Which factor determines the amount of bladder injury?

• A. How full the bladder was at the time of injury
• B. The color of urine
• C. The patient’s blood type
• D. The speed of the vehicle

Answer: (A)

The amount of bladder injury in blunt trauma is mainly determined by how full the bladder is at the moment of impact. A full bladder is stretched and its walls are thinner, especially at the dome, so sudden forces or rapid increases in pressure are more likely to cause rupture or significant injury. An empty bladder is smaller and better protected by the pelvis, so the same impact tends to produce less damage. The color of urine and a person’s blood type don’t influence the bladder’s mechanical response to trauma, and while the speed of the vehicle affects overall energy transfer, fullness at the moment of injury is the primary factor that determines how much injury occurs.