Roberts, T., Hirst, R., Birse, F. et al. (97 more authors) (2024) Subarachnoid haemorrhage in the emergency department (SHED): a prospective, observational, multicentre cohort study. Emergency Medicine Journal, 41 (12). pp. 719-727. ISSN 1472-0205
Abstract
Background
People presenting to the ED with acute severe headache often undergo investigation to exclude subarachnoid haemorrhage (SAH). International guidelines propose that brain imaging within 6 hours of headache onset can exclude SAH, in isolation. The safety of this approach is debated. We sought to externally validate this strategy and evaluate the test characteristics of CT-brain beyond 6 hours.
Methods
A prospective, multicentre, observational cohort study of consecutive adult patients with non-traumatic acute headache presenting to the ED within a UK National Health Service setting. Investigation, diagnosis and management of SAH were all performed within routine practice. All participants were followed up for 28 days using medical records and direct contact as necessary. Uncertain diagnoses were independently adjudicated.
Results
Between March 2020 and February 2023, 3663 eligible patients were enrolled from 88 EDs (mean age 45.8 (SD 16.6), 64.1% female). 3268 patients (89.2%) underwent CT-brain imaging. There were 237 cases of confirmed SAH, a prevalence of 6.5%. CT within 6 hours of headache onset (n=772) had a sensitivity of 97% (95% CI 92.5% to 99.2%) for the diagnosis of SAH and a negative predictive value of 99.6% (95% CI 98.9% to 99.9%). The post-test probability after a negative CT within 6 hours was 0.5% (95% CI 0.2% to 1.3%). The negative likelihood ratio was 0.03 (95% CI 0.01 to 0.08). CT within 24 hours of headache onset (n=2008) had a sensitivity of 94.6% (95% CI 91.0% to 97.0%). Post-test probability for SAH was consistently less than 1%. For aneurysmal SAH, post-test probability was 0.1% (95% CI 0.0% to 0.4%) if the CT was performed within 24 hours of headache onset.
Conclusion
Our data suggest a very low likelihood of SAH after a negative CT-brain scan performed early after headache onset. These results can inform shared decision-making on the risks and benefits of further investigation to exclude SAH in ED patients with acute headache.
Data availability statement
Data are available upon reasonable request. We will share anonymous data with others upon reasonable request in line with ethical and data protection requirements.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Authors. Except as otherwise noted, this author-accepted version of a journal article published in Emergency Medicine Journal is made available via the University of Sheffield Research Publications and Copyright Policy under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ |
Keywords: | Computed Tomography; headache; stroke |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > School of Medicine and Population Health |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 21 Oct 2024 14:03 |
Last Modified: | 25 Feb 2025 12:07 |
Status: | Published |
Publisher: | BMJ |
Refereed: | Yes |
Identification Number: | 10.1136/emermed-2024-214068 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:218655 |