Magnetic resonance imaging findings of bilateral thalamic involvement in severe paroxysmal sympathetic hyperactivity: a pediatric case series

Purpose

Paroxysmal sympathetic hyperactivity is a complication of brain injury that has mainly been described in the adult brain injury literature.

Methods

We present a case series of three pediatric patients that developed paroxysmal sympathetic hyperactivity of varying severity following hypoxic brain injury.

Results

Comparison of brain magnetic resonance imaging revealed bilateral and symmetric global ischemic changes in all three cases. However, the thalamus was not affected in the patient with the mild case of paroxysmal sympathetic hyperactivity. In contrast, bilateral and symmetric damage to the thalamus was observed in the two severe cases.

Conclusions

Our case series suggests that in hypoxic brain injury, evidence of bilateral ischemic injury to the thalamus on magnetic resonance imaging may be an important early predictor of severity and length of paroxysmal sympathetic hyperactivity. While this is an interesting observation, definite proof of our hypothesis requires further research including analysis of larger numbers of patients and comparison of MRI findings in children with hypoxic brain injury that do not develop paroxysmal sympathetic hyperactivity.