BOSTON--Emergency room physicians should more strictly follow evidence-based guidelines to assess when it is appropriate to image pediatric head trauma patients, according to a presentation by Nathan W. Mick, MD, this week at the 2009 American College of Emergency Physicians (ACEP) Scientific Assembly.
One problem for physicians faced with pediatric head trauma is how difficult it is to predict which patients have an intracranial injury or skull fracture based on patient history and a physical exam.
"So, if it is so difficult," asked Mick, director of pediatric emergency medicine at Maine Medical Center, Portland, Me., "why not give all children who have minor head trauma a CT scan?"
According to Mick, that’s problematic for a variety of reasons, including CT's expense, and it is often a scarce resource that has to be efficiently utilized. Most importantly, he said, the evidence suggests that CT is "not benign,” when it comes to radiation risks, particularly for young patients.
The estimated cancer risk for a child under the age of one who receives a head CT is one in 1,000, while it is one in 1,500 for children 10 and under. These figures are extrapolated from studies performed on survivors of the atomic bomb attacks on Japan in World War II, according to Mick.
But studying how much of an additional cancer risk a head CT would provide is a difficult proposition, Mick said. The lifetime risk of cancer death for anyone is about 20 percent and the proposed additional risk from a single CT scan is 0.05 percent. Therefore, a study looking at the lifetime risk of undergoing a CT scan would need to be powered to make a determination between 20.0 percent and 20.05 percent.
“So you would need a study with hundreds of thousands of patients,” Mick said. “And that’s just not feasible.”
There are certainly advantages to radiography over CT, Mick said, pointing out that it is less expensive, takes less time, requires no sedation of the child and, most importantly, provides a radiation dosage about one-tenth that of a CT scan.
The problem, Mick said, is that skull radiographs have utility for children the older they get, are harder to interpret and if they are positive for a skull fracture, still require a CT scan to confirm the diagnosis.
So, who should get imaged? Mick pointed out that one set of guidelines from the American Academy of Pediatrics/American Academy of Family Physicians recommended that children between the age of two and 20 should be imaged if they have an abnormal fundoscopic exam, if there are abnormal neurological findings or if they present physical evidence of a skull fracture. They may be imaged, or observed, if there is a history of loss of consciousness with a negative evaluation, and should not be imaged if there is no loss of consciousness or negative evaluation.
For children under two years of age, Mick referenced a study (Schutzman et al, Pediatrics 2001;107(5):983-93) which proposed guidelines that divide this group into four categories, according to risk of intracranial injury due to minor head trauma:
- Children at high risk include those with focal neurological findings, skull fracture, seizure, irritability, bulging fontanel, vomiting five or more times more than six hours after the injury or loss of consciousness greater than one minute. These patients should be scanned, according to Mick.
- Children at intermediate risk with potential indicators of brain injury include those who vomit three to four times more than six hours after the injury, lose consciousness for less than one minute or present a history of lethargy or irritability. Physicians can choose to either scan or observe the patient for a period of four to six hours.
- Children at intermediate risk with additional risk factors include those with evidence of hematoma, a fall onto a hard surface, a vague or no available history or unwitnessed trauma. These children can also be managed with a CT scan or with four to six hours of observation.
- Children at low risk include those with no signs or symptoms two hours after an injury. They should not be imaged.