The last few National Trauma Data Bank® (NTDB®) columns have centered on potential traumatic injuries associated with alcohol consumption. One of the side effects of alcohol ingestion is the inhibition of antidiuretic hormone, a nine-amino acid peptide secreted from the posterior pituitary, which results in increased urine flow by reducing water reabsorption in the renal medullary and cortical collecting ducts. This increase in urine flow can begin within 20 minutes of consumption. An increase in urine volume will ultimately result in a distended bladder, which is more prone to rupture when subjected to compressive forces than one that is collapsed and empty.
Causes of bladder injury
Nearly 80 percent to 85 percent of bladder injuries are caused by blunt abdominal trauma. Blunt injuries to the bladder arise as a result of two distinct mechanisms. The first is a direct blow to the abdomen in a patient with a distended bladder. Normally, the bladder resides within the pelvis and is fairly well protected by the surrounding bony structure. As it becomes distended, the bladder rises into the abdomen, thereby reducing its pelvic protection. A direct blow increases intravesical pressures, resulting in rupture of the dome of the bladder (the weakest point) and intraperitoneal urine extravasation. Children anatomically have an intra-abdominal bladder; therefore, the majority of pediatric bladder injuries are intraperitoneal in nature.*
The second distinct mechanism of blunt bladder injury is a pelvic fracture, which accounts for more than 80 percent of bladder injuries. If the injury is an extraperitoneal bladder rupture, the association with pelvic fracture increases to more than 95 percent. A pelvic fracture may cause injury by sheer force or by direct laceration from bone fragments. Approximately 65 percent of pelvic fracture-associated bladder lacerations occur as a result of a contrecoup burst injury opposite to the pelvic fracture site, as opposed to a direct bone laceration.
Bladder injuries in the U.S.
To examine the occurrence of injuries that include blunt bladder rupture in the NTDB research dataset for 2013, admissions medical records were searched using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnoses codes. Specifically searched were records containing a blunt mechanism of injury and a diagnosis code 867.0, injury to bladder and urethra, without mention of open wound into cavity.
A total of 3,003 records containing a blunt mechanism of injury and a diagnosis of injury to bladder and urethra were found, of which 2,257 records contained a discharge status, including 1,096 patients discharged to home, 578 to acute care/rehab, and 356 sent to skilled nursing facilities; 227 died. These patients were 70 percent male, on average 41.6 years of age, had an average hospital length of stay of 13.4 days, an intensive care unit length of stay of 8.9 days, an average injury severity score of 24.3, and were on the ventilator for an average of 8.4 days.The most common mechanism of injury was motor vehicle (59 percent) followed by fall (15 percent), pedestrian (12 percent), other transport (6.7 percent); struck by/against, pedal cyclist, and machinery make up the final 7 percent. (See Figures 1 and 2.)
Figure 1. Hospital discharge status
Figure 2. Mechanism of injury
With the holidays upon us, there will be the usual holiday parties. This may lead to a toast or two. Before getting into that taxi or vehicle with your designated driver, stop by the restroom, keep your bladder within the pelvis, and make sure you go before you go.
Throughout the year, we will be highlighting these data through brief reports in the Bulletin. The National Trauma Data Bank 2013 Annual Report is available on the ACS website as a PDF file at www.ntdb.org. In addition, information about how to obtain NTDB data for more detailed study is available on the website. To learn more about submitting your trauma center’s data, contact Melanie L. Neal, Manager, NTDB, at email@example.com.
Statistical support for this article has been provided by Chrystal Caden-Price, Data Analyst, and Alice Rollins, NTDB Coordinator.
*Broghammer J, Wessells H. Acute Management of Bladder and Urethral Trauma. AUA Update Series. 2008;27(24):222-231.