Introduction:
Fecal incontinence is a difficult yet seldom talked about problem. The impaired ability to control gas or stool ranges from mild (difficulty with gas) to severe (loss of control of liquid and formed stools); symptoms can be continuous or recurrent. Nearly 18 million U.S. adults – about one in 12 – suffer from fecal incontinence. This number is likely underestimated as patients are reluctant to discuss this disabling problem. Incontinence causes emotional distress, loss of dignity, embarrassment, shame, frustration, anger, depression as well as social isolation. Perianal skin irritation may lead to pain, itching, and ulcers which may require medical or surgical treatments.
Causes of fecal incontinence include:
- diarrhea
- constipation
- muscle or nerve damage (due to constant straining, spinal cord injury, stroke)
- childbirth related trauma (episiotomy, forceps)
- anal operations
- traumatic injuries
- rectocele (a weakness of the recto-vaginal septum allows rectal tissue to bulge into the vagina. Rectoceles are uncommon in men as the prostate gland provides structural support)
- rectal prolapse
- inflammation (colitis)
- radiation
- tumors
- diseases such as diabetes, multiple sclerosis
- dementia (the prevalence of fecal incontinence is estimated at 47% for nursing home residents )
- aging (the prevalence of fecal incontinence is estimated at 15% in those 70 or older)
Other risk factors further include:
- poor general health
- physical disabilities
- chronic obstructive pulmonary disease
- irritable bowel syndrome
- urinary incontinence
- colectomy
- chronic diarrhea
- fecal impaction
- depression
Anorectal function and continence depend on factors such as stool volume, stool consistency, colonic transit, rectal distensibility, anal sphincter function, anorectal sensation and intact anorectal reflexes. Anatomical structures which help preserve continence include the rectum, the internal and external anal sphincter muscles, and the pubo-rectalis muscle. Defecation is initiated when stool enters the rectum, leading to rectal distention with reflex relaxation of the internal anal sphincter. The urge to defecate increases as more stool passes into the rectum. During defecation the anorectal angle is straightened and abdominal pressure is increased; pelvic floor descent, rectal contraction, and external anal sphincter relaxation then lead to emptying of stool.
Workup:
To better understand incontinence, a detailed history, physical exam and supplemental studies are required.
The clinical history should assess for onset of disease, duration, frequency, severity, precipitating events, and look for a history of difficult or traumatic vaginal delivery, anorectal surgery, pelvic irradiation, diabetes, and neurologic diseases.
A physical exam should include inspection of the perianal area which may reveal dermatitis (suggesting chronic incontinence), fistulizing disease, prolapsing hemorrhoids, or even rectal prolapse. Perianal sensation should be tested, with the absence of an anal wink reflex suggesting nerve damage. A digital rectal exam may provide information about the resting anal sphincte tone and may detect obvious anal pathology such as masses or fecal impaction . Inspection of the anus, rectum and large intestine via anoscopy, flexible sigmoidoscopy or colonoscopy may help to exclude mucosal inflammation, masses, or other pathology.
Anorectal manometry measures resting anal pressures, amplitude and duration of squeeze pressures, the rectoanal inhibitory reflex, threshold of conscious rectal sensation, rectal compliance, and anal rectal pressures during straining. Rectal sensation can be assessed by balloon inflation. Pudendal nerve terminal latency may assess potential nerve damage.
Endorectal ultrasound and magnetic resonance imaging are helpful to define structural abnormalities of the anal sphincters, the rectal wall, and the puborectalis muscle.
Defecography assesses anorectal anatomy at rest and during defecation; it assesses the anorectal angle, pelvic descent and may detect occult or overt rectal prolapse.
Intervention:
Three treatment approaches are commonly used for fecal incontinence:
- medical therapy such as dietary changes (i.e. avoidance of sphincter relaxing foods), constipating medications (treatment of diarrhea) and bulking agents (to enhance stool control)
- biofeedback and muscle strengthening exercises
- surgery, such a surgical sphincter muscle repair or implantation of an artificial anal sphincter
Medical therapy should be aimed at reducing stool frequency and improving stool consistency. Specific treatment for the underlying cause of diarrhea should be implemented, as formed stool is easier to control than liquid stool. While stool consistency can be improved with bulking agents (i.e. fiber supplements, bile binders), this may exacerbate incontinence in patients with decreased rectal compliance (i.e. in radiation proctitis or rectal stricture).
Stool frequency can be reduced with antidiarrheals such as loperamide (Imodium®) or diphenoxylate (Lomotil®); anticholinergic agents i.e. hyoscyamine (Levsin®, NuLev®, Anaspaz®, Levsinex®, Levbid®) may help with postprandial leakage if taken before meals.
Patients with fecal impaction should be disimpacted and treated with a bowel training regiment to prevent recurrent impaction.
Pelvic floor exercise and biofeedback may help retrain pelvic floor and abdominal wall musculature and may enhance the ability to sense rectal distention, thereby improving sensory as well strength components required for continence. Pelvic floor exercises involve squeezing and relaxing pelvic floor muscles 50-100 times a day. A health care provider can help with proper technique. Biofeedback therapy may help to perform these exercises properly and may improve anorectal sensation. Biofeedback uses special anal and rectal pressure sensors, as well as rectal balloons to produce graded sensations of rectal fullness. Measurements are displayed on a video screen and are used to modify or change abnormal function. Success depends on the cause of fecal incontinence, its severity, and the person’s ability to follow instructions; the role of biofeedback in the management of fecal incontinence is still debated, as the optimal protocol, equipment, and duration of treatment are undefined.
Surgical approaches to fecal incontinence include direct sphincter repair, plication of the posterior part of the sphincter, anal encirclement, implantation of an artificial sphincter, and muscle transfer procedures with or without electrical stimulation. Patients with a sphincter tear (obstetric trauma, fistula surgery) can be cured with a sphincteroplasty. It is the most common fecal incontinence surgery and reconnects the ends of a torn sphincter muscle.
A synthetic sphincter device or magnetic anal sphincter may be available in highly specialized centers. The Acticon (TM) neosphincter, consisting of an occlusive cuff (implanted around the anal canal), a pressure-regulating balloon (implanted in the prevesical space) and a control pump (implanted in the labium or scrotum) enables users to squeeze the control pump to permit defecation.
Sacral nerve electrical stimulation may restore continence in patients with structurally intact muscles. This approach appears to be effective in patients with neurologic disorders. The FDA approved the sacral nerve stimulator (InterStim®, Medtronics) for the treatment of chronic fecal incontinence in patients who have failed or are not candidates for more conservative treatments.
Injectable materials allow augmentation of the function of the internal anal sphincter. Injection of dextranomer-hyaluronic acid (Solesta®), used for the treatment of urinary incontinence, has also been approved for patients with fecal incontinence.
Anal plugs have been studied as a possible treatment for fecal incontinence. Fecal incontinence improved only in a minority of patients, anal plugs were poorly tolerated and their usefulness is thereby limited.
In extreme cases patients may need a colostomy to improve quality of life as a colostomy may be the only option for patients with intractable symptoms who are not candidates for any other therapy, or in whom other treatments have failed.
Utah Gastroenterology Blog 