Sympathetic activation and inflammatory response in patients with subarachnoid haemorrhage

Abstract

Objective: The aim of this study was to evaluate the correlation between sympathetic nervous activation and the immune response in patients following subarachnoid haemorrhage (SAH). Design and setting: Clinical study in a neurosurgical intensive care unit. Patients and participants: Fourteen patients with acute non-traumatic SAH were included. Fifteen healthy, agematched volunteers served as controls for measurement of catecholamine spillover. Intervention: Blood sampling for C3a, C5b-9, IL-6, IL-8 and norepinephrine kinetic determination was made within 48 h, at 72 h and on the 7th-10th day after the SAH. Measurements and results: SAH patients exhibited a profound increase in the rate of norepinephrine spillover to plasma at 48 h, 72 h and 7-10 days after the insult, 3-4 times that in healthy individuals. The plasma levels of C3a, IL-6 and C5b-9 were significantly elevated at 48 h, at 72 h and 7-10 days after the SAH, but the plasma level of IL-6 decreased significantly 7-10 days after the SAH. There was no relationship between the magnitude of sympathetic activation and the levels of inflammatory markers. Conclusions: Following SAH a pronounced activation of the sympathetic nervous system and the inflammatory system occurs. The lack of significant association between the rate of spillover of norepinephrine to plasma and the plasma levels of inflammatory markers indicates that the two processes, sympathetic activation and the immune response, following SAH are not quantitatively linked. In spite of a persistent high level of sympathetic activation the plasma level of IL-6 decreased significantly one week after SAH.

Temperature Rhythm in Aneurysmal Subarachnoid Hemorrhage

“…In the current study, cosinor parameters describing overt diurnal temperature patterns were typically abnormal, with elevated mesors, blunted magnitudes, and variable acrophases that were often substantially shifted from the normative time. The finding of an elevated mean mesor temperature (37.7°C) in this study is consistent with findings of other studies indicating the common occurrence of temperature elevation following SAH [27][28][29][30]. This study additionally identifies a significant association of impairment of consciousness on hospital admission with a subsequent higher mean temperature mesor over the following 2 weeks of hospitalization.…”

Systemic interleukin-6 concentrations in patients with perimesencephalic non-aneurysmal subarachnoid hemorrhage

“…However, increased levels have been reported. 11,18,19 Systemic IL-6 might originate from the central nervous system and/or reflect the systemic inflammatory response. Although the prognostic significance of systemic leukocytosis for the outcome of patients with SAH has been recognized earlier, 16,17 the positive relationship between systemic inflammatory response, occurrence of CVS and subsequent worse outcome is a newer observation.…”

“…16,17 Less has been reported on systemic IL-6 levels, however, increased levels were described. 11,18,19 Systemic IL-6 might originate from the central nervous system and/or reflect the systemic inflammatory response. The systemic IL-6 levels can be assumed to reflect the severity of illness and risk of CVS to a certain extent.…”

The Burden of the Systemic Inflammatory Response Predicts Vasospasm and Outcome after Subarachnoid Hemorrhage

“…Not only does a local inflammatory response propagate from blood breakdown, but a systemic state of inflammation is triggered. This may result either directly from the action of liberated cytokines, or indirectly through release of high levels of circulating catecholamines which promote immune activation [26]. The acutely injured brain releases significant quantities of interleukin-6 (IL-6), as evidenced by the much higher levels measured in the jugular vein compared to a peripheral artery after SAH [27].…”