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Faecal incontinence is the involuntary loss of anal sphincter control that leads to unwanted release of liquid or solid faeces (not flatus), at an inappropriate time or in an inappropriate place.188 Prevalence increases with age; 17% in men and women aged over 60 years,189 and 54% of aged care home residents.190
Causes of faecal incontinence in older people are:191
- faecal impaction - this may result from chronic constipation associated with immobility or decreased fluid and fibre intake192
- neurogenic incontinence - higher central nervous system damage from stroke or advanced dementia, autonomic neuropathy
- anal sphincter or pelvic muscle weakness - from obstetric trauma or surgery
- intestinal hurry - diarrhoeal illness, dietary excess, alcohol abuse, medications (eg. antibiotics, laxatives)
- rectal or colon disease - carcinoma, villous papilloma, rectal prolapse.
Faecal impaction is the most common cause. The faecal mass causes reflex anal sphincter relaxation and irritation of the rectal mucosa leading to mucous and fluid production, with overflow of liquid stools. Neurogenic faecal incontinence, the second most common cause, is due to the failure to inhibit the defaecation reflex (eg. from strokes and advanced dementia).193 Often faecal incontinence co-exists with urinary stress incontinence.
Ask about frequency and type of incontinence (solid, liquid or gas), other symptoms (constipation, pain or straining), and impact on lifestyle and hygiene. Review medical conditions, diet (fruit, fibre) and medication use (including use of laxatives and enemas). Consider cognitive status, mobility, access to toilet and carer assistance.
Perform a rectal examination to exclude faecal impaction, prostate enlargement or rectal mass, and to assess anal sphincter tone (resting and squeeze pressure), rectal prolapse and pelvic muscle tone. If the rectum is empty, a plain abdominal X-ray is helpful to exclude colonic loading. Stool consistency can help distinguish between faecal impaction (liquid stool) and neurogenic incontinence (formed stool). Loose anal sphincter tone can occur with severe constipation, anal sphincter damage and spinal cord lesion (with reduced perineal sensation).
Treatment depends on the underlying cause. Multiple interventions may be required. Faecal incontinence in residents is most commonly due to colonic loading and overflow. Simulate the usual bowel pattern. Use daily enemas until no more results (glycerine suppository, bisacodyl suppository, or microenema [eg. docusate 5 mL]). Add a daily osmotic laxative (MgSO or MgOH) and bowel training. Stool transit can be stimulated with abdominal massage in the direction of colonic transit.194 Impaction may require manual evacuation in some residents, after a premedication for pain. To prevent constipation, ensure adequate dietary fibre and fluid intake, easy access to toilet, and regular exercise within the resident's ability.
Neurogenic faecal incontinence is treated with a regular toileting program or regular enemas alternating with constipating medications.
- Respond promptly on urge to defaecate
- Use coffee to stimulate the gut
- Position of toilet to facilitate rectal evacuation: back support, foot stool to achieve squat position
- Exercise to improve bowel function
- Rectal sphincter exercises (tighten rectal sphincter for 10 seconds 50 times/day using digital rectal examination or biofeedback).
Residents with anal sphincter weakness can benefit from:196,197,198
- altering stool consistency (eg. decreasing dietary fibre)
- careful use of constipating medications (eg. loperamide to reduce diarrhoea and increase external anal sphincter tone)
- teaching to resist urgency
- sphincter training - referral to continence adviser or physiotherapist for biofeedback and sphincter exercises
- pelvic floor exercises
- referral for surgical sphincter repair.