Rectal Intussusception / Internal or Occult Rectal Prolapse

What is it?
Rectal intussusception is known by a number of other terms including internal or occult rectal prolapse. It refers to when the rectum telescopes down either within the rectum (low grade internal prolapse) or down into the anal canal (high grade internal prolapse) [marked in red in the diagram]. When the rectum protrudes through the anal canal, this is described as an overt or external rectal prolapse and is different from intussusception.

What causes intussusception?
Rectal intussusception is more common in women (90% of patients) because of damage to the pelvic floor from childbirth. In some subgroups (men and women not having given birth) there may be an underlying tendency to pelvic floor weakness. Rectal intussusception frequently co-exists with other pelvic floor abnormalities including rectocoele and enterocoele.

What symptoms does intussusception cause?
The common symptoms are of obstructed defaecation syndrome (ODS). Most strikingly, they often get the sensation of a blockage which is made worse by straining. Some patients get pelvic pain. Others may also suffer with a degree of incontinence.

How is it diagnosed?
We often suspect the diagnosis on the basis of symptoms and examination in clinic. You will need tests and a proctogram is the one that usually confirms the diagnosis.

How is intussusception treated?
About one third of patients will get significant or complete resolution of their symptoms with simple measures like dietary changes or biofeedback. In other patients, we may suggest laparoscopic ventral rectopexy, which lifts the rectum out of the pelvis and restores it to its normal position. Intussusception rarely occurs in isolation but often in association with a rectocoele and/or enterocoele.