CHAPTER 78

Head Trauma

Joseph Ravera, MD

Although most childhood head injuries are minor and can be managed on an outpatient basis, it is important for physicians to become adept at recognizing and managing concussions and more severe forms of head injury. Health professionals can also help reduce mortality from head trauma by actively promoting injury prevention to patients and communities.

Epidemiology

Head trauma is among the most common pediatric injuries and the leading cause of morbidity and mortality among pediatric trauma patients. Pediatric head trauma accounts for more than 500,000 emergency department (ED) visits, 95,000 hospital admissions, 7,000 deaths, and 29,000 permanent disabilities per year in the United States. Hospital care costs exceed $1 billion annually. In pediatric patients with multiple injuries, 70% of deaths that occur within 48 hours of hospitalization are the result of trauma to the head. Rates of intracranial injuries in children with only minor head trauma are low, however, with the largest numbers occurring in young children and infants, with a prevalence of 3% to 6%. Only 0.4% to 1% of children require surgical intervention after minor closed head injury.

Falls account for most cases of pediatric head trauma. Other major causes include motor vehicle crashes, vehicle versus pedestrian collisions, bicycle crashes, sports-related injuries, and recreational activities. Nonaccidental trauma (ie, child abuse) must be recognized as another important cause of head injury in children, particularly among those younger than 2 years.

Clinical Presentation

The child who has sustained head trauma may present with a history of an antecedent event (eg, fall, collision with another child) or signs and symptoms related to the injury. These include external bruising or lacerations, alterations in the level of consciousness, and neurologic findings, including seizure. Vital signs may be altered; in particular, deep or irregular respirations, hypertension, or bradycardia may be apparent (Box 78.1). These changes are indicative of elevated intracranial pressure (ICP).

Pathophysiology

Children have significant anatomic differences from adults that predispose them to head trauma and certain types of intracranial injury (Figure 78.1). They have a higher center of gravity, an increased head to body ratio, and weaker neck muscles compared with adults. Additionally, children have thinner cranial bones and less myelinated brain tissue, which predisposes them to intraparenchymal injuries. Whereas adults are more likely to have focal intracranial hematomas, children are more likely to develop diffuse cerebral edema. Cerebral edema can disrupt cerebral blood flow, resulting in ischemic injury.

^a All symptoms need not be present for a diagnosis of head trauma.

Normally, blood flow to the brain is maintained at a constant rate by the process of autoregulation. With severe brain injury, autoregulation is disrupted and blood flow to the brain is determined by cerebral perfusion pressure (CPP), which is a measure of the mean arterial pressure (MAP) less ICP (CPP = MAP – ICP). Cerebral blood flow is therefore compromised when the MAP is too low (ie, hypotension) or the ICP is too high (ie, cerebral edema). Several of the management strategies in children with severe brain injuries focus on maintaining MAP and reducing ICP; however, control of CPP after head injury can be quite difficult. Children have a greater capacity for recovery than adults; this is especially true for infants and very young children, whose open sutures and fontanels permit expansion of the skull in response to edema and blood.

In head trauma, primary and secondary brain injury can occur. Primary injury is the structural damage that occurs to the cranium and its contents at the time of injury. Secondary injury is damage to the brain tissue after the initial event. Such damage may result from hypoxia, hypoperfusion, hypercapnia, hyperthermia, and altered glucose or sodium metabolism. The main treatment strategies for patients who have sustained head trauma focus on the prevention of secondary brain injury. Primary brain injury can be prevented only through education and safety, such as advocating for wearing helmets in appropriate situations.

Figure 78.1. Functional anatomy of the brain and surrounding structures with sites of pathology. 1, Caput succedaneum. 2, Subgaleal hematoma. 3, Cephalhematoma. 4, Porencephalic or arachnoid cyst. 5, Epidural hematoma. 6, Subdural hematoma. 7, Cerebral contusion. 8, Cerebral laceration.

Reprinted with permission from Tecklenburg FW, Wright MS. Minor head trauma in the pediatric patient. Pediatr Emerg Care. 1991;7(1):40–47, with permission from Wolters Kluwer Health.

Types of Head Injury

Even minor head trauma in a child can result in skull fracture or intracranial injuries. Most skull fractures are simple and linear. Other fracture types are comminuted, diastatic, basilar, and depressed. A comminuted fracture is one involving multiple skull fragments. A diastatic fracture is one with a wide separation at the fracture site. Basilar fractures occur at the base of the skull and often have characteristic findings on physical examination (ie, bilateral periorbital ecchymosis [ie, raccoon eyes], hemotympanum, postauricular ecchymosis [ie, Battle sign]). In a depressed fracture, fragments of the skull are displaced inward, potentially damaging intracranial structures.

Head trauma may result in concussion, mild traumatic brain injury, or intracranial hemorrhage. A concussion is defined as a trauma-induced impairment of neurologic function. This may occur with or without a loss of consciousness (LOC). Neurologic examination is usually normal, but the patient may experience somatic symptoms (eg, headache), physical signs (eg, LOC, amnesia), behavioral changes, cognitive impairment, or sleep disturbances. Some of these minor and subtle neurologic sequelae can last for months after the injury (ie, postconcussion syndrome). Most resolve within a relatively short period, typically 7 to 10 days; however, with more severe trauma the symptoms can last longer.

A cerebral contusion is a bruise of the brain tissue and typically occurs with a more severe injury, such as a high-speed motor vehicle crash. A contrecoup contusion may be sustained when the brain strikes the skull on direct impact, bruising 1 portion of the brain, with resulting injury to the opposite side of the brain on rapid deceleration. Clinical manifestations depend on the location of the contusion but often include altered mental status, excessive sleepiness, confusion, and agitation. Small intraparenchymal hemorrhages and swelling of the surrounding tissues are often seen on computed tomography (CT).

An epidural hematoma is a collection of blood that accumulates between the skull bone and the tough outer covering of the brain (ie, dura mater). These are often the result of tears in the middle meningeal artery caused by skull fractures. Classically, patients have initial LOC followed by a lucid interval and then rapid deterioration secondary to brain compression. On CT, an epidural hematoma appears as a large collection of blood with convex borders next to the skull (Figure 78.2A). Surgical evacuation is required in most cases.

The subdural hematoma accumulates between the dura and the underlying brain tissue. These are associated with skull fractures and contusions. On CT, they appear to have a crescent-shaped border (Figure 78.2B). Large subdural hematomas usually require surgical evacuation. In infants and young children, subdural hematomas are often the result of nonaccidental trauma.

Diffuse axonal injury (DAI) involves extensive damage to the axonal white matter of the brain that results from shearing forces that typically occur with rapid acceleration or deceleration of the brain (Figure 78.2C). The child with DAI may have normal or nonspecific findings on CT.

Figure 78.2. A, Epidural hematoma (asterisk). Note convex borders and midline shift. B, Subdural hematoma (arrows). Note the crescent shape. C, Diffuse axonal injury. Note the ground-glass appearance and tightly compressed ventricles.

Reprinted with permission from Harris JH Jr, Harris WH, Norelline RA. The Radiology of Emergency Medicine. 3rd ed. Baltimore, MD: Williams & Wilkins; 1993:15, 16, 17.

Evaluation

History

History is obtained during the secondary survey or reassessment phase of evaluation. Prehospital health professionals or witnesses to the injury should be asked about details of the event and the child’s status following the event (Box 78.2).

Physical Examination

Careful attention to the vital signs of the child with head injury is important. The presence of hypertension, bradycardia, and an irregular breathing pattern (ie, Cushing triad) is suggestive of a significant intracranial injury with associated increased ICP.

Secondary survey actions include palpation and inspection of the scalp for soft tissue swelling, step offs (ie, indentation of the skull), lacerations, and fullness of the fontanel. Facial bones should be tested for stability and deformities. Other clues to possible head trauma include the presence of a septal hematoma, draining blood or fluid from the nose or ears, dental injury, and malocclusion of the mandible. The tympanic membranes should be visualized for the presence of hemotympanum or cerebrospinal fluid otorrhea, which, along with postauricular ecchymosis (ie, Battle sign), periorbital ecchymosis (ie, raccoon eyes), or cranial nerve palsies, is suggestive of a basilar skull fracture. If possible, funduscopic examination should be performed to look for the presence of papilledema associated with increased ICP or retinal hemorrhages, which are indicative of nonaccidental trauma.

A comprehensive neurologic examination is the most important aspect of the secondary survey. This examination should include a mental status assessment, cranial nerve evaluation, and assessment of the presence and quality of deep tendon reflexes, muscle tone, muscle strength, sensation, and cerebellar function.

When describing mental status, imprecise terms such as “altered,” “lethargic,” and “obtunded” should be avoided. Several scoring systems are available for assessing the mental status of children who have sustained head trauma. Many are useful predictors of intracranial injury and are also useful in assessing level of consciousness in pediatric patients. The most universally accepted and widely used of these scales is the Glasgow Coma Scale (GCS). It is used routinely in children older than 5 years but can be modified for younger children. Like many other systems, the GCS measures responses to a variety of stimuli in 3 areas—eye opening, verbal, and motor. Scores should be tabulated when the child first presents to establish a baseline, after which the scores can be used for reassessment on a regular basis until the patient has stabilized or returned to normal mental status. Use of these scores helps promote consistent and accurate communication among health professionals. Table 78.1 shows how to calculate the GCS and modified GCS. In some circumstances the calculation of a precise GCS can be cumbersome, especially in time-critical situations. Several rapid scoring systems have been developed and are currently under active study. One system, the AVPU, describes the type of stimulus required to provoke response in a patient as either alert, verbal, painful, or unresponsive. Recent literature has shown that either an alert or a verbal response strongly correlates with a GCS above 8.

Laboratory Tests

A complete blood cell count and serum electrolyte panel should be performed for all pediatric patients with significant head trauma. Bedside glucose monitoring should be performed in any child with a head injury with an altered level of consciousness. Toxicology evaluation may be indicated in the adolescent who appears to be intoxicated or has an altered level of consciousness. The infant or child with an intracranial hemorrhage should undergo screening coagulation studies (ie, prothrombin time, activated partial thromboplastin time) as well as a type and screen test or crossmatch, in case surgery is required.

Reprinted with permission from Singh AP. Glasgow Coma Scale and Pediatric Glasgow Coma Scale. https://boneandspine.com/pediatric-glasgow-coma-scale.

Imaging Studies

In cases of acute pediatric blunt or penetrating trauma, a noncon-trast CT of the head is currently the diagnostic study of choice. It is quite sensitive for the detection of acute hemorrhage and skull fracture. It can also provide additional information on the severity of injury, indicating increased ICP, cerebral edema, or pending herniation. Among the findings on CT that indicate severe brain injury are the shift of midline structures, effacement of the sulci, ventricular enlargement or compression, and loss of normal gray/white matter differentiation.

An emergent head CT is warranted for any child with altered mental status, a GCS below 14, penetrating trauma, or focal neurologic deficit. The question of which children with minor head trauma should undergo CT was evaluated in a study of 17,000 children from the Pediatric Emergency Care Applied Research Network (PECARN) database. In this study, a decision rule was retrospectively derived and then prospectively validated as a method to identify children at very low risk for intracranial injury. These criteria can be found in Box 78.3. If a child is otherwise healthy and meets these criteria, the risk of intracranial injury is extremely low and the child can be safely discharged from the ED or clinic with anticipatory guidance and return precautions. Neither CT nor a period of observation is required. It should be noted that this decision rule was validated as “rule out” only and meant to identify the child at very low risk. If a child does not meet all the criteria, it does not mean a CT scan is required.

With the speed and widespread availability of CT machines, radiographs of the skull have relatively little role in the acute evaluation of pediatric patients with head trauma. Currently, CT can be performed very quickly, often with little or no need for sedation. Although plain radiographs are sensitive for the detection of skull fractures, they do not provide any information about associated intracranial injuries. Additionally, several studies have demonstrated that intracranial injuries occur in the absence of a skull fracture, particularly among young pediatric patients. Plain radiography is obtained only as part of the skeletal survey in cases of suspected nonaccidental trauma.

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