Retrograde Urethrography and Cystography
Floyd S. Ota
Introduction
Early recognition and treatment of injury to the pediatric lower genitourinary tract following trauma can prevent significant morbidity. Pediatric bladder and urethral injuries are most commonly seen in association with pelvic fractures from blunt motor vehicle trauma. Other injury mechanisms include straddle injury, penetrating trauma, and iatrogenic injury (e.g., during bladder catheterization) (1,2). The incidence of lower genitourinary tract injuries is reported to range from 7% to 28% among adult patients with pelvic fractures (3,4). In similarly injured children, this incidence appears to be much lower, ranging from 0.9% to 8% (5,6,7,8,9).
Retrograde urethrography and cystography are diagnostic procedures that have been used to evaluate the lower genitourinary tract following traumatic injury. The history of retrograde cystography dates back to the early 20th century. In 1905, the techniques of retrograde cystography and pyelography using Kollargol, a silver-containing preparation, were introduced by Volecker and Von Lichentberg (10). Since their introduction, these techniques have become widely available, aided, in part, by the development of newer and safer iodinated contrast agents (10).
The popularity and diagnostic utility of computed tomography (CT) in the evaluation of the patient with trauma is increasing. However, CT alone cannot replace retrograde urethrography and/or cystography in the complete evaluation of lower genitourinary tract injuries (4,8,11). For example, contrast-enhanced abdominal and pelvic CT cannot completely examine the urethra, differentiate intra-abdominal urine from blood, or determine the location of a bladder injury, and it may fail to detect small tears if the bladder is not fully distended by contrast during the study (8,11) (Fig. 32.1). Retrograde urethrography and cystography remain two readily available procedures that can provide important structural and functional information during emergency department evaluation.
Anatomy and Physiology
The urogenital diaphragm divides the male urethra into two portions, anterior and posterior. The penile urethra and bulbous urethra make up the anterior portion. The membranous urethra and prostatic urethra make up the posterior portion. The anterior urethra is more commonly injured by blunt trauma (straddle injury) or penetrating trauma, whereas posterior urethral injury is often associated with pelvic fractures.
Bladder injuries include bladder contusions and ruptures (intraperitoneal or extraperitoneal). Extraperitoneal rupture is more common and is often seen with pelvic fractures. Intraperitoneal ruptures generally occur at the dome of the bladder as the result of blunt lower abdominal trauma when the bladder is full of urine. Finally, it should be noted that there are other possible causes of hematuria. Hematuria in a child following relatively minor trauma may be the first sign of an occult renal anomaly or kidney disease (e.g., glomerulonephritis, hydronephrosis, Wilms tumor).
Retrograde Urethrography and Cystography
Indications
Retrograde urethrography and cystography may be emergently indicated in the evaluation of blunt or penetrating trauma to
the perineum, penis, or pelvis to evaluate the integrity of the urethra and bladder (1,2,4,8,9,12). Urethral tears and bladder injuries should be suspected whenever there is the finding of blood at the urethral meatus, gross hematuria, an inability to void, or an abnormal genital examination (scrotal hematoma or direct trauma to the penis) (1,2,4,9). An injured child with a pelvic fracture and isolated microscopic hematuria (less than 50 RBC per high-powered field) does not require imaging of the lower genitourinary tract (9,11). The evidence suggests that in the pediatric population there is a low incidence of urethral injuries associated with pelvic fractures (7,8,9). Furthermore, in the absence of gross hematuria, no clinically significant injuries were found in one study of 212 children with pelvic fractures (9).
the perineum, penis, or pelvis to evaluate the integrity of the urethra and bladder (1,2,4,8,9,12). Urethral tears and bladder injuries should be suspected whenever there is the finding of blood at the urethral meatus, gross hematuria, an inability to void, or an abnormal genital examination (scrotal hematoma or direct trauma to the penis) (1,2,4,9). An injured child with a pelvic fracture and isolated microscopic hematuria (less than 50 RBC per high-powered field) does not require imaging of the lower genitourinary tract (9,11). The evidence suggests that in the pediatric population there is a low incidence of urethral injuries associated with pelvic fractures (7,8,9). Furthermore, in the absence of gross hematuria, no clinically significant injuries were found in one study of 212 children with pelvic fractures (9).
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