Intracranial hemorrhage

Epidural hematoma	Rupture of the middle meningeal artery, often secondary of temporal bone fracture. Lucid interval. Rapid expansion under systemic arterial pressure produce transtentorial Herniation, CN III palsy	CT shows= biconvex disk, not crossing suture lines, but can cross falx and tentorium
Subdural hematoma	Rupture of bridging veins, slow venous bleeding (less pressure= hematoma develop overtime) with delayed onset of symptoms. Seen: elderly, alcoholics, blunt trauma, and shaken baby. Predisposing factor: brain atrophy, shaking, whiplash.	Crescent-shaped hemorrhage that crosses suture lines. Gyri are preserved, since pressure is distributed equally. Cannot cross falx, tentorium.
Subarachnoid hemorrhage	Rupture of aneurysm or arteriovenuos malformation. Patients complain of “worst headache of my life”. Bloody or yellow spinal tap. 2-3 days afterward.
Parenchymal hematoma	Caused: hypertension, amyloid angiopathy, diabetes mellitus, and tumor. Typically occurs in basal ganglia and internal capsule.