What causes urethral bleeding?

Causes of Urethral Bleeding

Urethral bleeding most commonly results from traumatic injury to the urethra, which can be categorized into posterior urethral injuries (almost exclusively associated with pelvic fractures) and anterior urethral injuries (from blunt straddle-type trauma or penetrating mechanisms), with blood at the urethral meatus being the hallmark clinical finding present in 37-93% of cases. 1

Traumatic Causes

Posterior Urethral Injuries

• Pelvic fractures are the predominant cause, occurring in 1.5-10% of all pelvic fractures 1
• The risk increases by 10% for every 1-mm increase in pubic symphysis diastasis 1
• These injuries involve the prostatic or membranous urethra (proximal to the perineal membrane) 1
• Concomitant bladder injuries are present in 15% of posterior urethral injuries 1
• In females, posterior urethral injuries occur almost exclusively from pelvic fractures and should be suspected with labial edema and/or blood in the vaginal vault 1

Anterior Urethral Injuries

• Straddle injuries occur when the bulbar or penile urethra is crushed between the pubic bones and a fixed object 1
• Penetrating trauma (gunshot wounds, stab wounds) can lacerate, crush, or disrupt the anterior urethra 1
• Penile fracture during sexual intercourse causes urethral injury in 10-22% of cases, presenting with blood at the meatus 1, 2
• Traffic accidents are a major cause of both anterior and posterior injuries 3

Iatrogenic Causes

• Urethral catheterization is a common iatrogenic cause, particularly with traumatic or improper placement 1, 4
• Prolonged pressure from a wrongly placed catheter can cause arterial wall necrosis and pseudoaneurysm formation with subsequent bleeding 5
• Catheter balloon inflation in the bulbar urethra rather than the bladder can cause severe hemorrhage 6, 5
• Transurethral surgery is the most common etiology of iatrogenic strictures in men 1
• In women, painful or traumatic catheterization and multiple urethral dilations lead to fibrosis from bleeding and extravasation 1
• Other surgical procedures including prostatectomy and sling operations for continence can cause urethral injury 4

Other Causes

• Urethral stricture disease from prior trauma, instrumentation, or lichen sclerosus can present with bleeding 1
• Foreign bodies deliberately introduced into the urethra 4
• In women: obstetric complications (particularly cephalopelvic disproportion), malignancy, radiation, urethral/vaginal atrophy, recurrent infections, and skin diseases like lichen planus 1

Critical Diagnostic Pitfall

Never attempt blind catheterization when blood is present at the urethral meatus in trauma cases—this may worsen the injury and increase the extent of urethral disruption. 7 Retrograde urethrography must be performed first to confirm the diagnosis and characterize the injury 1, 7, 3