MedicalResearch.com Interview with:
Jeff Perry, MD, MSc, CCFP-EM
Professor, Department of Emergency Medicine
Senior Scientist, Ottawa Hospital Research Institute
Research Chair in Emergency Neurological Research, University of Ottawa
Emergency Physician and Epidemiology Program
The Ottawa Hospital
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Headache accounts for about 1-2% of all emergency department visits. One of the most feared diagnosis within these patients is subarachnoid hemorrhage. While investigations are clearly warranted for patients with a diminished level of consciousness or new focal neurological deficits, approximately 50% of patients with subarachnoid hemorrhage (SAH) have no focal or global neurological findings. Deciding whether to image headache patients with no deficits is difficult, especially since timely diagnosis and treatment results in substantially better outcomes.
The desire to never miss a subarachnoid hemorrhage, however, contributes to escalating neuroimaging rates and a dogmatic adherence to lumbar puncture, even if the scan is negative, despite the very high sensitivity of computed tomography. However, a recent population-based study suggested that over 5% of confirmed subarachnoid hemorrhages were missed at initial presentation, especially in smaller hospitals. Therefore, identifying which headache patients require investigations to rule-out SAH is of great importance.
We have previously derived (N=1,999) and refined (N=2,131) the Ottawa SAH Rule. In this study, we conducted an multicenter prospective cohort study at six tertiary care hospitals, and found that the Ottawa SAH Rule performed well, with an 100% sensitivity, and specificity of 13.6%.