What are the causes and risk factors of urethral stricture?

Causes and Risk Factors of Urethral Stricture

The primary causes of urethral stricture include iatrogenic injuries, idiopathic factors, trauma, inflammatory conditions, and specific skin diseases, with iatrogenic causes being the most common in developed countries. 1

Common Causes in Men

Iatrogenic Causes (32-45%)

• Urethral catheterization or instrumentation 1
• Transurethral surgery (most common among iatrogenic causes) 1
• Prostate cancer treatment 1
• Prolonged catheterization 2
• Repeated urethral instrumentation 2

Idiopathic Causes (30-34%)

• Unknown etiology (surprisingly common) 1, 2
• May represent unrecognized trauma or inflammation 3

Traumatic Causes (14-20%)

• Direct trauma to the urethra 1
• Pelvic fractures (particularly associated with posterior urethral injuries) 4
• Straddle injuries 2

Inflammatory/Infectious Causes (20%)

• Bacterial urethritis 3
• Recurrent urinary tract infections 1

Other Specific Causes

• Hypospadias surgery (late failure) 1
• Lichen sclerosus (LS) 1
  • Tends to create longer strictures than other causes
  • More commonly affects the penile urethra
  • Higher association with urethral cancer

Common Causes in Women

Urethral strictures in women are less common but have specific etiologies:

• Iatrogenic causes (most common) 1, 5
  • Painful or traumatic catheterization
  • Multiple urethral dilations leading to fibrosis, bleeding, and extravasation
• Blunt pelvic trauma 1
• Obstetric complications, particularly cephalopelvic disproportion 1
• Malignancy 1
• Radiation 1
• Urethral and/or vaginal atrophy 1
• Recurrent infections 1
• Skin diseases 1, 5
  • Lichen planus
  • Lichen sclerosus

Geographic Variations in Etiology

• In developed countries: idiopathic and iatrogenic causes predominate 1
• In developing countries: trauma is the most common cause, reflecting:
  • Higher rates of road traffic injuries
  • Less developed trauma systems
  • Inadequate roadway infrastructure
  • Socioeconomic factors 1

Anatomical Distribution

• Bulbar urethra: most commonly affected (52% of strictures) 2
• Pendulous urethra: typically longer strictures (mean 6.1 cm) 2
• Fossa navicularis: shorter strictures (mean 2.6 cm) 2

Clinical Implications and Prevention

• Unnecessary urethral catheterization should be avoided 2
• Careful technique during transurethral procedures is essential 3
• Early recognition and appropriate management of urethral trauma may prevent severe strictures 4
• Patients with lichen sclerosus require monitoring due to higher risk of urethral cancer 1

Warning Signs of Urethral Stricture

Clinicians should include urethral stricture in the differential diagnosis for patients presenting with:

• Decreased urinary stream
• Incomplete bladder emptying
• Dysuria
• Urinary tract infections
• Rising post-void residual 1
• Urinary spraying 1

Understanding these causes and risk factors is essential for both prevention and appropriate management of urethral strictures, ultimately improving patient outcomes and quality of life.