In a patient post‑fistulotomy with perineal trauma who started diazepam and now has urinary burning, urgency, and frequency, does this indicate nerve compression rather than medication‑induced bladder irritation?

Diazepam-Induced Urinary Symptoms: Medication Effect, Not Nerve Compression

The urinary burning, urgency, and frequency after starting diazepam in this post-fistulotomy patient are most likely caused by the medication itself—not nerve compression—as benzodiazepines are well-documented to cause bladder irritation and urinary retention through anticholinergic effects and detrusor dysfunction. 1, 2, 3

Why This Points to Medication Effect

Benzodiazepines Directly Cause Bladder Symptoms

• Diazepam and other benzodiazepines impair bladder function through multiple mechanisms: they interfere with the complex neurological control of micturition, cause detrusor muscle dysfunction, and can produce both urinary retention and irritative symptoms 1, 2, 3

• Drug-induced bladder dysfunction manifests as burning, urgency, and frequency—the exact symptom constellation this patient is experiencing—because medications can activate or inhibit the adrenergic and cholinergic pathways controlling bladder contraction and relaxation 1, 2

• Up to 10% of urinary retention episodes are attributable to concomitant medication, with benzodiazepines specifically listed among the causative drug classes 3

Nerve Compression Would Present Differently

• True nerve compression from perineal trauma would cause urinary retention (inability to void), not irritative symptoms like burning and urgency 4

• Mechanical urethral or bladder injuries from pelvic/perineal trauma present with hematuria, inability to urinate, blood at the meatus, or suprapubic tenderness—not isolated urgency and burning 5, 4

• Nerve damage severe enough to cause symptoms would typically produce retention with overflow incontinence or complete inability to sense bladder fullness, not the heightened urgency sensation this patient describes 4

Clinical Reasoning Algorithm

Step 1: Assess for Structural Injury (Rule Out First)

• Check for blood at the urethral meatus, gross hematuria, or inability to void—these indicate urethral or bladder injury requiring imaging 5, 4

• If present: obtain retrograde urethrogram or contrast-enhanced CT with delayed phase to evaluate for structural damage 5

• If absent and patient can void: structural injury is unlikely 5, 4

Step 2: Evaluate Medication Timeline

• Document exact temporal relationship: Did symptoms begin within days of starting diazepam? 1, 2

• Review for other anticholinergic medications: antipsychotics, antidepressants, antihistamines, or opioids that could compound bladder effects 1, 2, 3

• Consider patient age and comorbidities: elderly patients are at higher risk for drug-induced bladder dysfunction 3

Step 3: Trial Discontinuation

• Stop diazepam if clinically feasible and observe for symptom resolution over 3-7 days 1, 2

• If symptoms resolve: diagnosis confirmed as medication-induced bladder dysfunction 1

• If symptoms persist: consider alternative diagnoses including catheter-related bladder discomfort (if catheter present), urinary tract infection, or delayed presentation of trauma-related injury 6, 7

Key Distinguishing Features

Medication-Induced (This Patient)

• Burning, urgency, frequency without retention 1, 2
• Temporal correlation with drug initiation 1
• Ability to void (though with discomfort) 2
• No hematuria or structural findings 2

Nerve Compression/Damage

• Urinary retention as primary feature 4, 3
• Inability to sense bladder fullness 4
• Post-void residual >100 mL 5
• Associated with pelvic fracture or severe perineal trauma 4

Management Approach

Discontinue diazepam immediately and substitute with a non-benzodiazepine anxiolytic or muscle relaxant if needed for the original indication 1, 2

• Avoid other anticholinergic agents during the recovery period 1, 2

• Ensure adequate hydration to dilute urine and reduce irritative symptoms 2

• If catheter is in place: remove as soon as medically appropriate, as catheter-related bladder discomfort mimics and compounds drug-induced symptoms 5, 7

• Monitor for symptom resolution over 3-7 days; persistence beyond this warrants urinalysis to exclude urinary tract infection 5, 6

Critical Pitfall to Avoid

Do not attribute new urinary symptoms to "nerve damage" without first excluding medication effects, as this leads to unnecessary invasive testing and delays simple treatment (drug discontinuation) 1, 2. The presence of irritative symptoms (urgency, burning, frequency) rather than retention strongly favors a medication etiology over structural nerve injury 1, 2, 3.