The course of cerebrospinal fluid parameters ≤ 20 days after aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) patients have an inflammatory response in the cerebrospinal fluid (CSF). We determined CSF cell counts, erythrocyte/leukocyte ratio, and glucose- and protein concentrations in patients ≤20 days after aSAH without bacterial meningitis. Such knowledge may help to interpret CSF parameters in patients with an external drain if nosocomial bacterial meningitis or ventriculitis is suspected.

Patients with aSAH admitted between 2010 and 2017 with at least one CSF sample ≤ 20 days after ictus were included from a prospectively collected database. CSF samples were excluded if the patient used antibiotics or if the CSF culture was positive. We calculated estimated marginal means with 95% confidence intervals (CIs) with linear mixed models for CSF cell counts, glucose- and protein concentrations.

We included 209 patients with 306 CSF samples. Highest estimated median leukocyte count was 305 (95%CI:225-412) x10^6/L, and the lowest estimated median erythrocyte/leukocyte ratio was 109 (95%CI:73-163). Estimated mean glucose concentrations remained within the normal range. The estimated median protein concentration decreased from 3.3 g/L (95%CI:2.5-4.2) on day 0 to 1.0 g/L (95%CI:0.8-1.2) on day 14.

The limits we found for the inflammatory reaction in aSAH patients may help physicians to interpret CSF parameters in aSAH patients with an external CSF drain. Future studies are needed to compare CSF parameters in aSAH patients with and without bacterial meningitis or ventriculitis.