My Baby Hit His Head and Needs an X-Ray
Abstract & commentary
Source: Greenes DS, Schutzman SA. Clinical indicators of intracranial injury in head-injured infants. Pediatrics 1999;104:861-867.
This prospective study analyzed the risk of intracranial injury (ICI) in infants based on the presence of clinical symptoms and scalp hematoma. Patients younger than 2 years of age who were seen in the ED over a 12-month period were included in the study. Prior to radiographic imaging, physicians were asked to complete a data form recording information about mechanisms of injury, symptoms reported by the parents, and signs of head injury or neurologic abnormalities on physical examination.
Babies were considered symptomatic if they had any of the following: history of loss of consciousness, history of lethargy or irritability, seizures, two or more episodes of vomiting, irritability or depressed mental status on physical examination, bulging fontanel, abnormal vital signs suggesting increased intracranial pressure, or focal neurologic findings. Physicians rated scalp hematomas as "barely perceptible," "moderate," or "obvious swelling and/or boggy consistency." "Significant scalp hematoma" was defined as any scalp hematoma in infants younger than 1 year of age, or moderate or large scalp hematoma in children older than 1 year of age. Imaging protocols were not uniform among the physicians. All cases discharged were followed-up at two weeks by phone (98% were contacted).
A total of 608 babies were enrolled in the study, 84% of whom suffered falls. Falls were categorized as less than 3 feet (44%), greater than 3 feet (28%), or falling down stairs (12%). Blows to the head were reported in 11%, and 3% resulted from motor vehicle collisions (MVC). Of the 608, 31% received a CT scan, 20% received skull radiography but no CT, and 49% had no imaging studies.
Of the 608 babies, 30 (5%) were diagnosed with intracranial injury and 63 (10%) were diagnosed with an isolated skull fracture with no associated ICI. Of the 30 subjects with ICI, 77% also had an associated skull fracture. There was a clear relationship between younger age and the presence of ICI, with 12 of 92 (13%) of infants 0-2 months of age having ICI compared to 6% in ages 3-11 months and 2% in ages 12 months or older.
All of the babies with ICI had either a scalp hematoma or at least one of the clinical findings mentioned previously. Of the 608 babies, 265 had neither scalp hematoma nor clinical findings. Only one of these children had an intracranial injury, a 2-month-old child with a small epidural hematoma that required no intervention.
In summary, this prospective study with rigorous follow-up demonstrated that only one of 608 (0.4%) patients younger than 2 years of age without significant scalp hematoma or clinical findings by history or physical examination had ICI evidenced by CT or two-week follow-up.
Comment by Jeffrey W. Runge, MD, FACEP
In a world replete with retrospective chart reviews attempting to use clinical criteria to assign risk groups, this is a well-done prospective study of patients with excellent follow-up evaluating which babies may safely be sent home without radiographic imaging after head injury. The meat of the matter is in the figures and tables in the paper, and is well worth the reader’s time. The bottom line of this paper reinforces common sense of experienced clinicians: asymptomatic children who have hit their heads, absent physical findings including scalp hematoma, will be fine without a CT scan. One important caveat is that patients younger than 2 months of age are at much higher risk for intracranial injury, and the threshold for radiographic imaging should be lower in this group. Moreover, any child with a history of child abuse with suspected head injury should be considered for radiographic imaging.
There are other limitations to this paper related to the fact that it is a single-center study. There is a clear bias toward falls as a mechanism of injury in the patient population. Larger community hospitals or trauma centers are more likely to see a higher ratio of MVC patients, which may present a much different risk group. Only 3% of patients in this study were involved in MVCs, and no comment was made about crash severity or age-appropriate restraint use. The delivery of energy to the head of an unrestrained child in an MVC is quite different from that of a fall or a blow to the head with respect to the likelihood of scalp hematoma. A blow to the head or a fall onto an unyielding surface must be interpreted differently from deceleration into forgiving padded surfaces in the interior of a motor vehicle. Thus, this article may very well present a useful risk stratification method for patients with falls or a blow to the head, but is not useful in the setting of an MVC. Many children received plain films of the skull in the presence of scalp hematoma for reasons that were not mentioned, but may have more to do with local tradition than well-reasoned approaches to imaging. A negative skull film does not rule out ICI, and a positive plain film is an indication for CT anyway, so plain films of the skull have very limited indications when CT is available.
The study also does not address the long-term effects or need for further medical care for patients who sustain a brain injury without radiographic evidence of abnormality. It is well known that radiographically negative traumatic brain injury (TBI) may lead to future problems with the sequelae of concussion syndrome, including seizures and behavioral and learning disabilities. Still, admission to the hospital for mild TBI, even recurrent mild TBI without evidence of non-accidental trauma, is unwarranted. However, conservative management is not synonymous with lack of management. The value of follow-up with an appropriate specialist or a primary care physician familiar with TBI cannot be overestimated.
This is a well-done prospective study that should make clinicians aware of the need to include imaging for babies with significant scalp hematomas or who are younger than 2 months of age in addition to those who are symptomatic following head injury. More importantly, it provides an evidence basis to validate simple observation for children older than 2 months of age without scalp hematoma or clinical findings.
All of the following are true with regard to babies younger than 2 years old with falls except:
a. skull fracture on plain film guarantees significant intracranial pathology.
b. skull fracture on plain film mandates head CT.
c. skull plain films are probably not helpful.
d. infants younger than 2 months are at increased risk for intracranial injury.
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