What is an internal prolapse?

An internal rectal prolapse describes the condition where the lowest part of the bowel (rectum) telescopes on itself. This generally happens when an individual is straining to pass stool.  

What causes an internal prolapse?

Internal prolapse probably occurs because of weakness in the tissues supporting the rectum. This may be the result of damage sustained during childbirth, but it may also develop in patients who have to strain excessively to open their bowels. In many cases a n exact cause is not easy to find. 

Internal prolapse in women may be associated with other pelvic floor weaknesses which include rectoceles and enteroceles. 

What symptoms does internal rectal prolapse cause?

In some cases the internal prolapse does not cause any symptoms at all. Unlike an external rectal prolapse where part of the bowel actually comes out there is nothing external to see or feel. The common symptoms are those of the obstructed defaecation  syndrome. 

These include: 

• desire to strain excessively  
• feeling of incomplete evacuation 
• fruitless visits to the lavatory. 
• pressure sensation within the back passage. 

How is internal rectal prolapse investigated?

It is important to make sure that it is the internal rectal prolapse that is causing the bowel problem. Most women will require some form of endoscopic examination of the bowel either by flexible sigmoidoscopy or colonoscopy to ensure that it is otherwise healthy. 

It can be difficult to make the diagnosis in clinic. Sometimes the surgeon is able to see the internal prolapse during a rigid sigmoidoscopy examination. 

The most useful test to determine the cause of obstructed defaecation is a MRI proctogram or a  videoproctogram. One of these tests should confirm the diagnosis and they are also useful to detect other areas of prolapse such as a rectocele or an enterocele which may require treatment at the same time. 

Most patients will also have tests of their sphincter muscle function (anorectal physiology) and an endoanal ultrasound scan to look for any damage to the muscle. 

How is internal prolapse (intussusception) treated?

If symptoms are minimal then no surgical treatment may be necessary. Keeping the stools soft and avoiding straining should help to prevent the prolapse getting larger. Pelvic floor physiotherapy and biofeedback can also be helpful. Sometimes glycerine suppositories will help emptying. Enemas and rectal irrigation can be beneficial if simpler measures are not working.  

For patients who have a internal prolapse (intussusception) that is causing severe problems with bowel emptying an operation may be recommended. Usually, a rectopexy is performed and if other types of pelvic floor weakness are identified, such as an rectocele or an enterocele, these can be corrected during the same procedure.