Each year, 600,000 children in the United States are seen in emergency departments for head trauma. Approximately half of them receive CT scans. Yet less than 1 percent of pediatric head injuries are serious, raising increased concerns about unnecessary exposure to ionizing radiation.
Although the exact numbers are a matter of debate, it's estimated that 1 in 1,000 to 1 in 5,000 CT scans will cause a fatal brain cancer. The risk is greatest for children whose brains are still developing.
To help reduce the number of unnecessary scans (those with negative or insignificant findings), Mayo Clinic has adopted imaging guidelines for minor head trauma.
James L. Homme, M.D., assistant professor of emergency medicine and pediatrics at Mayo Clinic in Rochester, Minn., says the guidelines draw on a landmark study published in The Lancet in 2009.
"This large, multicenter study involved 42,000 kids at 25 hospitals. Using study data, researchers established decision rules for identifying cases where scans aren't needed. One rule was established for children under age 2 and another for kids ages 2 to 18," notes Dr. Homme.
Six predictive factors apply to each group. For children under age 2, these factors include either Glasgow Coma Scale (GCS) of 14 (13 at Mayo Clinic), or:
The guideline for children older than 2 includes some key differences. In addition to altered mental status and mechanism of injury, it cites basilar skull fracture, any loss of consciousness, vomiting and severe headache.
If none of these factors is present in the respective age groups, Mayo Clinic does not perform imaging studies. "The guidelines have essentially a 100 percent negative predictive value, so we feel very comfortable not scanning these kids," Dr. Homme says.
How to proceed with children who have one or more predictors depends on the clinical situation and age of the patient. In general, any child who has a change in mental status and visible signs of a skull fracture is scanned. But most children are simply observed for a brief period in the emergency department to watch for worsening or improving symptoms.
Dr. Homme points out that according to these guidelines, only a small subset of children need imaging studies. "We believe we are armed with very good data so that we can identify children with significant injuries without needlessly exposing the majority of kids to radiation."