Ottawa SAH Rule mneumonic: “ANT LEaF” (warning – this rule not yet validated)
· Age >40
· Neck pain or stiffness
· Thunderclap headache
· Loss of consciousness (witnessed)
· Exertion (onset during)
· Flexion (limited of the neck on exam)
Asimos approach is no “routine” LP needed if thunderclap onset H/A with normal head CT performed within 6 hours of H/A onset, with the following caveats:
· Recognize this approach is not incorporated into any published guidelines
· Assumes all of the following:
1. Classic thunderclap headache
2. No neurological findings
3. No meningismus
4. No prominent neck pain
5. No family history of SAH
6. CT performed within 6h of onset, and read by a neuroradiologist
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