History and exam

Key diagnostic factors

common

headache

Most important clue to diagnosis when described as sudden, severe, or "worst ever."[37] Around 10% to 43% of patients experience a sentinel headache in the 3 months prior to subarachnoid hemorrhage.[2]

photophobia

Eye pain with exposure to light.

loss of consciousness

On admission, up to two-thirds of people with subarachnoid hemorrhage have a depressed level of consciousness, half of whom are in a coma.[39]

uncommon

third cranial nerve palsy

The presence of third cranial nerve palsy can be very useful and specific, as it typically signals the presence of a posterior communicating artery aneurysm compressing the ipsilateral third cranial nerve. Given their proximity to the third cranial nerve, aneurysms arising from the superior cerebellar artery or posterior cerebral artery can result in the same.

Other diagnostic factors

common

age >50 years

Average age between 50 and 55 years.[1][11][12]

female sex

After the sixth decade, women are affected 1.6 times more than men.[79]

black people

When adjusted for age and sex, in the US the incidence of aneurysmal subarachnoid hemorrhage is greater in black patients (15.4) compared with that in non-Hispanic white patients (9.9) and other races and ethnicities.[80]

nausea/vomiting

Seen in majority of patients with subarachnoid hemorrhage but nonspecific.[81][82]

altered mental status

Common but nonspecific.[81]

uncommon

meningismus

A clue to diagnosis only when associated with sudden, severe headache.

unilateral or bilateral sixth cranial nerve palsies

This indicates increased intracranial pressure. Nonspecific.[83]

intraocular hemorrhage

Intraocular hemorrhages are seen in 10% to 40% of patients with subarachnoid hemorrhage.[42] Intraocular hemorrhages cause visual loss in the affected eye. This is associated with worse prognosis and increased mortality.[42]

focal neurologic deficits

Focal neurologic deficits reflect presence of mass effect from subdural or parenchymal hematomas.[81] Independently associated with higher in-hospital mortality rates and severe disability at discharge.[84]

seizures

Seizures occur in around 1% to 10% of patients with subarachnoid hemorrhage.[85][86][87]

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