The most common cause of stroke in the elderly is a reduction or obstruction of blood flow to arteries in the brain. These are called ischemic strokes, and they can be caused by an embolus or a thrombus, explains Mayo Clinic.
Ischemic strokes account for about 85 percent of all strokes, explains Mayo Clinic. Around 75 percent of all strokes occur in adults older than 65 years, according to The Internet Stroke Center. Thrombotic strokes happen when fatty plaques build up in the arteries of the brain and decrease blood flow to the part of the brain supplied by the artery. Embolic strokes happen when a piece of debris or a blood clot breaks off from a distant blood vessel, flows up to an artery in the brain and blocks it, explains Mayo Clinic.
The other 15 percent of strokes are hemorrhagic, and they are caused by blood leaking into the brain from a broken blood vessel. The two types of hemorrhagic strokes are intracerebral and subarachnoid, according to Mayo Clinic.
An intracerebral hemorrhage happens when a blood vessel in the brain bursts and blood leaks out, damaging brain cells. A subarachnoid hemorrhage occurs when a blood vessel in the brain develops an aneurysm and bursts. In this case, blood leaks into the space between the brain and the skull, explains Mayo Clinic.