Lois K. Lee and Nathan Kuppermann
CLINICAL PRESENTATION
Blunt head trauma occurs commonly in children 0 to 18 years old, with more than 600,000 children evaluated in US emergency departments (EDs) annually for this complaint. Most children present with minor head trauma, and approximately 90% of children are treated and then discharged home (1). Falls, sports, and motor vehicle crash–related mechanisms are the leading causes of head trauma (1); however, injury mechanism alone is not strongly predictive of traumatic brain injury (TBI). Although severe mechanisms can lead to severe injuries, an isolated severe mechanism of injury (“Key Testing” table), without signs or symptoms of TBI, is not a substantial predictor of clinically important TBI (2). This is defined as TBI resulting in death, neurosurgery, intubation for greater than 24 hours, or hospitalization for two or more nights in association with TBI on CT (3).
The definition of minor head trauma varies in the research literature, but for the purposes of this chapter minor head trauma will be defined as Glasgow Coma Scale (GCS) scores of 14 to 15 after blunt head trauma (Table 247.1) (3,4). Children with minor head trauma can present variably and with a spectrum of symptoms and signs. For example, an infant who falls off a table onto a hard surface can present with a normal mental status and a large scalp hematoma. A school-aged child with head trauma sustained in a motor vehicle crash may present with vomiting and complaints of a headache. An adolescent with head trauma from playing football can present with a history of loss of consciousness (LOC) and may be slow to respond to questioning. All of these children could meet the definition of minor head trauma on the basis of their GCS scores. The challenge in assessing a child with seemingly minor head trauma in the ED is weighing the immediate risk of clinically important TBI against the long-term risk of exposure to ionizing radiation from emergent cranial CT neuroimaging (5–7). Most earlier studies regarding the evaluation of children with blunt head trauma were characterized by their small sample sizes, retrospective nature, and varied definitions of predictors and outcomes. Recently, however, there have been several large prospective multicenter studies to guide clinicians in the evaluation of these patients.
TABLE 247.1
Pediatric Glasgow Coma Scale (GCS) Score Modified for the Preverbal Child (8)
DIFFERENTIAL DIAGNOSIS
Minor head trauma uncommonly results in clinically important TBI. In a large prospective multicenter study of children 0 through 17 years with GCS scores of 14 to 15 after blunt head trauma, only 0.9% had clinically important TBIs (3). Another large population-based study of children with minor head trauma reported that a delayed diagnosis of intracranial hemorrhage occurred rarely after ED evaluation and discharge home (9). Nevertheless, children with seemingly minor head trauma may rarely have a serious intracranial hemorrhage. Such children may initially present with headache and a GCS of 15 and then progress to altered mental status, ultimately requiring emergent neurosurgical intervention (e.g., for an epidural hematoma). Although most children with minor head trauma have no intracranial injury, some may have skull fractures or concussions. The clinician must also remain vigilant for nonaccidental trauma in young, preverbal children (<2 years old) with blunt head trauma (10), as clinical prediction rules for the evaluation of blunt head trauma are not predictive if the history provided by the guardians is not accurate (3,4).
ED EVALUATION
The use of CT in the evaluation of children with blunt head trauma has greatly increased over the past two decades, but appears to have leveled off in recent years (6,11). Although cranial CT is the reference standard for emergently diagnosing TBI, there is a dose- and age-dependent increased lifetime risk of cancer attributable to the ionizing radiation associated with cranial CT scans (5,7). The estimated risks for leukemia range from 1 case per 5,250 scans for children younger than 5 years old to 1 case per 21,160 scans for children 11 to 14 years old; and for solid tumors the risk ranges from 1 tumor per 570 scans for girls younger than 5 years old to 1 solid tumor per 4,660 scans for boys 10 to 14 years old (6). As a result, the decision to evaluate a child with cranial CT imaging after minor head trauma should be considered carefully in the context of the history and physical examination.
The clinician should elicit a thorough history, (3,4) while the physical examination should begin with an overall assessment of the child’s mental status, including the GCS score. For children with moderate to severe head trauma (defined as GCS scores 3–13) emergent neuroimaging should be obtained, as the risk of intracranial injury is substantial (please refer to Chapter 246, Severe Head Trauma) (4,12). A detailed physical examination of the head should be conducted to explore for any scalp hematoma, ecchymosis, lacerations, evidence of skull fracture, hemotympanum, and other signs of basilar skull fractures. A complete neurologic examination including level of consciousness, as well as motor and sensory deficits, should be documented.
There have been several large, prospective observational studies in the past decade that have greatly helped clinicians evaluate children with blunt head trauma for the risk of TBI. One study developed two age-based rules, with a goal of identifying children at very low risk for clinically important TBIs who do not require emergent neuroimaging (3). These prediction rules were derived and validated in a prospective multicenter study of more than 42,000 US children with head trauma and GCS scores of 14 to 15, seen in the EDs in the Pediatric Emergency Care Applied Research Network (PECARN). The factors for these two age-based prediction rules are presented below under “Key Testing.” The sensitivities of the age-based rules, one for children 2 through 17 years, and the other for children younger than 2 years, were between 97% and 99%, and the negative predictive values (NPV) were nearly 100%, with narrow confidence intervals (CI). Most importantly, in both age groups, in the absence of any of the PECARN prediction rule factors, the risk of clinically important TBI was on the order of 1:2,000 to 1:5,000; therefore, cranial CT imaging is not routinely recommended for children with no PECARN risk factors (Fig. 247.1) (3).
FIGURE 247.1 Suggested CT Algorithm for Children Younger than 2 Years (A) and for Those Aged 2 Years and Older (B) With GCS Scores of 14–15 After Blunt Head Trauma3 Reprinted from The Lancet, Vol. number 374, Kuppermann N., Holmes JF, Dayan PS, et al., Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study, Pages 1160–1170, Copyright 2009, with permission from Elsevier.
In contrast to the PECARN prediction rules, which focus on identifying children at very low risk of clinically important TBI not requiring CT, two other rules focus on identifying children with significant intracranial pathology. The Children’s Head Injury Algorithm for the Prediction of Important Clinical Events (CHALICE) was derived from a multicenter cohort of English children <16 years with a history or signs of head trauma (13); however, the complexity of the rule makes clinical implementation challenging. Another rule, the Canadian Assessment of Tomography for Childhood Head injury (CATCH) rule, was derived from a prospective multicenter cohort of Canadian children with blunt head trauma presenting with GCS scores of 13 to 15 and a history of LOC, amnesia, disorientation, persistent vomiting, or irritability (4). In this rule, the main outcome was need for neurosurgical intervention, and the variables associated with this outcome and for which a cranial CT is recommended include: a GCS score <15 2 hours after injury; suspected open/depressed skull fracture; history of worsening headache; or irritability on examination. This rule had a sensitivity of 100% (95% CI 86.2 to 100) (4). Although these last two rules have a high sensitivity for identifying children with significant TBI, only the PECARN prediction rules focus on children with minor head trauma, defined by GCS scores of 14 to 15, to identify children who do not require cranial CT evaluation (14,15). The American Academy of Pediatrics has identified the PECARN prediction rules in the “Choosing Wisely” campaign (16) and recommends the use of clinical observation prior to CT decision making for those children determined to be at low risk for clinically important TBI (17).
Although plain skull radiographs have limited utility in the evaluation of head trauma, for children younger than 2 years old who are asymptomatic and have only a scalp hematoma on physical examination, the use of skull x-rays (18) or point-of-care ultrasound to evaluate for a possible underlying skull fracture may be considered. Some recent studies have found point-of-care ultrasound to be an excellent test to rule out skull fractures in children (19,20). Most (>90%) linear skull fractures in children younger than 2 years of age have overlying soft tissue swelling or scalp hematomas, and 15% to 30% of skull fractures are associated with TBIs (18). Therefore, if a skull fracture is identified by either x-ray or ultrasound, a cranial CT should be obtained to assess for TBI (18). If there is no skull fracture on x-ray in an asymptomatic child with only a scalp hematoma, no further imaging is routinely required, and the patient may be discharged home, as the risk of intracranial injury is very low (21).
KEY TESTING
• Consider PECARN prediction rule factors in the decision to avoid emergent neuroimaging. Children with none of the PECARN factors are at very low risk for clinically important TBI and typically do not warrant immediate CT imaging.
ED MANAGEMENT
In the PECARN head trauma cohort, observation of selected children was associated with decreased CT use. There was no difference in the rate of clinically important TBI between those who were observed before a decision was made on the use of CT and those who were not observed before CT decision making (17). For children who are observed and either do not improve or develop a worsening clinical picture (change in mental status, worsening headache, persistent vomiting, or more ill appearance), cranial CT should be seriously considered.
CRITICAL INTERVENTIONS
• Cranial CT is recommended for children with persistent GCS scores <15 or altered mental status, or if there are signs of skull fracture (or if there are worsening signs or symptoms of TBI).
• Consider observation before CT decision making for children with isolated PECARN risk factors, other than those mentioned above.
Cranial CT is not recommended for children with no PECARN risk factors for clinically important TBI. These children should be discharged home, with instructions on when to return immediately (for developing signs of TBI).
DISPOSITION
Most children with minor head trauma can be discharged home (3,8). If a child with minor head trauma has a cranial CT performed with normal results, the risk of subsequent worsening is very low and the risk of requiring neurosurgical intervention is extremely low (23). Assuming a normal mental status, these children may be safely discharged home, unless they have persistent symptoms (e.g., vomiting) or develop new symptoms that require reevaluation.
Common Pitfalls
• Failure to recognize clinical deterioration, which can occur with an expanding intracranial hemorrhage, when a child presents with an initial GCS score of 15, but then deteriorates.
• Failure to recognize nonaccidental trauma, based on the history (vague or inconsistent with developmental stage or physical findings) or examination findings suggestive of inflicted trauma.
REFERENCES
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