The SHED Trial for SAH in ED
Dec 08, 2024
Acute headache acounts for up to 2% of Emergency Department presentations, with up to 10% of those patients having a serious cause for their headache. Subarachnoid Haemorrhage(SAH) is the most frequent serious pathology found. Most patients with suspected SAH will undergo non-contrast head CT. There is some concensus, that a negative CT, performed within 6 hours of headache onset, requires no further investigation. However the sensitivity of CT scan in these situations is a not perfect, ie., 98.7% and so the debate continues. The area that needs more work is what we do with patients presenting greater than 6 hours following headache onset. There were some interesting insights in this study.
The Study
The Trainee Emergency Research Network (TERN). Subarachnoid Haemorrhage in the emergency department (SHED): a prospective, observation, multi centre cohort study. Emerg Med J 2024;42:719-727.
Bottom Line
CT imaging within 6 hours of headache onset had a high sensitivity 97% CI (92.5 - 99.2) and a very low post-test probability for SAH. The sensitivity of CT reduced over time, interestingly, the post-test probability for aneurysmal SAH after a negative CT up to 24 hours was 0.1%.
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