Lacunar stroke (small vessel stroke)

Deep within the brain, including the basal ganglia, thalamus, internal capsule and pons, are structures supplied by narrow arteries that branch directly off larger vessels. Years of high pressure thicken and stiffen those small arteries, a process often called small vessel disease or lipohyalinosis. When one blocks, a small cavity, or lacune, forms. Several lacunes can accumulate silently over time, some are discovered only on a scan done for another reason.

Not every small deep infarct has the same cause. Occasionally a small clot from the heart or from a narrowed carotid artery lands in a small vessel. This is why a lacunar pattern on imaging is followed by checks on the heart rhythm and neck arteries before the cause is labelled as small vessel disease.

The NHS recognises the FAST signs of stroke: face drooping, arm weakness and speech problems, with time to call 999. In lacunar stroke these often appear as clear-cut patterns: pure motor stroke with weakness of the face, arm and leg on one side; pure sensory stroke with numbness; ataxic hemiparesis with weakness and poor coordination; and dysarthria-clumsy hand syndrome. Language, vision and awareness are usually spared, which can lead people to underestimate what has happened.

Symptoms may fluctuate or worsen over the first day or two. Some people have a transient ischaemic attack, with symptoms resolving within hours, in the days before a lacunar infarct. This is a warning that needs urgent assessment.

• Sudden weakness of one side of the face, arm or leg.

• Sudden numbness or tingling down one side of the body.

• Slurred speech with a clumsy hand.

• Unsteadiness or difficulty walking without dizziness or loss of consciousness.

Anyone with suspected stroke is taken to a hospital with stroke services. A brain scan, CT initially and often MRI, shows the infarct and rules out bleeding. Further tests look for causes: blood tests for cholesterol and glucose, an ECG or longer heart monitoring for atrial fibrillation, and imaging of the neck arteries by ultrasound, CT or MR angiography. The NHS describes atrial fibrillation and high blood pressure among the major risk factors for stroke, which is why both are looked for.

MRI may also show background small vessel disease such as white matter changes and old lacunes, which carries information about future risk of stroke and also of vascular cognitive impairment.

Acute treatment follows the standard ischaemic stroke pathway, including clot-dissolving treatment in suitable people within the time window, and early antiplatelet medicine. After the first days the focus shifts to rehabilitation with physiotherapy, occupational therapy and speech and language therapy as needed. Because lacunar strokes damage a small area, many people recover well, although mild weakness, clumsy hand function, fatigue or mood changes can linger.

Fatigue and low mood are common and deserve a conversation with the stroke team. Repeated lacunar strokes over time may lead to problems with walking, balance, thinking speed and swallowing, which is the main reason secondary prevention is taken so seriously.

Secondary prevention combines medicines and lifestyle. Blood pressure treatment is the most important single step. Antithrombotic therapy to make clots less likely and a statin to lower cholesterol are normally prescribed, along with treatment for diabetes where present. The NHS advises stopping smoking, eating well, staying active, reducing alcohol and continuing prescribed medicines.

• Check blood pressure at home if your team advises it and bring the log to reviews.

• Do not stop antithrombotic medicines or statins without discussing with your prescriber.

• Report any new episode of weakness, numbness or speech trouble immediately, even if it passes.