- If you think CT will show a cause for the headache, do a CT
- If a CT is indicated for other reasons (depressed conscious level, focal neurology), do a CT
- If a GCS 15 patient is to undergo LP for suspected (or to rule out) meningitis, and they have a normal neurological exam (including fundi), and are not elderly or immunosuppressed, there is no need to do a CT first.
- If you’re seriously worried about meningitis and are intent on getting a CT prior to LP, don’t let the imaging delay antimicrobial therapy.