Clinical Review

2014 Update on pelvic floor dysfunction

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Bowel management for the gynecologist

IN THIS ARTICLE

  • Long-term PEG usage safe and effective?
  • New and trendy OTC treatment option
  • Bowel prep before laparoscopic gynecologic surgery
  • Bowel prep before vaginal surgery


 

References

Constipation is estimated to affect up to 27% of the general population and is more common in women, with a 2:1 female-to-male ratio.1 Because gynecologists are frequently the main care provider for many women, understanding the diagnosis and treatment options for constipation is important. Additionally, gynecologists must manage bowel function during the perioperative period.

The diagnosis of constipation is based on the Rome III criteria.2 Besides frequency of bowel movements (BMs), these criteria include evacuation symptoms and the presence of hard stools (TABLE 1). These symptoms can result from delay in colonic transit or outlet dysfunction. Constipation may be secondary to medical illness, such as central or peripheral neurologic disease, diabetes mellitus, hypothyroidism, or medications. Evaluation begins with a careful history and vaginal and perianal/anal examination.3 Initially, a trial of fiber supplementation with or without over-the-counter (OTC) laxatives may be tried (TABLE 2). If patients have an inadequate response to this therapy, further evaluation may be pursued (ALGORITHM).

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TABLE1 Rome III criteria for functional constipation in adults*

1. Must include ≥2 of the following signs
or symptoms:

  • Straining during ≥25% of defecations
  • Lumpy or hard stools in ≥25% of defecations
  • Sensation of incomplete evacuation for ≥25% of defecations
  • Sensation of anorectal obstruction/blockage for ≥25% of defecations
  • Manual maneuvers to facilitate ≥25% of defecations (ie, digital evacuation, support of the pelvic floor)
  • <3 defecations per week

2. Loose stools are rarely present without the use of laxatives

3. Insufficient criteria for irritable bowel syndrome
*At least 3 months, with symptoms beginning ≥6 months before diagnosis.

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TABLE 2 Common treatments for constipation
Bulk-forming laxatives absorb water, increasing fecal mass
  • psyllium seed (Metamucil)
  • methylcellulose (Citrucel)
  • calcium polycarbophil (FiberCon)
  • wheat Dextran (Benefiber)

Surfactant agents lower the surface tension of stool, allowing water to enter the stool

  • docusate sodium (Colace)

Osmotic laxatives contain poorly/nonabsorbed substances, leading to intestinal water secretion

  • polyethylene glycol (MiraLAX)
  • magnesium citrate (Milk of Magnesia)

Stimulant laxatives increase colonic transit and alter electrolyte transport across the colonic mucosa

  • bisacodyl (Dulcolax)
  • senna (Senokot)

In this article, we review the results of randomized trials comparing the efficacy of OTC medical treatments for constipation, including daily, low-dose polyethylene glycol (PEG) and probiotics. Additionally, we review key trials evaluating perioperative bowel management prior to laparoscopic gynecologic and vaginal surgery.

LONG-TERM PEG USAGE SAFE AND EFFECTIVE?

Corazziari E, Badiali D, Bazzocchi G, et al. Long-term efficacy, safety, and tolerability of low daily doses of isosmotic polyethylene glycol electrolyte balanced solution (PMF-100) in the treatment of functional chronic constipation. Gut. 2000;46(4):522–526.

In this multicenter, randomized, double-blind, placebo-controlled, parallel trial, investigators evaluated the safety, efficacy, and tolerability of a daily low-dose PEG-based osmotic diuretic.

Details of the study
Seventy-eight patients (80% of them female) aged 18 to 75 years with chronic constipation, defined by Rome III diagnostic criteria, underwent a 4-week “run-in” period, with a standardized daily diet of fiber 15 g, water 1500 mL, and twice-daily PMF-100 (PEG/osmotic solution). Patients were randomized if they responded to the regimen, with response defined as having at least two BMs per week and no defecatory disturbance or at least three BMs per week with or without defecatory disturbance. Eight patients were not randomized, one due to nonresponsiveness. Study patients completed 20 weeks of either twice-daily PMF-100 or placebo. Patients, at their own discretion, decreased the frequency of the study drug based on the frequency of their BMs. Use of another laxative was not allowed unless a BM had not occurred over a 5-day period.

The combined primary outcome was at least three BMs per week, no defecatory disturbances, and no additional laxative use. Secondary outcomes (frequency of BMs and defecatory disturbances) were assessed using a bowel diary.

No differences were noted in baseline measurements between the two groups. Of the PMF-100 group, 70% completed the study, compared with 30% of the placebo group (P<.01). Nonresponse to treatment was the reason for dropout in 7% and 46% of patients, respectively (P<.005). Other causes of withdrawal did not differ between the groups.

At the end of the 20 weeks, 77% of patients in the PMF-100 group reported remission, compared with 20% in the placebo group (P<.001). During the study, the PMF-100 group reported more BMs per week (7.4 vs 4.3; P<.001). Furthermore, the treatment group was less likely to report straining at defecation, hard/pellet stools, and need for use of additional laxatives. Adverse events (nausea, anal pain/itching, hematochezia, epigastric pain, and fecal incontinence) were similar between groups. There were no differences in laboratory values.

Study strengths
This was a well-designed trial showing the safety, efficacy, and tolerability of a daily low-dose PEG-based osmotic diuretic. The population was mainly women with functional chronic constipation, similar to a gynecologic population. The results of this trial are consistent with what has been shown for other trials various PEG preparations.4,5

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