The correct answer is:

Bradycardia

Educational Objective:

Recognize potential complications in pediatric neck trauma.

Key Point:

This patient has a flexion injury with resultant compression of the spinal cord and anterior cord syndrome. 

Explanation:

There is a teardrop shaped fracture shown on the x-ray by the yellow arrow:

This patient could present with spinal shock, in which loss of autonomic sympathetic input results in bradycardia.

In addition, he could have hypotension and warm flushed skin, not hypertension or cool clammy skin.

Temperature autoregulation is not affected in anterior cord syndrome or spinal shock, so hypothermia is not correct.

Finally in contrast to cardiogenic, hypovolemic, and septic shock where patients might have a narrow pulse pressure, spinal shock would more likely present with a widened pulse pressure.

References:

Woodward GA, et al. Neck Trauma. F&L 2016; pp 1263-76.