Skip to main content

Main menu

  • Home
  • Content
    • Current issue
    • Past issues
    • Early releases
    • Collections
    • Sections
    • Blog
    • Infographics & illustrations
    • Podcasts
    • COVID-19 articles
    • Obituary notices
  • Authors & Reviewers
    • Overview for authors
    • Submission guidelines
    • Submit a manuscript
    • Forms
    • Editorial process
    • Editorial policies
    • Peer review process
    • Publication fees
    • Reprint requests
    • Open access
    • Patient engagement
  • Physicians & Subscribers
    • Benefits for Canadian physicians
    • CPD Credits for CMA Members
    • Subscribe to CMAJ Print
    • Subscription prices
    • Obituary notices
  • Alerts
    • Email alerts
    • RSS
  • JAMC
    • À propos
    • Numéro en cours
    • Archives
    • Sections
    • Abonnement
    • Alertes
    • Trousse média 2023
    • Avis de décès
  • CMAJ JOURNALS
    • CMAJ Open
    • CJS
    • JAMC
    • JPN

User menu

Search

  • Advanced search
CMAJ
  • CMAJ JOURNALS
    • CMAJ Open
    • CJS
    • JAMC
    • JPN
CMAJ

Advanced Search

  • Home
  • Content
    • Current issue
    • Past issues
    • Early releases
    • Collections
    • Sections
    • Blog
    • Infographics & illustrations
    • Podcasts
    • COVID-19 articles
    • Obituary notices
  • Authors & Reviewers
    • Overview for authors
    • Submission guidelines
    • Submit a manuscript
    • Forms
    • Editorial process
    • Editorial policies
    • Peer review process
    • Publication fees
    • Reprint requests
    • Open access
    • Patient engagement
  • Physicians & Subscribers
    • Benefits for Canadian physicians
    • CPD Credits for CMA Members
    • Subscribe to CMAJ Print
    • Subscription prices
    • Obituary notices
  • Alerts
    • Email alerts
    • RSS
  • JAMC
    • À propos
    • Numéro en cours
    • Archives
    • Sections
    • Abonnement
    • Alertes
    • Trousse média 2023
    • Avis de décès
  • Visit CMAJ on Facebook
  • Follow CMAJ on Twitter
  • Follow CMAJ on Instagram
  • Listen to CMAJ podcasts
Practice

Subarachnoid hemorrhage

Shannon M. Fernando and Jeffrey J. Perry
CMAJ November 20, 2017 189 (46) E1421; DOI: https://doi.org/10.1503/cmaj.170893
Shannon M. Fernando
Department of Emergency Medicine (Fernando, Perry); Division of Critical Care, Department of Medicine (Fernando), University of Ottawa; Clinical Epidemiology Program (Perry), Ottawa Hospital Research Institute, Ottawa, Ont.
MD MSc
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Jeffrey J. Perry
Department of Emergency Medicine (Fernando, Perry); Division of Critical Care, Department of Medicine (Fernando), University of Ottawa; Clinical Epidemiology Program (Perry), Ottawa Hospital Research Institute, Ottawa, Ont.
MD MSc
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: [email protected]
  • Article
  • Responses
  • Metrics
  • PDF
Loading

Nontraumatic subarachnoid hemorrhage is an uncommon but potentially fatal cause of headache

Headaches are common and account for 2% of visits to the emergency department.1 Subarachnoid hemorrhage, often from a bleeding cerebral aneurysm, causes 1% of headaches seen in emergency departments and has a mortality rate of 44%.2 In 2012, a guideline for the management of aneurysmal subarachnoic hemorrhage was published by the American Heart Association and the American Stroke Association.2

Subarachnoid hemorrhage can confidently be ruled out using specific criteria

In patients presenting to the emergency department with sudden onset, nontraumatic and rapidly peaking (less than one hour) headache, and in the absence of any neurologic deficits, the Ottawa Subarachnoid Hemorrhage Rule can be used to exclude subarachnoid hemorrhage without testing. Subarachnoid hemorrhage can be ruled out if all of the following conditions are absent in the patient: age 40 or more years of age, neck pain or stiffness, loss of consciousness, onset during exertion, thunderclap (instantly peaking) headache and limited neck flexion on examination.3 The rule has 100% (95% confidence interval [CI] 97.2%–100%) sensitivity for subarachnoid hemorrhage.3

Computed tomography (CT) can rule out subarachnoid hemorrhage within six hours

For at-risk patients (i.e., those not ruled out by the Ottawa Subarachnoid Hemorrhage Rule), CT imaging of the head within six hours of headache onset is 100% sensitive (95% CI 97%–100%) and 100% specific (95% CI 99.5%–100%) for subarachnoid hemorrhage.4 Therefore, rapid CT scanning should be undertaken for at-risk patients. In anemic patients, blood appears isodense, and CT is unreliable.

At-risk patients presenting after six hours will require a lumbar puncture

Lumbar puncture is indicated in patients with normal CT who present six or more hours after headache onset. One-third of lumbar punctures are associated with blood from a traumatic tap. Absence of xanthochromia and the presence of fewer than 2000 × 106/L red blood cells on a tap excludes the diagnosis of aneurysmal subarachnoid hemorrhage, with a sensitivity of 100% (95% CI 74.7%–100%) and a specificity of 91.2% (88.6%–93.3%).5

CT angiography may be considered

Presence of an aneurysm may help guide the decision for neurosurgical repair.2 CT angiography may be considered in patients with any of the following: elevated erythrocyte counts or xanthochromia on lumbar puncture, subarachnoid hemorrhage visible on CT, presentation six or more hours after onset of headache with contraindication to lumbar puncture, presentation one week after onset of headache or a high index of clinical suspicion without a completely normal lumbar puncture.1

CMAJ invites submissions to “Five things to know about …” Submit manuscripts online at http://mc.manuscriptcentral.com/cmaj

Footnotes

  • Competing interests: None declared.

  • This article has been peer reviewed.

References

  1. ↵
    1. Carpenter CR,
    2. Hussain AM,
    3. Ward MJ,
    4. et al
    . Spontaneous subarachnoid hemorrhage: a systematic review and meta-analysis describing the diagnostic accuracy of history, physical examination, imaging, and lumbar puncture with an exploration of test thresholds. Acad Emerg Med 2016;23:963–1003.
    OpenUrl
  2. ↵
    1. Connolly ES Jr.,
    2. Rabinstein AA,
    3. Carhuapoma JR,
    4. et al
    . Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2012;43:1711–37.
    OpenUrlAbstract/FREE Full Text
  3. ↵
    1. Perry JJ,
    2. Stiell IG,
    3. Sivilotti ML,
    4. et al
    . Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA 2013;310:1248–55.
    OpenUrlCrossRefPubMed
  4. ↵
    1. Perry JJ,
    2. Stiell IG,
    3. Sivilotti ML,
    4. et al
    . Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ 2011;343:d4277.
    OpenUrlAbstract/FREE Full Text
  5. ↵
    1. Perry JJ,
    2. Alyahya B,
    3. Sivilotti ML,
    4. et al
    . Differentiation between traumatic tap and aneurysmal subarachnoid hemorrhage: prospective cohort study. BMJ 2015;350: h568.
    OpenUrlAbstract/FREE Full Text
PreviousNext
Back to top

In this issue

Canadian Medical Association Journal: 189 (46)
CMAJ
Vol. 189, Issue 46
20 Nov 2017
  • Table of Contents
  • Index by author

Article tools

Respond to this article
Print
Download PDF
Article Alerts
To sign up for email alerts or to access your current email alerts, enter your email address below:
Email Article

Thank you for your interest in spreading the word on CMAJ.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Subarachnoid hemorrhage
(Your Name) has sent you a message from CMAJ
(Your Name) thought you would like to see the CMAJ web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Subarachnoid hemorrhage
Shannon M. Fernando, Jeffrey J. Perry
CMAJ Nov 2017, 189 (46) E1421; DOI: 10.1503/cmaj.170893

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
‍ Request Permissions
Share
Subarachnoid hemorrhage
Shannon M. Fernando, Jeffrey J. Perry
CMAJ Nov 2017, 189 (46) E1421; DOI: 10.1503/cmaj.170893
Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like

Jump to section

  • Article
    • Nontraumatic subarachnoid hemorrhage is an uncommon but potentially fatal cause of headache
    • Subarachnoid hemorrhage can confidently be ruled out using specific criteria
    • Computed tomography (CT) can rule out subarachnoid hemorrhage within six hours
    • At-risk patients presenting after six hours will require a lumbar puncture
    • CT angiography may be considered
    • Footnotes
    • References
  • Responses
  • Metrics
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Google Scholar

More in this TOC Section

  • SARS-CoV-2 vaccination in pregnancy
  • Infantile perianal pyramidal protrusion
  • Topical nonsteroidal anti-inflammatory drugs
Show more Practice

Similar Articles

Collections

  • Article Types
    • Five Things to Know About
  • Topics
    • Emergency medicine
    • Neurology
    • Neurosurgery
    • Screening & diagnostic tests

 

View Latest Classified Ads

Content

  • Current issue
  • Past issues
  • Collections
  • Sections
  • Blog
  • Podcasts
  • Alerts
  • RSS
  • Early releases

Information for

  • Advertisers
  • Authors
  • Reviewers
  • CMA Members
  • CPD credits
  • Media
  • Reprint requests
  • Subscribers

About

  • General Information
  • Journal staff
  • Editorial Board
  • Advisory Panels
  • Governance Council
  • Journal Oversight
  • Careers
  • Contact
  • Copyright and Permissions
CMAJ Group

Copyright 2023, CMA Impact Inc. or its licensors. All rights reserved. ISSN 1488-2329 (e) 0820-3946 (p)

All editorial matter in CMAJ represents the opinions of the authors and not necessarily those of the Canadian Medical Association or its subsidiaries.

To receive any of these resources in an accessible format, please contact us at CMAJ Group, 500-1410 Blair Towers Place, Ottawa ON, K1J 9B9; p: 1-888-855-2555; e: [email protected]

CMA Civility, Accessibility, Privacy

 

Powered by HighWire