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