Is LP indicated for patients with recurrent thunderclap headaches over a 4-week period and negative head imaging for SAH?

I think this depends on what kind of head imaging was done to rule out SAH. If the patient has had a totally normal head MRI and MRA (not only ruling out SAH, aneurysm but also RCVS), then LP is warranted to insure there is no inflammatory or infectious component as a cause for the headache. I think...

Such benign presentation (recurrent thunderclap headaches only) may have been RCVS but the diagnosis may have been missed. Spasm peaks around 10 days after headache onset. When arterial imaging is done too early or too late, arterial spasm and specific RCVS diagnosis might be missed. CTA, MRA, and a...