Subarachnoid Hemorrhage

About Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space between the brain and skull, most commonly caused by rupture of cerebral aneurysms. It presents as sudden onset of severe headache, often described as the 'worst headache of my life,' and constitutes a neurosurgical emergency requiring immediate intervention.

Pathophysiology

SAH occurs when blood vessels rupture and bleed into the cerebrospinal fluid-filled subarachnoid space, causing increased intracranial pressure and potential brain tissue damage. The bleeding triggers inflammatory cascades, vasospasm, and can lead to secondary brain injury through mechanisms including cerebral ischemia, hydrocephalus, and elevated intracranial pressure.

Clinical Reasoning

Diagnosis requires high clinical suspicion based on sudden severe headache with associated symptoms like neck stiffness, photophobia, or altered consciousness. CT scan without contrast is the initial imaging modality, followed by lumbar puncture if CT is negative, and CT angiography or conventional angiography to identify the bleeding source and guide surgical or endovascular treatment planning.