What are the common causes of urinary retention?

Common Causes of Urinary Retention

The most common causes of urinary retention include benign prostatic hyperplasia (BPH) in men, neurological disorders, medication side effects, urinary obstruction, and infection or inflammation of the urinary tract.

Classification of Urinary Retention

Urinary retention can be classified as:

1. Acute urinary retention: Sudden inability to void urine completely, often painful
2. Chronic urinary retention: Persistent inability to completely empty the bladder, often with post-void residual volume >300 mL measured on two separate occasions over at least six months 1

Obstructive Causes

In Men

• Benign prostatic hyperplasia (BPH): Accounts for approximately 53% of urinary retention cases 1
  • Risk increases significantly with age, especially in men >70 years
  • Presents with gradual worsening of lower urinary tract symptoms (LUTS)
  • Finasteride can reduce risk of acute urinary retention by 57% compared to placebo 2

In Women

• Pelvic organ prolapse
• Pelvic masses
• Urethral stricture

In Both Sexes

• Urinary stones
• Bladder/urethral tumors
• Urethral stricture
• Fecal impaction

Neurological Causes

• Spinal cord injury/damage: Especially affecting sacral levels S2-S4 3

  • Disrupts the micturition reflex pathway
  • Affects neural control of detrusor muscle and urethral sphincter coordination
  • Can cause detrusor underactivity or areflexia

• Detrusor sphincter dyssynergia: Uncoordinated contraction of external sphincter during detrusor contraction 4

  • Common in neurogenic bladder dysfunction
  • May require sphincterotomy in selected male patients 4

• Multiple sclerosis

• Diabetic neuropathy

• Parkinson's disease

• Stroke/cerebrovascular accidents

Medication-Induced Causes

Medications account for up to 10% of urinary retention cases 5. Common culprits include:

• Anticholinergic drugs:

  • Antipsychotics
  • Tricyclic antidepressants
  • Antihistamines
  • Antiparkinsonian medications

• Alpha-adrenergic agonists:

  • Decongestants
  • Some cold medications

• Opioid analgesics

• Calcium channel blockers

• Benzodiazepines

• NSAIDs

• Botulinum toxin therapy: Risk of urinary retention ranges from 2.6-54% in neurogenic lower urinary tract dysfunction patients 4

Infectious and Inflammatory Causes

• Prostatitis
• Cystitis
• Urethritis
• Vulvovaginitis

Diagnostic Approach

1. Measure post-void residual (PVR) volume:

   • PVR >300 mL on two occasions over six months indicates chronic retention 1

2. Urodynamic studies:

   • Essential for proper characterization of neurogenic bladder dysfunction 3
   • May include cystometrography (CMG) and pressure flow studies (PFS) 4

3. Imaging:

   • MRI of lumbar spine without IV contrast for suspected sacral spinal cord damage 3

Management Considerations

1. Initial management: Prompt and complete bladder decompression via catheterization 6, 1

2. For BPH-related retention:

   • Alpha blockers started at time of catheter insertion increase chance of returning to normal voiding 6
   • 5-alpha reductase inhibitors (finasteride) can reduce risk of acute urinary retention by 57% and need for BPH-related surgery by 55% 2

3. For neurogenic causes:

   • Clean intermittent self-catheterization
   • Sphincterotomy may be considered for selected male patients with detrusor sphincter dyssynergia 4

4. For medication-induced retention:

   • Discontinuation or dose reduction of the causative medication 5

Special Considerations

• Elderly patients are at higher risk for drug-induced urinary retention due to existing comorbidities like BPH and polypharmacy 5

• Neurogenic bladder patients treated with onabotulinumtoxinA must be counseled about the specific risks of urinary retention and potential need for intermittent catheterization 4

• Suprapubic catheterization may be superior to urethral catheterization for short-term management, improving patient comfort and decreasing bacteriuria 6, 1