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Urinary Retention: Etiology, Classification, Diagnosis, and Management

Urinary retention is the inability to voluntarily empty the bladder completely, resulting in elevated post-void residual (PVR) volume. It is a urologic emergency when acute; chronic retention insidiously damages the upper tracts.

Classification

  • Acute urinary retention (AUR): Sudden, painful inability to void; distended bladder; requires immediate catheterization
  • Chronic urinary retention (CUR): Painless, progressive; large PVR (>300–500 mL); often asymptomatic until complications arise
  • High-pressure vs. low-pressure: Urodynamic distinction; high-pressure → hydronephrosis, renal failure

Etiology (by Mechanism)

CategoryCauses
Obstructive (Mechanical)BPH (men), urethral stricture, bladder neck contracture, prostate cancer, pelvic organ prolapse, urethral stones, phimosis, meatal stenosis
Neurogenic (Detrusor Underactivity / Acontractility)Spinal cord injury, MS, Parkinson's, diabetic neuropathy, cauda equina, post-surgical (pelvic surgery), herpes zoster (S2–S4)
PharmacologicAnticholinergics, antihistamines, opioids, α-agonists (pseudoephedrine), β-blockers, tricyclics, antipsychotics, antispasmodics
Infectious / InflammatoryAcute prostatitis, urethritis, herpes sacralitis, GBS
PsychogenicConversion disorder, anxiety (rare)

Clinical Presentation

  • AUR: Suprapubic pain, palpable bladder, distress, inability to void despite urge
  • CUR: Frequency, hesitancy, weak stream, straining, incomplete emptying, recurrent UTIs, overflow incontinence, nocturia

Diagnostic Workup

  1. History: Medications, voiding diary, neuro symptoms, prior pelvic surgery
  2. Exam: Abdominal (palpable bladder), DRE (prostate), neurologic (saddle sensation, reflexes), pelvic (prolapse)
  3. PVR measurement: Bladder scan (ultrasound) or straight catheterization
  4. Urinalysis + culture
  5. Urodynamics: Pressure-flow study (gold standard for etiology)
  6. Imaging: Renal US (hydronephrosis), CT/MRI if neurogenic suspected
  7. Labs: Creatinine, electrolytes, PSA (men)

Management

  • AUR: Immediate catheterization (urethral 14–16F; suprapubic if urethral failed); α-blocker (tamsulosin) facilitates trial without catheter (TWOC)
  • CUR: Clean intermittent catheterization (CIC) – gold standard; indwelling catheter if CIC not feasible
  • Obstructive: TURP, HoLEP, UroLift, stricture dilation/urethroplasty
  • Neurogenic: CIC + anticholinergics (if high pressure); sacral neuromodulation; botox
  • Pharmacologic: Offending agent discontinuation/substitution

Complications of Untreated Retention

  • Recurrent UTI, pyelonephritis, urosepsis
  • Bladder decompensation, detrusor overactivity, stones
  • Hydronephrosis, renal failure (high-pressure retention)
  • Overflow incontinence, skin breakdown

Early recognition and catheterization prevent irreversible upper tract damage.

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