Epidemiologic Trends and Diagnostic Evaluation of Fecal Incontinence

Abstract

Fecal incontinence (FI) is a prevalent condition that occurs in up to 15% of the Western population and significantly impairs quality of life. The current understanding of the epidemiology of FI is shifting because of an increasing recognition of FI in men, better appreciation for the impact of changing obstetric practices on FI in women, and comprehension of the effect of modifiable risk factors on the development of FI over time. The pathophysiology of FI is complex and multifactorial, which necessitates the use of multiple diagnostic tests, including tests of anorectal sensorimotor function, peripheral nerve function, and anatomic structure. Translumbosacral anorectal magnetic stimulation is an emerging noninvasive diagnostic test for assessing lumbosacral neuropathy. This article is not intended as a comprehensive recitation of the literature, but rather focuses on recent developments in the understanding of the epidemiology of FI, as well as on the diagnostic evaluation of this condition. This article aims to increase awareness of FI and to outline an initial diagnostic approach to affected patients.

Keywords: Fecal incontinence; International Anorectal Physiology Working Group; London classification; high-resolution anorectal manometry; translumbosacral anorectal magnetic stimulation.

Figure 1.

High-resolution anorectal manometry in an individual without fecal incontinence (A, C) and with fecal incontinence (B, D). Pressure topography plots are shown in A and B. Waveform plots are shown in C and D, with each line of the y-axis representing 0 to 100 mm Hg. The green line tracings in C and D represent the anal sphincter during the squeeze maneuver. Maximum squeeze pressure is shown by the black arrows, and sustained squeeze pressure is outlined by the red arrows. The black dotted lines demarcate the transition from maximum squeeze pressure to sustained squeeze pressure.

Figure 2.

The International Anorectal Physiology Working Group standardized protocol for anorectal manometry evaluation in the assessment of anorectal disorders. RAIR, rectoanal inhibitory reflex.

Figure 3.

London classification part II: disorders of anal tone and contractility. LLN, lower limit of normal; ULN, upper limit of normal.

Figure 4.

A: TAMS testing is performed with single-pulse stimulations delivered at bilateral L2 to L3 (lumbar) locations (1) and bilateral S2 to S3 (sacral) locations (2) via a magnetic coil. B: MEPs are recorded with an anorectal EMG probe that has rectal and anal electrodes. C: A classic MEP recording of a healthy individual with normal latency (2.94 ms). D: A representative MEP recording of an FI patient with prolonged latency (5.85 ms). EMG, electromyography; FI, fecal incontinence; MEP, motor-evoked potential; ms, millisecond; TAMS, translumbosacral anorectal magnetic stimulation; µV, microvolts.

Figure 5.

Anal endosonography images. A shows a healthy individual with a hypoechoic internal anal sphincter (orange arrow) and mixed hypo- and hyperechoic external anal sphincter (blue arrow). B shows an FI patient with both internal and external anal sphincter defects (between the red arrows) and hemicircumferential anal sphincteroplasty (between the yellow arrows). C shows an FI patient with lateral anal sphincterotomies (green arrows). FI, fecal incontinence.