Anteroposterior and lateral roentgenograms, interpreted with the knowledge of entrance and exit wounds, are particularly helpful in determining if a rectal injury is likely to be present. Digital examination of the rectum is required. Endoscopy to determine the presence of intraluminal blood is indicated in these patients. Blood in the rectum should be assumed to be evidence of a transmural injury. A search for the specific location of the injury must be made.
Rectal injuries are difficult to diagnose at the time of laparotomy.
If no injury can be found in a patient with frank blood in the rectum, the surgeon must treat the patient as if a rectal injury has occurred. Figure 38 Bladder Injuries of the bladder are usually associated with hematuria, The surgeon should suspect a bladder injury when the entrance or exit wound, the two-plane roentgenograms, or hematuria suggest that this is the case. A cystogram is the definitive test. It is obtained by the instillation of contrast into the bladder via an indwelling urethral catheter. Two roentgen views should be taken, one with the bladder full and the other after voiding.