What is a thrombotic stroke?
A thrombotic stroke is a type of ischemic stroke. This means a part of the brain gets injured because the artery that normally supplies blood to it gets blocked, so blood flow is reduced or stops completely.
According to the National Stroke Association, almost 90 percent of all strokes are ischemic. About 10 percent are due to bleeding in your brain from a torn or ruptured blood vessel. This is called a hemorrhagic stroke.
In a thrombotic stroke, the artery is blocked by a thrombus (blood clot) that forms there. The thrombus is made up of a hardened buildup of cholesterol and other substances, which is called plaque.
The disease causing the buildup is called atherosclerosis. Your body sees this buildup as an injury, so it responds by sending clotting factors to form a blood clot. When it gets big enough, the clot blocks the artery.
Vs. embolic stroke
The other type of ischemic stroke is an embolic stroke. In this case, the blood clot, called an embolus, forms in another part of the body. It moves with your blood to an artery in your brain where it gets stuck and blocks off the artery.
Types of thrombotic stroke
A thrombotic stroke can affect large or small arteries in your brain:
Large vessel thrombosis
Large arteries supply blood to bigger sections of your brain. When a blood clot forms in one, the damage can be significant and affect important body functions.
Most often, plaque builds up slowly over time without you noticing any symptoms. Symptoms occur when a clot suddenly forms, blocking the artery.
Small vessel thrombosis
Small arteries are found deep inside your brain. They supply blood to small areas of your brain. When they become blocked, lacunar strokes occur. Research estimates about 25 percent of all strokes are lacunar strokes.
Symptoms of thrombotic stroke
General symptoms may include:
- headache (though this is more common in hemorrhagic stroke)
Sometimes there are no general symptoms.
Symptoms of large vessel thrombosis
Everything your body does, such as move an arm, speak, and stay in balance, is controlled by a specific part of your brain. So, the symptoms of a large vessel thrombotic stroke depend on its location and how severe the injury is.
The symptoms caused by a large vessel thrombosis usually occur suddenly. However, they can also come on gradually. Symptoms may include:
- weakness or paralysis of your arm, leg, and/or face on one side of your body (hemiparesis)
- numbness or loss of sensation on one side of your body
- loss of part of your vision in one or both eyes
- balance problems that can affect walking, standing, and staying upright while sitting
- difficulty finding the right word to say
- difficulty speaking clearly (dysarthria), finding the right word to say, or understanding what you hear or read (aphasia)
- loss of coordination
Symptoms of small vessel thrombosis/lacunar stroke
Typically, small vessel thrombosis has no symptoms. The condition worsens until a lacunar stroke occurs. Lacunar strokes usually cause one of five classic syndromes. The symptoms of each syndrome usually affect only one side of your body. They are:
- Pure motor hemiparesis: weakness or paralysis of the face (facial droop), arm, and/or leg
- Pure sensory syndrome: abnormal sensation
- Sensorimotor stroke: weakness or paralysis and loss of sensation
- Ataxic hemiparesis: weakness and clumsiness in the arm or leg
- Dysarthria-clumsy hand: inability to form or pronounce words and clumsy hand movements
Causes of thrombotic stroke
Thrombotic strokes are caused by inadequate blood flow to a part of your brain due to a blocked artery.
The risk factors for a thrombotic stroke are the same as for atherosclerosis. They include:
- high cholesterol
- high blood pressure
- smoking cigarettes
- lack of exercise
Your risk is also higher if you or someone in your family has had a thrombotic stroke. Your risk increases as you get older. Strokes are more common in men at younger ages and in women at older ages.
Of all the risk factors, high blood pressure is the major risk factor for lacunar strokes and plays a big role in causing them.
High cholesterol is the primary risk factor for large vessel thrombotic strokes.
Treatment for thrombotic stroke
The current standard treatment for an ischemic stroke is a “clot buster” drug called alteplase. This tissue plasminogen activator (tPA) must be given via a vein within 4.5 hours of stroke onset. It breaks up the clot and opens the artery, so blood can flow to the brain tissue again.
Doctors can also inject alteplase directly into the area with the clot by inserting a catheter into the artery in your groin and threading it up to your brain.
When the large vessel thrombosis is in a carotid artery (in the neck) or the first part of the middle cerebral artery (in the brain), your doctor will do a procedure called mechanical thrombectomy after tPA, if possible. It must be done within six hours of the stroke.
In this procedure, your doctor removes the clot and places a stent to keep the artery open using a catheter inserted into an artery. This procedure is used alone for blood clots in these vessels when tPA isn’t an option or isn’t recommended.
A head CT scan is always done first to make sure it’s not a hemorrhagic stroke. Giving tPA to someone who’s bleeding in their brain will increase the bleeding. This makes a hemorrhagic stroke significantly worse and potentially life- threatening.
If you’re at high risk or have had a previous thrombotic stroke, your doctor will probably prescribe an antiplatelet medication to make it harder for your blood to clot to help prevent a future stroke. These medications include:
- clopidogrel (Plavix)
- combination of aspirin and dipyridamole (Aggrenox)
Anticoagulants used to treat embolic strokes, such as warfarin (Coumadin), aren’t typically used for thrombotic strokes.
Recovery from thrombotic stroke
Receiving appropriate treatment quickly is critical for a good outcome. When part of the brain doesn’t get blood, cells start to die in just a few minutes. Once the artery is reopened, the injured brain tissue gets blood again and begins to heal.
If the damage isn’t severe, it’s possible to regain some of the lost function caused by the stroke and have a better outcome. The longer the time between stroke onset and reopening of the artery, the more long-term effects you’ll have.
A full recovery is possible when a thrombotic stroke is successfully treated within a few hours. You’re almost two times as likely to have a positive outcome if an ischemic stroke is treated with tPA within 4.5 hours of symptom onset.
Physical, speech, and occupational therapy are important for improving the outcome after a stroke:
- Physical therapy can strengthen your muscles and help with problems in balance, coordination, walking, and dealing with loss of function, like weakness on one side of the body.
- Speech therapy can help with problems in talking, writing, reading, and swallowing.
- Occupational therapy helps you relearn skills you need to perform daily activities, like cooking and getting dressed.
Outlook after thrombotic stroke
A thrombotic stroke can be difficult. It can leave a person unable to walk, talk, or think clearly. But when diagnosed and successfully treated within a few hours, complete recovery is possible.
The most important indicator of your outlook is how quickly the artery is reopened after the stroke starts. If too much time passes before the blocked artery is opened, some or all of the symptoms can be permanent. You can also not survive the stroke.
It’s important to remember the warning signs for a stroke so you can recognize when someone is having one and immediately call 911 or your local emergency services.
An easy memory aide from the National Stroke Association is “FAST”:
- F is for facial droop. One side of your face is numb or droopy and you have a lopsided smile.
- A is for arm weakness. Your arm on one side is numb or weak and it slips downward when both arms are raised.
- S is for speech difficulty. You can’t speak or be understood, your words are slurred, you can’t think of the word you want to say, or you can’t repeat a sentence.
- T is for time to call 911. Any of these can be a sign you’re having a stroke, even if they only last a short time. If you or someone around you has any of them, immediately call 911, tell them someone is having a stroke, and remember when the symptoms started (so you can tell the doctor). This is the best and fastest way to get treatment started and improve the outcome.
Preventing a thrombotic stroke
There are things you can do to help prevent a thrombotic stroke. The best way is to reduce or eliminate your risk factors. Do the following:
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