What is the appropriate diagnostic work‑up and management for a 33‑year‑old woman with chronic constipation requiring manual evacuation, bloating, heartburn, right iliac fossa colicky pain, tenesmus, anal pain while sitting, abdominal fullness, borderline vitamin B12 deficiency, subclinical hypothyroidism, and mild circumferential thickening of the distal rectum on contrast‑enhanced computed tomography?

Diagnostic Work-Up and Management

Immediate Diagnostic Impression

This patient has a defecatory disorder (dyssynergic defecation) requiring anorectal manometry, balloon-expulsion testing, and biofeedback therapy as first-line definitive treatment. 1, 2, 3

The need for regular manual evacuation, tenesmus, sharp anal pain while sitting, and passage of small soft stools with mucus are pathognomonic clinical features that strongly indicate pelvic floor dysfunction rather than slow-transit constipation or irritable bowel syndrome. 1, 2, 3

---

Critical Diagnostic Algorithm

Step 1: Confirm Defecatory Disorder Through History

Key historical features that establish the diagnosis:

• Manual digital evacuation on a regular basis is the single strongest clinical clue for dyssynergic defecation, with 85% specificity. 1, 4
• Tenesmus (persistent urge with inability to evacuate) combined with soft stools indicates outlet obstruction, not colonic inertia. 1, 2
• Type 4 stools that require manual extraction definitively excludes slow-transit constipation; soft stools that are difficult to pass are the hallmark of pelvic floor dyssynergia. 1, 2, 3
• Small bits of soft stool with mucus/jelly suggest incomplete rectal emptying due to paradoxical pelvic floor contraction. 1, 3

Step 2: Perform Digital Rectal Examination

The DRE must assess four specific parameters: 1, 2

• Resting anal sphincter tone – high tone suggests dyssynergia. 1, 3
• Puborectalis contraction during squeeze – paradoxical contraction during simulated defecation confirms dysfunction. 1, 3
• Perineal descent during simulated evacuation – absent or reduced descent indicates impaired pelvic floor relaxation. 1, 2
• Ability to "expel my finger" – inability to generate coordinated expulsive force is diagnostic. 1, 2

Important caveat: A normal DRE does not exclude defecatory disorder; up to 30% of patients with proven dyssynergia have unremarkable digital examination. 1, 2

Step 3: Laboratory Evaluation

Order only a complete blood count. 1, 2, 3

• Her hemoglobin of 12.7 g/dL and MCV of 87 fL are normal, excluding anemia as an alarm feature. 1, 3
• Do not order metabolic panels (glucose, calcium, TSH) unless other clinical features warrant them; the diagnostic utility is extremely low in the absence of systemic symptoms. 1, 2, 3
• Her TSH of 4.36 mIU/L is borderline elevated but does not meet criteria for overt hypothyroidism; subclinical hypothyroidism is not a primary cause of her defecatory symptoms and should not delay anorectal testing. 3
• Her vitamin B12 of 222 pg/mL is borderline low but does not cause constipation; supplementation can be considered separately. 3

Step 4: Address the Rectal Thickening on CT

The mild circumferential thickening of the distal rectum requires colonoscopy with biopsy. 1, 3

• Although she lacks classic alarm features (no rectal bleeding, no anemia, no weight loss), any structural abnormality on imaging mandates endoscopic evaluation to exclude proctitis, inflammatory bowel disease, or early malignancy. 1, 3
• Colonoscopy should be performed before anorectal manometry to exclude structural causes that could confound functional testing. 1, 3
• If colonoscopy and biopsies are normal, proceed immediately to anorectal physiologic testing. 2, 3

Step 5: Order Anorectal Manometry and Balloon-Expulsion Test

These are the essential first-line diagnostic tests for suspected defecatory disorder. 1, 2, 3

• Anorectal manometry measures resting and squeeze anal pressures, evaluates anal sphincter relaxation during simulated defecation, and assesses rectal sensory thresholds. 2, 3
• Balloon-expulsion test is abnormal if the patient cannot expel a 50-mL water-filled balloon within 1–3 minutes; failure to expel confirms dyssynergic defecation. 2, 3
• Do not order colonic transit studies at this stage; transit testing is reserved for patients with normal anorectal function or those who fail biofeedback therapy. 2, 3, 5

Expected manometric findings in this patient: 2, 3

• Paradoxical anal sphincter contraction or <20% relaxation during push maneuvers.
• Failure to expel the balloon.
• Possibly elevated rectal sensory thresholds (hyposensitivity), which would predict poorer biofeedback response.

Step 6: Consider Defecography Only if Manometry Results Are Discordant

Fluoroscopic or MR defecography is a third-line test. 2, 3

• Order defecography only if anorectal manometry and balloon-expulsion results are contradictory or if structural pelvic floor abnormalities (rectocele, intussusception, enterocele) are suspected. 2, 3
• In this patient, defecography is not indicated initially because her clinical presentation is classic for dyssynergia. 2, 3

---

Management Algorithm

Phase 1: Immediate Symptomatic Relief (First 1–2 Weeks)

While awaiting anorectal testing, initiate empiric treatment to reduce straining and improve quality of life: 2, 3

1. Discontinue any constipating medications – review all prescriptions and over-the-counter agents (opioids, anticholinergics, calcium-channel blockers, iron supplements). 1, 2, 3
2. Polyethylene glycol (PEG) 17 g daily – osmotic laxative with superior efficacy and safety; softens stool to reduce straining. 2, 3
3. Bisacodyl 10 mg orally once daily – stimulant laxative to promote daily bowel movements and reduce the need for manual evacuation. 2, 3
4. Increase fluid intake to at least 1.5 L/day – essential to prevent stool desiccation. 2, 3
5. Toileting habits – defecate 30 minutes after meals (gastrocolic reflex), use a footstool to elevate knees above hips (squatting position), and limit straining to ≤5 minutes. 2, 3
6. Avoid high-fiber supplementation until adequate hydration is ensured; fiber can worsen symptoms in defecatory disorders. 2, 3

Important pitfall: Do not assume this is irritable bowel syndrome or slow-transit constipation and prescribe fiber or prokinetics; these will fail because the primary problem is outlet obstruction. 1, 2, 3

Phase 2: Definitive Treatment After Anorectal Testing

Biofeedback therapy is the first-line definitive treatment for dyssynergic defecation, with a Grade A recommendation and 70–80% success rate. 2, 3

• Mechanism: Biofeedback uses visual or auditory feedback to train patients to relax pelvic floor muscles during straining, restoring normal recto-anal coordination. 2, 3
• Protocol: Typically 4–6 sessions over 8–12 weeks with a trained pelvic floor therapist. 2, 3
• Predictors of success: Lower baseline rectal sensory thresholds and absence of depression predict better outcomes. 3
• Predictors of failure: Elevated first-sensation threshold and presence of depression independently predict poor response. 3

If biofeedback fails or is unavailable, consider:

• Rectal bisacodyl suppositories 10 mg once daily for local stimulation. 2
• Referral to a colorectal surgeon for evaluation of structural abnormalities (e.g., rectocele requiring repair). 1, 3

Phase 3: Reassess Only if Biofeedback Fails

If symptoms persist after 8–12 weeks of biofeedback, order colonic transit study. 2, 3, 5

• Rationale: Up to 30% of patients have combined dyssynergic defecation and slow-transit constipation; transit testing identifies this subset. 1, 3, 5
• If transit is slow despite successful biofeedback: Add prucalopride 2 mg once daily (prokinetic agent with strong evidence for slow-transit constipation). 5
• If transit is normal: Reassess for rectal sensory impairment and consider sensory retraining biofeedback. 3

---

Management of Concurrent Symptoms

Bloating, Heartburn, and Abdominal Fullness

These symptoms are secondary to incomplete rectal evacuation and chronic straining, not primary gastrointestinal pathology. 1, 3

• Bloating and abdominal fullness result from retained stool and gas in the rectum due to outlet obstruction; they will improve with successful biofeedback. 1, 3
• Heartburn may be exacerbated by increased intra-abdominal pressure from chronic straining; treat empirically with a proton-pump inhibitor (e.g., omeprazole 20 mg daily) while addressing the defecatory disorder. 1

Right Iliac Fossa Colicky Pain

This is likely referred pain from rectal distension or secondary to irritable bowel syndrome overlap. 1, 3

• Do not attribute RIF pain to appendicitis or ovarian pathology unless other clinical features emerge; the CT already excluded acute intra-abdominal pathology. 1, 3
• Reassess after biofeedback – if pain persists despite resolution of constipation, consider IBS-C and add low-dose tricyclic antidepressant (e.g., amitriptyline 10–25 mg at bedtime) for visceral hypersensitivity. 1, 3

Acne Over Mandible and Under Chin

This is unrelated to constipation and should be managed separately by dermatology. 1

Sleep Deprivation (4–5 Hours/Night)

Chronic sleep deprivation exacerbates gastrointestinal symptoms and impairs pelvic floor coordination. 1

• Address sleep hygiene as part of holistic management; poor sleep independently worsens constipation and pain perception. 1

---

Common Pitfalls to Avoid

1. Do not order routine colonoscopy in young patients without alarm features or incomplete age-appropriate screening; however, this patient's rectal thickening on CT mandates endoscopic evaluation. 1, 2, 3
2. Do not order colonic transit studies before anorectal testing – up to one-third of patients with slow transit have secondary slowing due to untreated dyssynergia. 1, 2, 3, 5
3. Do not prescribe high-dose fiber or bulk laxatives – these worsen symptoms in defecatory disorders by increasing stool volume that cannot be evacuated. 2, 3
4. Do not assume irritable bowel syndrome without first excluding defecatory disorder; the two conditions overlap in 30% of cases but require different treatments. 1, 2, 3
5. Do not proceed to surgery (e.g., colectomy) without confirming normal anorectal function; surgical outcomes are disastrous in unrecognized dyssynergia. 1, 5

---

Referral Pathway

Refer to gastroenterology or a pelvic floor specialist for: 2, 3

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

Refer to colorectal surgery only if: 1, 5

• Structural abnormalities (e.g., large rectocele, rectal prolapse) are identified on defecography and require surgical repair.
• True slow-transit constipation is confirmed after excluding and treating defecatory disorder, and medical therapy has failed.