Rectal Prolapse

Rectal prolapse is the downward displacement of the rectum — the last part of the large bowel — from its normal position, and in some patients its coming out through the anus. People describe it as “the bowel dropping” or “the bowel coming out of the back passage”.

It can be confused with haemorrhoids, but rectal prolapse and haemorrhoids are not the same condition.

How does rectal prolapse happen?

Weakening over time of the structures that support the rectum and the pelvic floor can allow the rectum to move downwards.

Long-standing constipation and excessive straining, pelvic floor weakness, older age, previous childbirth and certain neurological or anatomical disorders can all contribute to its development.

Even so, a single cause may not be identified in every patient.

What types of rectal prolapse are there?

Rectal prolapse can appear in different forms.

Full-thickness rectal prolapse

All the layers of the rectal wall come out through the anus. This is what patients usually describe as “the bowel comes out when I am on the toilet”.

Mucosal prolapse

Only the mucosa lining the inside of the rectum slides outwards.

Internal rectal prolapse (intussusception)

The rectum folds into itself but may not come out through the anus. It can be related to difficulty opening the bowels and a sense of not emptying completely.

What are the symptoms?

The most typical symptom is noticing a reddish tissue or mass coming out through the anus, particularly while opening the bowels.

At the start it may appear only during defaecation and go back by itself. Later on the patient may have to push it back by hand, or the prolapse may stay outside all the time.

Besides that:

• A sense of not emptying completely
• Difficulty opening the bowels
• Excessive straining
• Constipation
• Mucus discharge
• Bleeding from the back passage
• Wetness and irritation around the anus
• Leakage of wind or stool

can occur.

Why can it lead to leakage of stool?

The rectum coming out repeatedly can impair the function of the anal sphincters. In addition, some patients with a prolapse have pelvic floor and anal sphincter dysfunction from the outset.

Faecal incontinence is therefore one of the important problems that can accompany rectal prolapse.

What is the difference between rectal prolapse and haemorrhoids?

Patients confuse the two easily.

In haemorrhoids the vascular cushions of the anal canal enlarge or slide outwards.

In a full rectal prolapse the whole wall of the rectum comes out.

On examination the appearance of the prolapse and the pattern of the mucosal folds help make this distinction.

How is the diagnosis made?

In an obvious full-thickness rectal prolapse the diagnosis can usually be made from the history and examination.

If the prolapse only occurs while the bowels are being opened it may not be seen during the examination. A photograph the patient takes while the prolapse is out can sometimes help with the diagnosis.

Further investigations may be needed according to the patient’s complaints.

Is a colonoscopy needed?

A colonoscopy is not always needed to demonstrate the prolapse itself. But taking into account the patient’s age, bleeding, changes in bowel habit and other findings, colonoscopy can be carried out to look for accompanying disease in the colon.

What is defaecography?

Defaecography is an examination that images the movements of the rectum and the pelvic floor during defaecation.

It can be useful particularly in assessing internal prolapse that cannot be seen from the outside, rectocele and other disorders of defaecation. MR defaecography can also be used in selected patients.

Can anorectal manometry be done?

Yes. Anorectal manometry can be used to assess anal sphincter pressures and anorectal function, particularly in patients with leakage of stool or a disorder of defaecation.

It is not, however, obligatory in every patient with rectal prolapse.

Does rectal prolapse get better on its own?

Permanent spontaneous resolution of an established, true full-thickness rectal prolapse in adults is generally not expected.

Treating the constipation and reducing straining can ease the complaints and slow the deterioration; but they may not remove an anatomical prolapse that has already formed.

How is it treated?

Treatment is determined by the type and degree of the prolapse, the patient’s age and general state of health, and whether there is constipation or leakage of stool.

Correcting constipation, keeping the stool at a suitable consistency, avoiding excessive straining and, in selected patients, pelvic floor treatments all matter.

But in adults the definitive treatment of full-thickness rectal prolapse is mostly surgical.

How is the operation done?

Surgical methods fall broadly into two groups:

• Abdominal operations: the rectum is returned to its normal position and fixed there. The procedure is called rectopexy. Laparoscopic or robotic methods can be used in suitable patients.
• Perineal operations: the procedure is carried out through the anus and the perineum. It can be preferred particularly in some older patients, or where an abdominal operation is not suitable.

Which method is appropriate is decided for the individual patient.

Does it come back after the operation?

Yes, rectal prolapse can recur after surgery. The risk of recurrence varies with the method used and with the patient’s own characteristics.

How the operation will affect not only the prolapse but also the patient’s constipation and leakage of stool also matters in choosing the method.

Is rectal prolapse cancer?

No. Rectal prolapse is not cancer and is not regarded as a precancerous condition.

But where there are symptoms such as bleeding from the back passage, a new change in bowel habit, anaemia or weight loss, these should not be attributed to the prolapse alone.

What should be done if the bowel that has come out will not go back?

A rectum that has come out and will not go back, that becomes progressively swollen, very painful, or darker in colour, may need emergency assessment. Interruption of the blood supply is a rare but serious complication.

In brief

Rectal prolapse = the rectum sliding downwards and sometimes coming out through the anus.

What patients most often notice is:

Opening the bowels → tissue coming out of the back passage → at first going back by itself, later needing to be pushed back by hand

In adults the lasting treatment of full-thickness rectal prolapse is mostly surgical. In planning treatment, constipation, difficulty opening the bowels and faecal incontinence should be assessed alongside the prolapse itself.

Note: not every tissue that comes out of the back passage is a haemorrhoid. Because rectal prolapse, mucosal prolapse and haemorrhoids are treated differently, examination matters for a correct diagnosis.