Constipation Defecatory Disorder

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name: constipation-defecatory-disorder
description: Step-wise management of constipation caused by defecatory disorder (pelvic floor dysfunction, dyssynergia, outlet obstruction) using the WGO cascade framework. Trigger when a patient strains excessively even with soft stools, uses manual manoeuvres to defecate, has difficult defecation with a feeling of blockage, is suspected of having pelvic floor dyssynergia, anorectal dyssynergia, obstructed defecation, or rectocele causing constipation.
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# Constipation — Defecatory Disorder Management Pathway

> **Use this skill when constipation features suggest outlet obstruction / pelvic floor dysfunction, NOT simple slow-transit constipation.**
> Alarm symptoms must be excluded before starting.

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## STEP 1 — Recognise Defecatory Disorder

**Suspect defecatory disorder if ≥1 of the following:**

- Prolonged/excessive straining even when stools are soft
- Difficult defecation despite the urge to defecate
- Sensation of blockage or incomplete evacuation
- Patient applies perineal or vaginal pressure to defecate
- Manual manoeuvres required to aid defecation (digital evacuation)
- High basal sphincter pressure on anorectal manometry
- Failed balloon expulsion test

> ⚠️ Up to 50% of defecatory disorder patients also have delayed colonic transit — treat the outlet problem first.

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## STEP 2 — Confirm and Classify (if resources allow)

| Finding | Suggests |
|---|---|
| Failed balloon expulsion test | Evacuation disorder (screening test) |
| High anal resting pressure + paradoxical sphincter contraction | Dyssynergia / anismus |
| Anorectal manometry: impaired push effort, absent RAIR | Hirschsprung disease (refer) |
| MR proctography / defecography: rectocele, rectal prolapse, intussusception | Structural cause |

**Investigation cascade (resource-dependent):**
- **Level 1:** Anorectal exam + balloon expulsion test + 1-week bowel diary
- **Level 2:** Defecography
- **Level 3:** MR proctography + anorectal manometry + sphincter EMG

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## STEP 3 — Treatment by Resource Level

### 🟢 LEVEL 1 — All patients, start here

**A. Dietary and behavioural modifications:**
- Increase dietary fibre gradually (target 20–30 g/day)
  > ⚠️ Exception: avoid fibre supplementation if obstructive symptoms dominate (can worsen bloating/distension)
- Adequate hydration
- **Timed bowel training:** attempt defecation 20–30 minutes after meals (gastrocolic reflex); use squatting posture; do not suppress urge
- Avoid straining — teach relaxation technique during defecation attempt

**B. Basic laxative therapy for constipation component:**
- Osmotic laxative (PEG 17 g daily or lactulose 15 g daily) to soften stool
- Stimulant laxatives (bisacodyl 5–10 mg) for short-term rescue if needed
- Goal: achieve soft, easy-to-pass stool — this reduces outlet resistance

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### 🟡 LEVEL 2 — If Level 1 fails; medium-resource setting

**A. Biofeedback therapy (first-choice for pelvic floor dyssynergia):**
- Retrains coordination of abdominal and pelvic floor muscles during defecation
- Particularly effective for dyssynergia / anismus
- Typically 4–6 sessions with a trained physiotherapist or GI specialist
- Can retrain paradoxical sphincter contraction and improve push effort

**B. Psychological therapy:**
- CBT or gut-directed hypnotherapy
- Address comorbid anxiety, depression, catastrophising, maladaptive coping
- Psychological factors can drive and perpetuate defecatory dysfunction

**C. Neuromodulators (if visceral pain or hypersensitivity prominent):**
- Secondary-amine TCAs: nortriptyline or desipramine (avoid amitriptyline — worsens constipation)
- SNRIs: may benefit patients with predominant pain + mood symptoms
- Prescribe within a shared decision-making framework with bowel habit monitoring

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### 🔴 LEVEL 3 — Extensive resources; surgical evaluation

Indicated only after failure of conservative and biofeedback therapy AND thorough evaluation by a multidisciplinary team.

**Structural causes amenable to surgery:**
- **Rectocele** → resection rectopexy, laparoscopic ventral mesh rectopexy (83–100% improvement in studies)
- **Rectal internal prolapse / intussusception** → laparoscopic ventral mesh rectopexy or suture rectopexy
- **Obstructed defecation (rectocele + intussusception)** → STARR (Stapled Trans-Anal Rectal Resection)
  - Effective but complication rate up to 36% (bleeding, fecal urgency, flatus incontinence)
  - Recurrence ~12% at 36 months
- **Severe refractory functional constipation with confirmed STC** → subtotal colectomy with ileorectal anastomosis (highly selected, specialised centre only)

> ⚠️ Surgery should only be offered after physiological testing confirms the cause lies in the colon/rectum. All conservative options must be exhausted first.

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## Clinical Guardrails

- **Don't prescribe fibre supplements blindly** — in defecatory disorders with obstructive features, fibre worsens bloating and distension
- **Biofeedback is the cornerstone of dyssynergia management** — not laxatives alone
- **Laxatives treat the constipation component, not the outlet problem** — use both, but don't rely only on laxatives
- **Normal balloon expulsion test does NOT exclude dyssynergia** — always interpret alongside anorectal manometry
- **STARR has significant complication risk** — patient selection must be rigorous; reserve for confirmed obstructive defecation with structural cause
- **Up to 50% of these patients have mixed pathology** (outlet + slow transit) — reassess transit after treating the outlet
- **Sacral nerve stimulation (SNS) is NOT recommended for chronic constipation** — lack of consistent efficacy in RCTs

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*Source: WGO Global Guideline — A Global Cascade Approach to Diagnosis and Management of Chronic Constipation. World Gastroenterology Organisation, 2025.*