A brain hemorrhage can be characterized by bleeding into and around a number of spaces within the skull. An intraparenchymal hemorrhage occurs within the nerve tissues of the brain. A meningeal bleed occurs when the lining of the brain fills with blood. An intraventricular hemorrhage occurs when the inner cavities of the brain called ventricles are the site of bleeding. Hemorrhage into these spaces is linked to specific causes affecting the blood or blood vessels.
Aneurysms
Aneurysms are bulging, stretched arteries with weakened walls. They are prone to be a site of breakdown of the vessel wall and subsequent bleeding into the brain. Bleeding through the site of an aneurysm is even more likely when it is associated with certain conditions. High blood pressure, advanced age and vascular disease, characterized by the build up of plaque on the vessel walls, all contribute to the risk of bleeding through a ruptured aneurysm.
Trauma
Trauma such as car collisions or falls can cause bleeding within and around the brain by shearing blood vessels. Two types of bleeds around the brain include subdural and epidural hematomas. Epidural hematomas form between the outer layer of tissue covering the brain and the skull. These usually occur when a blood vessel, generally an artery, is torn by a skull fracture. They are characterized by severe headaches and waxing and waning levels of consciousness. In contrast, subdural hematomas form between the outer and middle layers covering the brain. These occur from bleeding veins, may form quickly or slowly over months, and are more common in the elderly and alcoholics.
Vascular and Blood Disease
Certain vascular and blood disorders also increase the risk of bleeding into the brain. Vascular disease associated with smoking and diabetes increases the risk of bleeding, as do problems in the organization of blood vessels, such as arteriovenous malformations, or AVMs. An AVM is an abnormal connection between arteries and veins that interrupts normal blood flow and is prone to bleeding. In addition, certain drugs that thin the blood such as aspirin and warfarin increase the risk of bleeding in the brain, though if prescribed their benefits may outweigh the risks.
References
- American Heart Association: Stroke
- Merck Manual: Intracranial Hematomas
- MayoClinic.com: Brain AVM
- "Stroke"; Combined anticoagulant-antiplatelet use and major bleeding events in elderly atrial fibrillation patients; Shireman et al; 2004
- American Heart Association: What You Should Know About Cerebral Aneurysms
