The correlation between the severity of paroxysmal sympathetic hyperactivity and plasma catecholamine levels in patients with severe traumatic brain injury.

Background: There is limited literature investigating the catecholamine levels in patients with paroxysmal sympathetic hyperactivity (PSH) after traumatic brain injury (TBI). The primary objective of this study was to correlate the severity of PSH (assessed using the PSH-Assessment measure [AM]) with plasma catecholamine levels at a resting state.
Methods: In this prospective case-control study, blood samples for epinephrine and norepinephrine estimation were obtained at rest on three consecutive days, only for 'cases' of PSH after severe TBI (s-TBI) and for control patients (matched for age, gender, and Glasgow coma scale [GCS].
Results: Twenty-seven patients with PSH and 16 controls were recruited. The median PSH-AM score was 20 and 9 in cases and controls, respectively. The epinephrine and norepinephrine levels at rest did not correlate with the severity of PSH assessed during PSH paroxysms ( p  = 0.949 and 0.975). Norepinephrine levels increased in PSH patients over the 3 consecutive days, once PSH was diagnosed ( p  = 0.022). The length of hospital stay was longer and the motor-GCS score was lower in PSH patients, with no differences in other outcomes between the groups.
Conclusion: Catecholamine levels in the inter-paroxysmal interval cannot be correlated with PSH severity assessed during the paroxysms. However, the results of the study need to be confirmed by a larger sample size as the study is underpowered.