Lacunar syndromes

Lacunar Syndromes – Clear Clinical Overview Lacunar syndromes are a group of distinct neurological presentations caused by small deep infarcts (lacunes) in the brain. These infarcts result from occlusion of small penetrating arteries, most commonly due to chronic hypertension, but also diabetes and smoking. Unlike large strokes, lacunar strokes do not involve the cerebral cortex, which explains their characteristic pattern of symptoms. The Five Classical Lacunar Syndromes 1. Pure Motor Stroke (Pure Motor Hemiparesis) Most common lacunar syndrome Weakness or paralysis of the face, arm, and leg on one side No sensory loss Common lesion sites: Posterior limb of the internal capsule Basis pontis 2. Pure Sensory Stroke Numbness, tingling, or altered sensation on one side of the body No motor weakness Typically involves the thalamus (especially the ventral posterolateral nucleus) 3. Ataxic Hemiparesis Combination of: Ipsilateral weakness Poor coordination (ataxia), especially affecting gait Often appears as “clumsy walking” Common lesion sites: Pons Internal capsule Corona radiata 4. Dysarthria–Clumsy Hand Syndrome Slurred speech (dysarthria) Clumsiness and poor fine motor control of the hand Facial weakness may be present Lesions usually located in: Pons Internal capsule 5. Mixed Sensorimotor Stroke Motor weakness and sensory loss on the same side of the body Often due to lesions involving both: Thalamus (sensory) Internal capsule (motor) Causes & Pathophysiology Lacunar strokes result from disease of small penetrating arteries: 🔹 Main mechanisms Occlusion of a single small artery Lipohyalinosis Vessel wall thickening and degeneration from chronic hypertension Microatheroma Small atherosclerotic plaque within the penetrating artery 🔹 Resulting lesion Lacune: A small, fluid-filled cavity in brain tissue Size: 3–15 mm Common Brain Locations Involved Internal capsule Thalamus Pons Basal ganglia Corona radiata These are deep brain structures, which explains the symptom pattern. Diagnosis & Key Clinical Characteristics Diagnosis Clinical syndrome recognition is essential MRI (especially DWI) confirms diagnosis by showing a small deep infarct Key distinguishing features ✅ Deficits confined to motor and/or sensory pathways ❌ No cortical signs, such as: Aphasia Neglect Visual field loss Seizures This absence of cortical features helps differentiate lacunar syndromes from larger territorial strokes. Clinical Importance Lacunar strokes often have better short-term survival, but: Recurrent lacunes can lead to vascular dementia Associated with chronic small vessel disease Strongly linked to long-standing uncontrolled hypertension