ISCHEMIC STROKE / ETIOLOGY
Lacunar stroke
Created 02/12/2022, last revision 04/09/2023
- lacunar stroke (lacunar cerebral infarct – LACI) is defined as a small subcortical lesion ≤ 1.5 cm in diameter that is caused by the occlusion of small penetrating arteries
- penetrating arteries arise at sharp angles from larger vessels and are, therefore, anatomically prone to stenosis and occlusion
- the term “lacune” was first described in the late 19th and early 20th centuries – it usually describes a small, chronic cavity that represents the healed phase of a lacunar infarct
- etiology of the lacunar infarct is not necessarily of arteriolopathic origin ⇒ various mechanisms can cause occlusion!
- the most frequently affected structures are:
- basal ganglia (globus pallidus, putamen, thalamus, and caudate)
- pons
- subcortical white matter structures (internal capsule and corona radiata)
- lacunar stroke syndrome (LACS) is a clinical manifestation of lacunar stroke; the most common are:
- pure motor hemiparesis
- pure sensory stroke
- sensorimotor stroke
- ataxic hemiparesis
- dysarthria-clumsy hand syndrome
Etiopathology
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Clinical presentation
- lacunar infarcts usually cause symptoms within minutes but may also exhibit a more gradual progression
- symptoms usually do not include cortical signs ( agnosia, aphasia, neglect, apraxia, or hemianopsia)
- cortical functions must be tested to differentiate the MCA stroke and the subcortical stroke (thalamus, internal capsule)
- most common syndromes are:
- pure motor hemiparesis
- pure sensory stroke (unilateral numbness of the face, arm, and leg; affecting all sensory modalities)
- ataxic hemiparesis (unilateral limb ataxia that is disproportionate to the strength/motor deficit)
- sensorimotor stroke (unilateral weakness and numbness)
- dysarthria-clumsy hand syndrome (unilateral facial weakness, dysarthria, dysphagia, and dysmetria/clumsiness in one upper extremity)
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- a silent lacunar infarction (SLI) is an incidental finding on imaging, without any prior history of stroke symptoms
- silent strokes are much more common than previously believed
- SLIs increase the risk of a future major stroke, and multiple lesions may eventually become symptomatic (lacunar state)
- multiple lesions can affect various aspects of a person’s mood, personality, and cognitive functions (lacunar state / Binswanger’s disease)
Diagnostic evaluation
- brain imaging (CT/MRI)
- excludes hemorrhage
- DWI is more sensitive in detecting acute infarcts compared to other MRI sequences or CT scans
- in the acute phase, CT or even MRI may be negative; later, a small noncortical infarct may be visible
- vascular imaging (CTA/MRA)
- excludes large vessel occlusion/stenosis
- small perforating arteries are difficult to visualize effectively with CTA and MRA
- high-resolution MRI can detect the ostial microatheroma in penetrating artery; larger lesions are found in such cases (Sun, 2018)
- the definitive diagnosis is established by a combination of a typical lacunar syndrome + negative findings on CTA/MRA + small, noncortical infarct visible on CT/MRI
- history of longstanding diabetes, hypertension, and hyperlipidemia is typical
- such a stroke is classified as TOAST 3
- history of longstanding diabetes, hypertension, and hyperlipidemia is typical
- for young patients without traditional risk factors, further evaluation may be necessary to exclude an embolic source
Differential diagnosis
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Management
Acute stroke therapy
- IV thrombolysis in eligible patients
- contraindications to IV thrombolysis are the same as for other stroke subtypes
- contraindications to IV thrombolysis are the same as for other stroke subtypes
- for patients ineligible for thrombolytic therapy, aspirin or dual antiplatelet therapy is recommended
- routine symptomatic treatment of acute stroke + early rehabilitation with speech and physiotherapy
Prevention of cerebrovascular disease
- antiplatelet therapy – according to the CHANCE and POINT trials, dual antiplatelet therapy (DAPT – ASA+CLP) for 3 weeks followed by single antiplatelet therapy provides the best results
- aggressive treatment of other vascular risk factors (most commonly hypertension, diabetes, dyslipidemia, etc.)
- high-dose statin
- aggressive treatment of hypertension (target BP of <130/80 mmHg in the absence of significant extra-or intracranial stenosis and if tolerated)