You are in: eMedicine Specialties > Radiology > GENITOURINARY Bladder, TraumaArticle Last Updated: Aug 21, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Daniel L Platter, MD, Consulting Staff, Department of Emergency Medicine, Kaiser Permanente Medical Center Daniel L Platter is a member of the following medical societies: American College of Emergency Physicians Coauthor(s): Jonathan P Vaccaro, MD, Assistant Clinical Professor of Radiology, Department of Diagnostic Imaging, Rhode Island Hospital; Lawrence E Nelson, DO, Consulting Staff, Department of Surgery, Eastern Maine Medical Center, Marshfield Clinic Editors: Neela Lamki, MD, Professor, Department of Radiology, Sultan Qaboos University, Oman; Adjunct Professor, Department of Radiology, Baylor College of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Joshua A Becker, MD, Professor, Department of Radiology, New York University School of Medicine; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center Author and Editor Disclosure Synonyms and related keywords: bladder rupture, bladder contusion, bladder injury in pelvic trauma, bladder insult, urologic injury in pelvic fractures INTRODUCTIONSection 2 of 12
  BackgroundTrauma continues to be a major cause of morbidity and mortality in all areas of the world. Many immediately life-threatening insults are to the vital organs or to their blood supplies, and many diagnostic skills and studies are meant to rapidly reveal these complications. However, other life-threatening conditions must be addressed in a timely manner to avoid morbidity and, occasionally, mortality. Ideally, these conditions are diagnosed simultaneously, rather than individually, and the search for a universally applicable study is underway. Immediate surgery or another approach is commonly the diagnostic and therapeutic procedure of choice if the patient is exsanguinating or if his or her condition is deemed otherwise unstable by the trauma physicians. One semi-emergent condition is trauma to the bladder, especially trauma that results in uroperitoneum. In these injuries, sepsis can develop within 24 hours if surgery with repair is not performed. Radiologic examination is of paramount importance and should be performed to identify and classify the injury and to plan surgical repair, but it should not hinder patient treatment and stabilization. Several radiologic evaluations are appropriate, ranging from computed tomography (CT) cystography to basic retrograde cystography. All have been moderately well studied and require different equipment, locations, protocols, and operator expertise. It is always necessary to consider the stability of the patient's condition with regard to airway patency and circulation during the transfer and radiologic evaluation of the patient. For excellent patient education resources, visit eMedicine's Kidneys and Urinary System Center. Also, see eMedicine's patient education article Blood in the Urine. PathophysiologyMechanism of injury Bladder trauma can occur in a number of settings. They are usually considered in the context of whether blunt or penetrating trauma is the inciting event. Blunt trauma is responsible for a large number of severe associated injuries, such as pelvic, splenic, renal, aortic, bowel, and hepatic insults. Injury is not necessarily localized to obviously traumatized areas. Penetrating injury is often secondary to missiles, impaling objects, or knives. These injuries are of varying severity and often, but not always, result in damage to more focal areas. Some missile injuries have a vaguely estimable trajectory when one considers the entrance and exit wounds, and in the case of knife wounds, the impaling blade is often still in place at the time of presentation. Classification of injury Any discussion of bladder trauma must include the classification of injuries and associated injury patterns. In bladder trauma, the following 5 grades of insults are recognized:
FrequencyUnited StatesTrauma to the genitourinary system occurs in approximately 5-10% of all patients with trauma. Most of these injuries are secondary to blunt trauma, and approximately 10% of genitourinary calamities result in bladder trauma. Although limited accurate data are available, similar numbers apply to adults and in children. Bladder trauma is considered to be the second most common genitourinary injury after renal trauma. InternationalAccurate data are limited. Mortality/MorbidityMorbidity and mortality are most commonly infectious in nature. Therefore, complications are usually associated with bladder rupture. Bladder disruption occurs in 5-10% of patients with pelvic fractures, and the type of perforation, with respect to classification, is important to prognosis. Broadly classified, approximately 50-85% of ruptures (many of which have associated pelvic fractures) are extraperitoneal, 15-45% of them are intraperitoneal, and only 1-10% of disruptions consist of both types. In the event of an intraperitoneal rupture, a preexisting urinary tract infection, if present, will greatly influence morbidity and mortality. Thus, under certain circumstances, sepsis can ensue within 24 hours. Treated properly with operative repair and urologic consultation, nearly all patients with an intraperitoneal bladder rupture have few or no long-term complications. RaceTo the author's knowledge, no studies have been performed to determine whether racial differences exist in the frequency of bladder trauma. SexNo significant difference has been appreciated between the sexes with regard to the percentage of patients with concomitant bladder injury in the event of abdominopelvic trauma. AgeBladder trauma does not appear to be age specific.
AnatomyThe bladder is located within the bony pelvis. (In adults it is considered to be a mostly extraperitoneal organ). There, the bladder, prostate, and proximal urethra are protected by 1 of the most secure bony enclosures in the body. The bladder has a tetrahedral form when empty and has 4 primary surfaces. A superior, a posterior, and 2 inferolateral surfaces define the shape. The superior portion is triangular and is lined completely by the visceral peritoneum. This portion extends into the abdomen when distended and has little support from other structures. It is considered to be a dome when distended; in the female, it contacts the uterus, and in the male, it contacts the sigmoid colon in addition to loops of bowel. The posterior surface, or fundus, of the bladder is anterior to the rectum, but it remains mostly retroperitoneal. A male bladder has the seminal vesicles coursing between the posterior bladder wall and the rectum. The posterior base of the bladder is supported by the rectum and is secured by the rectovesicular ligaments. In females, the posterior surface and the superior surface are loosely fixed to the upper vaginal wall and the uterus. The pelvic floor musculature and overlying, loose areolar tissue support the inferolateral margins of the bladder. The pubovesical, medial, and paired lateral umbilical ligaments strengthen the bladder's association with the anterior body wall. The space of Retzius exists anterior to the bladder. This area consists of loose connective tissue that allows easy mobilization of the bladder from other surrounding structures. There is little preventing motion of the bladder, in that the only rigidly fixed point is the bladder neck. This is the primary adaptation to allow distention during filling. Clinical DetailsTrauma to the bladder is associated with significant trauma to the pelvis and intra-abdominal organs. Thus, patients present in a wide variety of ways, with large differences in the stability of their condition. Commonly, patients have few symptoms secondary to their bladder injury or even to rupture. The literature suggests that these patients have no strong propensity to develop peritonitis initially, even with a large amount of uroperitoneum. Physical examination findings that are suggestive of bladder trauma include vague peritoneal signs or abdominal tenderness. However, more suggestive findings include isolated suprapubic tenderness, pelvic instability, or lap-belt ecchymosis. One study revealed that approximately 4% of children with lap-belt ecchymosis had suffered bladder rupture.1 Unlike upper renal trauma, bladder injury is essentially ruled out when no red blood cells (RBCs) are observed in the urine. Urogenital injury is suggested when microscopic hematuria is present (defined as >25,000-35,000 RBCs per high-power field). Gross hematuria is highly suggestive and certainly warrants full investigation. Gross hematuria is present in 95% of patients, and the remaining patients have microscopic hematuria. A problem can arise when bladder trauma is presumed to be the cause of hematuria, because this finding is not specific and can stem from more ominous sources, such as renal fracture. Urine should be collected from the first few hundred milliliters of the initial sample to prevent errors in interpretation. Furthermore, urethral trauma should always be ruled out before a Foley catheter is placed, especially when gross hematuria is present. Suggestive findings include blood at the meatus, a high-riding prostate, the patient's inability to void, perineal hematoma or scrotal swelling, and pelvic fracture. Bladder injury is strongly associated with pelvic fracture. Eighty percent of bladder ruptures that are associated with pelvic fracture are extraperitoneal. Pelvic fracture is associated with bladder injury in 80% of patients, but the reverse is not true. Indeed, only 10% of pelvic fractures are associated with a major bladder trauma. When a pubic rami fracture exists or pubic symphysis diastasis is present, a higher index of suspicion should be maintained. A great deal of effort has been made to determine which pelvic fractures are associated with bladder injury. Patients with disruption of the pubic symphysis or pubic rami or with a vertically unstable pelvic fracture have a high incidence of concomitant bladder trauma, whereas those with an isolated acetabulum, femur, or iliac crest fracture have a low incidence of bladder injury or rupture. Preferred ExaminationThe extent and type of radiologic evaluation required depends on the patient's condition and on the size of the area that may be affected. Many patients in stable condition require extensive screening, which means that diagnostic procedures should ideally provide views of large areas following quick and common preparation. For many patients in unstable condition or in patients with penetrating abdominal injuries who are immediately treated in the operating room (at the discretion of the surgeon), intraoperative radiologic evaluation is needed. Retrograde cystography, performed after urethrography, was considered the criterion standard for evaluation of bladder trauma. However, support has grown for using computed tomography (CT) cystography in proper diagnosis. Initial studies were not indicative of the reliability of CT scanning when retrograde contrast enhancement was not used. However, contemporary studies have overwhelmingly demonstrated that the technique is sensitive and accurate, provided that adequate bladder distention (with at least 350-400 mL of contrast material) is achieved before the study is performed. In diagnosing bladder rupture, CT cystography, performed with 400 mL of contrast material that is administered in a retrograde fashion, is as accurate as plain radiography with retrograde cystography. Ultrasonography is not sensitive or specific enough to be useful for evaluation of bladder rupture. Retrograde cystograms have long been used for detecting bladder rupture. They are nearly 100% sensitive for detecting rupture, provided that adequate distention is accomplished and that postvoiding images are obtained. However, they are time consuming, the examinations are costly when one considers their value relative to their benefit, and they require extra radiography that does not occur in addition to necessary trauma evaluation. Furthermore, they are not useful in thoroughly evaluating other structures present in the abdomen and pelvis. CT retrograde cystograms are completed in the radiology suite when routine spiral scans of the head, neck, chest, and abdomen and pelvis are performed. CT retrograde cystography generally requires the same retrograde introduction of contrast agent as does retrograde cystography. However, unlike plain radiography, the technique does not require multiple images, including postvoiding and oblique views. Thus, this procedure is less time consuming and, some would argue, less costly. At 1 hospital cited in the literature, the cost of CT cystography was $500 or more, a marginal increase over a plain radiographic examination. Costs should be specifically evaluated at each institution. A final step is the washout study. After the full-bladder findings are recorded (on radiographs or CT scans), the bladder is drained. If no residual contrast enhancement is present, the examination is completed, and the results are negative. If residual contrast enhancement is present in the bladder area, fluid (eg, sterile water) is used to lavage the bladder. If no residual contrast enhancement is noted after drainage, the examination is completed, and the results are negative. If contrast enhancement remains, a bladder wall injury is present. CT cystography may be used somewhat less often in patients who are not undergoing CT scanning for another reason. In a study of 157 patients with hematuria, an absence of free fluid on abdominopelvic CT scans was a strong negative predictor of bladder rupture.2 In such patients, not performing cystography may be reasonable. Further study into this matter is warranted. Perhaps 1 of the greatest advantages of retrograde CT cystography with prior abdominopelvic CT scanning is the ability to detect renal parenchymal injury. In these patients, intravenous urography is not necessary, as it commonly is with traditional retrograde cystography. A few studies have focused on delayed evaluation of the bladder. For example, the use of contrast material for chest and abdominal CT scanning (for which a large amount of contrast material is routinely required) has been studied. In these examinations, the contrast agent was allowed to distend the bladder in an anterograde fashion. However, in such cases this distention occurs at the expense of valuable time, because the Foley catheter should be clamped for at least 20-30 minutes to have any opportunity to achieve accurate results. Furthermore, if preexisting renal insufficiency or renal pedicle injury is present, this method may be inadequate. The author does not recommend this diagnostic strategy for the reasons mentioned. Because study results have also cast doubt on the consistent accuracy of this method in the evaluation of blunt trauma, its use is discouraged. Limitations of TechniquesCystography generally has served to greatly decrease trauma morbidity and mortality by helping to successfully screen for bladder rupture. Little doubt exists concerning the accuracy of plain film cystography, as long as a bladder hematoma does not occlude a rift in the bladder wall and prevent dye from flowing out into the surrounding spaces. The primary concern is that the examination often does not occur in parallel with other radiologic examinations of patients with trauma who require CT scanning. A caveat should be noted: a normal cystogram finding does not exclude a bladder rupture. At surgery, intraperitoneal or extraperitoneal extravasation may be found. The consideration in this scenario is the spasm of the detrusor muscle, which is possibly secondary to the irritation effect of the contrast medium, which causes a leak to become sealed. With general anesthesia, the detrusor relaxes; this is associated with the eventual intraoperative leak. CT cystography is faster than are plain radiographic studies; moreover, it has no labor-intensive requirements for completion, and it can be used to diagnose large hematomas of the bladder, which potentially could overlie an occult breech in the bladder wall. Furthermore, classification of bladder injury patterns requires CT scanning because cystography addresses perforations but not more subtle findings. The cost in each prospective hospital should be considered, because the monetary costs, which favor classic cystography, may not reflect actual benefits. For instance, because radiographic technologists currently are in short supply, increasing their use adds to the expense. Furthermore, time is valuable in the trauma setting, especially because patients in seemingly stable conditions can deteriorate quickly, and a more rapid evaluation can facilitate their transfer to the trauma intensive care unit or operating room. In general, the author believes that evaluation with CT cystography is the study of choice when patients already require transfer to the radiology suite for CT scanning evaluation. This is true especially when microscopic hematuria is present and a possibility of renal trauma exists. DIFFERENTIALSSection 3 of 12
Lumbar Spine, Trauma Urethra, Trauma Other Problems to Be ConsideredRenal trauma, especially if hematuria is present
RADIOGRAPHSection 4 of 12
FindingsRetrograde cystography was considered the criterion standard for detecting bladder rupture (see Images 1-2). Reliability depends on several variables. To obtain dependable results, adequate bladder distention, requiring 350-400 mL of contrast material, is of paramount importance. To correctly perform the study, postevacuation images also should be obtained. Degree of ConfidenceWith this method, diagnostic accuracy has been reported to be near 100%. However, the author was unable to find literature reporting sensitivity and specificity of retrograde cystography for intraperitoneal rupture. False Positives/NegativesFalse-negative findings occur, most commonly in association with penetrating injury. In this scenario, wound margins are believed to align well and prevent leakage. Some authors have recommended fluoroscopy, with the patient in the Trendelenburg position during the examination to increase sensitivity. Others have suggested instilling contrast material until discomfort occurs. Rarely, as mentioned before, a bladder hematoma also may block the wound orifice and prevent the leakage of contrast material. CT SCANSection 5 of 12
FindingsCT scanning is rapidly becoming the most recommended study for trauma evaluation of the bladder. It is fast, it can be used to evaluate other urologic organs, and it requires no additional manipulation of the patient beyond that needed for routine evaluation. Furthermore, the literature suggests that plain abdominopelvic CT scanning may have a high negative predictive value for bladder rupture in a select subset of patients, even without cystography. This makes delaying cystography until after routine abdominopelvic CT scanning even more valuable. However, this approach applies if no hematuria is present and if no free fluid is observed anywhere in the abdomen or pelvis during routine abdominopelvic contrast-enhanced CT scanning. Additionally, all studies reviewed by the author demonstrated that bladder ruptures were not seen in patients in whom no free fluid was observed on standard contrast-enhanced CT scans, regardless of the degree of hematuria. Further study is needed to determine whether cystography, either CT scanning or standard cystography, can be safely omitted in this scenario. Degree of ConfidenceMany patients do not present with the above parameters, and when these parameters are not met, routine contrast-enhanced abdominopelvic CT scanning is highly inaccurate and insensitive in detecting bladder rupture. However, the results of CT cystography have been shown to be diagnostic. Overall, it is 95% sensitive and 100% specific in detecting bladder rupture. A group performing 1 small study took exception, suggesting that it is slightly less accurate when intraperitoneal rupture is present, with 80% sensitivity and 99% specificity. However, this is not a common concern. Furthermore, CT cystography can be used to fully classify bladder injury beyond noting whether a rupture is intraperitoneal or extraperitoneal (see Images 3-6). Studies have demonstrated that CT cystography has requirements similar to those of retrograde cystography for diagnostic accuracy. Specifically, good bladder distention, provided with 350-400 mL of contrast material by means of retrograde infusion, is required. False Positives/NegativesSee Degree of Confidence, above. MRISection 6 of 12
FindingsMagnetic resonance imaging (MRI) is not considered in the acute trauma setting in most centers. ULTRASOUNDSection 7 of 12
FindingsUltrasonography is mentioned here only in passing. It may be helpful in diagnosing bladder contusion, but it has been demonstrated to be unreliable in diagnosing bladder rupture. NUCLEAR MEDICINESection 8 of 12
FindingsNuclear medicine is not generally used for the acute trauma evaluation of the bladder. ANGIOGRAPHYSection 9 of 12
FindingsAngiography has no role in the evaluation of bladder trauma. INTERVENTIONSection 10 of 12
Currently, interventions are performed by the trauma surgeon or by the consulting urologist, and the treatment is often surgical. When an extraperitoneal rupture is present, a Foley catheter is placed and the patient is closely monitored, because most bladders heal without intervention. Passing a catheter should be avoided when a urethral injury is suggested, as described in this article. However, in the event of an intraperitoneal rupture, operative repair is required. Most other injuries, such as contusions, heal spontaneously. Medical/Legal Pitfalls
MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Article Last Updated: Aug 21, 2007 | ||||||||||||||||||||||||||||||||||||||||||
