Rectal prolapse - Disorders of the rectum and anus

Rectal prolapse

Definition

Prolapse of the rectum through the anal canal. Rectal prolapses may be incompletely through the anus (Type I), complete prolapse by intussusception of the rectum (Type II) or complete prolapse due to a sliding hernia of the pouch of Douglas (Type III).

Incidence

Type I is more common in children, type II and III in adults, 85% female.

Aetiology

Partial prolapse is more likely when there is a shallow sacral curve such that the rectum is directly above the anus. Complete prolapse results from poor pelvic floor muscle tone, which may follow gynaecological surgery. 10% of children with cystic fibrosis present with rectal prolapse.

Pathophysiology

Initially prolapse only occurs on defecation with spontaneous return; however, with time the prolapse becomes more permanent.

Clinical features

There is often discomfort on passing stool possibly with bleeding and mucus due to inflammation of the pro lapsed segment. Weakness in the surrounding musculature may cause irregular bowel motions, faecal incontinence may occur. The prolapse may only be demonstrated on straining.

Management

·        Children are often managed conservatively, it is rare for the prolapse to persist beyond the age of 5. Constipation should be avoided by dietary intervention.

·        Partial prolapsing mucosa is excised by dissection and ligation. If the sphincter control is poor, surgery will not affect bowel habit which may improve with sphincter exercises.

·        Complete prolapse requires a pelvic repair procedure including mobilisation of the rectum, fixation to the sacrum and suture of the levator ani muscles to the front of the rectum. If incontinence persists suturing of the sphincters may help. Colostomy may be considered in frail elderly patients.