- Bleeding into the intracranial or spinal subarachnoid space, most resulting from intracranial aneurysm rupture. It can occur after traumatic injuries (subarachnoid hemorrhage, traumatic). Clinical features include headache; nausea; vomiting, nuchal rigidity, variable neurological deficits and reduced mental status.
- Bleeding into the intracranial subarachnoid space
- Congenital or acquired abnormal outpouching of an intracranial blood vessel wall; saccular (berry) aneurysms are the most common variant, and tend to form at arterial branch points near the base of the brain; rupture results in subarachnoid hemorrhage or intracranial hemorrhages; giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the oculomotor nerve.
- Hemorrhage within the intracranial or spinal subarachnoid space.
- Intracranial hemorrhage into the subarachnoid space.