Neuropediatrics 2017; 48(S 01): S1-S45
DOI: 10.1055/s-0037-1602882
KSS – Key Subject Session
Georg Thieme Verlag KG Stuttgart · New York

Traumatic Head Injury in Pediatric Head Trauma

L. Porto
1   Klinikum der Johann Wolfgang Goethe-Universität, Zentrum für Radiologie, Institut für Neuroradiologie, Munich, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
26 April 2017 (online)

 

The cause of the traumatic head injury (THI) and the capacity of the brain to respond to trauma depend on the age of the patient. The most common abnormality seen in newborns after birth trauma is the subdural hematoma, which is usually posteriorly located, caused by tearing of the tentorium and venous structures after difficult delivery. At this age, intradural hematomas may occur within the opposing layers of the falx and tentorium, which are loosely attached. Doctors should be aware of complications such as intraparenchymal hemorrhage, subarachnoidal hemorrhage (in this case, hydrocephalus may follow), epidural hematomas and fractures. Children under 2 years of age, particularly small infants, have large heads, weak neck muscles, thin and deformable skull and nonfused sutures. This last feature leads to a greater degree of intracranial expansion. In case of cerebral swelling, the calvarium expands, but the brain does not herniate infratentorially. However, the perimesencephalic cistern can be obliterated and the brain stem compressed. In addition, the lack of myelination makes the parenchyma more compressible and permits, at least partially, the absorption of impact. As a consequence, less damage occurs. The same unmyelinated white matter is however unfortunately sensitive to shearing injury, i.e., diffuse axonal injury (DAI). In addition, exclusive to this age group is the risk of a growing skull fracture. A further complication after THI in all age-groups with fractures and associated dura laceration is meningitis. After the age of 2, and especially within adolescents, DAI is more common and results from stress to axons during severe trauma, such as may occur in a motor vehicle accident. DAI is always multiple, regardless whether or not magnetic resonance imaging (MRI) recognizes more than one lesion. In this group, computed tomography (CT) and MRI findings do not differ from those seen in the adult population.

The choice of imaging depends on the age of the patient, severity of trauma, neurological manifestations and, if nonaccidental trauma is under consideration, in the differential diagnosis.

Although head ultrasound (US) can provide rapid evaluation in some infants who still have open fontanels, US has limited sensitivity for parenchymal injuries as well as small or peripheral collections, and is typically not sufficient for evaluating intracranial trauma (examiner dependent). It is. However. still a good screening method in case of mild trauma. CT remains the imaging modality of choice for evaluating a child with acute neurologic findings after severe THI. It is more specific than MRI with regard to the diagnosis of skull/facial fractures, can answer the question whether or not the cervical spine is stable and, in addition, is also able to date extra-axial hemorrhages (important in suspected child-abuse cases). However, brain MRI is more sensitive in the detection of parenchymal, subdural, and epidural hematomas; it permits the identification of small bleeds, particularly in the posterior fossa or brainstem with heme-sensitive sequences such as gradient echo imaging and susceptibility-weighted imaging. Diffusion-weighted imaging is very helpful in the detection of early ischemic injury, in identifying nonhemorrhagic injuries (such as those associated with DAI) and is frequently used in trauma to help determine prognosis. In addition, MRI lacks radiation and when combined with MR-angiography can rule out vascular lesions. Current practice typically employs an initial head CT during critical care in the emergency department, which may be followed by MRI in cases where a patient’s neurologic exam remains abnormal and to rule out the diagnosis of DAI. MRI and/or US should be the first imaging in selected stable children and infants with mild THI.

Take-home points:

  • Craniocerebral maturity influences the brain response to trauma. The injury depends not only on the mechanism of impact/trauma but also on the age of the patient.

  • US can provide rapid evaluation in some infants who still have open fontanels, but has limited sensitivity for parenchymal injuries.

  • CT is the first and most important step in evaluation for head or spinal injuries in a child with severe THI.

  • MRI should be performed to rule out the diagnosis of DAI and in cases where a patient’s neurologic exam remains abnormal.

  • MRI should be the first imaging in selected stable children with mild THI.

  • CT and MRI should both be performed in case of suspected child abuse.