A coronal section of brain through the thalamus showing a large intracerebral hemorrhage. Note the shift of structures toward the opposite side including the cingulate gyrus, lateral and third ventricles and thalamus. There is blood in the ventricles as well. Other causes include blood dyscrasias or rupture of vascular malformations. Hypertensive hemorrhages are often due to hypertensive lipohyalinosis of of small arteries with formation of small Charcot-Bouchard aneurysms.
Blood dyscrasias cause bleeding due to inability of the blood to clot.
Hemorrhages from vascular malformations are caused by trauma or hypertension further damaging an abnormal blood vessel wall. They may also rupture into the ventricle which may cause death or may be helpful in decompression. Blood dyscrasias such as leukemias often produce many small petechial or larger hemorrhages. Vascular malformations may rupture due to hypertension, trauma or abnormalities of the blood vessel wall. The walls of a large hemorrhage thought to be due to hypertension should be examined for abnormal vessels.