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FECAL SOILING AND INCONTINENCE

Up to 4% of the adult population of the United States may suffer from fecal incontinence. The incidence of fecal incontinence rises with age and is more common in women than in men. The prevalence of incontinence corresponds to identifiable risk factors. Women are at greater risk because of obstetrical injury and trauma. Vaginal deliveries, even without sphincter disruption, cause minor, cumulative trauma that increases the chance of incontinence. Women with sphincter injury at delivery have a higher incidence of incontinence to flatus later in life. Studies of nursing home residents show that up to 50% of residents may be incontinent to stool. The pathophysiologic causes of fecal incontinence are myriad. General categories include: neurologic disorders (impaired sensory or motor function of the anal sphincter).

Evaluation

The patient who reports consistent inability to control gas, liquid stool, or solid stool should first be evaluated with a thorough history and physical examination. In taking the history, the onset, quality, and duration of the incontinence control is determined. If the consistency of the stool is abnormal, a brief dietary history should be obtained, with particular attention to the amount of fluid consumed. There is a myth in American culture that drinking a minimum of eight glasses of water is magically good for one's health, and many people assume that even more is better.

After a thorough history, the patient is examined and evidence of systemic disease is sought. The abdomen is assessed for tenderness or masses. The perineum is inspected for deformity or scarring. The anus may appear asymmetric or patulous. On digital rectal examination, palpable defects in the muscle may be appreciated. The resting tone of the anal canal and the strength of contraction with voluntary effort are assessed. In general, patients without evidence of muscle asymmetry on examination, especially those with decreased resting tone, are likely to have a neuropathic component.

Treatment

When all diagnostic data are collected, an appropriate treatment regimen can be developed. Conservative measures are very important to control symptoms and improve quality of life. Dietary modifications can be of clear benefit in lactose-intolerant patients and in those with excessive fluid consumption. Gastrointestinal transit can be slowed with anticholinergic agents. Loperamide is known to inhibit gastrointestinal muscle activity and therefore slow transit time. Additionally, loperamide increases resting anal pressure of the internal sphincter muscle. As the internal sphincter contributes up to 85% of continence with resting tone, improved resting pressure translates into improved control of stool.

Surgery is appropriate for a relatively small percentage of incontinent patients. Essentially, surgery can be offered to those patients with mechanical disruption of sphincter muscle (such as failure of healing an obstetrical injury) or minor tissue loss with a 90% plus expectation of functional improvement. Reconstructive operations for major tissue loss.

Graciloplasty, recreation of the sphincter by tissue transfer from the thigh, and gluteoplasty, gluteal muscle transposition, are two advanced and complicated techniques that are used for appropriate patients.

The artificial anal sphincter is an implanted, inflatable device that is deactivated to allow for passage of stool at a desired time. For patients with significant loss of sphincter, severe neuropathy, or who have failed simpler treatment methods, it is a promising alternative. The surgery is less extensive and complicated than muscle transfer.