Q & A: Rectal Prolapse after Long-term Laxative Use

Q. One of my patients with anorexia nervosa binge/purge type who has always complained of constipation and who in the past used large quantities of laxative tablets was recently diagnosed with rectal prolapse. What sort of condition is that? Is that common in patients with eating disorders? (JH, Philadelphia)

A. While not a common feature of eating disorders, cases of rectal prolapse have certainly been reported in the literature, primarily in patients with anorexia nervosa of the binge/purge type, but also in patients with bulimia nervosa, particularly those who suffer from irritable bowel syndrome (IBS), chronic constipation, and laxative abuse (Dis Colon Rectum 1997; 40:1382; IJED 2011; 44:95).

Rectal prolapse consists of the protrusion of rectal muscle wall beyond the verge (opening) of the anus. Factors contributing to the chronic constipation include poor diet and inadequate fiber, dehydration, and a variety of other constitutional and external causes including the anticholingeric effects of some medications. The increased intra-abdominal pressures associated with vomiting are also thought to possibly contribute to the mechanism of prolapse. In rare instances patients have been known to engage in “rectal purging,” i.e., intrarectal digital dilatation to help relieve the constipation, or for the sensation (IJED 2012; 45:456). Little is known about this phenomenon since few clinicians routinely ask patients about this behavior, and shame is likely to prevent many patients from talking to their clinicians about this practice.

Treating rectal prolapse usually requires surgery, but to prevent future recurrences steps are needed to reduce constipation (and rectal digitation in instances where the patient is practicing this behavior).

— JY