The vascular system that carries blood to the brain includes the heart, the aorta and great vessels, the carotid arteries and vertebrobasilar and intracranial branches and brain capillary network. There is an important need to assess the underlying heart disease or ischemic stroke associated and abnormality in intracranial arteries, including atherosclerosis, the most common disorder affecting the cerebral circulation.
The carotid system has two segments, one extracranial and intracranial one, with their respective branches. In the extracranial system there are certain branches: occipital artery, superficial temporal and maxillary, from the rising of the middle meningeal artery. Intracranial system has other branches: posterior communicating artery, which connects to the posterior cerebral artery.
The characteristics of the brain do basically dependent glucose to function normally, be consuming 75mg per minute (18% of the glucose used in the body). Hence the cerebral circulation have an autoregulation mechanism, which involved biogenic, biochemical and neurogenic factors that ensure a constant flow, provided that the average blood pressure between 50 and 160 mm of mercury. Sustained hypertension, for example, preventing proper operation of arterioles, to not change their diameter with pressure changes.
Cerebral infarction or stroke: when it occurs, incidence , and risk factors
Arterial blockage can cause a stroke or not, what depends: speed of onset, time of obstruction and adequate collateral circulation. Neurons do not work when the cerebral blood flow is less than 23ml / 100g / min. When a power failure occurs that can be "solved" if the flow is restored in a time less than three hours takes place. This phenomenon is called ischemic penumbra and infarction occurs regardless of how long it lasts. Regarding incidence by sex, it affects slightly more men, with an overall incidence of 160 cases per 100,000 inhabitants.
There are also certain important risk factors for cerebral vascular disease:- Arterial hypertension- Mellitus diabetes- Hyperlipidemia- Smoking (triply increases the risk)- Alcohol consume- Heart disease, the most important atrial fibrillation, mitral stenosis and dilated cardiomyopathy- Stress- Obesity- Sedentary- Increased blood viscosity
Symptoms perceived by the patient during a stroke or stroke
It is difficult to explain the different clinical conditions involving cerebral infarcts, depending on the infarcted artery territory. Broadly speaking one could say that the infarction of the middle cerebral artery dependent on the internal carotid, so showing symptoms of hemiparesis brachial-crural left (decreased motor strength or paralysis) if the stroke is right and right hemiparesis if infarction it is left. In the case of left myocardial it leads also aphasia or language disorder, what we call Broca. Sensory symptoms of left or right is also associated members when the infarcted territory includes the parietal lobe or thalamus.
If the attack becomes the territory that irrigates the trunk of the basilar artery and posterior cerebral artery ocular manifestations as double vision and paralysis of conjugate gaze occur. Also impaired cortico-spinal motor pathway, producing Heli or tetraparesia, dysarthria, dysphagia, emotional lability, paralysis of the seventh pair, impaired level of consciousness, which is caused by damage to the brain stem reticular substance.
Myocardial or cerebral artery becomes posteri with choreoathetosis, tremor, hemiparesis contralate ral or thalamic syndrome. Also vertical gaze palsy, hemianopia alexia, visual hallucinations and delusions, blindness without the occipital cortical infarct is bilateral.
Transient ischemic attack or stroke
Transient ischemic attacks (TIAs) are secondary to reversible ischemia of a brain vessel disorders sudden deficit, which must not exceed 24 hours. MRI has shown tissue damage in patients with TIA.
The AIT can be produced by fibrinoplaquetarios emboli from large arteries or cardiac emboli. Hemoconcentration, hypotension, severe carotid stenosis are contributing factors.
The cynical depends on the affected territory. AIT can be Carotid or vertebral origin. Thus territories affecting the ophthalmic artery leading to transient monocular blindness. If it affects the middle cerebral artery results in motor or sensory disorder of the contralateral side of the body, and if left to language disorder. In the vertebrobasilar territory resulting in ataxia, diplopia, vertigo, dysarthria, hemiparesis, or drop attacks with sudden loss of strength in the lower extremities ischaemia bulbar pyramids.
Treatment of stroke
Stroke treatment depends on the mechanism of production. So, if cardioembolic stroke expert physician in Neurology provide anticoagulation; if artery-artery embolism treatment will be of antiplatelet therapy. In addition, it is necessary to explore the supra-aortic trunks doppler ultrasound or magnetic resonance angiography, if it is susceptible of operation if there is carotid stenosis greater than 70%. For diagnosis will be very important doppler ultrasound of the supra-aortic trunks and Transcranial, angioresonance, general analysis and, in specific cases, arteriography femoral artery.
The goal of treatment is to reduce the area of necrosis in the acute phase, in addition to treatment and prevention of complications, rehabilitation and secondary prevention.
Moreover, it has proven the effectiveness of fibrionolíticos in the first three hours after stroke, intravenous tPA and prourokinase intraarterial stroke preactivation code stroke hospital units.
Moreover, they are accurate for treating cardiac monitoring, control of hypoglycemia, monitoring blood pressure, urinary control, control of PCO2 and PO2, coagulation tests and radiological tests such as brain CT and resonance magnetic. Also worth adding assessing the level of consciousness, the existence of seizures, fever and a correct position 30º in supine (lying face up), maintaining electrolyte balance, air, possible brain edema or infections and prevention of pulmonary thromboembolism.
During rehabilitation should be carried out secondary prevention controlling risk factors ASA with antiplatelet therapy with clopidogrel or derivatives. Surgical treatment is endovascular carotid endarterectomy or angioplasty.
Embolic infarctions in sodium heparin anticoagulation is recommended prior within 48 hours after infarction. The forecast atherothrombotic infarction is 20% mortality, while more than 70% of the affected population can carry out a normal and independent life after six months, combining proper medication prescribed by the neurologist.
Edited by Patricia Crespo Pujante