BLADDER INJURIES
The vast majority of bladder injuries result from external trauma. Most cases result from blunt trauma, such as motor vehicle accidents, whereas a smaller number result from penetrating trauma, such as gunshot or stab wounds. A minority of bladder injuries not associated with external trauma are iatrogenic. The highest risk procedures include transabdominal hysterectomy, Cesarean section, transurethral resection of a bladder tumor, and bladder biopsy.
Bladder
trauma may lead to contusions (partial-thickness mucosal tears resulting from
blunt forces), interstitial injuries (partial-thickness lacerations that
involve the serosa), and ruptures. The remainder of this section will focus on
ruptures, which can be classified as either extraperitoneal or intraperitoneal
based on the region of the bladder wall that tears, which determines the
consequent site of urine collection. Overall, approximately 60% of ruptures are
extraperitoneal, 30% are intraperitoneal, and 10% are combined.
Extraperitoneal
ruptures involve the lateral or inferior surfaces of the bladder, which are not
in contact with peritoneum. Urine extravasates into the pelvis and collects
around the base of the bladder. This type of rupture almost always occurs in
the setting of a pelvic fracture, resulting from the shearing forces of the
pelvic fragments, rather than from perforation by bony spicules. If additional
fascial planes are disrupted, urine may extend into the abdominal wall, thigh,
and genitals.
Intraperitoneal
ruptures, in contrast, involve the superior surface (dome) of the bladder,
which is covered with peritoneum. As a result, urine extravasates into the
intraperitoneal space. This type of rupture occurs when a full bladder is
subject to a sudden and dramatic increase in pressure. The bladder’s superior
surface has the most widely spaced muscle fibers and is thus most likely to
rupture. A common victim is a person with a full bladder who is wearing a
seatbelt during a motor vehicle
accident.
EXTRAPERITONEAL BLADDER RUPTURES
PRESENTATION
AND DIAGNOSIS
Hematuria is
a nearly universal feature of bladder rupture. Other signs include suprapubic
tenderness, lower abdominal bruising, and low urine output. On laboratory
assessment, patients may be found to have elevated serum creatinine
concentration, acidosis, hyperkalemia, and azotemia secondary to reabsorption
of extravasated urine. Women should receive a careful pelvic examination to
assess for possible vaginal injuries, which can result in vesicovaginal
fistulae. In addition, patients
should be assessed for urethral injuries, which can lead to difficulty with
voiding.
After blunt
trauma, an absolute indication for imaging the bladder is the combination of
pelvic fracture and gross hematuria. Relative indications include gross
hematuria without pelvic fracture, as well as microhematuria with or without
pelvic fracture, occurring with any of the following: the clinical signs and
symptoms listed previously, free intraperitoneal fluid on abdominal imaging, or
known prior bladder abnormality.
After penetrating trauma of the pelvis, lower abdomen,
or buttocks, imaging of the bladder is mandatory if there is any degree of
hematuria.
In most
patients, computed tomographic cystography is the initial imaging test of
choice. After urethral injury has been excluded, a Foley catheter is placed and
the bladder is retrograde filled with 350 to 400 mL of dilute contrast. This
imaging modality is highly sensitive for the detection of tears and also
permits evaluation of other abdominopelvic organs. The previous gold standard
was conventional cystography; however, this test often requires more time and
may fail to detect subtle tears. In addition, post drainage films must be
obtained. Of note, neither ultrasound nor CT scan without bladder contrast is
sensitive enough to be an effective screening tool.
Using the
appropriate imaging techniques, bladder ruptures may be characterized based on
the location and extent of contrast extravasation. As previously noted,
extraperitoneal ruptures lead to contrast extravasation into the pelvis.
Meanwhile intraperitoneal ruptures cause contrast extravasation around loops of
the bowel and into the paracolic gutters. Injuries less severe than a complete
rupture may also be detected. Interstitial injuries cause contrast accumulation
within the bladder wall with minimal extravasation. Contusions often do not
cause any radiographic abnormalities but may, in some cases, result in an
abnormal bladder contour.
If an
iatrogenic bladder injury is suspected during a surgical procedure, a Foley
catheter should be placed, and the bladder should be filled with either
methylene blue (in open cases) or contrast (in endoscopic cases) to determine
if there is extravasation into the abdomen.
INTRAPERITONEAL BLADDER RUPTURES
TREATMENT
Most blunt
extraperitoneal bladder ruptures can be successfully managed with catheter
drainage alone and do not need to be explored. In most cases, the bladder will
heal spontaneously over the course of several weeks, which can be confirmed with
a follow-up cystogram. If the abdomen is explored because of other injuries,
however, extraperitoneal ruptures can be repaired at the same time.
In contrast,
blunt intraperitoneal ruptures require open repair. Delayed management often
results in significant morbidity,
including metabolic acidosis, ileus, abdominal/pelvic pain, sepsis, and
possibly peritonitis.
Penetrating
bladder injuries mandate surgical exploration to assess for other
intraabdominal injuries and to determine if there is damage to the ureters or
trigone. To explore injuries, the bladder should be exposed through a midline
abdominal incision and opened at the dome. This precaution minimizes the risk
of incising a pelvic hematoma, which
can cause brisk, difficult-to-control bleeding. All tears should be repaired
from within the bladder. The bladder neck and ureteral orifices should be
inspected for possible damage. Bladder neck injuries must be surgically
repaired or patients may experience stress urinary incontinence. Injuries to
the ureteral orifices require ureter reimplantation. After formal bladder
repair, the urine is diverted using a large-bore Foley catheter and/or suprapubic tube.
