Neurological Disorders: Lacunar Stroke

Lacunar Stroke (lacunar infarct) is a small stroke of size less than 1.5 cm (15 mm) in the brain.

These small strokes are caused by occlusion of small sized penetrating arteries of the brain. Some favored location includes brain stem, thalamus, cerebellum, internal capsule etc.

A pathological process called as lipohyalinosis is considered to be the main causative factor for these kinds of stokes. Another process called as microatheroma seems to be contributing too.

Please see a ministroke is not synonymous with a lacunar-stroke. The term mini stroke is used when stroke symptoms get better in less than 24 hours irrespective of whether they are related to small vessel or large vessel disease.

High blood pressure (HTN), DM (diabetes mellitus), smoking, heavy alcoholism, high cholesterol etc are thought to induce and/or contribute to the development of small vessel disease of the brain. Old age is considered to be an independent factor contributing to this disease.

There 5 typical lacunar-syndromes that produce certain well defined clinical manifestations;

1) Pure-motor lacular-stroke: Presents as isolated motor deficits in the form of hemiparesis. It is due to stroke taking place in the internal capsule (at the posterior limb). This is the most frequent lacunar infarct.

2) Ataxic-hemiparesis lacunar-stroke: This is the 2nd commonest lacunar-stroke. There is a combination of both motor and cerebellar type manifestations.

3) Dysarthria-clumcy hand syndrome: Speech difficulty and clumsiness of hand are seen. The lesion is thought to be in the basis pontis area.

4) Pure sensory type lacunar-stroke: The infarct occurs in the thalamic area. Only hemisensory manifestations are seen.

5) Mixed type (both motor & sensory features).

Some of these lacunar infarcts are silent, means patient never remembers having any symptoms and these infarcts are picked up incidentally on CT or MRI while undergoing investigations for some other symptoms.

The stroke of this kind is diagnosed by radiological studies. MRI is generally superior in picking up strokes earlier and more efficiently than a CT head.

The small vessel disease itself cannot be diagnosed by any radiological or angiogram studies since these branches are really small.

If patient is seen in less than about 3 to 4 hours after the onset of the symptoms then IV thrombolytics like tPA can be given. This may help in reversing the symptoms.

Other treatments are essentially prophylactic (to prevent future stroke) and include anti-platelet agents like aspirin, clopidogrel etc.

Patients are strongly advised to quit smoking, alcohol in moderation etc.

HTN, DM and other stroke predisposing medical risk factors are treated aggressively.

A neurologist is frequently involved in the care of patients with Lacunar Stroke.