Left Cerebral Hemisphere Infarction due to Middle Cerebral Stroke - Essay Example

 "Left Cerebral Hemisphere Infarction due to Middle Cerebral Stroke" is a wonderful example of a paper on neurology.
The presentation of right-sided hemiparesis, or the paralysis of the eight limbs, and dysphasia, defined as difficulty in speaking, is classic for left hemisphere infarction, which is the death of brain tissue at the left cerebral hemisphere due to occlusion or rupture of the supplying artery, usually, the left middle cerebral artery (MCA), which supplies the outer surface of the left frontal, parietal and temporal lobes near the Sylvian fissure, basal ganglia, and thalamus. The somatic sensory and motor functions are initiated by the cerebral cortex; the thalamus relays sensory information to and from the sensory organs, and the basal ganglia fine-tune movement. The death of one or all of these parts can result in varying degrees of motor deficits on the contralateral side, depending on the magnitude of damage (Purves, et al., 2004). Moreover, since for most individuals, the left hemisphere controls speech and language, difficulty in speech, further supports the clinical impression of left MCA stroke (Slater, 2011). 

To confirm this clinical impression, an imaging study should be done. The combination of computed tomography (CT) scan and CT angiography are the best imaging procedure for stroke, because of its relatively better accessibility, high sensitivity and fast results. While the scan determines the presence or absence of haemorrhage, angiography shows the perfusion status of the brain parenchyma. However, diagnosis within minutes after the presentation should be conducted through Magnetic Resonance Imaging. Six hours after onset, diffusion-weighted MRI provides better images of ischemic brain tissue than CT scan does. Perfusion-weighted imaging, on the other hand, allows the demarcation of the zone of ischemic injury (Slater, 2011).

Next, transcranial Doppler ultrasonography can be conducted to determine the patency of MCA, which has a prognostic value to MCA stroke. A meta-analysis has found that total MCA occlusion increases the risk of death, while the vessel’s patency can result in clinical improvement within 4 days. Once the patient is stable, carotid duplex ultrasonography can verify the presence of carotid artery stenosis, which is a source of embolus. In addition, barium swallow and voiding analysis can be conducted if the patient experiences dysphagia and urinary dysfunction, respectively (Slater, 2011).   

Other diagnostic studies include electrocardiography to determine the presence of arrhythmias that can predispose the patient to future embolic events and stroke. In addition, coagulation profile determines the possibility of developing an embolus (Slater, 2011).

MCA is the most common location of cerebrovascular accident, with the highest incidence observed in the seventh and eighth decades of life. Aside from the elderly, males are three times more at risk to be affected by MCA strokes than females. The most common cause of MCA stroke is hemorrhagic infarction, although African- and Mexican-Americans have a higher risk for ischemic stroke. In the United States, more than 80 out of every 100, 000 of the population have had MCA stroke. It must be noted that although stroke incidence decreased by 42% in high-income countries, it doubled in low- to middle-income nations. As a result, stroke incidence in low- to middle-income countries is 20% higher than that in high-income countries (Slater, 2011).

To improve function after MCA stroke, the patient can undergo rehabilitation programs, which has been shown to significantly increase functional independence and reduce mortality. However, this must be done as soon as possible as time delay is a vital factor in improving outcomes.