Significance of routine cerebrospinal fluid analysis in subarachnoid hemorrhage

BACKGROUND: The aim of this paper was to determine the diagnostic value of cerebrospinal fluid (CSF) analysis in the setting of aneurysmal subarachnoid hemorrhage (aSAH), hypothesizing that CSF analysis is only critical in confirming suspected infection and may be useful in predicting and/or detecting delayed cerebral ischemia (DCI). METHODS: Retrospective review of consecutive adult patients diagnosed with aSAH from 1/2000 to 12/2013 at Mayo Clinic, Rochester, MN, USA with cerebral aneurysm(s) identified by vascular imaging, and CSF drawn within 14 days of the date of hemorrhage. RESULTS: We identified 741 patients during the study period, 167 met inclusion criteria and 356 samples were collected. First Median CSF samples were taken 5 (4-8) days postbleed. Multiple samples were taken in 94 (54.5%) patients and the mean number of samples per patient was 2.1. Ventriculitis, confirmed by growth of organism from CSF culture was present in 2 (1.2%) patients and one patient (0.6%) developed meningitis. CSF WBC count remained elevated throughout the 14 days, even when corrected for red blood cell count (RBC). Peak CSF RBCs occurred 2-4 days post bleed, and then gradually normalized. Maximum CSF RBCs did not correlate with modified Fisher grades (P = 0.422). Delayed cerebral ischemia (DCI) was present in 86 (51.5%) patients and there was no difference in the CSF profile of patients with DCI compared with those without. CONCLUSIONS: Routine CSF sampling for cell count and chemistry in the setting of temporary diversion following aSAH appears to have little clinical benefit beyond the evaluation for infection.