Which children with head trauma need a CT scan?

The Pediatric Insider

© 2013 Roy Benaroch, MD

Last time, I wrote about the reasons for the overuse of CT scans in children. They’re incorrectly perceived as necessary, the risks are far away, and no one really cares about the costs and consequences. But I don’t mean to imply that CTs are always bad. Sometimes a CT scan really is a good idea.

Pediatric head trauma can cause significant and lasting problems, and sometimes needs urgent neurosurgical intervention. How can physicians and parents tell which children are at high risk for problems, versus children at such low risk that scanning is unnecessary?

Two recent studies have looked at this issue critically, reviewing “clinical decision rules” that help predict what children are more or less likely to have an important finding on a CT scan after trauma. Both studies tried to identify the best ways, based on only the clinical history and exam findings, to know with close to 100% accuracy which children can safely not have CT scan after head trauma. These rules aren’t designed to “rule in” serious illness—even applying these rules, most CT scans will be normal—but they hope to at least identify which children are very, very unlikely to need a CT scan as part of their evaluation.

From these studies, there are several characteristics that make it more likely that serious injury has occurred in a child, necessitating a CT scan.

The first, and probably the most important, is a persistent change in level of consciousness. A child who is running around and playing is unlikely to have had a serious injury; a child who is listless or sleepy in the doctor’s office or emergency department is very concerning.

Another consideration is the mechanism of injury. Examples of higher-risk injuries include a car crash with ejection of the passenger or a rollover, or a cyclist without a helmet being struck by a vehicle. Also, the distance of a fall is important. Though the exact numbers vary, many doctors consider a fall onto the head of more than 5 feet for a child or 3 feet for a baby or toddler to be “high risk.” Head bonks after lo risk mechanisms (such as falling backwards onto the floor or into furniture, or running into a door) are much less likely to result in a serious head injury.

Persistent vomiting or a persistent, severe headache are symptoms that can also raise concern for a more-serious injury. Now, many children get upset and vomit once; and everyone complains of a headache right after an injury. It’s persistent or severe symptoms that are concerning.

On the physical exam, certain findings should prompt increased need for a scan. These include large raised bumps (though NOT bumps on the forehead—those are common and unlikely to represent serious injury unless accompanied by other findings), or palpable depressions in the skull from fractures, or findings that suggest a fracture at the base of the skull like blood behind the ears.

Some people consider loss of consciousness at the scene of the injury to be at least a “minor” sort of red flag. A very brief loss of consciousness is unlikely to be indicative of a problem, but it may be worthwhile to observe patients with a history of even a brief period of unconsciousness to see if other issues develop.

Studies have confirmed that if none of these “red flags” are present, the chance of there being an important finding on CT scan approaches zero. But, of course, there can’t be any guarantees—there may still be a 1 in a million chance that even lacking any of these findings, there may be something on a CT. Making clinical decisions is never 100% ironclad certain.

These rules, of course, have to be individualized. Children who are younger or who have developmental challenges may not be able to tell you about symptoms; children may have complicating health issues that may increase their risk of problems or complications. Also, the exact history is sometimes unclear. So applying these rules isn’t something I’m encouraging parents to do—these are decisions to make with your doctor’s guidance. Still, I think it helps if parents know what kinds of things doctors are looking for.

Even if one or more than one of these “positive predictors” is present, the chance of an abnormal CT is still quite small—so not everyone with one of these findings needs a scan. That ought to be an individualized decision based on the judgment of the physician, the feelings of the parents, how well follow can be assured, the overall health of the child, any many other factors. But by trying to reduce at least some of these CTs when “red flags” aren’t present, many unnecessary studies can be safely skipped.

If your child has had head trauma, go to the ED immediately if there are persistent symptoms including loss of consciousness, altered consciousness, vomiting, or severe headache. Otherwise, it may be best to call your child’s physician to discuss what happened and get guidance on whether an ED eval is needed, and what to look for, and how to help your child be more comfortable. Not everyone benefits from a CT scan, and you can do your child a big favor by keeping him out of the scanner when he doesn’t need it.

Previously: Why are so many unnecessary CTs done?

Next: More about cancer and CT scans. I bet you can’t wait!

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