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High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study

BMJ 2010; 341 doi: (Published 28 October 2010) Cite this as: BMJ 2010;341:c5204

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  1. Jeffrey J Perry, associate professor1,
  2. Ian G Stiell, professor and chair1,
  3. Marco L A Sivilotti, associate professor2,
  4. Michael J Bullard, professor3,
  5. Jacques S Lee, assistant professor4,
  6. Mary Eisenhauer, associate professor of medicine5,
  7. Cheryl Symington, research coordinator1,
  8. Melodie Mortensen, research coordinator1,
  9. Jane Sutherland, research coordinator6,
  10. Howard Lesiuk, consulting neurosurgeon7,
  11. George A Wells, professor biostatistics and epidemiology8
  1. 1Department of Emergency Medicine, University of Ottawa and Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1Y 4E9
  2. 2Department of Pharmacology and Toxicology, Queen’s University, Kingston, Ontario
  3. 3Division of Emergency Medicine, University of Alberta, Edmonton, Alberta
  4. 4Division of Emergency Medicine, University of Toronto, Toronto, Ontario
  5. 5Division of Emergency Medicine, University of Western Ontario, London, Ontario
  6. 6University of Ottawa, Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario
  7. 7Division of Neurosurgery, Ottawa Hospital Research Institute, Ottawa, Ontario
  8. 8Department of Epidemiology and Community Medicine, Ottawa Hospital Research Institute, Ottawa, Ontario
  1. Correspondence to: J Perry jperry{at}
  • Accepted 31 August 2010


Objective To identify high risk clinical characteristics for subarachnoid haemorrhage in neurologically intact patients with headache.

Design Multicentre prospective cohort study over five years.

Setting Six university affiliated tertiary care teaching hospitals in Canada. Data collected from November 2000 until November 2005.

Participants Neurologically intact adults with a non-traumatic headache peaking within an hour.

Main outcome measures Subarachnoid haemorrhage, as defined by any of subarachnoid haemorrhage on computed tomography of the head, xanthochromia in the cerebrospinal fluid, or red blood cells in the final sample of cerebrospinal fluid with positive results on angiography. Physicians completed data collection forms before investigations.

Results In the 1999 patients enrolled there were 130 cases of subarachnoid haemorrhage. Mean (range) age was 43.4 (16-93), 1207 (60.4%) were women, and 1546 (78.5%) reported that it was the worst headache of their life. Thirteen of the variables collected on history and three on examination were reliable and associated with subarachnoid haemorrhage. We used recursive partitioning with different combinations of these variables to create three clinical decisions rules. All had 100% (95% confidence interval 97.1% to 100.0%) sensitivity with specificities from 28.4% to 38.8%. Use of any one of these rules would have lowered rates of investigation (computed tomography, lumbar puncture, or both) from the current 82.9% to between 63.7% and 73.5%.

Conclusion Clinical characteristics can be predictive for subarachnoid haemorrhage. Practical and sensitive clinical decision rules can be used in patients with a headache peaking within an hour. Further study of these proposed decision rules, including prospective validation, could allow clinicians to be more selective and accurate when investigating patients with headache.


  • We thank the hundreds of physicians who completed our data collection forms and all the emergency department nurses and clerks at the six study sites for their cooperation. We thank Albert E Lauwers, deputy coroner, and the Office of the Coroner of Ontario assistance with verifying outcomes. We also thank Evelyn Gilkinson (London Health Sciences Centre, London, Ontario); Erica Battram and Nicole Fortin (Ottawa Hospital, Civic Campus and General Campus, Ottawa, Ontario); Harris Lari, Leslie Saunders, Ginny Willis, and Sandy Sandilands (University of Alberta Health Sciences Centre, Edmonton, Alberta); Deborah Wright and Johanna Pak (Sunnybrook and Women’s College Health Sciences Centre, Toronto, Ontario); Kathy Bowes, Julie Richard, Deborah Crosby, and Jane Reid (Kingston General Hospital, Kingston, Ontario); and our colleagues at the Ottawa Hospital Research Institute (My-Linh Tran, Irene Harris, and Angela Marcantonio) for their assistance with this project.

  • Contributors: JJP developed and contributed substantially to study concept and design and secured research funding. JJP IGS, MLAS, MJB, JSL, ME, HL, and GAW participated in the study design and supervised in the recruitment of patients and management of data. All authors supervised in the conduct of the trial and data collection, drafted the manuscript and/or contributed to its revision, and approved the final version. JJP, IGS, and GAW provided statistical advice and data analysis. JJP is guarantor.

  • Funding: This study was funded by Ontario Ministry of Health and Long Term Care, physicians of Ontario through the Physician’s Services Incorporated Foundation (grant No 01-39), the Canadian Institutes for Health Research (grant No 67107). JJP was funded as a career scientist by the Ontario Ministry of Health and is now funded by a Canadian Institutes for Health Research New Investigator Award. IGS is a University Health Research Chair, University of Ottawa.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: no support from any institution for the submitted work; no financial relationships with any institutions that might have an interest in the submitted work in the previous 3 years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study protocol was approved by the research ethics boards at each centre without the need for written informed consent as patients continued to be investigated as per current practice. Participants were informed that they could be contacted by telephone for an update on their status, and verbal consent was obtained at the time of the telephone call.

  • Data sharing: No additional data available.

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