Effect of insular injury on autonomic functions in patients with ruptured middle cerebral artery aneurysms

Insular injuries are known to cause autonomic derangements. Patients with ruptured middle cerebral artery aneurysms frequently develop temporal hematomas (THs) in addition to subarachnoid hemorrhages, and those with TH may sustain autonomic derangements more frequently than those without TH. Hemispheric lateralization in autonomic derangements has been reported in patients with insular ischemic stroke, and this study was conducted to clarify whether such lateralization was also observed in patients with TH resulting from middle cerebral artery aneurysm rupture.

A retrospective analysis on the medical records of 79 patients with ruptured middle cerebral artery aneurysms was performed on the basis of lateralization and presence of TH. They were quadrichotomized as left TH+ (LTH+; n=17), right TH+ (n=25), left TH- (n=15), and right TH- (n=22). Comparisons, mainly between LTH+ and right TH+, were made on demographic variables, autonomic/cardiac parameters, plasma catecholamine and glucose levels, and outcomes.

There were no significant differences in demographic or cardiac parameters between the 2 groups. Systolic blood pressures were lower in LTH+ (139±34 versus 174±47 mm Hg; P=0.05). The LTH+ group also tended to be more bradycardiac (80±19 versus 101±22 bpm; P=0.13). The LTH+ group exhibited significantly lower plasma norepinephrine (1008±975 versus 2549±2133 pg/mL; P=0.03) and glucose levels (9.3±1.8 versus 12.2±4.5 mmol/L; P=0.04). However, in-hospital mortality did not differ significantly (41% versus 44%; P=1.00).

Lateralization of autonomic derangements observed might not have had a significant effect on the outcomes. Nevertheless, autonomic derangements associated with insular injury should be considered in the management of subarachnoid hemorrhage patients with TH.