Lacunar refers to small, noncortical infarcts in the brain, typically ranging from 2 to 15 mm in diameter, caused by the occlusion of a single, penetrating branch of a larger cerebral artery.
Understanding Lacunar Infarcts
These small strokes, also known as lacunar strokes, occur when tiny arteries that supply blood to the deep brain structures become blocked. These arteries often branch off at sharp angles from the main arteries of the Circle of Willis, the stem of the middle cerebral artery (MCA), or the basilar artery, making them susceptible to blockage.
Causes of Lacunar Infarcts
The primary cause is usually related to underlying conditions that affect the small blood vessels, such as:
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Hypertension (High Blood Pressure): Prolonged high blood pressure damages the walls of small arteries, leading to thickening and narrowing (lipohyalinosis).
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Diabetes Mellitus: Similar to hypertension, diabetes can also damage small blood vessels.
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Atherosclerosis: Although less common than in larger arteries, atherosclerosis can still affect the small penetrating arteries.
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Other conditions: Rarely, other conditions like certain autoimmune diseases or genetic disorders can contribute.
Location of Lacunar Infarcts
Lacunar infarcts commonly occur in specific areas of the brain, including:
- Basal ganglia (e.g., putamen, caudate, globus pallidus)
- Internal capsule
- Thalamus
- Pons
- Cerebral white matter
Clinical Syndromes Associated with Lacunar Infarcts
Because of their location, lacunar infarcts can cause specific clinical syndromes, including:
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Pure motor stroke: Weakness affecting the face, arm, and leg on one side of the body.
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Pure sensory stroke: Numbness or tingling affecting the face, arm, and leg on one side of the body.
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Sensorimotor stroke: A combination of weakness and sensory loss on one side of the body.
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Ataxic hemiparesis: Weakness and incoordination on one side of the body.
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Dysarthria-clumsy hand syndrome: Difficulty speaking and clumsiness of one hand.
Diagnosis and Treatment
Diagnosis typically involves neuroimaging, such as:
- MRI (Magnetic Resonance Imaging): MRI is the preferred method for visualizing small lacunar infarcts.
- CT scan (Computed Tomography): CT scans can sometimes detect lacunar infarcts, but they are less sensitive than MRI.
Treatment focuses on:
- Managing underlying risk factors: Controlling hypertension, diabetes, and high cholesterol.
- Antiplatelet medications: Such as aspirin or clopidogrel, to prevent further clot formation.
- Rehabilitation: Physical therapy, occupational therapy, and speech therapy may be needed to help recover lost function.
Summary
In summary, a lacunar infarct is a small stroke caused by the blockage of a small penetrating artery in the brain, often related to hypertension or diabetes. Recognition and management of risk factors are crucial in preventing future lacunar strokes.
