What is the appropriate evaluation and initial management for a 36‑year‑old adult presenting with bloating, excessive gas, right‑sided dull abdominal pain, constipation requiring straining, and associated malaise and weakness?

Evaluation and Management of a 36-Year-Old with Bloating, Gas, Right-Sided Pain, and Constipation

This patient most likely has a defecatory disorder (pelvic floor dyssynergia) and should undergo anorectal manometry with balloon expulsion testing as the first diagnostic step, followed by biofeedback therapy as definitive treatment. 1, 2

Initial Clinical Assessment

The constellation of constipation requiring straining, bloating, gas, and associated malaise strongly suggests either irritable bowel syndrome with constipation (IBS-C) or a defecatory disorder rather than slow-transit constipation. 1, 2 The key distinguishing features to elicit are:

Critical History Questions

• Does the patient require digital evacuation or manual perineal/vaginal pressure to pass stool? This is the single strongest clinical clue for dyssynergic defecation, with approximately 85% specificity. 1, 2

• Does straining occur even with soft stools? Prolonged excessive straining with soft stools definitively indicates outlet obstruction (defecatory disorder) rather than slow colonic transit. 1, 2

• Are the stools hard or soft? If Bristol Type 4 (soft) stools require manual extraction, this excludes slow-transit constipation and confirms pelvic floor dyssynergia. 2

• Is there a sensation of incomplete evacuation or blockage? This is a hallmark symptom of both IBS and defecatory disorders. 1, 2

• Do symptoms of bloating, pain, and malaise dominate over infrequent bowel movements? This pattern suggests underlying IBS rather than pure constipation. 1

Medication Review

Obtain a complete medication history, as opioids, anticholinergics, calcium channel blockers, and iron supplements commonly cause constipation. 1, 3 At age 36 without chronic pain conditions, opioid-induced constipation is less likely but must be excluded. 3

Physical Examination: Digital Rectal Examination

The DRE must evaluate four parameters systematically: 1, 2

1. Resting anal sphincter tone – high tone supports dyssynergia
2. Puborectalis contraction during squeeze – paradoxical contraction during simulated defecation confirms dysfunction
3. Perineal descent during simulated evacuation – reduced descent indicates impaired pelvic floor relaxation
4. Ability to "expel the examiner's finger" – inability to generate coordinated expulsive force is diagnostic

Important caveat: A normal DRE does not rule out dyssynergic defecation; up to 30% of patients with confirmed dyssynergia have an unremarkable examination. 2

Red Flag Assessment

At age 36, screen for alarm features that mandate urgent evaluation: 4, 3

• Rectal bleeding
• Unintentional weight loss >10%
• Anemia
• Family history of inflammatory bowel disease or colorectal cancer
• Fever or systemic symptoms

If any alarm features are present, colonoscopy is required before functional testing. 3 In the absence of alarm features, colonoscopy is not indicated at this age. 1, 3

Laboratory Evaluation

Order only a complete blood count (CBC). 1, 2, 3 Metabolic panels (glucose, calcium, thyroid-stimulating hormone) are not recommended for chronic constipation unless other clinical features warrant them, as their diagnostic yield is extremely low. 1, 3

Diagnostic Testing Algorithm

First-Line: Anorectal Manometry and Balloon Expulsion Test

Anorectal manometry combined with balloon expulsion testing is the essential first-line diagnostic work-up for suspected defecatory disorder. 1, 2 This testing should be performed before colonic transit studies, as up to one-third of patients have secondary colonic slowing due to untreated dyssynergia. 1, 2

Expected findings in dyssynergic defecation: 2

• Paradoxical anal sphincter contraction or <20% relaxation during push maneuvers
• Failure to expel a 50 mL water-filled balloon within 1–3 minutes
• Possibly elevated rectal sensory thresholds (which predict poorer biofeedback response)

Second-Line: Defecography (Only If Manometry Results Are Discordant)

Fluoroscopic or MR defecography is reserved for cases where anorectal manometry and balloon expulsion test results are discordant, or when structural pelvic floor abnormalities (rectocele, intussusception, enterocele) are suspected. 1, 2

Third-Line: Colonic Transit Study

Colonic transit studies are not indicated initially. 2, 3 They should only be performed if anorectal tests are normal or if symptoms persist after 8–12 weeks of biofeedback therapy, as approximately 30% of patients have combined dyssynergic defecation and slow-transit constipation. 2

Immediate Symptomatic Management (First 1–2 Weeks)

While awaiting anorectal testing, initiate the following: 2

1. Discontinue all constipating medications (if any)
2. Polyethylene glycol 17 g daily (osmotic laxative) to soften stools
3. Bisacodyl 10 mg orally once daily (stimulant laxative) to promote regular bowel movements
4. Fluid intake ≥1.5 L/day
5. Toileting habits:
   • Defecate 30 minutes after meals (gastrocolic reflex)
   • Use a footstool to achieve squatting position
   • Limit straining to ≤5 minutes

Critical pitfall to avoid: Do not prescribe high-dose fiber or bulk laxatives, as they increase stool volume that cannot be evacuated in outlet obstruction and may worsen symptoms. 2

Definitive Treatment: Biofeedback Therapy

Biofeedback therapy is the first-line definitive treatment for dyssynergic defecation, with a Grade A recommendation and 70–80% success rate. 1, 2 The therapy uses visual or auditory feedback to train patients to relax pelvic floor muscles during straining, restoring normal recto-anal coordination. 1, 2

Typical protocol: 4–6 sessions over 8–12 weeks with a trained pelvic floor therapist. 2

Predictors of success: 2

• Lower baseline rectal sensory thresholds
• Absence of depression
• Shorter colonic transit times

Predictors of failure: 2

• Elevated first-sensation threshold
• Presence of depression

Management of Associated Symptoms

Bloating and Gas

Bloating and abdominal fullness are secondary to retained stool and gas from outlet obstruction; they improve with successful treatment of the defecatory disorder. 2 If food intolerances are suspected, a 2-week dietary elimination trial of lactose, fructose, or FODMAPs is the simplest and most cost-effective diagnostic approach. 1, 2

Right-Sided Dull Pain

Right iliac fossa colicky pain is likely referred from rectal distension. 2 Reassess after biofeedback therapy. If pain persists despite resolution of constipation, consider IBS-C and low-dose tricyclic antidepressant (e.g., amitriptyline 10–25 mg at bedtime). 2

Malaise and Weakness

These systemic symptoms may reflect the burden of chronic constipation and should improve with effective treatment of the underlying defecatory disorder. 1 If they persist, reassess for metabolic causes (hypothyroidism, anemia) or depression. 3

When to Escalate or Refer

Refer to gastroenterology or pelvic floor specialist for: 2

• Anorectal manometry and balloon expulsion testing
• Biofeedback therapy
• Management of refractory symptoms after failed biofeedback

Refer to colorectal surgery when: 2

• Defecography reveals structural pelvic floor abnormalities requiring repair
• True slow-transit constipation persists after exhaustive medical management

Critical Pitfalls to Avoid

1. Do not assume IBS without first excluding a defecatory disorder – the two conditions overlap in approximately 30% of cases but require different therapies. 2

2. Do not order colonic transit studies before anorectal testing – up to one-third of patients have secondary slowing due to untreated dyssynergia. 1, 2

3. Do not treat empirically as IBS-C with fiber or prokinetics – the primary problem is outlet obstruction, not colonic inertia. 2

4. Do not perform routine colonoscopy in young patients without alarm features – however, any rectal wall thickening on imaging mandates endoscopic evaluation. 2

5. Do not prescribe proton pump inhibitors empirically for bloating – they are only effective when gastric belching is associated with proven GERD. 1, 2