Lacunar Infarct - Definition, Symptoms, Causes and Treatment
Lacunar Infarct Definition
Lacunar infarct is also referred to as lacunar stroke. It is a type of stroke considered as silent stroke which means it occurs without any symptoms of is rather asymptomatic. It is characterized as noncortical infarcts and small regions of dead tissue deep within the small arteries of the brain that are branching from the main arteries or of a large cerebral artery. Lacunar infarcts that are associated with smaller strokes are usually non-life threatening although they can cause brain damage and disabilities similar to the result of larger strokes which are potentially life-threatening.
A stroke arises when the blood filled with oxygen is unable to supply the tissues of the brain. The symptoms of stroke can be profound that it can be immediately perceived. A silent stroke on the other has no dramatic presentation. This type of stroke could be non-life threatening but can potentially damage the brain and is deemed dangerous. Lacunar infarct or lacunar stroke is one of the two types of silent stroke. There are no symptoms presented that can help identify the incidence of stroke right away. Lacunar infarcts on the other hand are small infarcts of about 0.2 to 15mm in diameter and accounts for approximately 20% of all reported cases of strokes.
The manifestation of lacunar infarcts has various symptoms which are classified into 5 lacunar syndromes each with distinct symptoms. The symptoms may come in suddenly or progressively or may come in a fluctuating manner.
The five syndromes resulting from lacunar infarcts include the following:
Pure motor stroke
This is the most common effect of lacunar infarct. The incidence is exhibited with an extreme weakness accompanied by a paralysis of the face, arms and legs. The symptoms may also include difficulty in speaking and in swallowing. Although the ability to speak is affected, the comprehension remains intact and unaffected. The infarct is usually located in the corona radiata, basis pontis and the posterior limb of the internal capsule. This syndrome accounts for half the majority of reported cases of lacunar infarct.
Ataxic hemiparesis is the second most common syndrome of lacunar infarcts. The syndrome is presented with general weakness and clumsiness on the ipsilateral side of the body. It is also known as homolateral ataxia as the syndrome usually affects the legs more than the arms. The patient may exhibit an awkward gait in when walking and may also complain of dizziness and problems with balance. The manifestation of symptoms usually lingers for hours or may linger for a number of days after the incidence of stroke.
Dysarthria or a clumsy hand is the third syndrome of lacunar infarcts. It is manifested by the clumsiness of the hand that is prominent when the patient is writing. The infarct in this syndrome can be located in anterior limb, basal ganglia, thalamus and cerebral peduncle. Inefficient use of pen or pencil is common and apparent in patients suffering from this syndrome resulting from a lack of coordination in the hand muscle and the eye sights.
Pure sensory stroke
Pure sensory stroke is the fourth syndrome of lacunar infarct. The infarct can be located in the midbrain, corona radiata and the contralateral thalamus. The syndrome is characterized by an unrelenting tingling sensation, numbness, burning and pain on one side of the body. The syndrome may also include symptoms such as lack of sensory perception and distance perception.
Mixed sensorimotor stroke
Mixed sensorimotor stroke involves hemiparesis or hemiplegia of one side of the body associated with sensory impairment of the ipsilateral. The infarcts in this lacunar syndrome can be located in the lateral pons, thalamus and the nearby posterior internal capsule.
The incidence of lacunar infarcts usually affects the basal ganglia and the lenticular nucleus. The occurrence in the deep cerebral white matter including the cerebellum and the anterior limb of the internal capsule is rare for most cases of lacunar infarcts. The lesions in the deep nuclei and the internal capsule of the posterior limb is the result of an occlusion of the deep penetrating artery that directly aroused from the parts of the Circle of Willis basilar artery and the cerebral arteries.
Thrombosis is the primary implicated in the cause of lacunar infarcts. It is an obstruction in the artery of the brain that is caused by a blood clot. The rupture in the brain due to the obstruction will lead to brain hemorrhage and bleeding into the surrounding tissues of the brain. The brain hemorrhage will later lead to constriction of the blood vessels in the brain subsequently stroke.
The treatment for lacunar infarcts depend on the severity and extent of the symptoms and the duration of the condition. A clot-dissolving medication is the initial treatment given to lacunar infarcts that occurs within three hours following the onset of symptoms. Administration of high dose of aspirin is given to lacunar infarct within 48 hours from onset of symptoms.
Physiotherapy intervention is beneficial for the rehabilitation of the lacunar stroke. The aim of the therapy is to improve the range of motion of the paretic limb.
The Lacunar infarct patient usually recovers within a few hours following the initial administration of treatment. The prognosis is good with better recovery compared to other types of stroke that involve the large blood vessels. It is however important to have a prompt treatment after diagnosis of lacunar infarct to prevent further complication and life-threatening situation.