History and Physical
An 8-year-old, previously healthy boy was traveling in the front seat of a car on his mother’s lap with an unfastened seatbelt. The car was hit on the right side by a truck, with both vehicles in transit at high speed. The mother died immediately, and the boy was found unconscious by paramedics. Time to first medical attention was unknown. The patient was hypoxemic, hypotensive, and unconscious (Glasgow Coma Scale [GCS] 3/15). He was intubated and received sedation and analgesia; his cervical spine was stabilized. Upon transfer to a level I trauma center, initial vital signs were heart rate 116/min, blood pressure 89/62, oxygen saturation 100% on F iO 2 50%, and respiratory rate 20/min on ventilator. There were no spontaneous respirations. The patient was unreactive to painful stimuli, and anisocoria was noted with a dilated and unresponsive left pupil. He had left otorrhagia, raccoon eyes, and an ecchymotic area in the anterior right chest wall. Examination of the lungs, heart, and abdomen was unremarkable.
Diagnostic Workup
Initial head CT revealed right temporal epidural/subdural hematomas and stellate fractures of the left parietal, temporal, and sphenoid bones ( Fig. 60.1 ). Rotterdam score was 1. Cervical spine CT was normal. Chest CT revealed bilateral lung contusions. Abdomen CT showed grade 1 laceration of liver segment 4 and pancreatic edema. Liver and pancreatic enzymes were elevated. Arterial blood gas and blood glucose were normal.
Moderate diffuse axonal injury. Head CT, soft tissue window shows (A) right temporal epidural/subdural hematoma ( white arrow ) (B) and left frontotemporal pneumocephalus ( white arrowheads ). (C) Sagittal three-dimensional reconstruction and (D) axial bone window show comminuted stellate fractures of the left parietal, temporal, and sphenoid bones ( black arrow ) with hemotympanum ( black arrowhead ).
The patient was admitted to the pediatric intensive care unit (PICU) and neurosurgery was consulted for intracranial pressure (ICP) monitoring, with first recording of 12 mm Hg. Normal ICP levels were observed during the PICU stay, along with normal video-electroencephalogram (EEG). On day 4 of admission, because of persistent anisocoria and absence of clinical improvement, a brain MRI was ordered. The findings were consistent with moderate (grade 2) diffuse axonal injury (DAI) according to the Adams classification. Multifocal restricted diffusion was seen in the left greater than right cortex and subcortical white matter, left splenium, and left cerebellar hemisphere ( Fig. 60.2 ). Time of flight (TOF) angiography was normal.
Moderate diffuse axonal injury. Brain MRI, axial DWI shows multifocal restricted diffusion involving the left cerebral cortex, subcortical white matter, splenium, and cerebellum ( arrows ).
Clinical Differential Diagnoses
Following acute head trauma, various injuries can occur, including DAI, epidural hematoma, subdural hematoma, subarachnoid hemorrhage, parenchymal hemorrhage, and ischemic and hemorrhagic stroke. Patient status may be complicated by seizures, status epilepticus, hypoxemia, and hypoglycemia. Diagnosis of DAI requires a combination of clinical and imaging findings. The mechanism of head injury is typically high-speed rotation or acceleration-deceleration closed head injury with a GCS <8 for more than 6 consecutive hours. DAI should also be strongly considered in patients who fail to improve after surgical evacuation of subdural or epidural hematomas.
Imaging Differential Diagnoses
The differential diagnosis includes acute ischemic infarction of the superficial territory of the middle cerebral artery, possibly associated with traumatic dissection or a hemodynamically low-flow state ( Fig. 60.3 ), and extra-limbic autoimmune or infectious encephalitis ( Fig. 60.4 ).
