Fecal Incontinence

Importance of Fecal Incontinence

• Fecal incontinence has significant social and economic impacts.
• It can impair quality of life and contribute to the loss of ability to live independently.

Terminology and Classification

• Fecal incontinence: involuntary loss of solid or liquid feces.
• Anal incontinence: involuntary loss of solid or liquid feces or flatus.
• Urge incontinence: desire to defecate, but incontinence occurs despite efforts to retain stool.
• Passive incontinence: lack of awareness of the need to defecate before the incontinent episode.

Epidemiology

• Fecal incontinence is more common in females.
• It is often underestimated and underreported due to patient factors.
• The prevalence of fecal incontinence is around 7% in people over 70 years old.

Risk Factors

• Older age.
• Diarrhea.
• Fecal urgency.
• Urinary incontinence.
• Diabetes mellitus.
• Hormone therapy.

Anatomy and Physiology

• The external anal sphincter is a striated muscle under voluntary control.
• The internal anal sphincter is a smooth muscle under autonomic control.
• The cerebral cortex, particularly the superior frontal and anterior cingulate gyri, play a role in the regulation of bowel movements.
• The enteric nervous system, including the inferior mesenteric ganglion and the hypogastric nerves, is involved in the regulation of bowel movements.

Anorectal Sampling

• The rectoanal inhibitory reflex (RAIR) is an important reflex in the regulation of bowel movements.
• The RAIR is mediated by the internal anal sphincter and the rectal wall.

Aetiology and Pathogenesis

• Fecal incontinence can be caused by dysfunction of the anal sphincters, abnormal rectal compliance, and decreased rectal sensation.
• Incontinence is often multifactorial.
• Urge incontinence patients have weakness of the external anal sphincter and decreased rectal capacity.
• Passive fecal incontinence patients often have weakness of the internal anal sphincter.

Evaluation

• History: determining whether fecal incontinence is truly present and its severity.
• Physical examination: inspection of the perianal area, digital rectal examination, and testing of perianal sensation.
• Investigations: laboratory studies, endoscopy, anorectal manometry, endorectal ultrasound, and defecography.

Aetiology

• Mechanical causes: obstetric injury, fistula disease, trauma, and iatrogenic injury.
• Neurogenic causes: pudendal nerve stretch, strain, and medical illness.
• Idiopathic causes: no clear etiology.

Principles of Management

• Patient selection is critical.
• Medically manage those with minimal symptoms or poor surgical candidates.
• Rehabilitation: physiotherapy.
• Surgery reserved for those with repairable, neurologically intact sphincter.

Treatment (Conservative)

• Dietary modification and medications.
• Biofeedback.
• Pelvic floor muscle training and electrostimulation.
• Anal plug.

Dietary Modification and Medication

• Dietary fiber.
• Stool bulking agents (e.g. psyllium).
• Avoid dairy products (especially in lactose intolerance).
• Loperamide.
• Codeine phosphate.
• Cholestyramine.
• Enema program (bowel washout).

Biofeedback

• Mind-body technique that involves using visual or auditory feedback to gain control over involuntary bodily functions.
• Improving the strength of the sphincter (motor skills training).
• Increasing the ability to perceive weak rectal distention (discrimination training).
• Combining the previous two mechanisms (training in the coordination of sphincter contractions with rectal sensation).
• Success more likely if patient is motivated, has intact cognition, and some rectal sensation.

Pelvic Floor Exercises

• Strengthen the pelvic floor muscles that support the bladder and bowel.
• Contract the muscles that normally stop the flow of urine.
• Hold the contraction for three seconds, then relax for three seconds.
• Repeat this pattern 10 times, gradually increasing the duration of the contraction.

Surgical Options

• Injection therapy.
• Sphincteroplasty.
• Sacral nerve stimulation.
• Sphincter reconstruction-muscle transposition.
• Artificial sphincters.
• Magnetic anal sphincter.
• Tibial nerve stimulation.
• Stoma.

Injection Therapy

• First described for use in fecal incontinence in 1993.
• Bulking effect of the injected materials with subsequent collagen deposition helping to enhance continence.
• This technique is safe and simple.

Conclusion

• Majority of patients have a non-surgical cause.
• Conservative management can improve symptoms in many patients.
• Patient selection for surgery is critical.
• Overlapping Sphincteroplasty is the gold standard procedure.
• For patients not amenable to surgery, alternative options include injection therapy, sacral nerve stimulation, artificial anal sphincter, and antegrade continent enemas.