A rectal prolapse is where a mucosal or full-thickness layer of rectal tissue protrudes out of the anus. It is a relatively uncommon condition, which mainly affects women greater than 30 years of age.
There are two main types of rectal prolapse:
- Partial thickness – the rectal mucosa protrudes out of the anus.
- Full thickness – the rectal wall protrudes out the anus.
In this article, we shall look at the pathophysiology, clinical features and management of rectal prolapse.
The current theories surrounding full prolapse suggest that is a form of sliding hernia, through a defect of the fascia of the pelvic region. This may be caused by chronic straining secondary to constipation (or a chronic cough in patients with COPD), or from multiple vaginal deliveries.
In contrast, partial thickness prolapses are associated with the loosening and stretching of the connective tissue that attaches the rectal mucosa to the remainder of the rectal wall. This often occurs in conjunction with long standing haemorrhoidal disease.
Patients with a rectal prolapse will typically present with rectal mucus discharge, faecal soiling, bright red blood on wiping, or even with visible ulceration.
Full thickness prolapses begin internally and thus can present with a sensation of rectal fullness, incomplete defecation or repeated defecation. With time, the rectum begins to prolapse with defecation, then later with minimal coughing and straining, eventually becoming completely external. These prolapses are particularly prone to ulceration.
On examination, the prolapse may not always be evident, but can be identified by asking the patient to strain. A digital rectal examination is also required, and a weakened anal sphincter is often identified. For a suspected internal prolapse may be identified by defecating proctography and examination under anaesthesia
Conservative management of rectal prolapse is particularly useful in those unfit for surgery, with minimal symptoms, or in children (as most prolapses will resolve spontaneously)
Initial management includes improved dietary fibre and fluid intake, reducing constipation and the time spent straining. Minor mucosal prolapses may be banded in clinic, although this is prone to recurrence.
Surgical repair is the only definitive management of rectal prolapse; the choice between an abdominal procedure and a perineal procedure is mainly dictated by the patient’s age and co-morbidities:
- Perineal approach
- Delormes operation involves part of the prolapsed lining of the rectal mucosa being removed and the muscle of the rectum reinforced with placating stitches
- Altmeirs operation* involves the perineal excision of the sigmoid colon and rectum
- Abdominal approach
- A rectopexy involves the rectum being mobilised and fixed onto the sacral prominence
*Whilst the Altmeirs operation does carry the risks associated with a resection, it is often a more effective procedure than a Delormes operation