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 (mucus coming from the anus), 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.

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:

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

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. 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 (partial rectal 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 (3rd or 4th degree) hemorrhoids (piles). However, both internal mucosal prolapse (see below) and circumferential mucosal prolapse are described by some. Others do not consider mucosal prolapse a true form of rectal prolapse.

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. The term "mucosal hemorrhoidal prolapse" is also used.