Rectal prolapse
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. 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.
Rectal prolapse may occur without any symptoms, but depending upon the nature of the prolapse there may be mucous discharge, rectal bleeding, degrees of fecal incontinence, and obstructed defecation symptoms.
Rectal prolapse is generally diagnosed more commonly in elderly women, although it may occur at any age and any sex. It is very rarely life-threatening, but the symptoms can be debilitating if left untreated. 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.
Classification
The different kinds of rectal prolapse can be difficult to grasp, as different definitions are used and some recognize certain subtypes and not others do not. Essentially, rectal prolapses may be:- full thickness, where all the layers of the rectal wall prolapse, or involve the mucosal layer only
- external if they protrude from the anus and are visible externally, or internal if they do not
- circumferential, where the whole circumference of the rectal wall prolapses, or segmental if only parts of the circumference of the rectal wall prolapse
- present at rest, or occurring during straining.
a full thickness, circumferential, true intussusception of the rectal wall which protrudes from the anus and is visible externally.
Internal rectal intussusception can be defined as a funnel shaped infolding of the upper rectal wall that can occur during defecation. This infolding is perhaps best visualised as folding a sock inside out, creating "a tube within a tube". Another definition is "where the rectum collapses but does not exit the anus". 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. This may signify that authors use the terms internal rectal prolapse and internal mucosal prolapse to describe the same phenomena.
Mucosal prolapse 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 hemorrhoids. However, both internal mucosal prolapse and circumferential mucosal prolapse are described by some. Others do not consider mucosal prolapse a true form of rectal prolapse.
Internal mucosal prolapse 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. The term "mucosal hemorrhoidal prolapse" is also used.
Solitary rectal ulcer syndrome occurs with internal rectal intussusception and is part of the spectrum of rectal prolapse conditions. 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 is recognized by some. It includes solitary rectal ulcer syndrome, rectal prolapse, proctitis cystica profunda, and inflammatory polyps. 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:
- Grade I: nonrelaxation of the sphincter mechanism
- Grade II: mild intussusception
- Grade III: moderate intussusception
- Grade IV: severe intussusception
- Grade V: rectal prolapse
- first degree prolapse is detectable below the anorectal ring on straining
- second degree when it reached the dentate line
- third degree when it reached the anal verge
Recto-rectal intussusception is where the intussusception starts in the rectum, does not protrude into the anal canal, but stays within the rectum.. These are usually intussusceptions that originate in the upper rectum or lower sigmoid.
Recto-anal intussusception is where the intussusception starts in the rectum and protrudes into the anal canal
An Anatomico-Functional Classification of internal rectal intussusception has been described, 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:
- Type 1: Internal recto-rectal intussusception
- * Type 1W Wide lumen
- * Type 1N Narrowed lumen
- Type 2: Internal recto-anal intussusception
- * Type 2W Wide Lumen
- * Type 2N Narrowed lumen
- * Type 2M Narrowed internal lumen with associated rectal hyposensitivity or early megarectum
- Type 3: Internal-external recto-anal intussusception
Diagnosis
Medical history
Patients may have associated gynecological conditions which may require multidisciplinary management. History of constipation is important because some of the operations may worsen constipation. Fecal incontinence may also influence the choice of management.Physical examination
Rectal prolapse may be confused easily with prolapsing hemorrhoids. Mucosal prolapse also differs from prolapsing hemorrhoids, where there is a segmental prolapse of the hemorrhoidal tissues at the 3, 7 and 11 o'clock positions. Mucosal prolapse can be differentiated from a full thickness external rectal prolapse by the orientation of the folds in the prolapsed section. In full thickness rectal prolapse, these folds run circumferential. In mucosal prolapse, these folds are radially. 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. 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.The prolapse may be obvious, or it may require straining and squatting to produce it. The anus is usually patulous, and has reduced resting and squeeze pressures. Sometimes it is necessary to observe the patient while they strain on a toilet to see the prolapse happen. A phosphate enema may need to be used to induce straining.
The perianal skin may be macerated and show excoriation.