In a patient with rectal heaviness, deep perineal pressure, reduced sexual sensation, mild bladder irritation after a single prolonged straining episode, preserved continence and normal superficial sensation, what is the likely underlying cause?

Rectal Heaviness: Likely Pelvic Floor Hypertonicity with Possible Pudendal Nerve Involvement

In a patient with rectal heaviness, deep perineal pressure, reduced sexual sensation, and mild bladder irritation following a single prolonged straining episode—with preserved continence and normal superficial sensation—the most likely underlying cause is acute pelvic floor muscle hypertonicity (spasm), potentially with transient pudendal nerve stretch injury. 1, 2

Clinical Reasoning and Pathophysiology

Your symptom constellation points to pelvic floor muscle dysfunction of the hypertonic type rather than structural prolapse or nerve transection:

• Rectal heaviness and deep perineal pressure are hallmark symptoms of pelvic floor muscle spasm (hypertonicity), which creates a sensation of incomplete evacuation and pelvic fullness even without anatomic prolapse 1, 2

• The acute onset after a single prolonged straining episode suggests that excessive Valsalva triggered protective muscle guarding or direct muscle injury, leading to sustained pelvic floor contraction 1

• Reduced sexual sensation with preserved continence and normal superficial sensation indicates selective involvement of deep pelvic structures (pudendal nerve branches to deep perineum and genitalia) while sparing the superficial perineal nerve and anal sphincter innervation 3, 4

• Mild bladder irritation reflects the shared neuromuscular pathways between urinary and defecatory function; pelvic floor hypertonicity commonly affects both systems simultaneously 5, 1

Why This Is NOT Structural Prolapse or Complete Nerve Injury

• Preserved fecal continence excludes significant pudendal neuropathy or sphincter denervation, which would manifest as incontinence to flatus or stool 6, 4

• Normal superficial sensation rules out complete pudendal nerve transection; complete injury would cause perianal numbness and anesthesia 4

• Acute onset after a single event is inconsistent with chronic pelvic organ prolapse, which develops gradually over years from cumulative obstetric trauma, chronic straining, or aging 7

Diagnostic Approach

Essential Clinical Examination

Perform a digital rectal examination (DRE) to assess:

• Resting anal sphincter tone—expect normal or elevated tone (hypertonicity) rather than the lax tone seen in pudendal neuropathy 5, 3

• Puborectalis muscle contraction during squeeze—assess for paradoxical contraction or inability to relax during simulated defecation, which confirms pelvic floor dyssynergia 5

• Localized tenderness along the puborectalis muscle (levator ani syndrome)—a key finding in pelvic floor spasm 5

• Perineal descent during straining—excessive descent suggests chronic pelvic floor weakness, while minimal descent with pain suggests acute hypertonicity 5

Laboratory and Imaging

• No routine laboratory tests are indicated in the absence of alarm features (rectal bleeding, anemia, weight loss, fever) 5

• MR defecography is NOT indicated as initial imaging for this acute presentation; it is reserved for chronic defecatory disorders unresponsive to conservative therapy or when structural abnormalities (enterocele, sigmoidocele, rectal intussusception) are suspected 7, 3

• Consider MR defecography only if symptoms persist beyond 8–12 weeks or if DRE reveals structural abnormalities requiring anatomic confirmation 7, 3

Specialized Testing (If Symptoms Persist)

• Anorectal manometry with balloon expulsion test is the first-line diagnostic test for suspected defecatory disorder, measuring recto-anal coordination and pelvic floor relaxation 5

• Diagnostic pudendal nerve block may be considered if neuropathic symptoms (reduced genital sensation) persist, though complete anesthesia of all pudendal branches occurs in only 13.2% of cases 3

Initial Management Algorithm

Step 1: Conservative Measures (First 2–4 Weeks)

• Avoid further straining—discontinue any constipating medications if feasible 5

• Increase dietary fiber to 25–30 g daily and ensure adequate hydration to soften stool and minimize anal trauma 5, 8

• Warm sitz baths 2–3 times daily to promote pelvic floor muscle relaxation 8

• Encourage regular physical activity and prompt toileting in response to urge 5

Step 2: Pelvic Floor Physical Therapy (If No Improvement After 2–4 Weeks)

• Refer to a pelvic floor physical therapist for manual therapy, trigger point release, and biofeedback training 2, 9

• Pelvic floor physical therapy (PFPT) is first-line treatment for pelvic floor hypertonicity, with evidence of efficacy in chronic pelvic pain, dyspareunia, and voiding dysfunction 2

• Biofeedback therapy trains patients to relax pelvic floor muscles during straining, restoring normal recto-anal coordination with success rates exceeding 70% in dyssynergic defecation 5

Step 3: Specialized Interventions (If Symptoms Persist Beyond 8–12 Weeks)

• Trigger point injections (local anesthetic ± corticosteroid) may relieve pain in refractory cases 9

• Botulinum toxin A injection into hypertonic pelvic floor muscles has been reported for refractory symptoms 9

• Sacral neuromodulation or acupuncture may be considered in highly selected cases unresponsive to conservative therapy 9

Red Flags Requiring Urgent Evaluation

• Rectal bleeding, anemia, unintentional weight loss, or fever mandate colonoscopy to exclude colorectal malignancy or inflammatory bowel disease 5

• Progressive fecal incontinence or new-onset urinary retention suggests evolving pudendal neuropathy or cauda equina syndrome requiring urgent neurological evaluation 3, 4

• Perianal numbness or anesthesia indicates complete pudendal nerve injury requiring immediate specialist referral 3, 4

Common Pitfalls to Avoid

• Do not rush to imaging (MRI, defecography) in acute presentations—these are reserved for chronic symptoms unresponsive to conservative therapy 7

• Do not attribute all pelvic floor symptoms to hemorrhoids or irritable bowel syndrome without performing a focused DRE to identify pelvic floor hypertonicity 5, 1

• Do not assume structural prolapse based on symptoms alone—preserved continence and acute onset argue against significant anatomic defects 7, 6

• Do not delay referral to pelvic floor physical therapy if symptoms persist beyond 2–4 weeks of conservative measures; early intervention improves outcomes 2, 9