Skip to main content
UC Davis School of Medicine

UC Davis School of Medicine

NEWS | July 7, 2014

Minor head injury not reason enough for CT scan in children

New study helps emergency physicians avoid CT scans that carry cancer risk for young patients

(SACRAMENTO, Calif.)

A nationwide study of more than 40,000 children evaluated in hospital emergency departments for head trauma found that if children had only loss of consciousness, and no other signs or symptoms related to the head trauma, they are very unlikely to have sustained serious brain injuries. Children who have only isolated loss of consciousness after head trauma do not routinely require computed tomography (CT) scans of the head, reported researchers from UC Davis Health System and Boston Children’s Hospital.

Dr. Nathan Kuppermann Dr. Nathan Kuppermann

Although CT scans are the standard way to determine if a child has life-threatening bleeding in the brain that may necessitate surgical intervention, the radiation involved carries a small but quantifiable long-term risk of cancer. As such, the data indicates CT evaluation for children with head trauma should not be routinely used if they are at low risk for clinically significant traumatic brain injuries.

The findings were published today in the journal JAMA Pediatrics in an article titled “Isolated loss of consciousness in children with minor blunt head trauma.”

“Fear of missing a clinically significant head injury, and the wide availability of CT scanners, have been the main factors driving an increase in the use of CT imaging over the past two decades,” said Nathan Kuppermann, professor and chair of the UC Davis Department of Emergency Medicine, and principal investigator of the original study from which the data and current analysis of head injuries were derived. “Our findings can help doctors confidently make a decision to forego CT testing when their patients are unlikely to benefit from it, enabling physicians to first observe their patients for a period of time before deciding on CT use.”

Whether the presence of a single factor suggestive of brain injury is reason enough to justify obtaining a CT scan has been a question Kuppermann and colleagues with the Pediatric Emergency Care Applied Research Network (PECARN) have been actively exploring through a series of studies over the past few years. The current study found that children who lost consciousness after head trauma, but then were awake and alert in the emergency department, and had none of the other five factors determined important by PECARN guidelines for identifying children at low risk for clinically significant brain injuries after head trauma (called the PECARN traumatic brain injury prediction rules), had a very low rate of clinically important brain injuries – only 0.5 percent, or 1 in 200 children.

If a child had isolated loss of consciousness without any other signs or symptoms of head trauma (i.e., including factors outside of the PECARN traumatic brain injury prediction rules), the incidence of an important brain injury dropped to only 0.2 percent, or 1 in 500 children. Furthermore, the duration of the loss of consciousness did not significantly affect risk.

Video: Dr. Nathan Kuppermann discusses use of CT scans on head-injured children

“Children with clinically important brain injuries rarely have loss of consciousness alone, and almost always present other symptoms, such as vomiting or showing signs of neurological problems,” said Lois K. Lee, lead author of the current study and director of trauma research at Boston Children’s Hospital. “Being able to make treatment decisions backed by strong data helps doctors and parents feel better about deciding whether further testing is really needed.” 

Lee added that in cases in which a parent or physician is uneasy about a child’s condition, it would be reasonable to observe the child in the emergency department for a few hours to see if any other signs or symptoms arise before making the decision whether to have a CT.

Studies show that exposure to the ionizing radiation associated with CT scans increases the risk of cancer. According to “The Essential Physics of Medical Imaging,” one head CT scan for a child — based on a youngster's age — is the equivalent of approximately 140 chest x-rays.  Radiation exposure in the brains of developing children is of particular concern and must be weighed carefully against the risk of traumatic brain injury that could cause permanent damage or death if not identified early. Lee and Kuppermann noted that if the guidelines are applied appropriately, the use of unnecessary CT scans could be significantly reduced.

An earlier, landmark study led by Kuppermann and published by The Lancet in 2009 developed and validated a traumatic brain injury prediction rule to identify children at low risk for clinically important head injuries who probably do not require CT evaluation. Factors in the rule included abnormal mental status, scalp hematoma (a large swelling on the scalp in children younger than 2 years old), evidence of a skull fracture, vomiting, history of loss of consciousness associated with the head trauma, and severity of the injury mechanism (such as a fall from a height or a car crash that killed other passengers). If a child with head trauma has none of the six associated factors, researchers determined that a CT scan would be very unlikely to reveal a clinically significant problem, making it unnecessary for a child to undergo the CT scan.

Two related studies led by Kuppermann and his team were recently published in the Annals of Emergency Medicine. One, in the June 2014 issue, examined whether vomiting alone warrants a CT scan in children who have acute head trauma (“Association of traumatic brain injuries with vomiting in children with blunt head trauma”). The second, in the March 2014 issue, evaluated whether swelling of the scalp in children younger than 2 years old, as a result of a head trauma by itself, warrants a CT scan (“Risk of traumatic brain injuries in children younger than 24 months with isolated scalp hematomas”). Both studies determined that the presence of these individual factors alone, with no other signs and symptoms of head trauma, were not sufficient to justify an immediate CT scan. Rather, the researchers said that children in these cases should be observed for a period of time before any decisions regarding CT use are made.

“Head trauma in children results in nearly half-a-million visits to U.S. emergency departments annually,” said Peter Dayan, lead author of both recent studies and an associate professor of pediatrics at Columbia University in New York. “Our research provides important support for frontline doctors to help them avoid unnecessarily exposing children to the radiation risks inherent in CT testing.”

The head trauma study was designed by Kuppermann and colleagues in PECARN to determine which children evaluated in the emergency department for head trauma are at low risk for clinically significant traumatic brain injuries and who do not require cranial CT evaluation. The pediatric research network comprises 18 hospital emergency departments across the nation and serves more than 1.2 million children. The enormous amount of data generated by this patient population enables investigators to answer questions about best practices with a high degree of confidence.  

Other authors of the JAMA Pediatrics study evaluating isolated loss of consciousness were James Holmes, UC Davis School of Medicine; David Monroe, Howard County General Hospital; Michael Bachman, Newark Beth Israel Medical Center; Todd Glass, now at Nemours Children's Hospital; Prashant Mahajan, Wayne State University School of Medicine; Arthur Cooper, Columbia University Medical Center at Harlem Hospital; Rachel Stanley, University of Michigan School of Medicine; and Michelle Miskin, University of Utah.

The study was supported by a grant from the U.S. Health Resources and Services Administration/Maternal and Child Health Bureau Division of Research, Education and Training, and the Emergency Medical Services for Children Program.   

The UC Davis School of Medicine is among the nation's leading medical schools, recognized for its research and primary-care programs. The school offers fully accredited master's degree programs in public health and in informatics, and its combined M.D.-Ph.D. program is training the next generation of physician-scientists to conduct high-impact research and translate discoveries into better clinical care. Along with being a recognized leader in medical research, the school is committed to serving underserved communities and advancing rural health. For more information, visit UC Davis School of Medicine at medschool.ucdavis.edu.