Fecal Incontinence

Fecal incontinence (also called anal incontinence) is the involuntary loss of stool, and often gas — classically defined as the continuous or recurrent uncontrolled passage of fecal material for at least 1 month in a person of at least 4 years' developmental age.^[1][2] It is a symptom with several genuinely distinct underlying mechanisms, not a single diagnosis, and the mechanism — not just the severity — determines the right first-line treatment.^[2]

^[2][1]

Fecal incontinence is common, and considerably more common than most patients or clinicians assume. A 2024 meta-analysis pooling 80 population-based studies and 548,316 people found a global prevalence of 8.0% among community-dwelling adults — roughly 1 in 12 — rising to 9.3% in adults 60 and older versus 4.9% in younger adults, and higher in women (9.1%) than men (7.4%).^[3] Among community-dwelling older adults specifically, prevalence has been reported in the 3-7% range in earlier population surveys, climbing to as high as 50% among nursing-home residents.^[1] In one English study of geriatric patients admitted to an acute-care hospital, 42% had fecal impaction.^[1]

Despite this, fecal incontinence remains genuinely underdiagnosed and undertreated — the social stigma attached to it makes many patients reluctant to admit the problem, and clinicians often do not ask, sometimes from similar discomfort, sometimes because they underestimate how important it is.^[1] Beyond the direct cost of managing it, fecal incontinence is a leading cause of institutionalization in older adults, and is linked to depression, social isolation, and — in at least one prospective community cohort — increased mortality.^[1] Asking about it directly, rather than waiting for spontaneous disclosure, is itself the single highest-yield first step in this chapter.^[4]

Presentation by mechanism

What looks like fecal incontinence but is not

Leakage from a perianal fissure, fistula, abscess, or a prolapsing internal hemorrhoid can mimic true anal incontinence ("pseudo-incontinence"). Visual inspection — including asking the patient to bear down to check for rectal prolapse, and looking for a gaping anus suggesting severe sphincter dysfunction — helps distinguish these from true fecal incontinence during the same examination used for the digital rectal exam (see Assessment & Diagnosis).^[1]

Associated findings worth asking about directly

Chronic soiling commonly causes perianal skin irritation or frank dermatitis, which is itself worth treating (see Non-Pharmacologic Treatment). In nursing-home residents, fecal incontinence frequently occurs together with urinary incontinence ("double incontinence"); a new combination of the two, or new rectosphincter dysfunction on its own, is a red flag for spinal cord compression rather than routine geriatric incontinence (see Red Flags/Refer).^[1] The psychosocial burden is genuinely significant — embarrassment, social withdrawal, and depression are common, and most patients have never told anyone about the problem before being asked directly.^[1]

• Obstetric anal sphincter injury — vaginal delivery, use of obstetric forceps, or delivery of a high-birth-weight infant; a careful obstetric history (number of vaginal deliveries, forceps use, infant birth weight) should be taken from every woman with unexplained incontinence, since it is an important and often unrecognized contributor even decades later.^[1]
• Prior anorectal surgery, including fistulotomy and internal sphincterotomy.^[4]
• Nontraumatic sphincter degeneration — scleroderma, or idiopathic internal anal sphincter degeneration of unknown cause.^[4]
• Peripheral neuropathy (e.g., pudendal nerve injury from chronic straining at defecation or occult childbirth injury) or generalized neuropathy, most often from diabetes mellitus; vitamin B12 deficiency, multiple myeloma, and hypothyroidism are less common causes of pudendal neuropathy worth considering.^[4][1]
• Disturbances of the pelvic floor — rectal prolapse, descending perineum syndrome.^[4]
• Inflammatory conditions — radiation proctitis, Crohn's disease, ulcerative colitis.^[4]
• Central nervous system disorders — dementia, stroke, brain tumours, multiple sclerosis, spinal cord lesions.^[4]
• Chronic diarrhea — irritable bowel syndrome, post-cholecystectomy diarrhea, or any other cause of persistently loose stool.^[4]
• Fecal retention with overflow (impaction) — see Recognize the Condition and Choose Initial Treatment.^[4]
• Aging itself — resting and squeeze anal pressures both decline with age, alongside increased perineal descent during defecation and increased pudendal nerve latency.^[1]
• Cognitive impairment or dementia — patients may not sense rectal distension, or may ignore the urge to stool, leading to impaction with subsequent intermittent leakage; this also limits the patient's ability to independently seek a toilet.^[1]
• Reduced mobility or limited access to a toilet.^[1]
• Chronic laxative overuse, and chronic opioid or anticholinergic medication use — see the medication-review discussion in Choose Initial Treatment, a genuinely pharmacist-relevant contributor in both directions (worsening diarrhea, or causing constipation and impaction).^[1]
• Female sex — reflected directly in the higher prevalence figures above.^[3]
• Behavioural disorders, and — in general population studies — any condition producing chronic diarrhea or urgency.^[4]

Ask directly

Ask every patient about fecal incontinence directly, as a routine part of any visit touching on bowel health, GI symptoms, mobility, or continence — do not rely on the patient to raise it spontaneously. Most will not, out of embarrassment, even when the symptom is genuinely bothersome.^[4][1]

History

• Systematically screen for predisposing conditions — obstetric, surgical, neurologic, and gastrointestinal — rather than accepting incontinence as unexplained.^[4]
• Quantify severity using the Bristol Stool Scale to characterize stool type, alongside frequency, amount of leakage, and the presence of urgency.^[4]

The Bristol Stool Chart — Types 1-2 indicate constipation/impaction risk, 3-4 are normal, and 5-7 indicate loose-to-liquid stool that drives urge and passive leakage. (Cabot Health, adapted by CFCF, CC BY-SA 3.0, via Wikimedia Commons)

• Obtain a bowel diary — genuinely superior to an unprompted self-report for characterizing actual bowel habits and incontinence episodes over time.^[4]
• Ask specifically whether leakage is passive (unaware) or preceded by urge (a sudden sensation the patient cannot act on in time) — this is a central bedside question that meaningfully narrows the likely mechanism before any testing is ordered.^[1]
• In women, take a careful obstetric history: number of vaginal deliveries, forceps use, and any high-birth-weight infants.^[1]

Physical examination

• A general physical examination to identify any disease to which the incontinence may be secondary.^[4]
• Inspect undergarments for fecal staining, and visually inspect the perianal skin and anus for a fissure, fistula, external hemorrhoid, or a gaping anus (suggesting severe sphincter dysfunction); ask the patient to bear down to check for rectal prolapse.^[1]
• Digital rectal examination: assess for a rectal mass, resting anal sphincter tone, voluntary squeeze tone, and tone during simulated defecation. Perform this before referring for anorectal manometry.^[4]
• Hardened stool palpable in the rectal vault supports a diagnosis of fecal impaction — but a negative digital rectal examination does not rule out impaction higher in the rectum or colon. If impaction is still clinically suspected despite a negative exam, obtain an abdominal plain radiograph.^[1]
• The "anal wink" reflex — gently stroking the perianal skin bilaterally and watching for reflexive external sphincter contraction — tests both perineal sensation and pudendal motor function.^[1]

Investigations — reserved for patients who fail simple conservative measures, or before surgery is considered

No single abnormal test is diagnostic on its own. This testing panel is for patients who do not respond to simple conservative measures (stool-consistency management, scheduled toileting) or for whom surgery is being considered — not for the routine first-visit workup of mild or infrequent symptoms, which should start with education, dietary and medication review, and stool-consistency management (see Choose Initial Treatment).^[4]

• Normalize stool consistency first — this is the single highest-yield, most pharmacist-actionable intervention in fecal incontinence, regardless of the underlying mechanism.^[4][5]
• Identify and correct the underlying, often reversible driver — disimpact overflow incontinence, treat active diarrhea or colitis behind reservoir/urge incontinence — rather than only managing the leakage symptomatically.
• Reduce the frequency and severity of incontinence episodes and the accompanying urgency.
• Review the medication list for both diarrhea-worsening and constipation/impaction-causing agents — a distinct, genuinely pharmacist-owned intervention (see Choose Initial Treatment).^[1]
• Protect perianal skin integrity and prevent secondary dermatitis or infection from chronic soiling.
• Escalate to pelvic floor rehabilitation, anorectal testing, and surgical referral when conservative measures fail, rather than letting symptoms persist untested indefinitely.^[4]
• Address the psychosocial impact directly — ask, normalize, and counsel — rather than treating the physical leakage as the entirety of the problem.^[1]

The medication review — a genuinely pharmacist-owned intervention

Because stool consistency is the single most modifiable driver of fecal incontinence, a careful medication review belongs at the centre of initial management, and runs in two opposite directions at once.

The 3-step fecal impaction protocol (overflow incontinence)

Step 1 — Disimpaction. Manual disimpaction with an anesthetic lubricant, or mineral oil enemas given over 2-3 days for maximal effect. Sodium phosphates enemas are a reasonable alternative, but avoid magnesium-, phosphate-, or citrate-containing disimpaction solutions in patients with hypertension, heart failure, or chronic kidney disease — electrolyte absorption is increased across impacted, often locally inflamed rectal mucosa.^[1]

Step 2 — Prevent reaccumulation. An oral polyethylene glycol solution, at a smaller volume (roughly 1-2 L) than a full bowel-preparation dose, is safe and effective for preventing stool from reaccumulating in the colon. Avoid it if colonic dilation or obstruction is suspected.^[1]

Step 3 — Maintenance. Once the impaction has cleared, add fiber supplementation and a stool softener, increase mobility where possible, avoid constipating medications where an alternative exists, and use scheduled (e.g., weekly) enemas or laxatives as needed. Enemas are generally preferred over stimulant laxatives for ongoing maintenance because their effect is more predictable and time-limited.^[1]

Stool-consistency pharmacotherapy for diarrhea-predominant, urge, and passive incontinence

First-line psyllium firms loose or watery stool and, in a randomized, double-blind, placebo-controlled crossover trial of 80 community-dwelling adults with fecal incontinence, reduced incontinence episodes and improved symptom severity and quality of life as effectively as loperamide — with constipation occurring in only 10% of patients on psyllium versus 29% on loperamide.^[5] Add-on or alternative loperamide is a reasonable next step if a bulking agent alone is insufficient, and is genuinely better tolerated for this specific indication than older combination opioid-anticholinergic antidiarrheals.^[1] Avoid in older adults the combination antidiarrheal diphenoxylate-atropine — its anticholinergic component carries a real risk of mental status change and urinary retention in this population, and it is not recommended here.^[1]

Reservoir/urge incontinence from colitis or a reduced-capacity rectum

The stool-consistency approach runs in the opposite direction here: treat the underlying disease (e.g., mesalamine or steroids for inflammatory bowel disease, treatment of an infectious or ischemic cause), and deliberately minimize fecal bulk with a low-fiber approach plus a constipating agent such as loperamide, to reduce rectal filling — rather than a bulking agent, which is the right choice for simple diarrhea-driven leakage but the wrong one here.^[1]

• Scheduled toileting, ideally timed after meals to take advantage of the gastrocolic reflex — a core habit-training strategy, and particularly useful in patients with dementia who cannot reliably self-initiate toileting.^[1]
• Pelvic floor physiotherapy and biofeedback — teaches patients to better perceive rectal distension and to voluntarily contract the external sphincter in response; superior to pelvic floor exercises performed without feedback, and recommended before surgical intervention is considered.^[4][2] In a Canadian academic-centre real-world cohort, biofeedback for fecal incontinence produced an overall response in 79.6% of patients and a reported symptom improvement in 67.3%, with a median 53.7% improvement in maximum anal squeeze pressure above baseline; the same cohort's experience suggested 3 sessions may be sufficient to teach and reinforce the sphincter-strengthening exercises, though published consensus guidelines still recommend 4-6.^[6]
• Biofeedback requires genuine cognitive engagement and motivation, and at least some preserved rectal sensation, to succeed — it is generally unsuccessful in patients with significant dementia or cognitive impairment. Habit training, not biofeedback, is the realistic first non-pharmacologic tool in this group.^[1]
• Adequate fluid intake and regular physical activity/mobility.^[2]
• Proper toilet positioning and avoiding straining at defecation, which itself is a proposed mechanism of pudendal nerve injury over time.^[2][1]
• Perianal skin care — gentle cleansing after each episode and a barrier ointment or cream — to prevent painful dermatitis and secondary infection from chronic soiling.
• Absorptive products (pads) or an anal insert can protect dignity and clothing while definitive treatment takes effect, but are not a substitute for treating the underlying mechanism.

Talk about it directly — the destigmatizing conversation

Fecal incontinence remains one of the most underreported conditions in medicine: patients are often reluctant to raise it out of embarrassment, and clinicians frequently do not ask, sometimes from similar discomfort, sometimes because they underestimate its importance.^[1] Ask directly, in plain and matter-of-fact language, as a routine part of any visit that touches on bowel health, GI symptoms, mobility, or continence, rather than waiting for the patient to bring it up.^[4] Naming how common the condition genuinely is — roughly 1 in 12 adults, and considerably more common again with age — is itself a useful clinical tool: patients who feel able to discuss it get evaluated and treated sooner, rather than quietly restructuring their lives around it.^[3][1]

Older adults — the central population for this chapter

Fecal impaction is the most common cause of overflow incontinence in nursing-home residents, with institutional prevalence reported as high as 50%.^[1] Both resting and squeeze anal sphincter pressures decline with age, alongside increased perineal descent during defecation and increased pudendal nerve latency, producing genuine age-related sphincter laxity and weakness.^[1] Polypharmacy with constipating medications is a major, modifiable contributor — see the medication review in Choose Initial Treatment.

Diabetes mellitus

Diabetic neuropathy is a leading cause of rectosphincter dysfunction: incontinent diabetic patients have higher rectal sensory thresholds (more volume is needed before they sense urgency) and a longer delay to voluntary external sphincter contraction in response to rectal distension, producing passive leakage; diabetic autonomic enteropathy frequently adds diarrhea on top of this mechanism.^[1] Anorectal manometry aids diagnosis, and biofeedback remains effective when the patient retains adequate rectal sensation.^[1]

Dementia and cognitive impairment

Biofeedback generally does not work in patients with significant dementia, since it requires the patient to comprehend and follow directions. Habit training — scheduled, typically post-meal toileting to take advantage of the gastrocolic reflex — plus adequate fluid intake, bulking agents, and maximizing mobility are the realistic first-line non-pharmacologic tools instead.^[1] Impaction risk is especially high in this group from reduced awareness of the urge to defecate combined with reduced mobility.

Inflammatory bowel disease and reservoir incontinence

Active or prior colitis (ischemic, infectious, radiation-induced, or ulcerative) and a reduced-capacity rectum after colonic resection both reduce rectal compliance and produce urge incontinence. Treat the underlying disease and minimize fecal bulk with a low-fiber approach plus a constipating agent (e.g., loperamide) to reduce rectal filling — the deliberate opposite of the bulking-agent approach used for simple diarrhea-driven leakage (see Choose Initial Treatment).^[1]

Obstetric sphincter injury and postpartum

Obstetric anal sphincter injury is a real and often under-recognized cause of "idiopathic" fecal incontinence presenting decades later in life — take a careful obstetric history (vaginal deliveries, forceps use, high-birth-weight infants) in any woman with new or unexplained incontinence.^[1] A postpartum pelvic floor physiotherapy referral is reasonable when an obstetric injury is suspected closer to the time of delivery.

Renal and hepatic impairment

Avoid magnesium-, phosphate-, or citrate-containing disimpaction solutions in significant renal impairment or heart failure, given increased electrolyte absorption across impacted rectal mucosa.^[1] Loperamide and psyllium do not require specific renal or hepatic dose adjustment at standard use.

Spinal cord and neurologic disease

New fecal incontinence combined with new urinary incontinence, or new-onset rectosphincter dysfunction on its own, should prompt urgent evaluation for spinal cord compression rather than being managed as routine fecal incontinence (see Red Flags/Refer).^[1]

• Use a bowel diary — frequency, Bristol stool type, leakage episodes, and urgency — at baseline and to track response over time; this is genuinely superior to relying on the patient's unprompted recollection at follow-up.^[4]
• Reassess 2-4 weeks after any medication-review change or new bulking-agent/antidiarrheal therapy.
• After disimpaction, confirm the impaction has actually cleared (repeat digital rectal exam and, if needed, abdominal imaging) before assuming the maintenance regimen alone is sufficient.^[1]
• For patients starting pelvic floor physiotherapy or biofeedback, reassess after the initial course (commonly 3-6 sessions) rather than continuing indefinitely without checking response.^[6]
• Check perianal skin integrity at follow-up, particularly in patients with frequent soiling or reduced mobility.
• Screen for the psychological impact of fecal incontinence — depression, social withdrawal — rather than treating it purely as a physical symptom.^[1]
• Refer for anorectal manometry, balloon expulsion testing, and rectal sensation testing if conservative measures have not meaningfully improved symptoms within a reasonable trial.^[4]

1. Conservative measures (medication review, stool-consistency management, scheduled toileting) not meaningfully improving symptoms after a reasonable trial: obtain anorectal manometry, balloon expulsion testing, and rectal sensation testing rather than continuing to escalate empirically.^[4]
2. Weak anal pressures on manometry after failed conservative therapy, particularly if surgery is being considered: obtain anal imaging (endosonography) and EMG to look for a structural sphincter defect.^[4]
3. Reduced rectal sensation, or an abnormal balloon expulsion test suggesting a coexisting evacuation disorder: pelvic floor retraining/biofeedback is the next step regardless of which specific abnormality is found.^[4]
4. Persistent symptoms despite an adequate course of pelvic floor retraining: consider anal sphincteroplasty if an anatomic sphincter defect is present, sacral nerve stimulation, or an injectable anal bulking agent — selected according to the specific findings above rather than by default.^[4]
5. Recurrent fecal impaction despite a maintenance regimen: reassess for an unaddressed constipating medication, inadequate mobility, or an inadequate maintenance dose or schedule before assuming the disimpaction technique itself failed.^[1]
6. Severe or intractable fecal incontinence refractory to all of the above: colostomy is a genuine last-resort option that can markedly improve quality of life — reaching this point in the right patient reflects thorough prior management, not a failure of care.^[4]

• Waiting for the patient to raise fecal incontinence rather than asking directly — most patients will not volunteer it.^[4][1]
• Assuming a normal digital rectal examination rules out fecal impaction — it does not reliably detect impaction higher in the rectum or colon; obtain an abdominal x-ray if clinical suspicion remains.^[1]
• Starting a fiber supplement or bulking agent during acute fecal impaction — it belongs in the maintenance phase only, after disimpaction.^[1]
• Reaching for a combination opioid-anticholinergic antidiarrheal (diphenoxylate-atropine) in an older adult rather than loperamide or psyllium alone.^[1]
• Treating overflow incontinence as ordinary diarrhea and starting an antidiarrheal without first checking for, and ruling out, fecal impaction — antidiarrheal therapy can worsen an unrecognized impaction.
• Missing medication contributors during reconciliation — both constipating agents (opioids, anticholinergics, calcium channel blockers, iron) and diarrhea-promoting agents (metformin, SSRIs) are common and genuinely modifiable.^[1]
• Referring a patient with significant dementia for biofeedback without first considering whether they can meaningfully participate — habit training is usually the more realistic first tool in this group.^[1]
• Missing red-flag features — rectal bleeding, unintentional weight loss, or new-onset incontinence in a younger patient — and attributing new symptoms to "normal aging" without any workup.
• Overlooking perianal skin care and allowing painful dermatitis or secondary infection to develop from chronic soiling.
• Treating the leakage as the entirety of the problem and not asking about, or addressing, its psychosocial impact.^[1]

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Bulking Agents and Antidiarrheals — First-Line for Diarrhea-Predominant or Urge Incontinence

Normalizing stool consistency is the single highest-yield intervention in fecal incontinence. Confirm no fecal impaction is present before starting these agents.

Fecal Impaction — Disimpaction and Maintenance (Overflow Incontinence)

A 3-step protocol: disimpaction, prevention of reaccumulation, then maintenance. Never give a fiber supplement or bulking agent during acute impaction.

Bile-Acid-Related Diarrhea

Consider specifically when a bile-acid diarrhea mechanism is identified, e.g., post-cholecystectomy diarrhea contributing to incontinence.

Medication Review — Common Contributors to Worsening Fecal Incontinence

Represents both directions of the medication-review discussion in Choose Initial Treatment. Do not stop any of these unilaterally — coordinate any dose, timing, or agent change with the prescriber.