What is the typical presentation of a subarachnoid hemorrhage?

The typical presentation of a subarachnoid hemorrhage is characterized by a sudden onset of a severe headache, often described as a "thunderclap" headache. This type of headache reaches its peak intensity within moments and is often unlike any headache the individual has experienced before. It can be associated with neck stiffness, photophobia, and altered mental status due to increased intracranial pressure and irritation of the meninges. The sudden nature of the headache typically indicates that there is an acute event, such as the rupture of a cerebral aneurysm or a vascular malformation, leading to bleeding in the subarachnoid space.

In contrast, other types of headaches that present with a gradual worsening or milder symptoms might suggest different etiologies, such as tension-type headaches or migraines, which do not have the same acute, alarming presentation as a subarachnoid hemorrhage. Conditions that involve fever and localized symptoms, such as infection or tumors, also differ significantly in clinical presentation and urgency compared to the classic presentation of a subarachnoid hemorrhage.