Pediatric Head Trauma Workup

Ultrasonography can be performed in neonates and small infants with open fontanel and may provide information regarding intracranial bleeding or obstruction of the ventricular system.

Electrocardiography (ECG) may be useful in certain cases. Patients with head trauma are prone to developing dysrhythmias through a reentry mechanism. ST-T wave abnormalities and prolonged QT interval could be present on ECG.

External ventricular drains are the standard for intracranial pressure (ICP) monitoring. They are also used as a therapeutic modality, allowing removal of cerebrospinal fluid (CSF) during episodes of increased ICP or drainage of hemorrhage-induced hydrocephalus. Placement is indicated for patients with severe head trauma and Pediatric Glasgow Coma Scale (PGCS) scores lowers than 8, abnormal CT scan findings on admission, and rapidly deteriorating neurologic examination results, as well as for patients in whom subsequent rises in the ICP are expected.

Lumbar drains are used for patients with refractory increased ICP, allowing further CSF removal. An external ventricular drain should be placed initially; basilar cisterns must be open on CT scan before placement of a lumbar drain.

Subarachnoid and epidural monitors have been used more often in the past, especially when an intraventricular catheter could not be placed. Their use has decreased since the development of fiberoptic transducers. The theoretical advantages (eg, ease of placement, reduced risk of infection, and decreased risk of hemorrhage) should be weighed against the risk of inaccurate readings and inability to remove CSF. Other disadvantages include zero drift, hysteresis in measurement, and temperature sensitivity.

A complete blood count (CBC), including platelets, provides a baseline hematocrit and should be monitored serially, especially when bleeding is suspected in patients with head trauma. Blood chemistry studies, including amylase and lipase levels, provides information regarding other organ injuries.

A coagulation profile, a prothrombin time (PT) or activated partial thromboplastin time (aPTT), and a fibrinogen level should be obtained in patients with head trauma because these patients may have an underlying or trauma-triggered coagulopathy.

Typing and cross-matching of blood is useful in anticipation of a possible need for transfusion, which is especially in patients with multiple trauma.

Arterial blood gas values provide information regarding oxygenation and ventilation and can be used to help direct further treatment.

A blood or urine toxicology screen should be obtained in addition to the routine panel, especially in patients who have altered mental status, seizures, and an unclear history.

Wound cultures should be taken from lacerations or open skull fractures; findings may help guide further therapy when infection is suspected.

Computed tomography (CT) of the head remains the most useful imaging study for patients with severe head trauma or unstable multiple organ injury.^{[13, 14]}

Indications for CT scanning in a patient with a head injury include posttraumatic seizures, amnesia, progressive headache, an unreliable history or examination because of possible alcohol or drug ingestion, loss of consciousness for longer than 5 minutes, physical signs of basilar skull fracture, repeated vomiting or vomiting for more than 8 hours after injury, and instability after multiple trauma.

One study noted that CT scanning may be unnecessary for children who are at very low risk for clinically important traumatic brain injury (TBI) after closed head trauma.^[15]

In this study, the prediction rules for children younger than 2 years were normal mental status, no scalp hematoma except frontal, no loss of consciousness or loss of consciousness for less than 5 seconds, nonsevere injury mechanism, no palpable skull fracture, and normal behavior as deemed by the parents. The prediction rules for children older than 2 years were normal mental status, no loss of consciousness, no vomiting, nonsevere injury mechanism, no signs of basilar skull fracture, and no severe headache.^[15]

A noncontrast study is useful in the immediate posttrauma period for rapid diagnosis of intracranial pathology that calls for prompt surgical intervention. A contrast-enhanced study should follow when the patient is stable and intravenous (IV) contrast is no longer contraindicated.

CT scanning provides information regarding the following:

• The integrity of soft tissue and bone, the size of the fontanel and suture lines, and the presence of foreign bodies
• The appearance of the normal structures, the presence or absence of hemorrhage, and signs of edema, infarct, or contusion
• Mass effect as indicated by midline shift
• The appearance of the ventricles and cisterns - Compression of the ventricles is suggestive of mass effect; ventricular enlargement may suggest development of hydrocephalus from intraventricular hemorrhage or blockage by mass effect
• The presence of cerebral edema as indicated by loss of gray-white matter demarcation

Xenon CT scanning is a modality that may be useful in assessing the impact of medical management on the cerebral perfusion of a patient with head trauma; however, it is not widely available and requires special equipment.

MRI is a more sensitive imaging study than CT in this setting, providing more detailed information regarding the anatomic and vascular structures and the myelination process and allowing the detection of small hemorrhages in areas that might escape CT scanning.

MRI is useful for estimating the initial mechanism and extent of injury and predicting its outcome in the neurologically stable patient. It is not practical in emergency situations, because the magnetic field precludes the use of the monitors and life-support equipment needed by unstable patients.

Radiography of the skull is not routinely indicated, except in the following situations:

• Patients younger than 1 year
• Loss of consciousness for 3 minutes or longer
• Skull penetration
• Preexistent shunt
• Scalp hematoma or depression
• Otorrhea or rhinorrhea
• Hemotympanum
• Battle sign
• Raccoon eyes
• Altered mental status
• Focal neurologic examination