In the setting of trauma, the classic triad of blood of the external urethral meatus or vaginal introitus may be seen but is an unreliable sign, as is hematuria. Inability to void may be seen in complete urethral disruption. Examination may reveal blood on digital rectal exam and perineal ecchymosis.
Dysuria, urinary urgency and suprapubic discomfort can ensue in the chronic stages of incomplete urethral injury due to complicating strictures.
Male urethral injuries are divided into anterior (penile/bulbar) and posterior (membranous/prostatic) urethral injuries. Injuries, of course, may be partial or complete. There are a variety of causes:
- blunt trauma: due to shearing/straddle injuries
- penetrating trauma: e.g. stab wounds, gunshot wounds, dog bites
- more commonly affect the anterior urethra
Voiding cystourethrography is the most appropriate way to evaluate the posterior part of the male urethra and injuries to the female urethra.
Retrograde urethrography is the modality of choice to investigate the anterior part of the urethra. It will demonstrate extraluminal contrast, which has extravasated from the urethra at the site of injury. It is important to determine if this is above the urogenital diaphragm (anterior) or below (posterior) it. Patients with incomplete injuries may represent subsequently with strictures.
The extent of injury can be categorized:
- radiographically normal
- extravasation of contrast with maintenance of normal urethral continuity
- extravasation of contrast with loss of urethral continuity and lack of proximal urethral filling
CT cystography can be performed but this is much less specific for urethral vs. bladder injury. Other features of urethral injury include retropubic and perivesical hematoma and obscuration of the urogenital fat plane.
Treatment and prognosis
Treatment consists from urinary diversion (e.g. suprapubic catheter) to primary or delayed urethral anastomosis depending on the severity (i.e. tear vs. complete rupture) of the injury. Urethral stricture is the most common long-term complication.
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