Lacunar syndromes and small-vessel disease — Rapid

Synopsis

Recognise the classic lacunar phenotypes, distinguish a small deep infarct from cortical and non-vascular mimics, and connect cerebral small-vessel imaging findings with acute stroke care and long-term vascular prevention.

Lacunar infarcts are small subcortical infarctions, usually caused by disease of a penetrating arteriole supplying structures such as the internal capsule, thalamus, basal ganglia, corona radiata or pons.
The five useful bedside patterns are pure motor stroke, pure sensory stroke, sensorimotor stroke, ataxic hemiparesis and dysarthria–clumsy hand syndrome; real presentations can be incomplete or overlap.
A convincing lacunar syndrome lacks cortical signs: aphasia, neglect, gaze deviation, visual field loss and a clear cortical sensory deficit should prompt consideration of a cortical or larger-vessel lesion.

Key red flags

Pure motor syndrome

Unilateral face, arm and leg weakness without aphasia, neglect, hemianopia or a primary sensory deficit suggests a compact corticospinal or corticobulbar lesion, classically in the internal capsule or pons.

Investigation priorities

Immediate non-contrast CT brainFirst step

Exclude intracranial haemorrhage and major structural mimics before acute antithrombotic or reperfusion decisions.

Management branches

HyperacuteTreat the syndrome as stroke

Any new, persistent focal deficit compatible with a lacunar syndrome.

1. Record onset or last-known-well time, perform ABCDE, check capillary glucose and quantify the deficit with the local stroke assessment.
2. Activate urgent stroke imaging, including arterial imaging when the pathway requires it, without waiting for a presumed small-vessel diagnosis.

Key medicines

Aspirin in acute ischaemic strokeAfter intracranial haemorrhage is excluded, NICE recommends 300 mg orally or rectally as soon as possible and within 24 hours, continued according to the acute stroke plan; timing differs after thrombolysis.

Clopidogrel for long-term non-cardioembolic preventionA common adult maintenance regimen is 75 mg once daily after the acute aspirin phase, selected in accordance with the current stroke secondary-prevention pathway.

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