Ruling Out Subarachnoid Hemorrhage at Nonacademic Hospitals

May 15, 2015

Ruling Out Subarachnoid Hemorrhage at Nonacademic Hospitals

  1. Jennifer L. Wiler, MD, MBA, FACEP

Brain CT scans read as negative by staff radiologists at community hospitals can safely rule out subarachnoid hemorrhage in patients with headache of <6 hours duration.

  1. Jennifer L. Wiler, MD, MBA, FACEP

Two recent studies reported a negative predictive value of 100% for third-generation brain computed tomography (CT) scans performed within 6 hours after onset of acute headache in patients with suspected aneurysmal subarachnoid hemorrhage (SAH; NEJM JW Emerg Med Sep 2011 and BMJ 2011; 343:d4277; and Stroke 2012; 43:2115). Both studies were performed in university-affiliated tertiary care hospitals where CT scans were interpreted by neuroradiologists or experienced general radiologists.

To determine whether these findings apply in the nonacademic setting, researchers retrospectively studied consecutive patients with acute headache who presented to 11 community hospitals in the Netherlands. Eligible patients had a brain CT scan within 6 hours of headache onset that was read as negative for SAH by a staff radiologist and subsequent cerebrospinal fluid (CSF) analysis by spectrophotometry. Exclusion criteria were Glasgow Coma Scale score ≤14 at presentation, unknown time of ictus, age ≤16 years, and lumbar puncture performed sooner than 12 hours after headache onset. For this study, each case was independently reviewed by two academic neuroradiologists and one stroke neurologist.

CSF was positive for bilirubin in 52 of 760 patients (7%). The independent reviewers deemed that one patient had a missed perimesencephalic nonaneurysmal SAH. The negative predictive value for detection of subarachnoid hemorrhage by staff radiologists at nonacademic hospitals was 99.9% (95% confidence interval, 99.3%–100.0%). Of note, eight patients with false-positive CSF results had incidental, unruptured aneurysms on subsequent vascular imaging.


The authors conclude that the routine practice of mandatory performance of lumbar puncture to rule out SAH after a negative CT scan is no longer appropriate, even in the nonacademic setting. Given that this is the third high-quality study with similar findings, there is sufficient evidence to change practice.

Dr. Wiler is Vice Chair and Associate Professor, Department of Emergency Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora.

Editor Disclosures at Time of Publication

  • Disclosures for Jennifer L. Wiler, MD, MBA, FACEP at time of publication Leadership positions in professional societies Colorado Medical Society (Member, Board of Directors)


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