[Suspected spontaneous subarachnoid hemorrhage: what diagnostic approach?]

Subarachnoid hemorrhage (SAH) is defined as sudden bleeding into the subarachnoid space. Although its incidence is low, mortality remains high. The most frequent cause of spontaneous SAH is aneurysm rupture. Cerebral CT scans are highly sensitive in ruling out SAH within the first 6 hours. Due to the recent improvement in imaging resolution, only a strong clinical suspicion can justify a cerebrospinal fluid analysis if the CT scan is normal after 6 hours. Cerebral MRI is also highly sensitive in both the acute and sub-acute phases. This article reviews the various clinical and paraclinical elements of the diagnostic approach, the main etiologies and the risk factors associated with SAH.