Explanation:
Fecal incontinence is the involuntary loss of loose or solid stool, which affects approximately 10% of women. Fecal continence depends on a complex interplay between the internal anal sphincter, the external anal sphincter, the puborectalis muscle, the nervous system, and the rectum. The etiology may be neurological and non-neurological. Anal sphincter disruption is the most common cause of fecal incontinence in women, particularly after an obstetrical anal sphincter injury. Neurological causes include a pudendal nerve dysfunction or nervous system disorder or injury (e.g., stroke, spinal cord injury, multiple sclerosis). Incontinence of flatus or loose or solid stool should be assessed and classified as passive incontinence, urge incontinence, or fecal seepage.
A detailed physical exam must include a perineal exam, digital rectal exam, and neurological exam. Absence of perianal creases, the “dovetail” sign, indicates disruption of the external anal sphincter. Physical exam findings may be confirmed with anorectal manometry, anal endosonography, the balloon expulsion test, and pudendal nerve terminal motor latency. Colonoscopy may also be considered with new onset of symptoms and concerns for malignancy. Nonsurgical treatment includes fiber supplementation, antimotility agents, laxatives, and pelvic floor muscles exercises. Surgical options include anal sphincter bulking agents, sacral nerve stimulation, sphincteroplasty, or artificial sphincter. Finally, a colostomy may provide an improved quality of life in patients with otherwise incapacitating fecal incontinence when other treatment options are not suitable or have been unsuccessful.
Loss of the anocutaneous reflex (B) indicates a neurological dysfunction along the afferent or efferent S2, S3, or S4 nerves or at the level of the spinal cord. Obtuse anorectal angle (C) on digital rectal exam indicates a dysfunction of the puborectalis muscles. The puborectalis muscles normally maintain a 90° angle at rest, an acute 70° angle with contraction for continence, and relax to an obtuse 120° angle to allow for defecation. Protrusion of the rectal mucosa (D) indicates rectal prolapse, which is due to an internal intussusception of the rectal wall.
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