Functional disorders associated with fecal incontinence include irritable bowel syndrome (diarrhea variant), functional diarrhea, decreased mobility, and decreased cognition.
Several conditions have the potential to cause both defecatory dysfunction and fecal incontinence (Table 28.1). Most of these disorders cause combined symptoms through the development of fecal impaction followed by overﬂow incontinence. This situation can be seen with many of the neurologic conditions, pelvic outlet obstructive disorders, functional disorders of irritable bowel syndrome, decreased mobility, and decreased cognition. The cause of these symptoms is often multifactorial.
Disordered Defecation Disordered defecation can result from outlet obstruction or functional motility disorders.
Anismus/Rectosphincteric Dyssynergia Anismus is otherwise known as rectosphincteric dyssynergia, pelvic ﬂoor dyssynergia, spastic ﬂoor syndrome, and paradoxical puborectalis syndrome. The anorectal angle narrows as a result of paradoxical contraction of the puborectalis and external anal sphincter during defecation. Frequent symptoms include dyschezia, straining, hard stools, incomplete emptying, and tenesmus. A recent prospective study of 120 patients with dyssynergic defecation found a higher prevalence in women (77%) (33,34). The need for digital assistance (digital disimpaction or splinting) to evacuate the rectum occurs in up to 58% of patients. Psychosocial factors, such as a history of sexual abuse, depression, eating disorder, obsessive-compulsive disorder, and stress, may play an important role in this disease. In this study, 22% reported a history of sexual abuse, and 31% reported a history of physical abuse. One-third believed the problem began during childhood, and 24% reported a precipitating illness or surgery was related to a particular event. Five percent of women claimed that pregnancy or childbirth was a precipitating factor. This condition also is seen in young children with constipation and dyschezia. The response to biofeedback and pelvic ﬂoor physical therapy, as well as the aforementioned patient characteristics, indicate a learned response mechanism is involved (33,34). Although this is often categorized as an outlet obstruction, the Rome III criteria for functional gastrointestinal disorders places this in the category of functional defecation disorders. The specific Rome III diagnostic criteria for dyssynergic defecation includes “inappropriate contraction of the pelvic ﬂoor or less than 20% relaxation of basal resting sphincter pressure with adequate propulsive forces during attempted defecation” (35).
Pelvic Organ Prolapse Pelvic organ prolapse bears special mention because it is often seen by gynecologists but inconsistently associated with defecatory dysfunction. Prolapse is very common, although many women with this condition are asymptomatic. Those with symptoms may report incomplete evacuation and the need to apply digital pressure to the posterior vaginal wall or perineum to aid in evacuation of stool (digitation or splinting). It is important to rule out other causes of constipation, because these symptoms are nonspecific, and rectocele can result from chronic straining and increased intra-abdominal pressure due to other etiologies of defecatory dysfunction. Defecatory dysfunction related to pelvic organ prolapse can result from rectocele, enterocele, or perineal descent, either individually or in combination.
Rectocele is a herniation of the rectal mucosa through a defect in the rectovaginal septum.