A cerebrovascular accident (CVA) is the medical term for a stroke. It happens when blood flow to part of the brain is suddenly cut off or when a blood vessel in the brain bursts, killing brain cells within minutes. Globally, nearly 12 million people have a stroke each year, and over 7 million die from one, making it one of the leading causes of death and long-term disability worldwide.
Types of Cerebrovascular Accident
There are two main categories, and they have very different causes.
Ischemic stroke accounts for roughly 83% of all strokes. It occurs when a blood clot blocks an artery supplying the brain. The clot can form locally in a narrowed brain artery, or it can travel from somewhere else in the body, often the heart, and lodge in a smaller vessel. Once the artery is blocked, the brain tissue it feeds begins to die from oxygen starvation.
Hemorrhagic stroke makes up the remaining cases and comes in two forms. An intracerebral hemorrhage (about 12% of strokes) is bleeding directly into the brain tissue, usually from a blood vessel weakened by years of high blood pressure. A subarachnoid hemorrhage (about 6%) is bleeding into the space surrounding the brain, often caused by a ruptured aneurysm. Hemorrhagic strokes are less common but tend to be more deadly.
What Happens Inside the Brain
When blood flow stops, brain cells lose their oxygen and glucose supply almost immediately. Within minutes, a toxic chain reaction begins. Dying cells release large amounts of a chemical messenger called glutamate, which overstimulates neighboring neurons. This forces excessive calcium into those cells, damaging them from the inside. The process, known as excitotoxicity, is the key link between the initial blood flow interruption and the wave of brain cell death that follows.
Oxidative stress and inflammation pile on top of this damage. The longer the brain goes without blood flow, the larger the area of permanent injury becomes. That’s why speed of treatment matters so much: every minute counts in limiting how much brain tissue is lost.
Recognizing the Symptoms
The BE-FAST acronym captures the warning signs to watch for:
- Balance: sudden difficulty walking or loss of coordination
- Eyes: sudden vision loss, double vision, or blurring in one or both eyes
- Face: one side of the face droops or feels numb
- Arm: sudden weakness or numbness in one arm (or leg)
- Speech: slurred words, trouble speaking, or difficulty understanding others
- Time: call emergency services immediately if any of these appear
Symptoms typically come on without warning and reach full intensity within seconds to minutes. A stroke can also cause sudden severe headache with no known cause, confusion, or trouble swallowing. The specific symptoms depend on which part of the brain loses blood flow.
Major Risk Factors
High blood pressure is the single leading cause of stroke. It damages artery walls over time, making them more likely to clog or rupture. Heart disease, particularly atrial fibrillation (an irregular heart rhythm), is another major contributor because it allows blood to pool and form clots that can travel to the brain.
Other conditions that raise your risk include high cholesterol, diabetes, and obesity. Each of these damages blood vessels or promotes clot formation in its own way. Diabetes, for instance, causes sugar to build up in the blood and prevents oxygen and nutrients from reaching the brain efficiently.
Behavioral risk factors are just as important. Smoking damages blood vessels and raises blood pressure. Excessive alcohol intake increases blood pressure and triglyceride levels. A diet high in saturated fat and sodium, combined with physical inactivity, sets the stage for nearly every condition on this list.
How a Stroke Is Diagnosed
A CT scan is the first imaging test most patients receive because it’s fast and widely available. Its primary job in the emergency setting is to determine whether the stroke is ischemic or hemorrhagic, since the treatments are completely different. CT is excellent at detecting bleeding in the brain, with about 89% sensitivity for acute hemorrhage. Its weakness is detecting ischemic strokes: CT picks up only about 12% to 27% of ischemic strokes in the first few hours.
MRI is far more accurate overall, detecting acute ischemic stroke in 73% of patients even within the first three hours, compared to just 12% for CT in that same window. A specialized MRI technique called diffusion-weighted imaging can reveal ischemic damage much earlier than a standard CT. MRI is also reliable for hemorrhage detection, with 81% sensitivity. When both speed and diagnostic accuracy matter, many stroke centers now use MRI as the primary tool if it’s available quickly enough.
Emergency Treatment
For ischemic strokes, the priority is dissolving or removing the clot to restore blood flow. Clot-dissolving medication can be given intravenously within 4.5 hours of symptom onset. For select patients whose stroke onset time is unknown, or who fall in the 4.5 to 9 hour window, advanced brain imaging can identify those who may still benefit from this treatment.
When a large artery in the brain is blocked, a procedure called mechanical thrombectomy may be performed. A catheter is threaded through a blood vessel, typically starting in the groin, up to the brain where the clot is physically pulled out. This procedure can be performed up to 24 hours after symptom onset in carefully selected patients, guided by brain imaging that shows salvageable tissue still remains. The combination of clot-dissolving medication and thrombectomy, when appropriate, gives the best chance of a good outcome.
Hemorrhagic strokes require the opposite approach. Since the problem is bleeding rather than a clot, treatment focuses on controlling blood pressure, stopping blood thinners if the patient takes them, and in some cases surgical intervention to relieve pressure on the brain.
Recovery and Rehabilitation
The first three months after a stroke are the most critical recovery period. This is when the brain is most adaptable, actively rewiring itself to compensate for damaged areas. During this window, many patients experience spontaneous recovery, where abilities that seemed lost suddenly return as the brain finds new pathways to perform tasks.
Rehabilitation typically begins within days of the stroke and may include physical therapy, occupational therapy, and speech therapy depending on what functions were affected. Progress is measured in practical terms: each time you need less help with a daily task, that counts as a meaningful milestone.
After six months, improvement continues but at a much slower pace. Most patients reach a relatively stable state around this point. Whether someone achieves a full recovery depends on the stroke’s severity, how quickly they received initial treatment, and the intensity of their rehabilitation. Some people return to their previous level of function. Others live with lasting impairments that require ongoing support and adaptation.
Preventing a Second Stroke
About one in four strokes is a recurrent event, making secondary prevention essential. Blood pressure control is the cornerstone. Current guidelines recommend keeping blood pressure below 130/80, which reduces the risk of a recurrent stroke by roughly 22% compared to less aggressive targets.
For people who’ve had a mild ischemic stroke, short-term dual antiplatelet therapy (typically two blood-thinning medications together for up to 90 days) followed by a single antiplatelet medication long-term is the preferred approach. Continuing dual therapy beyond 90 days increases bleeding risk without reducing stroke risk further.
Lifestyle changes carry real weight in prevention. Managing cholesterol, controlling blood sugar if you have diabetes, quitting smoking, limiting alcohol, eating a diet lower in sodium and saturated fat, and staying physically active all reduce the likelihood of another stroke. These aren’t vague recommendations: each one directly addresses one of the biological mechanisms that cause strokes in the first place.