The Patient with Fecal Incontinence

, Jenny Rex² and Patrick Stewart³

(1)

Department of Colorectal Surgery, Concord Repatriation General Hospital, Sydney, NSW, Australia

(2)

Stomotherapy Unit, Royal Prince Alfred Hospital, Sydney, NSW, Australia

(3)

University of NSW Medicine Program, Sydney, NSW, Australia

Abstract

Normally, the rectum is empty, containing only mucus and small amounts of fecal fluid. The anus is held closed at rest by the internal sphincter. Formed stool is usually stored in the sigmoid colon. A stimulus, such as food entering the stomach (gastrocolic reflex), initiates peristalsis in the colon, pushing stool into the rectum. The internal sphincter relaxes (anorectal inhibitory reflex) allowing the stool to be sampled at the level of the pelvic floor. If appropriate, the stool will pass; if not, the external sphincter will squeeze tight, maintaining continence.

Normal Defecation and Investigation of Fecal Incontinence

In order to maintain continence, one needs an intact gastrointestinal tract delivering formed stool to the rectum, a rectum which can distend and propel stool, intact sensory nerves to sense rectal distension and motor nerves to contract the external sphincter and pelvic floor, and unimpaired pelvic floor and sphincter muscles (Fig. 8.1).

Fig. 8.1

Treatment of fecal incontinence. ES external sphincter, IS internal sphincter, PF pelvic floor/puborectalis, PN pudendal nerve, SNS sacral nerve stimulation

Investigation of fecal incontinence includes examination of the gastrointestinal tract (colonoscopy, endoscopy, small bowel series, etc.). Specific pelvic floor investigations include:

Endoanal ultrasound to examine the sphincter muscles.
Anorectal manometry which measures resting and squeeze pressures, sensation to defecate, rectal distensibility and anorectal inhibitory reflex.
EMG studies, either single fiber or pudendal nerve terminal motor latency, to appraise pudendal nerve function.
Defecating proctography may be needed to assess rectal emptying and to exclude rectal prolapse and rectocele.

Case 8.1

A 74-year-old female complains of weeping from her anus with occasional loss of solid stool. The problem is worse with exercise and walking.

Q: What other relevant symptoms would be important to elicit in the history?

A: Usual stool habit: Normally one formed stool per day. No urgency. Rarely needs to strain at stool. Easy to clean after defecation

Pattern of incontinence: No episodes of major incontinence but there is soiling of small amounts of fecal fluid and occasional pellets of stool into underwear several times a week, particularly when out walking. A pad is sometimes worn during the day. There are no incontinent episodes at night. There are sometimes episodes of soiling when passing flatus. There is no urinary incontinence.

Other symptoms: No bleeding, diarrhea, or abdominal pain

Family history: No bowel cancer

Obstetric history: Never pregnant

Past history: No previous bowel or pelvic surgery. No major medical illnesses

Medications: Calcium carbonate

Q: What examination is important?

A: Abdominal examination: Unremarkable

Anal inspection: Perineal excoriation and possible candidiasis; Anus firmly closed at rest with good visible squeeze. No perineal descent, no prolapse on straining.

Digital rectal examination: Normal sphincter tone, length, and bulk. Reasonable puborectalis and external sphincter squeeze

Q: What investigations are important?

A: Endoanal ultrasound: Normal puborectalis. Thinned external sphincter anteriorly, no defect. Normal internal sphincter

Anal manometry: P(max) resting = 50 mmHg (normal = 70 mmHg)

P(max) squeeze = 105 mmHg (normal >85 mmHg). Poorly sustained

Anal single-fiber EMG: Normal during rest and squeeze

Defecating proctogram: Minor rectal mucosal prolapse

Q: What is the likely cause of this patient’s symptoms?

A: There is minor mucosal prolapse. There is probably minor atrophy and deconditioning of the external sphincter resulting in poorly sustained voluntary squeeze.

Q: How should the patient be treated?

A: Biofeedback is the initial treatment of choice with up to 70 % improvement in continence.

Q: What was this patient’s outcome?

A: She returned after treatment reporting much improved incontinence scores and improved quality-of-life score. Objectively, resting pressure was unchanged, but there was improvement in maximum squeeze and cough pressures. Isotonic and isometric fatigue times were very much improved.

What Is Biofeedback Retraining?

Biofeedback is the retraining of patients giving them visual, biological, and verbal feedback on their ongoing treatment. A typical program consists of several visits over a 3–4-month period. These involve: