Subarachnoid hemorrhage headache
Headache accounts for approximately 2% of Emergency Department (ED) visits, with subarachnoid hemorrhage (SAH) occurring in 0.5% to 6% 1).
Most patients with SAH experience abrupt headache, often thunderclap in nature, that reaches maximal intensity within one minute 2).
The patients without headache have no specific clinical characteristics over patients with common SAH 3).
Usually severe (classic description: “the worst headache of my life”) and sudden in onset 4).
Sentinel headaches are similar to SAH headaches, which may occur days to weeks prior to aneurysm rupture. The incidence appears in 10%-43% of patients with subsequent aneurysmal SAH 5)
If severe or accompanied by reduced level of consciousness, most patients‘ present for medical evaluation. Patients with H/A due to minor hemorrhages will have blood on CT or LP. However, warning. headaches may also occur without SAH and maybe due to aneurysmal enlargement or to hemorrhage confined within the aneurysmal wall.
Warning H/A are usually sudden in onset, severe, and clear within 1 day.
Headache developed almost instantaneously in only half the patients with aneurysm rupture and in two thirds of patients with benign thunderclap headache (BTH). In patients with acute severe headache, female sex, the presence of seizures, a history of loss of consciousness or focal symptoms, vomiting, or exertion increases the probability of aneurysmal subarachnoid hemorrhage aSAH, but these characteristics are of limited value in distinguishing aSAH from BTH. Aneurysm rupture should be considered even if focal signs are absent and the headache starts within minutes 6).
The diagnosis of aSAH itself may not be a challenge as the classical presentation is sudden severe headache described as “worst headache ever experienced in life.” Other manifestations such as brief loss of consciousness, sentinel headache, nausea and vomiting, photophobia, neck stiffness, seizures and focal deficits may however cause diagnostic confusion 7).