Incontinence of the bowel and bladder

Sandra J. Levi and Teri Elliott-Burke

Introduction

Bladder and bowel incontinence among older adults is common and often treatable. Unfortunately, embarrassment and inadequate knowledge of treatment options prevent many older adults from reporting incontinence to healthcare professionals. The social consequences of incontinence are profound. Older adults who live at home may reduce or eliminate trips outside the home due to care needs and embarrassment. Moreover, incontinence often precipitates institutional placement. About 13–34% of community-dwelling older adults report urinary incontinence (Komesu et al., 2009) and up to 15% report fecal incontinence (Whitehead et al., 2009). Among residents of nursing homes, over 50% have urinary incontinence (Offermans et al., 2009) and 33–65% (Shah et al., 2012) have some problem with fecal incontinence. Both types of incontinence are much more common in women than men but, in the case of fecal incontinence, the gender ratio decreases with increasing age.

Pelvic floor muscle dysfunction contributes to urinary and fecal incontinence. The pelvic floor contains three layers of muscles that have sphincter, support and sexual functions. Pelvic floor muscle function includes closing the urinary and anal sphincters as well as closing the vaginal opening. Pelvic floor muscles also support the abdominal viscera and aid in sexual function and appreciation in men and women.

Incontinence of the bowel

Normal control

Incontinence of the bowel is defined as an involuntary loss of stool through the anus that is severe enough to cause hygienic or social problems. In older adults, it may occur as an isolated incident in response to an acute event. Chronic fecal incontinence increases with increasing age.

Sensory and motor mechanisms contribute to the control of defecation. Typically, contractions in the proximal colon move feces into the rectum. The rectum stretches to hold the feces. The internal and external anal sphincters, as well as the puborectalis muscle, play especially important roles in preventing leakage. The internal anal sphincter is a 2–3 mm band of smooth muscle surrounding the anus. It is tonically contracted to keep the anal canal closed, except when it relaxes to allow emptying of the rectum. The external anal sphincter primarily consists of striated muscle; it voluntarily contracts, when needed, to prevent leakage. The puborectalis muscle forms a loop around the posterior aspect of the external sphincter. Contraction of the puborectalis muscle creates an anorectal angle. This angle and the puborectalis muscle assist in preventing defecation.

Defecation is initiated in response to rectal filling. Parasympathetic nerve impulses initiate strong peristaltic waves that move the fecal content along. At the same time, other body actions such as bearing down (i.e. the Valsalva maneuver) and upward and outward contraction of the pelvic floor musculature help to move the feces downward and outward. The final response is voluntary relaxation of the puborectalis muscle and the external anal sphincter.

With increasing age, pelvic floor musculature may weaken. Age-related loss of strength, as well as possible changes in tissue elasticity, may contribute to a decreased resting tone of the anus, particularly in women (Tariq, 2004).

Causes of incontinence

The causes of fecal incontinence in the elderly are shown in Box 55.1. Fecal impaction, often associated with constipation (Leung & Rao, 2009; Shah et al., 2012), and diarrhea are the most common causes of fecal incontinence and are often treatable. Leakage of stool may also result from loss of sensation or loss of muscle tone. Finally, stool loss may occur as a result of changes in the cognitive capacity to interpret sensory signals.

Box 55.1

Etiology of fecal incontinence

• Fecal impaction

• Loss of normal continence mechanism

– Local neuronal damage (e.g. pudendal nerve)

– Impaired neurological control

– Anorectal trauma/sphincter disruption

• Problems that overwhelm normal continence mechanism

• Psychological and behavioral problems

– Severe depression

– Dementia

– Cerebrovascular disease

• Neoplasm (rare)

Adapted from Tariq, 2004, with permission.

Stool leakage around an obstruction is often found in older adults. Most of these individuals have chronic fecal impaction, often as a result of inadequate fluid intake, chronic laxative abuse and poor bowel habits. Cancer or a benign polyp will sometimes be the cause. Whatever the cause, liquid stool from higher in the colon will leak past the hard immovable obstruction and drain from the anus, despite the best efforts of the patient.

A patient who has a condition that causes loose stool (drugs, inappropriate diet or infection) may suffer involuntary loss of this watery fecal material. For example, antacids containing magnesium, the consumption of dairy products by a person who is lactose intolerant and Salmonella infection can cause diarrhea. Loose stool may also be seen in bedridden patients who have poor muscle tone. A change of gravitational force may cause additional physiological and social demands on bedridden patients who are starting transfer and gait activities.

Loss of sensation of the perineum results in the patient not sensing the need for rectal emptying until natural forces have done so, leading to involuntary loss. Such perineal anesthesia may result from spinal cord injury, tumor or stroke, or previous injury including damage occurring during childbirth.

Loss of muscle tone by the muscles of continence may change the balance of forces such that the expulsive force of the colon exceeds any voluntary attempt by the patient to impede such force. Tumor, stroke, spinal cord injury, pudendal neuropathy and surgery frequently precipitate loss of muscle tone.

Patients may lose stool because they lack the cognitive capacity to realize what is happening. Such patients may have forgotten how to properly manage stool (as in dementia) or may not be sufficiently oriented to manage it (as in delirium).

Patients who have a moderate impairment – anatomical, physiological, mental or a combination of these – and who are impeded in some way from establishing a usable stooling position may appear to be incontinent. In addition, individuals with mobility limitations may be prevented from getting to a commode in a timely fashion. Rearranging their environment may make it easier for these patients to manage.

Diagnosis and therapeutic intervention

Multidisciplinary teams, including physicians, physical and occupational therapists, nursing staff and others provide optimal management of bowel and bladder incontinence.

Diagnosis of fecal incontinence begins by obtaining a careful history from the patient and the medical record. The history includes a description of: