Colon and Rectal Trauma
Most colon injuries are due to penetrating trauma. The colon is the second most injured organ in the abdomen in a gunshot injury, behind the small bowel. It is also commonly injured in stab wounds. In wartime injuries, where there is a lot of trauma to the abdomen, part of the colon has to be removed. Blunt trauma to the colon is uncommon and most of the time, the injury is superficial. In blunt trauma, the biggest injury comes from motor vehicle trauma, especially deceleration of a vehicle suddenly tearing the colon.
If there is evidence of seat belt trauma, the doctor should consider the possibility that the colon has been injured beneath the seat belt. The injury may be nothing more than a blood clot within the wall of the colon but this can perforate and rupture later in time.
Diagnosis of Colon and Rectal Trauma
The diagnosis of trauma to the colon and rectum is usually found at the time of surgery. A rectal examination can show blood in the stool, which could indicate a colon injury. The diagnosis may be made by the finding of free gas in the abdomen where it doesn’t belong or by the presence of fluid in the abdomen. Thickening of the wall of the colon can identify a colon injury in a CT scan.
Nondestructive colon injuries are those that involve less than half of the bowel wall and have not lost their circulation. These types of injuries can be treated by primarily closing the colon wall without having to resort to a colostomy, in which the colon is brought to a hole on the outside of the abdomen. There is, in fact, a higher rate of complications if a colostomy is performed on an injured colon.
Destructive colon injuries include those in which there is a loss of some of the colon as part of the injury. More than half of the colon wall has been injured or the blood supply to the colon has been compromised. There injuries were traditionally treated with a colostomy because of the high risk of blood infection following these types of injuries. Some research studies, however, have shown that primary repair of these injuries is possible without an increase in complications.
Risk Factors for Complications after Colon Injury
The incidence of abdominal complications after colon injuries is high—up to 20 percent or more developing a blood infection. Those patients who had to receive many blood transfusions in the first 24 hours after the injury had more complications than those who needed fewer transfusions (less than 6 units of blood). Severe leakage of stool is a risk factor for getting sepsis and complications of colon injury. Delays in surgery from the time of injury seem to increase the risk of complication. Retained foreign bodies, like bullets, caused an increase in complications but it was discovered that removing these foreign bodies did not change the outcome of the complication. Closing the skin in cases of injury involving a lot of stool spillage was associated with a high incidence of wound infections and the breaking open of the wound.
The incidence of colon leakage after repair of a colon injury is low. In one study, the incidence was only about 2 percent. Removing part of the colon and connecting the two ends was associated with a higher rate of complications than when the colon was just lacerated and repaired without removal of part of the colon. Most colon leaks can be fixed by having the patient have a low fiber diet and draining away of any of the fluid leaking out of the colon. Some patients, however, can end up with severe blood infections, requiring antibiotics and a colostomy tube.
Exploration of rectal wounds in surgery is difficult because the colon is located fairly deep in the abdomen. Most rectal injuries are due to penetrating trauma such as gunshot wounds, rectal procedures, and sexual misadventures. Blunt trauma can happen to the rectum if there is an associated fracture of the pelvis.
Most patients with rectal trauma will have signs of infection inside the abdomen and will be seen during surgery. The diagnosis can also be made by putting a camera up into the rectum and looking for injuries or by CT scan.
These injuries can be treated by sealing off the injured area and leaving the rectum to heal. They can also be treated by diverting the rectum to the outside of the abdominal wall, leaving a pouch behind where the rectum used to be. The bladder is often injured along with the rectum and both must be repaired in order to prevent a tunnel from occurring between the rectum and the bladder. In order to prevent this from happening, many surgeons place a piece of the fatty tissue in the abdomen between the two organs so they cannot connect with one another.
Antibiotics should be used to prevent infection in these kinds of injuries. The antibiotic must cover for the major microorganisms living inside the rectum. If this is done, the rate of complications goes way down. Antibiotics can be used from 1-5 days after the injury
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