Ottawa subarachnoid haemorrhage rule
Ottawa subarachnoid haemorrhage (SAH) rule
- is for alert patients >15 years old with new severe non-traumatic headache reaching maximum intensity within one hour
- is not appropriate for patients with new neurological deficits, history of previous aneurysms, or history of similar headaches (≥3 episodes over ≥6 months)
- it takes into account clinical features that were deemed a high risk for SAH, including:
- age ≥40 years,
- neck pain/stiffness,
- witnessed loss of consciousness,
- onset during exertion,
- thunderclap headache
- limited neck flexion on examination
- patients require investigation if one or more finding is present
- a validation study concluded that "..in patients presenting to the ED (emergency department) with an acute non-traumatic headache, the Ottawa rule can be used to safely exclude patients with SAH and can thereby inform decisions for further investigations.."
Reference:
- Foley RW et al. Subarachnoid haemorrhage rules in the decision for acute CT of the head: external validation in a UK cohort. Clin Med (Lond). 2021 Mar;21(2):96-100.
Create an account to add page annotations
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.