  colon  or  rectum  deviates anteriorly. [ 1 ]  This leads to the formation of an abnormal connection between the rectum and the  vulval vestibule , immediately posterior to the  hymen , so that an  ectopic anus  opens into the  fourchette , or frenulum, of the  labia minora . [ 3 ]  A common wall is shared between the rectum and  vagina  above the site of the fistula. [ 2 ]  Although the opening of the rectum into the  anal canal  is shorter and narrower than normal, the rectum itself is completely normal. [ 2 ]


The diagnosis of a rectovestibular fistula can be made in female newborns if the vulva is stained with  meconium  (the earliest form of  stool  in an infant). [ 3 ]  The opening of the  anus  may be difficult to see due to its small size and position, but it may be visible as a thickening of the median  perineal raphe  with an obvious anal dimple. [ 3 ] [ 2 ]  Patients with rectovestibular fistulae are commonly misdiagnosed with rectovaginal fistulae. [ 1 ]


Colostomy  is recommended by most surgeons, and has a good prognosis, with 90% of patients regaining normal bowel control. [ 4 ]  Since the rectal opening and  anal orifice  in a vestibular fistula tend to be short and narrow, a colostomy is usually performed to allow decompression of the bowel unless the orifice is wide enough to allow normal defecation. [ 2 ]  Colostomy is often followed by  posterior sagittal anorectoplasty  (PSARP), a surgical procedure to repair the anal orifice, at a later date. [ 4 ] [ 5 ]  Some surgeons prefer to perform an immediate PSARP without a colostomy first, while others perform neither a colostomy nor a PSARP and instead opt for a simple dilatation of the orifice to allow stool to pass and the bowel to decompress. [ 5 ]  It has been suggested that only experienced surgeons should perform repair without an initial colostomy. [ 1 ]


Rectovestibular fistula is the most common defect of the rectum and anal canal in females. [ 3 ]


Sigmoidocele  (also known as  pouch of Douglas  descent) is a medical condition in which a  herniation  of  peritoneum  containing loops of redundant  sigmoid colon  descends (prolapses) into the  rectouterine pouch  (in females), between the  rectum  and the  vagina . [ 1 ] [ 2 ]  This can obstruct the rectum and cause  obstructed defecation syndrome . [ 3 ]


Sigmoidocele may be internal if it is only detectable on  defecography , or external if it detectable without imaging and associated with a  rectocele  or  rectal prolapse . [ 2 ]  It is a type of posterior compartment prolapse. [ 4 ]


Sigmoidocele may be classified according to size relative to the pubococcygeal line. [ 2 ] [ note 1 ]


The severity of sigmoidocele can be described with reference to the position of the lowest loop of the sigmoid relative to lines drawn on defecography:


Sigmoidocele may not cause any symptoms. [ 5 ]


The phenomenon is caused by a weak section of   fascial supports  of the vagina (the uterosacral cardinal ligament complex and rectal vaginal septum), which allows a section of peritoneum containing the sigmoid colon to prolapse out of normal position and descend between the rectum and the vagina. [ 1 ]


The  mesentery  of the sigmoid colon (the structure which attaches the colon to the abdominal wall) is termed the mesosigmoid. This structure is very flexible, which means that the sigmoid colon is very mobile and may change position. During defecation it may be pushed down, eventually causing sigmoidocele. [ 7 ]


Sigmoidocele may be associated with  descending perineum syndrome . [ 8 ]


It is not possible to differentiate between a  rectocele  and a sigmoidocele on  vaginal examination .   Defecating proctography  will demonstrate a sigmoidocele during straining. [ 1 ]


Surgery is considered if there is a significant hernia combined with symptoms of obstructed defecation. [ 9 ]


Laparoscopic  ventral mesh rectopexy  has been used to correct sigmoidocele. [ 7 ]  This procedure involves inserting a mesh between the rectum and the vagina. The mesh is suspended from the sacral promontory without tension. This acts to support the recto-vaginal septum and elevate a deep pouch of Douglas. [ 7 ]  If there is prolapse of the middle compartment,  sacrocolpopexy  may be carried out to surgically correct all pelvic prolapse problems in the same procedure. [ 9 ]


Other treatment options are  anterior resection , [ 4 ]   sigmoidopexy  with rectocele repair, [ 4 ]  or  sigmoidectomy . [ 1 ]


Sigmoidocele normally occurs in females, and is uncommon. [ 1 ]  Sigmoidocele is detected about 4-5% of the time when defecography is carried out. [ 3 ] [ 1 ]


Solitary rectal ulcer syndrome  ( SRUS  or  SRU ) is a chronic disorder of the rectal  mucosa  (the lining of the rectum). [ 1 ]  Very often but not always it occurs in association with varying degrees of  rectal prolapse . The condition is thought to be caused by different factors, such as long term  constipation , straining during defecation, and  dyssynergic defecation  (anismus). Treatment is by normalization of bowel habits,  biofeedback , and other conservative measures. In more severe cases, various surgical procedures may be indicated. The condition is relatively rare, affecting approximately 1 in 100,000 people per year. It affects mainly adults aged 30–50. Females are affected slightly more often than males. The disorder can be confused clinically with  rectal cancer  or other conditions such as  inflammatory bowel disease , even when a  biopsy  is done. [ 2 ]


The signs and symptoms are variable, and in up to 25% of patients there may be no symptoms. [ 3 ]  The most common signs and symptoms are bleeding, which can vary from minor to severe, rectal prolapse and incomplete evacuation (35%-76% of cases). [ 4 ]  According to one report, constipation is present in about 55% of cases, but diarrhea is present in 20%–40% of cases. [ 1 ]  Reported symptoms are:


The exact cause is unclear and the condition is not fully understood. [ 3 ]  There are thought to be multiple factors which simultaneously cause the condition. [ 3 ]  Long term injury to the rectal mucosa and ischemic trauma are thought to be the main mechanisms. [ 5 ]  In a report of 36 patients with SRUS, the underlying cause was internal prolapse (intussusception) in 20 patients, external rectal prolapse in 14 patients, and dyssynergic defecation (anismus) in 2 patients. [ 7 ]


Self-digitation is when individuals with constipation resort to inserting a finger into the rectum in order to "hook out" fecal pellets or to apply pressure to an obstructing lesion (see:  obstructed defecation ). The rectal mucosa is fragile and vulnerable to trauma when such manoeuvres are performed chronically. It is thought that this self-induced trauma is one possible mechanism of SRUS. [ 1 ]  However, since sometimes the location of SRUS lesion(s) is much further than a finger could reach means that this cannot be the only cause. [ 5 ]  In constipation, the stools may be very hard and this is another possible mechanism of trauma. [ 1 ]


People with constipation or certain anatomical anomalies are more likely to end up using excessive straining during defecation attempts. [ 5 ]  Prolonged straining may cause direct trauma to the rectal mucosa. [ 5 ]  Most patients with SRUS have  dyssynergic defecation  (previously termed anismus). [ 8 ]  This is a failure of relaxation (or paradoxical contraction) of the  puborectalis muscle  during defecation attempts. This pelvic floor muscle is normally supposed to relax, thereby straightening the anorectal angle and allowing rectal contents to be evacuated. Dyssynergic defecation causes high pressure in the rectum and in the anal canal, [ 1 ]  which causes lengthening [ 1 ]  and compression of the rectal tissues, which in turn leads to ischema of the mucosa. [ 8 ]  There is also a shearing movement of the rectum against the pelvic floor muscles. [ 8 ]  In the long term this leads to repeated mucosal damage. [ 8 ]  Inappropriate contraction of puborectalis in the squatting position causes traumatic compression of the rectal wall against the anal canal. [ 5 ]  Also, it is reported that individuals with SRUS have not only increased pressure when squeezing, but also higher resting pressure compared to normal controls. [ 5 ]


SRUS is usually accompanied by prolapse (e.g. external prolapse or rectoanal intussusception/internal prolapse) or other pelvic-floor disorders. [ 1 ] [ 7 ]  This is association is common, but not always present. [ 9 ]  Some state that if SRUS is not treated, it would always tend to progress to rectal prolapse. [ 5 ]  The relationship of SRUS with  rectal prolapse  and rectal cystitis profunda is debated. [ 8 ]  Some see SRUS and prolapse as synonymous, while others see them as separate entities, [ 8 ]  and state that they do not share the same physiology. [ 6 ]  For example, the mucosal changes that occur with external rectal prolapse can be separated from the mucosal changes seen in SRUS. [ 6 ]


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). [ 5 ]  These conditions create chronic vascular trauma (ischemia or hypoperfusion) in the rectal mucosa, [ 1 ]  which predisposes it to ulceration, [ 8 ]  and pressure necrosis. [ 4 ]  Even the initial small areas of an intussusception can lead to vascular injury and reduce blood supply to the region. [ 5 ]  This is the first stage of ulcer development. [ 5 ]


Psychological factors are also thought to be involved, since patients with SRUS sometimes have psychological disorders such as  obsessive-compulsive disorder . [ 1 ]  Also, some unknown factors may also be involved, such as hormonal factors related to pregnancy. [ 5 ]  Other possible factors are rectal hypersensitivity, [ 4 ]  and impaired rectal evacuation of stool. [ 9 ]


Diagnosis is difficult because of rarity of the condition and because of the variability of the symptoms and the histologic appearance. [ 1 ] [ 5 ]  The condition is sometimes misdiagnosed. [ 1 ]  Clinicians may not be familiar with the condition, and treat for  inflammatory bowel disease , or simple constipation. [ 10 ] [ 11 ]  Diagnosis may be delayed by many years as a result. [ 4 ]


The  differential diagnosis  is as follows:


Investigations used in the diagnosis of SRUS include  defecography ,  endoanal ultrasound ,  colonoscopy  and histological examination of a  biopsy . [ 3 ]


The macroscopic appearance of SRUS is very variable. [ 8 ]  Indeed, the condition has been referred to as “the three-lies disease”, [ 4 ]  because the name of the condition is sometimes misleading. In reality, there may be more than one lesion, which may not be  ulcerative , [ 12 ]  and the condition may appear in different parts of the gastrointestinal tract (i.e. other than the  rectum ). [ 3 ]


Classically, there is a solitary ulcer. But only 20% of patients have a single ulcer whereas in other cases there may be multiple lesions. [ 6 ]  The size of the ulcers is usually 0.5–4 cm. [ 5 ]  The lesion is most often located on the anterior (front) or lateral (side) rectal wall, centered on a rectal fold, [ 1 ]  usually 10 cm from the anal verge. [ 8 ]  Less commonly there may be ulcers in the  anal canal  or even in the  sigmoid colon . [ 5 ]  The nature of the tissue changes can vary from simple  erythema  (redness) /  hyperaemia  (increased blood flow) of the mucosa in 18% of cases, [ 1 ]  to a chronic-appearing, small, shallow ulcer with nodular margins and a white or sloughing base. [ 8 ] [ 1 ]  In up to 33% of cases there is no ulceration but instead one or more well-developed polyps or mass lesions. [ 8 ] [ 5 ]  There is usually mild  proctitis  (inflammation of the rectal mucosa) surrounding the ulcer. [ 2 ]


Conventional defecography or magnetic resonance defecography may be used. [ 1 ]  Between 50-100% of patients with SRUS will have abnormal defecography results. [ 5 ]  Defecography findings in SRUS may include:


Endoanal ultrasound  can determine the depth of the ulcer and the structure of the external and internal anal sphincters. [ 8 ]  Endoanal ultrasound findings in SRUS include:


As a diagnostic investigation, anorectal manometry can evaluate defecation function. It can highlight excessive and prolonged straining effort during defecation attempts, and also record any improvement in function before and after treatment interventions. [ 13 ]  It is uncommonly used to diagnose SRUS, although biofeedback is still commonly used as a treatment.


The histological appearance is as follows:


If the biopsy includes polypoid lesions, there are villiform structures visible. [ 5 ]  Gland entrapment in the submucosa is sometimes seen, which is termed  colitis cystica profunda . [ 5 ]


Treatment of SRUS is difficult and there is a lack of evidence-based guidelines. [ 4 ]  The treatment is based on the pathophysiology of SRUS, [ 5 ]  and the main aim is restoration of a normal pattern of defecation. [ 1 ]  The exact treatment depends on the severity of the symptoms, the severity/type of SRUS, and whether rectal prolapse is present or absent. [ 5 ]


Conservative measures are the first line treatment for patients with no symptoms or only mild to moderate symptoms, and those who have no significant anatomical defect. [ 1 ]  Conservative measures by themselves may improve symptoms and prevent the condition getting worse. [ 1 ]  Where conservative measures fail, or with severe disease and symptoms, or with significant anatomical defects, surgical options may be indicated. [ 5 ] [ 1 ]  Improvement in symptoms does not always equate to healing of the ulcer as seen on endoscopy. [ 5 ]


Conservative management is focused on education of the patient and behavioral modification. Where indicated, conservative management may also involve treatment of psychological problems, [ 5 ]  and avoidance of anoreceptive sex (to prevent trauma to the rectum). [ 8 ]


Biofeedback targets pelvic floor behaviors and enables a reprogramming of autonomic neurologic pathways associated with defecation. [ 8 ]  The treatment is particularly helpful for dyssynergic defecation (anismus). Research studies have shown that there is improved blood flow to the rectal mucosa after biofeedback therapy. [ 1 ]  The overall rate of complete resolution of both symptoms and ulceration varies at 50-75%. [ 8 ]  Stool frequency and straining effort decrease after this treatment. [ 1 ]  In about 56% of cases, biofeedback treatment stops rectal bleeding. [ 1 ]  Some patients are able to cease relying on digitation. [ 1 ]  Biofeedback is more effective in children with SRUS compared to adults. [ 1 ]


A randomized controlled study compared topical agents (dexamethasone, sucralfate and bismuth) with biofeedback. Overall, biofeedback gave 80% improvements in evacuation difficulty, need for digitation, sensation of incomplete evacuation, evacuation time, and appearance of mucosa on colonoscopy compared to the topical agents (50% improvement). [ 13 ]  However, the degree of long term improvement is not known. [ 13 ]


Several different topical treatments have been reported, with variable outcomes. [ 1 ]  These are substances applied directly to the ulcer, usually administered by enema. [ 8 ]  They may be helpful for short term management of acute symptoms in SRUS. [ 8 ]  They are thought to work by reducing inflammation and physically forming a barrier over the surface of the ulcer to protect it from irritants, thereby allowing it to heal. [ 4 ] [ 5 ]  However, the long term efficacy is unknown. According to a systematic review, 57% of SRUS patients who received medical treatment had resolution of ulceration. [ 4 ]  Topical agents which have been used for SRUS include:


According to one report, topical agents had an efficacy between 28 and 90%. Sucralfate had a 45-81% resolution rate compared to sulfasalazine (30-64%) and combination of other topical agents (20-79%). [ 13 ]


Surgery may be indicated for severe cases of SRUS (either severe symptoms, severe ulceration, or significant associated anatomical defect such as prolapse), or when conservative measures fail. [ 8 ] [ 5 ]  Some authors state that most patients do not benefit from surgery. [ 5 ]  Overall, up to 33% of SRUS patients end up requiring surgery. [ 8 ]  A systematic review reported that SRUS improved in 77% of patients who underwent any type of surgery. [ 6 ]  However, recurrence of the condition later developed in 52% of cases. [ 6 ]  It has been suggested that any treatment which only addresses the ulcer without correcting the underlying causes will typically lead to recurrence. [ 8 ]


There are multiple different surgical procedures which have been reported for SRUS, [ 5 ]  including:


Various local treatments for SRUS have been reported. According to one report, such measures have generally unfavorable results, and sometimes the ulcer returns deeper and larger than before the treatment. [ 8 ]


Excision (removal) of the ulcer and suturing the resulting defect with surrounding healthy mucosa has been reported. However, there may not be any long-term benefit. [ 8 ]  Ulcers in the upper part of the rectum may be accessible to local excision using a transanal minimally invasive approach (TAMIS). [ 8 ]  Excision with  neodymium yttrium-aluminium garnet laser  has also been reported. [ 6 ]


Rectopexy is a surgery for rectal prolapse. [ 3 ]  A newer version of the procedure is termed ventral mesh rectopexy, which has also been used for SRUS. [ 14 ]  It may be performed with or without anterior resection (removal of a portion of the front wall of the rectum). [ 9 ]  A mesh may be used to reinforce the anterior rectal wall. [ 8 ]  It can be done as an open procedure or with a laparoscopic abdominal approach. [ 8 ]


Some authors state rectopexy is suitable in highly select cases, [ 9 ]  while others say it is the procedure of choice, [ 7 ]  since it directly addresses the most likely cause. [ 8 ]  There is not much evidence for the use of laparoscopic ventral rectopexy to treat SRUS, [ 13 ]  but there is more evidence to support the its use compared to other surgical procedures. [ 8 ]  Approximately 55-83% of patients with SRUS get reduced symptoms after rectopexy, [ 8 ]  and these benefits appear to be long term. [ 3 ]  In one study, 11 people with SRUS underwent laparoscopic ventral rectopexy. All of the patients showed resolved symptoms and mucosal injury one year after the procedure. In the long term, 1 patient developed recurrence after 4 years, and the other 7 who were evaluated in the long term did not develop recurrence. [ 13 ]  Another study combined laparoscopic ventral rectopexy and biofeedback for 48 patients with SRUS. In all cases there was healing of the mucosa 3 months after the procedure. In 65% of cases there was improvement in symptoms of obstructed defecation and in 45% of cases there was improved quality of life. The rate of recurrence was 4-8% after an average follow up time of 33 months. [ 15 ]


The stapled transanal rectal resection (STARR) procedure has been used both as an alternative to ventral mesh rectopexy and as a secondary procedure when ventral mesh rectopexy failed to completely resolve the condition. [ 16 ]  In one study, STARR gave improvement in all cases where biofeedback had not worked. [ 13 ]  In comparison with ventral mesh rectopexy, STARR may result in higher rates of bowel  urgency , recurrence and other complications, some of which may be serious. [ 13 ]


The following "last resort" surgical procedures (which may have significant consequences) have been reported in severe, persistent or recurrent cases of SRUS:


The condition is relatively rare, but the exact prevalence is not known. [ 3 ]  Prevalence has been estimated as 1 in 100,000 people per year. [ 3 ]  SRUS can occur at any age, but it is most common in adults aged between 30-50. [ 3 ]  Males and females are affected almost equally, [ 3 ]  or females slightly more. [ 1 ]


Misdiagnosis  as  inflammatory bowel disease  (IBD) or  rectal polyps  may hide the true prevalence of SRUS. [ 3 ]


Stapled hemorrhoidopexy  is a  surgical  procedure that involves the cutting and removal of anal hemorrhoidal vascular cushion, whose function is to help to seal stools and create continence. Procedure also removes abnormally enlarged  hemorrhoidal tissue , followed by the repositioning of the remaining hemorrhoidal tissue back to its normal anatomic position. Severe cases of hemorrhoidal prolapse will normally require surgery. Newer surgical procedures include  stapled transanal rectal resection  (STARR) and procedure for prolapse and hemorrhoids (PPH).  Both STARR and PPH are  contraindicated  in persons with either  enterocele  or  anismus . [ 1 ]