Chapter Outline
Epidemiology
The inability to control feces is a devastating problem. Many people find this problem socially incapacitating and stay home, thus minimizing social contact to avoid an embarrassing situation. Estimating the number of people afflicted with fecal incontinence is difficult because many do not mention the problem to their caregivers. In a study by , only about a third of patients discussed their incontinence with their physicians. Others incorrectly describe their symptoms and may refer to their incontinence as “diarrhea,” making it difficult for the physician to understand the problem without careful questioning. Thus, estimates probably grossly underreport the prevalence, which ranges from 0.1% to 18%. Studies in the United States found an overall prevalence of 18.4%, with a higher prevalence of 26% in patients who visited a gastroenterologist. Definitions of fecal incontinence also vary from report to report, making comparisons difficult.
Caring for incontinent patients is a tremendous financial responsibility. Over $400 million is spent annually on adult diapers, and fecal and urinary incontinence are primary reasons for nursing home placement (outnumbering senile dementia). Fecal incontinence probably increases progressively with age, although it can affect all ages, even children. It affects men as well as women, and some studies find men affected more commonly than women.
Etiology
Defecation is a complex process that involves an intricate interaction between anal function and sensation, rectal compliance, stool consistency, stool volume, colonic transit, and mental alertness. An alteration in any of these can lead to incontinence. Box 31.1 lists some common causes of fecal incontinence.
| ANAL |
| Injury |
| Obstetric (vaginal delivery/trauma) |
| Surgical (fistulotomy, hemorrhoidectomy, sphincterotomy, stretch) |
| Irradiation |
| Trauma |
| Congenital (e.g., imperforate anus) |
| INTESTINAL |
| Colitis or proctitis |
| Colon, rectum, or small bowel resection |
| Tumors |
| Fecal impaction |
| Decreased rectal compliance |
| Rectal prolapse |
| NEUROLOGIC |
| Central nervous system |
| Dementia |
| Neoplasm |
| Stroke |
| Trauma |
| Multiple sclerosis |
| Peripheral (e.g., diabetes) |
| OTHER |
| Diarrhea |
| Combinations of anal and rectal causes |
| Myopathy (e.g., scleroderma) |
| Functional |
A large component of continence is the function of the anal sphincter complex. It consists of the internal anal sphincter (IAS) muscle, the external anal sphincter (EAS) muscle, and the puborectalis (PR). The smooth muscle of the IAS is innervated by the autonomic nervous system. The IAS is responsible for more than half of the resting tone. The striated muscle of the EAS is innervated by the inferior branch of the pudendal nerve and is responsible for about a third of the resting tone. Defecation is a result of voluntary relaxation of the EAS and PR that are innervated by the S3 to S4 nerves in response to rectal distension that is dictated by receptors in the pelvic floor and the anal transition zone. Anatomic disruption of the sphincter complex or disruption due to neurologic reasons is a common cause of fecal incontinence. Childbirth commonly injures the mother’s sphincter complex. In a study by , women were evaluated before and after childbirth, with interviews, anal physiology testing, and anal endosonography. They found that 35% of primiparous women and 44% of multiparous women had sphincter defects after delivery. The IAS was injured more often than the external sphincter—sometimes even when no breach occurred in the perineal skin. A strong correlation was found between sphincter defects and the development of bowel symptoms, although only about a third of women with sphincter defects developed bowel symptoms. Incontinence may not appear until decades after the obstetric injury, so it remains to be seen how many of these women develop incontinence later in life. In the past, these patients, particularly women with delayed symptoms years after childbirth injury, were labeled with idiopathic incontinence. However, with the advent of more sophisticated evaluation techniques, defects in the sphincter complex have been found. Fecal incontinence also appears to be associated with urinary incontinence and pelvic organ prolapse. In one study by , a third of women presenting to a urogynecologist for urinary incontinence also had fecal incontinence, and 7% of women with isolated pelvic organ prolapse had fecal incontinence. In another study by , 18% of women who had a previous obstetric anal sphincter disruption had both urinary and fecal incontinence. Besides obstetric injury, other causes thought to possibly contribute to both conditions include chronic constipation with straining at stool, aging, and relaxation of pelvic support.
Evaluation
History
Evaluation of a patient with fecal incontinence starts with a comprehensive history. Important questions to ask include duration of the problem, frequency of incontinence, time of day of incontinence, quality of stool lost, ability to control flatus, use of pads, frequency of bowel motions, problems with constipation or diarrhea, and effects of incontinence on daily life. To differentiate incontinence from urgency is important. Urgency may reflect inability of the rectal reservoir to store stool (as with diarrhea or proctitis) rather than a true sphincter problem. Equally important is to differentiate diarrhea from incontinence because many patients incorrectly interchange the two problems. The quality of stool lost gives clues to the severity of the incontinence. Flatus is more difficult to control than liquid stool, and solid stool is the most easily controlled. Patients with incontinence of solid bowel motions without knowledge of the loss of stool are usually more distressed and reclusive than those with incontinence of flatus only.
Additionally, the physician should obtain a thorough obstetric history: number of vaginal deliveries, duration of second stage of labor, previous episiotomy, use of forceps, perineal tears or infections, weight of babies, and unusual presentations at birth. A sexual history, including the effect of incontinence on sexual behavior, should be obtained. Other medical and surgical conditions must be ascertained, including back injuries, previous anorectal or abdominal surgeries, irradiation history, diabetes, multiple sclerosis, and scleroderma. Medications, food intolerance, and activity restrictions may add information.
Physical Examination
The physical examination starts with inspection of the anal area, looking for soilage of stool on the skin, and evidence of skin irritation. Sometimes the underwear also gives evidence of stool soilage. The anus is inspected, looking for gaping of the muscles and any scarring. The patient is asked to squeeze and to simulate holding in a bowel movement to look for uniform circular contraction of muscle. Next, asking the patient to strain may show exaggerated perineal descent or prolapse of hemorrhoids or even the rectum. The anocutaneous reflex can be checked by rubbing the perianal skin gently (a Q-tip works well) and looking for the reflex contraction of the anal sphincter mechanism. Sensation to pinprick can also be checked. Both of these give a crude assessment of sphincter innervation. Palpation of the sphincter is next done with digital examination. The initial tone reflects the internal sphincter and should be noted. Then the patient is asked to squeeze on the index finger in the anus as if she were holding in a bowel movement. Strength, defects in the circle of muscle, and early fatigability are assessed. Scars or masses are appreciated.
A digital rectal examination checks for masses, occult or gross blood, fistula, and the presence of a rectocele. The physical examination is usually completed with a sigmoidoscopy or proctoscopy; this rules out proctitis or neoplasm as a source of the problem.
Scoring Scales for Fecal Incontinence
Qualifying fecal incontinence has been difficult because many scoring systems have been introduced. A validated questionnaire for measuring quality of life, the Fecal Incontinence Quality of Life (FIQL), was reported in 2000 by Rockwood et al. and has 29 items that relate to four scales: lifestyle, coping/behavior, depression/self-perception, and embarrassment. In the same year, developed a questionnaire to assess epidemiology of fecal incontinence and associated risk factors. This assessed general bowel habits, assessed presence and severity of fecal incontinence, measured symptoms related to pelvic floor dysfunction, and assessed risk factors for fecal incontinence. The FIQL is currently used routinely to assess quality of life during the patient’s follow-up after any mode of treatment.
The American Society of Colon and Rectum Fecal Incontinence Severity Index (FISI) is a severity rating score and consists of questions that rate continence to gas, mucus, solid, and liquid stool. The FISI is commonly used in conjunction with the FIQL as a tool to measure the efficacy of treatment. The other popular tool is the Wexner score that uses lifestyle alterations and wearing of a pad, in addition to incontinence to solids, liquid, and gas. In this score, zero is a score for perfect continence and 20 for complete incontinence. See Chapter 44 for further discussion of these outcome questionnaires.
Diagnostic Testing
The use of additional testing depends on the severity of the problem and the amount of distress it causes the patient. Further tests may be helpful in establishing the diagnosis and in planning the most appropriate treatment. These tests are discussed individually.
Enema
To determine whether the patient is truly having incontinence, an enema may help clarify the problem. About 100 mL of tap water is given, and it is noted whether the patient can hold this for more than a few minutes. Because liquid is more difficult to control than solid stool, patients who can hold a tap water enema probably do not have significant incontinence. They may need to be questioned more carefully to fully understand their symptoms.
Anorectal Physiology Testing
Many methods are available to assess anorectal physiology. Manometry, electromyography (EMG), rectal compliance, and pudendal nerve studies may all be helpful. Manometry provides quantitative information regarding the resting and squeeze pressures of the sphincter muscles. The resting pressures reflect the constant tone of the internal sphincter muscles. The squeeze pressures reflect the pressure generated by the external sphincter muscle. The length of the anal canal can be determined by the measured distance of these pressures. A shortened anal canal length may reflect injury to the muscle. Positive rectoanal inhibitory reflex rules out Hirschsprung’s disease (see Chapter 32 ).
Rectal compliance can be determined by inserting a balloon and determining the minimal volume that the rectum can sense, then sequentially inflating the balloon to a volume that cannot be tolerated. Decreased compliance signals a rectal reservoir that does not appropriately store stool and may push the fecal bolus past sphincter muscles, even if the sphincter muscle pressures are adequate. Note that normal manometric findings do not exclude incontinence, and normal people without symptoms of fecal incontinence may have abnormal manometry.
EMG is used to study the innervation of the external sphincter complex and to examine for reinnervation seen in pelvic neuropathy. Traditionally, needle EMG has been used with concentric or single-fiber electrodes, although this is quite painful for the patient. An increase in fiber density implies compensatory reinnervation after denervation of the external sphincter. Surface electrodes (attached to the skin overlying the subcutaneous portion of the EAS) give a less precise EMG but still provide some information.
Pudendal nerve terminal motor latency can be determined using an electrode attached to a glove inserted into the anal canal. A prolonged conduction in the pudendal nerve may signal damage to the innervation of the external sphincter and PR muscle (see Chapter 14 ).
Defecography
Defecography is indicated if rectal prolapse or internal intussusception (occult prolapse) is suspected. See Chapter 34 for a more thorough discussion.
Colonoscopy and Barium Enema
Proctoscopy, sigmoidoscopy, colonoscopy, and barium enema are appropriate in some patients, particularly if diarrhea and blood are associated or contributing symptoms. Colitis and neoplasms can be ruled out with these tests.
Endorectal Ultrasonography
Endosonography is recognized as a valuable tool in the assessment of fecal incontinence. A probe inserted into the rectum and withdrawn through the anal canal allows for a 360-degree visualization of the IAS and EAS. New models include three-dimensional (3D) visualization with features that render the EAS muscle anatomy, resulting in good visualization and a color Doppler feature. Particularly in patients with surgical or obstetric injury who did not develop incontinence until many years (even decades) after the insult, endosonography allows visualization of defects in the sphincter muscle, which, in turn, can lead to surgical correction ( Fig. 31.1 ). In the past, many of these patients would have been diagnosed with idiopathic incontinence, and surgical repair may have not been considered.
Additionally, the pictures obtained from endosonography provide a “road map” for repair of the sphincter. For instance, in some patients who become incontinent after a sphincterotomy for a fissure, it gives visualization of the ends of the internal sphincter muscle and the amount of gap between those ends. This allows planning of the surgical incision. Similarly, in patients with a past obstetric injury, the gap in the internal and external sphincter muscles can be noted and allows planning of the surgical procedure.
A study by measured perineal body thickness ultrasonographically and concluded that a perineal body thickness less than 10 mm is abnormal; patients with perineal body thickness greater than 12 mm are unlikely to have a defect, whereas those between 10 and 12 mm are associated with a defect in the sphincters in about a third of the patients. The use of 3D ultrasound is yet to prove its superiority, whereas magnetic resonance imaging (MRI) with endorectal coil has results that are similar to the two-dimensional (2D) endorectal ultrasonography (ERUS). Although use of MRI is still controversial, it is less operator dependent and is superior in defining EAS defects, whereas IAS defects are visualized more clearly with ERUS.
Conclusion
What tests are essential for treating patients with fecal incontinence? A suggested algorithm for the diagnosis and treatment of fecal incontinence is shown in Fig. 31.2 . Many excellent caregivers use few of these tests, although, recently, more testing is being used. To rule out colitis, proctitis, and neoplasia, evaluation of the colon and rectum by endoscopy or barium enema is needed. Defecography may or may not be needed for evaluation of rectal prolapse but may be necessary to diagnose internal intussusception (or occult prolapse). The enema test is easy and inexpensive and helps determine whether a patient has true fecal incontinence. Many clinicians do not have access to an anorectal physiology laboratory or endosonography machine. Additionally, it takes experienced personnel to perform and interpret the results of these tests. Even for some surgical procedures these tests are not mandatory but may be helpful for planning surgery and predicting success. For complicated surgical repairs or previously failed repairs, anal physiology testing and endosonography have significant value in planning an appropriate repair or determining why a previous repair failed. As caregivers become aware of this previously silent group of patients, more testing will be needed to study these patients in an effort to understand their problem. Then, as incontinence becomes analyzed more accurately, these tests and others yet to be discovered will allow more precise treatment planning.
Nonsurgical Treatment
Treatment begins with correction of underlying medical and surgical problems. Preliminary surgical treatments may include cancer resection, treatment of inflammatory bowel disease, repair of rectal prolapse, and removal of impactions.
Medical Treatments
In patients with minor incontinence, the use of bulking agents, such as Metamucil, Citrucel, or Konsyl, can change the consistency of the stool, making it firmer and more easily controlled. Starting with a teaspoon daily and working up to a tablespoon up to three times daily helps decrease side effects, such as abdominal distension and bloating. If one agent gives these side effects, sometimes switching to another agent produces fewer side effects. Restricting the amount of fluid taken with these products may enhance their ability to increase stool bulk, especially if diarrhea is a problem.
Agents designed to slow down the intestinal tract may also help with stool control. Even in patients without diarrhea, these agents may slightly constipate patients, allowing them to better control their stool. Loperamide hydrochloride (Imodium) is often prescribed in this capacity. It prolongs intestinal transit time, allowing fecal volume to be reduced (secondary to the increased time allowed for removal of fluid from stool) and bulk density to be increased. It also increases rectal compliance, which decreases urgency. Side effects are rare, and physical dependence does not occur. The dosage must be individualized for each patient. If patients have particular trouble after meals, 2 to 4 mg may be given before a meal to decrease the chance of stooling. The maximum daily dosage is 16 mg. Some patients with diarrhea require the maximum dosage, but patients with mild incontinence who use it to mildly decrease the intestinal transit may need only two or three 2 mg doses daily, or as needed. Diphenoxylate hydrochloride (Lomotil) is another agent used in this capacity, especially if diarrhea is a primary contributor to the incontinence. Diphenoxylate hydrochloride is less expensive than loperamide hydrochloride but is a Schedule V substance (under the Controlled Substances Act). It has minimal potential for physical dependence. Side effects are rare but may include abdominal distension, drowsiness, dizziness, depression, restlessness, nausea, headache, blurred vision, and dry mouth. The dosing is similar to that of loperamide. One or two 2.5 mg tablets are used up to four times daily. As with loperamide, the dosing must be individualized. Other agents that focus on control of diarrhea include tincture of opium, paregoric, and codeine. Side effects and the risk of physical dependence make them less attractive. Amitriptyline has been used to improve symptoms in patients with idiopathic fecal incontinence. It acts by decreasing intrarectal pressures by reducing the amplitude and frequency of rectal motor complexes, possibly through an anticholinergic mechanism.
Biofeedback and Pelvic Muscle Exercises
Successful treatment of fecal incontinence has been achieved with biofeedback and pelvic muscle exercises. showed that functional outcomes after sphincteroplasty improved in patients who initially did not experience optimal results from surgery and were then treated with biofeedback. Biofeedback is indicated for alert, motivated patients because it is labor intensive and requires a dedicated therapist.
Reported results are difficult to compare because three methods of biofeedback therapy are available, and most reports do not distinguish the type, duration, and exact method of performing the biofeedback. The three types are: (1) EAS strengthening, (2) coordination of rectal distension and anal sphincter contraction, and (3) improving sensation of stool in the rectum. For all three, the initial setup is similar. A balloon is placed in the rectum to simulate stool. Anal sphincter contraction is measured with a different balloon in the anal canal, by an anal plug, or by perianal surface electrodes. When contraction of the sphincter muscles is initiated, the patient observes this on the monitor. Visual (and in some systems, auditory) feedback is given regarding contraction of the external sphincter. For sphincter strengthening, patients are encouraged when the proper sphincter response is made. They are encouraged to exercise the muscle by replicating this type of contraction outside the therapy session. The goal is to increase the strength of the striated muscle.
Rectoanal coordination uses the same equipment. The goal is to train the patients to achieve maximum voluntary squeeze in less than 1 s after the balloon is inflated in the rectum by consciously contracting the sphincter muscles. This method is customized for each patient. Patients may need one or more sessions to be able to perform the maneuver at home in the correct way.
Rectal sensory perception is used to teach the patients to sense smaller volumes of stool. The patients are urged to defecate with the balloon in the rectum. The patients observe this on the monitor. Gradually, the volume in the balloon is decreased, and patients learn to sense smaller volumes with less rectal distension.
Improvement has been reported in 63% to 90% of patients after biofeedback. As stated earlier, most studies do not elaborate on exactly the type and how the biofeedback was taught. In one study, found that anal squeeze pressures improved, the duration of squeeze increased, and the capacity to retain liquid increased. These findings correlated with a decrease in the number of episodes of fecal incontinence.
Few studies definitively show that pelvic muscle–strengthening exercises (Kegel exercises) alone benefit patients with fecal incontinence. However, they are safe and cost nothing. Therefore, they should be discussed with most patients afflicted with fecal incontinence. They may particularly benefit patients who have early fatigability of the sphincter muscle on digital examination when asked to squeeze. Sometimes biofeedback is used to assist patients in performing these exercises by giving visual feedback when the correct muscles are contracted. When using biofeedback, we attempt to have patients hold the contraction for a full 10 s while watching a screen that tells them when the contraction decreases. Consultation with an interested physical therapist may optimize results.
The scientific evidence supporting the use of biofeedback and/or sphincter exercises for the treatment of fecal incontinence in adults was reported in several recent Cochrane Reviews ( ). Although pelvic floor muscle training is commonly recommended during pregnancy and after birth, there is little evidence about long-term effects for prevention of fecal incontinence. Regarding biofeedback, it appears that rectal volume discrimination training improves continence more than sham training and that anal biofeedback combined with exercises and electrical stimulation provide more short-term benefits than vaginal biofeedback and exercises for women with obstetric-related fecal incontinence ( ). One study questioning biofeedback was reported by . She assigned 171 patients to two groups: those with an intact sphincter and those with a disrupted sphincter. Subjects were further randomized to four treatment groups: the first received standard care; the second received standard care, verbal instruction, and a leaflet explaining pelvic exercises; the third received standard care and computer-assisted biofeedback at each session; and the fourth received standard care plus a home EMG biofeedback device. The results showed that overall, 75% patients recorded improvement, with equal numbers (54% versus 53%) in the biofeedback and nonbiofeedback groups. The study concluded that no significant differences were present between the treatment groups and leads one to wonder whether standard diet, bowel management counseling, and verbal instructions may be sufficient.
A recent systematic review of biofeedback and electrical stimulation for the treatment of fecal incontinence by found that there was sufficient evidence for the efficacy of biofeedback plus electrical stimulation in treating fecal incontinence. Amplitude-modulated medium-frequency stimulation, also termed premodulated interferential stimulations, combined with biofeedback was superior to both low-frequency electrical stimulation and biofeedback alone.
Bowel Management
Some patients find that daily enemas with approximately two pints of tap water, usually at the same time each morning just after eating, induce a bowel motion and empty the rectum. Sometimes a cone-tipped catheter (the same type used for colostomy irrigation) may be needed for incontinent patients to instill an enema so that it does not run out with instillation. Some advocate inserting a glycerine or bisacodyl (Dulcolax) suppository 20 to 30 min after eating along with abdominal massage to induce a bowel motion daily. With either method, bulking agents can be used, in addition to medications, to stop stooling in between desired defecation.
Passive Barrier Devices
Passive barrier devices are indicated when no other option is available or if patients refuse other options or have too many medical or physical issues preventing them from a surgical option. There is only one product available in the U.S. market that is U.S. Food and Drug Administration (FDA) approved as a barrier device. This is called the Procon-2 ® device (ICD Inc., Kingwood, TX). This is a single use silicone catheter with a balloon attached to one end. The catheter incorporates a filter that allows passage of gas but not stool. The device requires manual dexterity to be inserted into the anal canal and can be retained for about 8 h. Contraindications to its use include inflammation of the anorectum, rectal bleeding, sepsis in the anal area, and a low-lying suture line in the rectum. A single study done that used the Procon-1 ® device reported good patient compliance in 5/7 patients. The incontinence score (Wexner) also decreased from 12.7 to 5.2 and the modified fecal incontinence quality of life scale increased from 95.3 to 135. Two patients reported dissatisfaction.
Other anal plugs like the Peristeen anal plug made by Coloplast are available in United Kingdom and Europe only. It is available in two sizes and is made of a soft foam that has a water soluble film that dissolves in the anal canal. The plug expands to three to four times its size and can be retained for 8 h. No complications were reported.
In general, the available data suggest that anal plugs can be difficult to tolerate. However, if they are tolerated, they can be helpful in preventing incontinence in selected patients.
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