Bladder Trauma Workup

Updated: Mar 26, 2019
  • Author: Bradley C Gill, MD, MS; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Workup

Laboratory Studies

In the subacute setting, the serum creatinine level can aid in the diagnosis of bladder rupture. In the absence of acute kidney injury and urinary tract obstruction, elevated serum creatinine can be indicative of a urinary tract leak with systemic reabsorption of the excreted creatinine. A creatinine level alone is not diagnostic, however, and further workup is required when clinical suspicion for bladder leak exists.

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Imaging Studies

Computed Tomography Imaging

Often, computed tomography (CT) is the first test performed in patients with blunt abdominal trauma. Cross-sectional images through the pelvis provide information on the status of both the pelvic organs and bony structures. [19] CT without opacification of the bladder may depict a sentinel clot sign abutting the bladder dome which indicates injury, with a reported sensibility of 84%.

CT, and specifically CT cystography, has also largely replaced conventional plain film or fluoroscopic cystography as the most sensitive means for identifying bladder perforation. [13]

A CT cystogram is performed by filling the bladder with contrast via urethral catheter (once urethral injury has been excluded) and performing a non-contrast abdominopelvic CT scan to assess for extravastion. Imaging in this manner is able to detect even subtle perforations and can often clearly define whether the leaks are intraperitoneal or extraperitoneal.

Cystography

The historical standard for imaging suspected bladder injury is well-performed cystography. Although the ideal examination is performed under fluoroscopy, clinical circumstances often do not permit this. In such cases, plain film cystography is performed. The study can easily be completed at bedside using portable imaging equipment.

While most trauma patients with bladder perforation have multiple injuries and CT imaging is a regular part of the trauma evaluation, this does not preclude obtaining a separate cystogram if bladder findings on the CT scan are equivocal.11 A properly performed cystogram consists of an initial kidney-ureter-bladder (KUB) film followed by both anteroposterior (AP) and oblique views of the bladder filled with contrast as well as another AP film obtained after contrast drainage.

The following procedure is recommended, if urethral injury is excluded and a urethral catheter can be placed:

  • Obtain a scout radiograph

  • Place a urethral catheter into the bladder

  • Using a contrast medium that is suitable for systemic absorption and has been diluted (50% contrast and 50% water or saline), slowly fill the bladder by gravity (approximately 75 cm above the pelvis) to a 300 or 400 mL volume

  • Obtain a single anterior-posterior (AP) film of the pelvis and lower abdomen after the first 100 mL of contrast is instilled

  • If gross extravasation is noted, the procedure can be concluded, and the bladder emptied; if no leak is evident, continue filling the bladder with the remaining contrast solution

  • With the bladder at maximal capacity, obtain another AP film; if possible, obtain oblique and lateral films at this time, as well

  • Completely drain the bladder and obtain the post-drainage film; this is a crucial aspect of the study, as it may reveal extravasation that was obscured by the distended contrast-filled bladder

In children, determine the estimated filling volume for the cystogram using the following formula:

Bladder capacity = 60 mL + [(30 mL) x (Years of Age)]

Key Points

The importance of properly executed filling and post-drainage films is paramount. Injuries may be missed if the cystogram is not performed correctly. A well-performed static cystogram has 85-100% accuracy at detecting leaks.

Oblique films may be difficult to obtain in a trauma patient with pelvic fractures. As such, they may be omitted in selected cases.

The volume infused is less important than achieving adequate bladder distention. With sufficient bladder distention, intravesical pressure will rise high enough to cause extravasation of contrast even in patients with small bladder injuries. False-negative readings might otherwise occur with small puncture wounds or lacerations, which may be self-sealing because of mucosal edema or may be sealed by overlying hematomas, omentum, sigmoid colon, small bowel, or other pelvic viscera.

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Diagnostic Procedures

Operative Exploration

If the patient is immediately taken to the operating room for surgical exploration, inspection of the bladder can be performed. At this time, if urethral injury is excluded a urethral catheter can be placed. Otherwise, a suprapubic cystotomy can be made and catheter inserted in an open fashion.

Thereafter, the bladder can be thoroughly inspected for perforation and distended with irrigation to aid in doing such. The use of intravenous indigo carmine or methylene blue to dye the urine can also aid in visualizing urinary extravasation.

If surgery is delayed or not indicated, access to the bladder is obtained via urethral or suprapubic catheterization. A CT or plain film cystogram can then be obtained to ensure that a bladder injury is not overlooked. [20]

A study of patients with abdominal gun shot wounds found that nonoperative management, with CT scanning as appropriate, is safe and effective in selected cases. In a study of 1106 patients with abdominal gunshot injuries admitted to a single trauma center, 834 (75.4%) patients with peritonitis, hemodynamic instability, unreliable physical examination, or head and spinal cord injury underwent immediate laparotomy. The remaining 272 (24.6%) patients were selected for nonoperative management; 82 (30.1%) received serial clinical examination only, while 190 (69.9%) also underwent abdominal CT scanning. Only 13 patients (4.7%) required delayed laparotomy. [21]

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Histologic Findings

Tissue is not generally taken for histology in the setting of bladder injury and repair. However, if bladder perforation occurs secondary to a disease process originating from or adjacent to the bladder wall, specimens may be sent for analysis. Results would be reflective of the underlying condition.

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Staging

Bladder trauma produces ruptures that are classified as one of the following:

  • Extraperitoneal

  • Intraperitoneal

  • Combined extraperitoneal and intraperitoneal

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