PDF | Reportamos el caso de un paciente con enfermedad diabética tipo 1 que sufrió un ACV isquémico lacunar talámico derecho y. A watershed stroke or watershed infarct is defined as a brain ischemia that is localized to the . as total anterior circulation infarct (TACI), partial anterior circulation infarct (PACI), lacunar infarct (LACI) or posterior circulation infarct ( POCI). A stroke is a medical condition in which poor blood flow to the brain results in cell death. .. This subset of cryptogenetic stroke is defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. About one out of.
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A stroke is a medical condition in which poor blood flow to the brain results in cell death. The main risk factor for stroke is high blood pressure. Prevention includes decreasing risk factors, as well as possibly aspirinstatinssurgery to open up the arteries to the brain in those with problematic narrowingand warfarin in those with atrial fibrillation.
In approximately 6. Strokes can be classified into two major categories: Bleeding can develop inside areas of ischemia, a condition known as “hemorrhagic transformation. In the s the World Health Organization defined stroke as a “neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours”,  although the word “stroke” is centuries old.
This definition was supposed to reflect the reversibility of tissue damage and was devised for the purpose, with the time frame of 24 hours being chosen arbitrarily. The hour limit cav stroke from transient ischemic attackwhich is a related syndrome of stroke symptoms that resolve completely within 24 hours.
In an ischemic stroke, blood supply to lacunxr of the brain is decreased, leading to dysfunction of the brain tissue in that area.
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There are four reasons why this might happen:. There are various classification systems for acute ischemic stroke. These four entities predict the extent of the stroke, the area of the brain that is affected, the underlying cause, and the prognosis. There are two main types of hemorrhagic stroke: The above two main types of hemorrhagic stroke are also two different forms of intracranial hemorrhagewhich is the accumulation of blood anywhere within the cranial vault ; but the other forms of intracranial hemorrhage, such as epidural hematoma bleeding between the skull and the dura materwhich is the thick outermost layer of the meninges that surround the brain and subdural hematoma bleeding in the subdural spaceare not considered “hemorrhagic strokes”.
Hemorrhagic strokes may occur on the background of alterations to the blood vessels in the brain, such as cerebral amyloid angiopathycerebral arteriovenous malformation and an intracranial aneurysmwhich can cause intraparenchymal or subarachnoid hemorrhage.
ENFOQUE CLINICO, DE DIAGNOSTICO Y TRATAMIENTO DE LOS INFARTOS LACUNARES
In addition to neurological impairment, hemorrhagic strokes usually cause specific symptoms for instance, subarachnoid hemorrhage classically causes a severe headache known as a thunderclap headache or reveal evidence of a previous head injury.
Stroke symptoms typically start suddenly, over seconds to minutes, and in most cases do not progress further. The symptoms depend on the area of the brain affected. The more extensive the area lacunarr the brain affected, the more functions that are likely to be lost. Some forms of stroke can cause additional symptoms.
For example, in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with a headacheapart from lacuna hemorrhage and cerebral venous thrombosis and occasionally axv hemorrhage.
Various systems have been proposed to increase recognition of stroke. Different findings are able to predict the presence or absence of stroke to different degrees. Sudden-onset face weakness, arm drift i.
Similarly, when all three of these are absent, the likelihood of stroke is decreased — likelihood ratio of 0. For people referred to the emergency roomearly recognition of stroke is deemed important as this can expedite diagnostic tests and treatments. A scoring system called ROSIER recognition of stroke in the emergency room is recommended for this purpose; it is based on features from the medical history and physical examination.
If the area of the brain affected includes one of the three prominent central nervous system pathways —the spinothalamic tractcorticospinal tractand the dorsal column—medial lemniscus pathwaysymptoms may include:.
In most cases, the symptoms affect only one side of the body unilateral. Depending on the part of the brain affected, the lafunar in the brain is usually on the opposite side of the body. However, since these pathways also travel in the spinal cord and any lesion there can also produce these symptoms, the presence of any one of these symptoms does not necessarily indicate a stroke.
In addition to lcunar above CNS pathways, the brainstem gives rise to most of the twelve lacuanr nerves. A brainstem stroke affecting the brainstem and brain, therefore, can produce symptoms relating to deficits in these cranial nerves: If the cerebral cortex is involved, the CNS pathways can again be affected, but also can produce the following symptoms:.
If the cerebellum is involved, ataxia might be present and this includes:. Loss of consciousnessheadache, and acf usually occur more often in hemorrhagic stroke than in thrombosis because of the increased intracranial pressure from the leaking blood compressing the brain. If symptoms are maximal at onset, the cause is more likely to be a subarachnoid hemorrhage or an embolic stroke.
In thrombotic stroke, a thrombus  blood clot usually forms around atherosclerotic plaques. Since blockage of the artery is gradual, onset of symptomatic thrombotic strokes is slower than that of a hemorrhagic stroke. A thrombus itself even if it does not completely block the blood vessel can lead to an embolic stroke see below if the thrombus breaks off and travels in the bloodstream, at which point it is called an embolus.
Two types of thrombosis can cause stroke:. Sickle-cell anemiawhich can cause blood cells to clump up and block blood vessels, can also lead to stroke. A stroke is the second leading cause of death in people under 20 with sickle-cell anemia. An embolic lzcunar refers to an arterial embolism a blockage of an artery by an embolusa traveling particle or debris in the arterial bloodstream originating from elsewhere.
An embolus is most frequently a thrombus, but it can also be a number of other substances including fat zcv. Because an embolus arises from elsewhere, local therapy solves the problem only temporarily. Thus, the source of the embolus must be identified.
Because the embolic blockage is sudden in onset, symptoms usually are maximal at the start. Also, symptoms may be transient as the embolus is partially resorbed and moves to a different location or dissipates altogether.
Emboli most commonly arise from the heart especially in atrial fibrillation but may originate from elsewhere in the arterial tree. In paradoxical embolisma deep vein thrombosis embolizes through an atrial or ventricular septal lacunat in cav heart into the brain.
Causes of stroke related to the heart can lacumar distinguished between high and low-risk: Among those who have a complete blockage of one of the carotid arteries, the risk of stroke on that side is about one percent per year.
A special form of embolic stroke is the embolic stroke of undetermined source ESUS. This subset of cryptogenetic stroke is defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources. About one out of six ischemic strokes could be classified as Lacknar. Cerebral hypoperfusion is ,acunar reduction of blood flow to all parts of the brain. The reduction could be to a particular part of the brain depending on the cause. It is most commonly due to heart failure from cardiac arrest or arrhythmias, or from reduced cardiac output as a result of myocardial infarctionpulmonary embolismpericardial effusionor bleeding.
Because the reduction in blood flow is global, all parts of the brain may be ladunar, especially vulnerable “watershed” areas—border zone regions supplied by alcunar major cerebral arteries. A watershed stroke refers to the condition when the blood supply to these areas is compromised. Blood flow to these areas does not necessarily stop, but instead it may lessen to the point where brain damage can occur.
Cerebral venous sinus thrombosis leads to stroke due to locally increased venous pressure, which exceeds the pressure generated by the arteries. Infarcts are more likely to undergo hemorrhagic transformation leaking of blood into the damaged area than other types of ischemic stroke.
It generally occurs in small arteries or arterioles and is commonly due to hypertension,  intracranial vascular malformations including cavernous angiomas wcv arteriovenous malformationscerebral amyloid angiopathyor infarcts into which secondary hemorrhage has occurred. The hematoma enlarges until pressure from surrounding tissue limits its growth, or until it decompresses by emptying into the ventricular systemCSF or the pial surface. A third of intracerebral bleed is into the brain’s ventricles.
ICH has a mortality rate of 44 percent after 30 days, higher than ischemic stroke or subarachnoid hemorrhage which technically may also be classified as a type of stroke . Other causes may include spasm of an artery. This may occur due to cocaine. A silent stroke is a stroke that does not have any outward symptoms, and the patients are typically unaware they have had a stroke. Despite not causing identifiable symptoms, a silent stroke still damages the brain, and places the patient at increased risk for both transient ischemic attack and major stroke in the future.
Conversely, those who have had a major stroke are also at risk of having silent strokes. Approximately adv, of these strokes were symptomatic and 11 million were first-ever silent MRI infarcts or hemorrhages.
Silent strokes typically cause lesions which are detected via the use of neuroimaging such as MRI. Silent strokes are estimated to occur at five times the rate of symptomatic lafunar. Ischemic stroke occurs because of a loss of blood supply to part of the brain, initiating the ischemic cascade. This is why fibrinolytics such as xcv are given only until three hours since the onset of the stroke.
Atherosclerosis may disrupt the blood supply by narrowing the lumen of blood vessels leading to a reduction of blood flow, by causing the formation of blood clots within the vessel, or by releasing showers of small emboli through the disintegration of atherosclerotic plaques. Since blood vessels in the brain are now blocked, the brain becomes low in energy, and thus it resorts to using anaerobic metabolism within the region of brain tissue affected by ischemia.
Anaerobic metabolism produces less adenosine triphosphate ATP but releases a by-product called lactic acid.
Lactic acid is an irritant which could potentially destroy cells since it is an acid and disrupts the normal acid-base balance in the brain. The ischemia area is referred to as the “ischemic penumbra “. As oxygen or glucose becomes depleted in lacinar brain tissue, the production of high energy phosphate compounds such as adenosine triphosphate ATP fails, leading to failure of energy-dependent processes such as ion pumping necessary for tissue cell survival.
This sets off a series of interrelated events that result in cellular injury and death. A major cause of neuronal injury is the release of the excitatory neurotransmitter glutamate.
However, stroke cuts off the supply of oxygen and glucose which powers the ion pumps maintaining these gradients. As a result, the transmembrane ion gradients run down, and glutamate transporters reverse their direction, releasing glutamate into the extracellular space. Glutamate acts on receptors in nerve cells especially NMDA receptorsproducing an influx of calcium which activates lafunar that digest the cells’ proteins, lipids, and nuclear material.
Calcium influx can also lead to the failure of mitochondriawhich can lead further toward energy depletion and may trigger cell death due to programmed cell death. Ischemia also induces production of oxygen free radicals and other reactive oxygen species.
These react with and damage a number of cellular and extracellular elements.
Damage to the blood vessel lining or endothelium is particularly important. In fact, many antioxidant neuroprotectants such as uric acid and NXY work at the level of the endothelium and not in the brain per se.
Free radicals also directly initiate elements of the programmed cell death cascade by means of redox signaling. These processes lcaunar the same for any type of ischemic tissue and are referred to collectively as the ischemic cascade. However, brain tissue is especially vulnerable to ischemia since it has little respiratory reserve and is completely dependent on aerobic metabolismunlike most other organs.