Interleukin 6 in the Cerebrospinal Fluid as a Biomarker for Onset of Vasospasm and Ventriculitis After Severe Subarachnoid Hemorrhage.

OBJECTIVE The aim of the study was to investigate the diagnostic potential of interleukin 6 (IL-6) and other soluble biomarkers in serum and cerebrospinal fluid (CSF) for early diagnosis of cerebral vasospasm (cVSSAH) and external ventricular drain-associated ventriculitis (VCSAH) and to separate these conditions from aneurysmal subarachnoid hemorrhage (aSAH) without further complication (SAHw/o/c). METHODS The concentrations of serum biomarkers and markers in the CSF were collected in 63 consecutive patients with aSAH and external ventricular drainage. Arithmetical means and standard deviations, area under the curve (AUC), cutoff values (C-OFF), sensitivity (SE), and specificity (SP) were calculated for markers and their correlation with SAHw/o/c, cVSSAH, and VCSAH. RESULTS Clinical courses included 27 patients with cVSSAH, 17 with VCSAH, and 19 with SAHw/o/c. Mean ± standard deviationCSFIL-6 values were 7588 ± 4580 pg/mL at onset of VCSAH and 4102 ± 4970 pg/mL for cVSSAH and higher than 234 ± 239 pg/mL in SAHw/o/c (P < 0.001). CSFIL-6 showed excellent diagnostic potential for differing between VCSAH and SAHw/o/c (AUC, 1.00; C-OFF, 707; SE, 100%; SP, 100%), and a moderate diagnostic potential for differing VCSAH from cVSSAH (AUC, 0.757; C-OFF, 3100 pg/Ml; SE, 86.7%; SP, 70.6%). The concentration of CSFIL-6 within the cVSSAH group was significantly increased compared with SAHw/o/c (AUC, 0.937; C-OFF, 530 pg/mL; SE, 87.5%; SP, 91.7%). CONCLUSIONS CSFIL-6 is increased after aSAH in patients with cVSSAH or VCSAH. Patients with a CSFIL-6 level higher than a C-OFF of 3100 pg/mL have an increased likelihood for VCSAH; patients with CSFIL-6 levels between 530 and 3100 pg/mL have an increased posttest probability for cVSSAH.