Managing faecal incontinence

Faecal incontinence is a major problem. A recent systematic review of the literature shows a prevalence of 11-15% in the community.¹ These figures have to be interpreted with caution because the relevant studies are hampered by possible under-reporting and, more importantly, by a lack of a consensus definition. Incontinence of flatus, liquid stool, or solid stool that has an impact on quality of life is a practical definition,² and here we summarise the management of this heterogeneous condition mostly from a primary care perspective but including possible surgical interventions.

Faecal incontinence has many causes and varies in severity from minor faecal soiling to frank incontinence of solid stool. When a patient presents with this symptom we need to establish the degree of debility and obtain an obstetric history.³ Inspection of the anal canal and digital rectal examination is essential. Anal skin tags associated with haemorrhoids can hinder adequate toilet, and poor anal tone implies a defect in the anal sphincter. Diminished sensation and lack of anal contraction or “winking” indicate an underlying neurological condition.

Disruption of the anal sphincter results most commonly from vaginal delivery, occurs in 30% of parous women, and is associated with symptomatic incontinence in about 80% of cases.⁴ Injury to the pudendal nerve often accompanies injury to the anal sphincter owing to obstetric causes and contributes to incontinence, as does pre-existing irritable bowel syndrome.⁵,⁶ Other causes of acquired faecal incontinence include anal trauma, anal surgery, a wide range of neurological and psychiatric disorders, and rectal prolapse.

Although damage to the anal sphincter must always be considered, most patients do not have a serious physical disorder requiring intensive investigation and surgery. Those with minor soiling or difficulty in cleansing can be helped greatly by simple reassurance and advice on washing with a sponge after defecation. Some will also benefit from insertion of a glycerine suppository immediately after defecation and retention for about 20 minutes, as this will facilitate further rectal emptying and ameliorate subsequent soiling. We also need to recognise that causes of loose stool—such as inflammatory bowel disease, malabsorption, overuse of laxatives, and overflow from faecal impaction—may present as incontinence with a normally functioning anal sphincter.² Even people with poor functioning of the sphincter can obtain much symptomatic benefit from measures to firm up the stool. If an underlying cause for diarrhoea is not found dietary advice can be very helpful, bearing in mind that a diet rich in fibre may exacerbate incontinence. Occasionally, antidiarrhoeals such as codeine phosphate or loperamide may be required.

In a few patients these measures will be insufficient, and referral for testing of anorectal physiology and endo-anal ultrasonography becomes necessary. These investigations provide objective measures of sphincter pressures, anorectal sensation, rectal capacity,⁷ and sphincter defects.⁸ A continence adviser can then help most patients by providing support and advice on diet, lifestyle, and pelvic floor exercise. Thereafter pelvic floor physiotherapy and biofeedback—in which patients are taught effective muscle contraction in response to information from a manometric or electromyographic rectal probes—are the mainstays of therapy.⁹

In unresponsive patients with a noteworthy sphincter defect, surgical repair will produce a good outcome in 60-90% of patients, but unfortunately the results deteriorate with time.¹⁰ When surgical repair fails or is inappropriate and where biofeedback is ineffective three options remain for severely symptomatic patients—anal encirclement, sacral nerve stimulation, and diversion.

Encirclement is achieved by means of muscle, and the dynamic graciloplasty, which involves a gracilis muscle wrap augmented by electrical stimulation, is perhaps the most successful. Another approach is the artificial sphincter, which consists of a fluid filled cuff implanted around the anal canal. However, these are specialised techniques which, although they can restore continence, often result in difficulty in passing stools and in morbidity.²

Sacral nerve stimulation (or neuromodulation) is a relatively new technique for treating faecal incontinence and is used in patients with an intact or repaired sphincter complex.¹¹ It involves placing a percutaneous electrode in a sacral foramen (usually S3), and if a two week test period is successful a permanent pulse generator can be implanted. Recent studies suggest that notable improvement can be achieved with little morbidity, and this procedure looks set to have a major impact.¹² Despite these new treatments, the role of faecal diversion should not be ignored. If all else fails quality of life with a stoma can be excellent for the unfortunate patient with refractory incontinence.

Although faecal incontinence is responsible for a great deal of misery and social isolation it lacks a high profile and vocal advocates. It is amenable to treatment that often can be delivered in primary care. Moreover, those unresponsive to simple measures should be given the opportunity for assessment by specialists and appropriate treatment.