Sentinel [[headache]] (SH) is a kind of secondary headache that is characterized as sudden, intense, and persistent, preceding [[spontaneous subarachnoid hemorrhage]] (SAH) by days or weeks. It can occur in 15-60% of patients with spontaneous SAH and its pathophysiology has not been fully elucidated. The current consensus is that structural changes in the aneurysm wall or minor bleeding could be the factors responsible for the pain
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