Faecal incontinence

Chapter 19 FAECAL INCONTINENCE




KEY POINTS



• Faecal incontinence is the involuntary passage of stool through the anus.

• A detailed history and clinical examination is important. A special note on vaginal delivery and any complications should be noted.

• On rectal examination, it is important to ask the patient to strain to assess resting tone and squeeze tone.

• A flexible sigmoidoscopy or colonoscopy is mandatory.

• Medical treatment includes dietary changes, perineal exercises and, if needed, high doses of antidiarrhoeal drugs.

• There have been good results with biofeedback training.


DEFINITION


Faecal incontinence is the involuntary passage of stool through the anus.



PREVALENCE


The reported prevalence rates of faecal incontinence in the world vary from 0.7%–11%, depending on the definition and population group studied. This is demonstrated in Table 19.1.


TABLE 19.1 International prevalence rates of faecal incontinence
















































Country Population Prevalence
Holland Women >60 y 4.2% to 16.9% with rising age
France All >45 y 11%, 6% to faeces, 60% women
UK Community service 1.9%
USA Market mailing 7% soiling, 0.7% to faeces
USA Wisconsin households 2.2%, 63% women
USA Wisconsin nursing homes 47%
New Zealand >65 y 3.1%
Australia Household survey 6.8% men
10.9% women >15 y
Australia Postal survey Liquid incontinence 9%
Random selection from electoral roll (subjects ≥18 y) Solid incontinence 2%

Based on Continence Foundation of Australia. Incontinence: some key statistics and quotes clarified. Online.


Available: www.contfound.org.au/pdf/Keystatsquotsmay03.pdf.


Incontinence is such an embarrassing condition that few people speak of it. As a result, its true prevalence is believed to be higher than that reported.



AETIOLOGY


Table 19.2 lists the possible causes of faecal incontinence. Looser stool consistency is an important precipitating factor in those predisposed to faecal incontenance by anorectal abnormalities.


TABLE 19.2 Classification of the aetiology of faecal incontinence











Altered stool consistency—diarrhoeal states
• Irritable bowel syndrome

• Inflammatory bowel disease

• Infectious diarrhoea

• Laxative abuse

• Malabsorption syndrome

• Short-gut syndrome

• Radiation enteritis
Inadequate reservoir capacity or compliance
• Inflammatory bowel disease

• Absent rectal reservoir
– Sphincter-saving operations
• Low anterior resection

• Coloanal anastomosis

• Ileorectal anastomosis

• Ileoanal reservoir

• Rectal ischaemia

• Collagen vascular disease
– Scleroderma

– Dermatomyositis

– Amyloidosis

• Rectal neoplasms

• Extrinsic rectal compression
Inadequate rectal sensation
• Neurologic conditions
– Dementia

– Cerebrovascular accidents

– Tabes dorsalis

– Multiple sclerosis

– Injuries
• Brain

• Spinal cord

• Cauda equina

– Neoplasms
• Brain

• Spinal cord

• Cauda equina

– Sensory neuropathy

• Overflow incontinence
– Faecal impaction

– Encopresis

– Psychotropic drugs

– Antimotility drugs
Abnormal sphincter mechanism or pelvic floor
• Anatomic sphincter defect
– Traumatic

– Obstetric injury
• Third-degree or fourth-degree lacerations

• Episiotomy wound complications

• Forceps injury

– Anorectal surgery
• Anal fistula surgery

• Haemorrhoidectomy

• Sphincterotomy

• Dilatation or stretching injury

– Neoplastic

– Inflammatory

• Pelvic floor denervation
– Primary (‘idiopathic’ neurogenic incontinence)
• Pudendal neuropathy

• Chronic straining at stool

• Descending perineal syndrome

• Vaginal deliveries

– Secondary
• Injuries to spinal cord/cauda equina/pelvic floor nerves

• Diabetic neuropathy

• Congenital abnormalities
– Spina bifida

– Myelomeningocele

– Imperforate anus

• Miscellaneous
– Ageing

– Rectal prolapse


Obstetric injuries


During vaginal delivery, perineal tears are common and complications of vaginal delivery are among the most common causes of incontinence seen by the surgeon. In fact one-third of vaginal deliveries lead to some form of sphincter injury. However, the majority of patients present with incontinence at a later stage when the muscles are unable to compensate.


The risk factors of vaginal delivery include primigravidas, babies with high birth weight and instrumental delivery, e.g. forceps delivery. The tear is not prevented by episiotomy. It is reported that 70% of women who experience a third or fourth-degree tear will report incontinence to flatus.


Another indirect mechanism of incontinence attributed to childbirth is stretch injury to the pudendal nerve during labour. This injury may then lead to denervation of the external sphincter, the internal sphincter and puborectalis muscle. The denervation injury may develop decades after the injury.



Ageing


A common form of anal incontinence is that associated with old age and general debilitation. It is usually a neurogenic incontinence.

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Mar 29, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Faecal incontinence

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