Pediatric Trauma

Michelle Walsh

The management of traumatic injuries in children is unique to the field of pediatric emergency medicine. It is an important topic to understand because of the vast number of children presenting for medical care secondary to an injurious event. Trauma is the most common cause of morbidity and mortality in children. There are more than 500,000 pediatric trauma admissions in the United States, and trauma is the leading cause of death in children >1 year of age. There have been many advances in the management of the trauma patient and in the prevention of trauma in the past decade. However, despite the advances, there are >20,000 pediatric deaths each year secondary to trauma.

EPIDEMIOLOGY

Blunt trauma is the mechanism in 80% to 90% of cases of pediatric trauma. Although the number of children being injured by penetrating forces is lower, the mortality rate of penetrating trauma, which would include injuries from knives and firearms, is much higher. The ratio of blunt to penetrating injuries has been changing over the past decade with the rates of penetrating trauma slowly increasing steadily, especially in urban areas. The ease of obtaining firearms and the prevalence of gang violence are two factors contributing to the recent changes.

The age and development of the child play important roles in determining injury patterns. In nonambulating infants, abuse is the leading cause of trauma. The advancing gross motor skills and curiosity of the surrounding world in toddlers make falls the most common cause of injury in this age group. Pedestrian injuries and bicycle accidents are the leading cause of trauma in school-age children. Adolescents have increasing independence in the world, but not always good judgment, making motor vehicle accidents, with or without alcohol use, the most common cause of trauma in this age group.

INITIAL ASSESSMENT AND RESUSCITIATION OF TRAUMA PATIENT

Trauma management is a very systematic process. It begins with the primary survey with simultaneous initial resuscitation. The primary survey is often referred to as the ABCDEs and consists of the following steps:

Airway control with cervical spine stabilization
Breathing and ventilation
Circulation and hemorrhage control
Disability (neurological screen)
Exposure

The evaluation begins with the assessment of the airway and proceeds down the list. If serious alterations in one of the body systems is encountered, resuscitative care is performed prior to moving to the next step. For example, an airway would need to be established in a patient with stridor and breathing difficulty before managing a bleeding wound. Once stabilized, a secondary survey is performed. The secondary survey is a focused and detailed evaluation of each body area, proceeding from head to toe. The secondary survey helps to find more subtle injuries that may not be life threatening, but may increase the potential morbidity.

HEAD TRAUMA

Head trauma is the leading cause of morbidity and mortality in children. Children are more prone to head injuries than adults because of their relatively large occiputs as compared with body habitus, weaker neck musculature, and immature cognitive development. Falls are the most common cause of head injuries in children, followed by motor vehicle accidents, bicycle accidents, and assaults. Eighty percent of children who die from trauma have significant head injuries.

Brain injury may be classified as primary or secondary. Primary brain injury refers to the injury that occurs at the
time of impact. This injury is very rarely influenced by initial medical interventions. This type of injury includes skull fractures and intracranial hemorrhages. Secondary brain injury occurs after the time of impact and refers to the neuronal injury and neuronal death resulting from hypoxia, ischemia, and mechanical distortion of the neurons. An example of secondary injury is diffuse cerebral edema and herniation after diffuse axonal injury. The goal in the management of the head injured patient is to provide interventions that limit secondary brain injury.

The final common pathway in the development of secondary brain injury is increased intracranial pressure (ICP) and/or decreased cerebral perfusion pressure (CPP). The CPP is influenced by two factors, the ICP and the mean arterial pressure (MAP). The equation CPP = MAP – ICP illustrates the relationship. The goal is to maintain the CPP within normal limits. Maintaining an adequate MAP and limiting elevations of the ICP help to achieve this goal.

The intracranial volume is a fixed and is comprised of three components: CSF volume, blood volume, and brain volume. Changes in one component will directly affect the other two components. Once compliance of the intracranial volume is exceeded, any small changes in any component will lead to large increases in the intracranial pressure. Early symptoms of increased ICP include:

Headache
Vomiting
Altered mental status, or
Abnormal posturing

The management of increased intracranial pressure includes:

Intubation
Mild hyperventilation
Sedation
Neuromuscular blockade
Mannitol

In the evaluation of a child with head trauma, a decision needs to be made concerning potential radiographic studies. One option is to obtain skull films, which can help determine if there are any bony abnormalities, but will not demonstrate any intracranial lesions. A negative skull film does not rule out intracranial injury. The availability of computed tomography (CT) scanning has been increasing significantly over the past decades, and is becoming the study of choice given the ease of access and rapidity of the study. The decision, however, to obtain a CT scan is not always clear. One must weigh the risks of potential radiation exposure and the potential need of sedation when considering the study. The absolute indications for a head CT in the evaluation head trauma are:

Penetrating injury to the head
Focal neurologic deficits
Post-traumatic seizures
Extensive facial injury
Signs of basilar skull fracture

Relative indications for obtaining a head CT in the management of an injured child include:

A history of a change in level of consciousness
Alcohol or drug intoxication
Suspected child abuse
Unreliable or inadequate history
Age <2 years
Postconcussive amnesia
Severe headaches

Magnetic resonance imaging (MRI) has no role in the initial evaluation of the head-injured patient.

Skull Fractures

There are several types of skull fracture in children, including linear, depressed, and basilar fractures.

Linear skull fractures are the most common type of skull fracture in children. Isolated linear fractures without intracranial hemorrhage usually result in minimal symptoms except for focal scalp swelling. Management includes symptomatic care with follow-up CT or skull radiographs to determine resolution.
Depressed skull fractures typically occur after a large force strikes a small area (e.g., hammer), causing the bone fragment to be depressed under the inner table of the skull. These can be associated with brain injury. Management includes neurosurgical evaluation with possible elevation of the bone fragment.
Basilar skull fractures are those extending through the basal portion of the skull. They are characterized by periorbital hematomas, periauricular hematomas, cerebrospinal fluid (CSF) rhinorrhea, and hemotympanum, otorrhea, and cranial nerve palsies. Management includes mandatory neurosurgical evaluation. Ninety-five percent of basilar skull fractures heal with bed rest and elevating the head of the bed. Complications of basilar skull fractures include meningitis, CSF fistula, and facial nerve palsies.

Intracranial Hemorrhages

There are several types of intracranial hemorrhages that may occur after head trauma:

Intracerebral hematoma
Subdural hematoma
Epidural hematoma

Each of these injuries has the potential to cause significant brain damage and requires mandatory neurosurgical consultation.

Intracerebral hemorrhages, or cerebral contusions, are bruises of the cerebral cortex. They occur as the brain moves about in the skull. A coup injury occurs at the site of the impact, whereas a contrecoup injury occurs at the side opposite the impact. Cerebral contusions are characterized by focal parenchyma swelling and small areas of hemorrhage within the brain tissue itself. This type of injury may be associated with other types of intracranial injury.

Subdural hematomas are secondary to tearing of bridging veins and lead to blood accumulating between the dura and arachnoid membrane. Subdural hematomas occur more commonly in infants and young children as compared with older children and adults. The most common mechanism causing subdual hematomas are forces with rapid acceleration and decelerations, such as with shaken impact syndrome. Children often present with signs of increased ICP. Infants with open fontanelles may have delayed symptoms. A crescent shaped density compressing the brain will be noted on CT scan. Mortality rates range from 10% to 20%. Neurologic sequelae are common.

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