Neurologic Disorders Chapter 174. Less often, the cause is a congenital aneurysm or other vascular malformation. Amyloid angiopathy may cause polar hemorrhages. Occasional causes include mycotic aneurysms, brain infarct, blood dyscrasias, collagen vascular diseases, and abuse of cocaine or other illicit drugs. Hypertensive intracerebral hemorrhage is usually large, single, and catastrophic.
Intracerebral hemorrhages can occur almost anywhere in the brain.
Most clinically destructive are those located near the basal ganglia, internal capsule, thalamus, cerebellum, or brain stem. A hematoma dissects, compresses, and displaces adjacent brain tissue and, if large, increases intracranial pressure. Pressure from supratentorial hematomas and the accompanying edema may cause transtentorial herniation, compressing the brain stem and often causing secondary hemorrhages in the midbrain and pons. If the hemorrhage ruptures into the ventricular system, blood may reach the subarachnoid space. Cerebellar hematomas can expand to block the ventricular system, causing acute hydrocephalus, or dissect into the brain stem.