Types of Stroke

There are four major types of strokes - two are caused by clots, and two by hemorrhage. The two caused by clots, cerebral thrombosis and cerebral embolism, account for 70 to 80 percent of all strokes. The remaining two, cerebral and subarachnoid hemorrhages, are caused by ruptured blood vessels and have a much higher fatality rate than strokes caused by clots.

• Cerebral thrombosis: Cerebral thrombosis, the most common kind of stroke, occurs when a blood clot forms in an artery, blocking the flow of blood to the brain. A TIA often proceed these types of strokes.
• Cerebral embolism: This type of stroke occurs when a blood clot forms in a distant body part, often the heart, and is carried to one of the major arteries in the brain, where it blocks blood flow. A heart disorder called atrial fibrillation is a risk factor for this kind of stroke.
• Subarachnoid hemorrhage: This type of stroke is caused when a blood vessel on the surface of the brain ruptures, bleeding into the space between the brain and the skull.
• Cerebral hemorrhage: About 10 percent of strokes are cerebral hemorrhages, which occur when an artery in the brain bursts because of a head injury or an aneurysm. An aneurysm is a weak blood vessel that swells out like a balloon - though they're not always dangerous, the artery wall can weaken and burst.

Damage can result from cerebral hemorrhages in two ways - loss of blood supply to the brain and pressure from the accumulated blood. Although this type of stroke has a fairly high fatality rate, those who survive have an especially good chance of full recovery.

Ischemic Stroke and Hemorrhagic Stroke Defined

Ischemic Stroke—An ischemic stroke, the most common stroke, happens when an artery bringing blood to your brain is completely blocked. Brain tissues die and parts of one side of your body become weak or numb for days or weeks or even permanently.

• Causes of Ischemic Strokes
  • Most are caused by atherosclerosis, the buildup of fatty deposits inside artery walls. Blood clots can form along walls damaged or narrowed by these deposits.
  • Clots also can flow from other areas and get stuck in a narrowed artery.
  • Pieces of plaque can break free and travel to the brain.
• Treatment. Treatment usually begins in the emergency room so doctors can diagnose the type of stroke you are having. You may be given drugs to dissolve a possible clot. If your brain swells (edema) from blood leaking from damaged vessels, you may receive medications to reduce this swelling. Once a patient becomes stable, doctors may prescribe medications to improve blood flow to the brain over the long-term.
  • Aspirin
  • Other medications
  • Anticoagulants (blood thinners)

Hemorrhagic Stroke—Hemorrhagic Stroke is a stroke that results from an artery rupturing in the brain, causing tissues in that area to die. While less common than ischemic strokes, this stroke usually is more severe.

• Types of Hemorrhagic Strokes
  • Aneurysms. A weakened part of a blood vessel ruptures.
  • Subarachnoid hemorrhage. Blood leaks between the brain and the skull wall.
  • Intracerebral hemorrhage. Bleeding occurs deep within the brain
• Hemorrhagic Stroke Symptoms
  • A sudden, extremely severe headache is main symptom
  • Weakness
  • Dizziness
  • Confusion
  • Extreme sensitivity to light
  • Stiff neck
  • Paralysis or unconsciousness in severe cases
• Diagnosis—Doctors use symptoms, CT scans and a test called a lumbar puncture (tests to find blood in the spinal cord fluid) to determine if it is a hemorrhagic stroke.
• Treatment—Limiting brain damage is the primary treatment goal for hemorrhagic stroke. Monitoring blood pressure and draining blood from the brain to reduce swelling and prevent damage are two priorities. A subarachnoid hemorrhage requires immediate surgery to repair the ruptured vessel.
• Results—The effects of a stroke vary among individuals, depending on the area of the brain affected and severity of the stroke. Common effects include the following.
  • Vision difficulties
  • Speech difficulties
  • Paralysis in parts of the body
  • Loss of consciousness
• Recovery—Most people can resume many of their usual activities once they go home from the hospital. About 20 percent of people who have strokes continue to need help with some tasks; another 15 percent become dependent on others. Stroke patients can benefit from
  • Physical therapy. Keep joints of paralyzed limbs flexible.
  • Occupational therapy. Teaches ways to adapt to new tasks.
  • Speech therapy. Helps with speaking and understanding of language, including learning new ways to communicate.
  • Support groups. Can help with recovery, learning new behaviors, and countering depression.

UT Medical Center’s Rehabilitation Services offers each of these recovery methods/tools.