Lacunar Stroke


What Is It?

A lacunar stroke occurs when blood flowing in small arteries leading to the brain is blocked. These arteries are 0.1 to 0.3 millimeters in diameter. They branch from larger arteries near the underside of the brain. They carry blood to the brain’s deeper regions, such as the thalamus, basal ganglia and pons. In a lacunar stroke, a blood clot (thrombus) blocks blood flow. The blood clot can form inside the small artery because the artery has been damaged. A clot can also form in a large artery in the neck or chest, break loose and travel (as an “embolus”) in the bloodstream to lodge in these small brain arteries. Clots typically form because an artery has become damaged by atherosclerosis, a condition in which fatty deposits (plaques) build up along the walls of blood vessels.

The small arteries that may cause a lacunar stroke are uniquely vulnerable. Unlike most arteries, which gradually taper to a smaller size, the arteries of a lacunar stroke branch directly off of a large, high pressure, heavily muscled main artery. High blood pressure (hypertension) is a major contributor to lacunar strokes because of the pounding pulse it causes. High blood pressure can cause direct damage to these arteries. It also can dislodge small clumps or clots that can block blood flow.

When a blood clot blocks one of the brain’s small arteries, brain cells in a relatively small area (3 millimeters to 2 centimeters) are damaged or killed by lack of oxygen. These small areas of brain destruction are called lacunes. Lacunar strokes account for about 20 percent of all strokes in the United States.


The symptoms of lacunar stroke vary depending on the part of the brain that is deprived of its blood supply. Different areas of the brain are responsible for different functions, such as sensation, movement, sight, speech, balance and coordination.

Symptoms can include:

  • Weakness or paralysis of the face, arm, leg, foot or toes
  • Sudden numbness
  • Difficulty walking
  • Difficulty speaking
  • Clumsiness of a hand or arm
  • Weakness or paralysis of eye muscles
  • Other neurological symptoms

In a person with prolonged, untreated high blood pressure, many areas of brain destruction can form, causing additional symptoms, including emotional behavior and dementia.

The sudden appearance of one or more of these symptoms is a warning sign that a stroke may be in progress. Sometimes, the small clots that can cause a lacunar stroke interfere with blood flow only for a few minutes. If the clot dissolves before damage is done, then symptoms can begin to improve within minutes and may go away completely. When symptoms go away without treatment and full recovery occurs within 24 hours, the event is called a transient ischemic attack (TIA). Never decide to “wait and see” if you are having stroke symptoms. Get to an emergency room as quickly as possible to get treatment.


Your doctor will ask about your medical history (high blood pressure, heart disease, smoking, High cholesterol and diabetes). He or she will check your vital signs (temperature, pulse, respirations and blood pressure) and might order an electrocardiogram (EKG).

Lacunar strokes usually are identified by a computerized tomography (CT) scan or magnetic resonance imaging (MRI) scan of your brain. An MRI technique known as diffusion weighted imaging is articularly sensitive for identifying very new lacunar strokes. In some cases, specialized studies of blood vessels, such as angiography or Doppler ultrasound, may be needed.

Expected Duration

If your symptoms persist without improvement during the time you are traveling to an emergency center, it is best to assume that your event is a full blown stroke, not a TIA. Lacunar strokes that receive early treatment may have the same full recovery as a TIA. If medicines restore circulation to the brain quickly, symptoms of a lacunar stroke may go away within hours. With longer interruptions in blood supply, brain injury may be more severe and symptoms may last for many weeks or months, requiring physical rehabilitation. There may be permanent disability.


You can help to prevent lacunar stroke by preventing or controlling the risk factors for stroke — high blood pressure, smoking, heart disease and diabetes. If you have high blood pressure or heart disease, follow your doctor’s recommendations for modifying your diet and taking your medication. Exercise regularly, eat plenty of fruits and vegetables, and avoid foods filled with saturated fats and cholesterol. If you smoke, quit. If you have diabetes, monitor your blood sugar level frequently, follow your diet, and take your insulin or oral diabetes medication as your doctor has prescribed.

If you have an increased risk of stroke, your doctor may recommend a daily aspirin or other medication — ticlopidine (Ticlid) or clopidogrel (Plavix). These medicines can reduce your risk.


If doctors are able to provide treatment within three hours after symptoms start, they probably will use with a clot dissolving medication. Although the blood thinning medication, heparin, often is used in large artery stroke treatment, it has not appeared to result in improved recovery for people with lacunar stroke.

A person who has had a lacunar stroke is usually hospitalized so that he or she can be observed in case symptoms worsen. A severe stroke can affect breathing, and require the use of a mechanical ventilator, or can cause a person to require assistance with self-care or feeding. In the hospital, an occupational therapist and a physical therapist can help the person to work around a new disability and to regain strength after brain injury. Commonly, hospitalization is followed by a period of residence at a rehabilitation center, where additional intensive therapy may be given. The goal of rehabilitation is to maximize recovery. To prevent recurring strokes, it is very important for you to control high blood pressure. Taking a daily aspirin or other blood thinning medication (ticlopidine or clopidogrel) is beneficial.

When To Call A Professional

Call for emergency treatment immediately whenever the symptoms of lacunar stroke occur, even if these symptoms last only a few minutes. For best results, stroke treatment must occur within three hours of the start of symptoms.


People often begin to recover within hours or days of a lacunar stroke. Lacunar strokes have a better rate of recovery than other strokes that involve larger blood vessels. More than 90 percent of people with a lacunar stroke will recover substantially within the first three months following the stroke. About half of people with large vessel strokes experience substantial recovery during this time.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.