Fecal seepage and soiling: a problem of rectal sensation

To determine the physiologic alteration resulting in fecal seepage and soiling, results of anorectal manometric testing were evaluated in patients with varying degrees of fecal incontinence.

Anal manometric studies performed on 170 patients with fecal incontinence were reviewed. Results of their studies, including mean resting pressure, maximum resting pressure, maximum squeezing pressure, minimum rectal sensory volume, and minimum volume at which reflex relaxation first occurs, were compared with those of 35 control group subjects with normal fecal continence. Manometric studies were performed using a four-channel, water-perfused catheter. Incontinent patients were divided into three groups based on presenting complaints: complete incontinence (incontinence of gas and liquid and solid stool), partial incontinence (incontinence of gas and liquid), and seepage and soiling (incontinence of small amounts of liquid and solid stool without immediate awareness).

Resting pressures were significantly lower in complete incontinence, partial incontinence, and seepage and soiling groups than in the controls (P < 0.001). Resting pressures of the complete incontinence group were also significantly lower than those of the partial incontinence and seepage and soiling groups (P = 0.03). Squeezing pressures were lower for both the complete incontinence and partial incontinence groups than for those in the control group (P < 0.001) and in the seepage and soiling group, which did not differ significantly from controls. The minimum rectal sensory volume was greater in all incontinent groups than in controls (P < 0.001). Sensory volume of the seepage and soiling group was significantly greater than that of the complete incontinence and partial incontinence groups (P < 0.01). The difference between sensory volume and the volume producing reflex relaxation was greatest in the seepage and soiling group and differed from that of the partial incontinence and control groups.

These findings suggest that the mechanism of incontinence is different in seepage and soiling patients and involves a dyssynergy of rectal sensation and anal relaxation. Patients with the pattern of seepage and soiling may be successfully treated with stool bulking agents (e.g., psyllium or bran).