Background: Aspirin, or acetylsalicylic acid, is widely used to prevent ischemic vascular disease. Clinical and experimental data suggest that a rebound effect occurs 4 or fewer weeks after interruption of aspirin therapy. Objective: To study the discontinuation of aspirin therapy as a risk factor for ischemic stroke (IS).

Background: While it is known that posterior cerebral artery (PCA) infarction may simulate middle cerebral artery (MCA) infarction, the frequency and localization of this occurrence are unknown. Objective: To determine the frequency of PCA infarction mimicking MCA infarction and the territory of the PCA most commonly involved in this simulation. Design: We studied 202 patients with isolated infarction in the PCA admitted to our stroke center to determine the frequency of PCA infarction simulating MCA infarction, the involved PCA territory, and the patterns of clinical presentation. Results: We found 36 patients (17.8%) with PCA ischemic stroke who had clinical features suggesting MCA stroke. The PCA territory most commonly involved was

Review of results of experimental and clinical studies indicates that the area of physiologically impaired, but potentially salvageable, tissue surrounding the central core of focal cerebral ischemia that develops shortly after onset of vessel occlusion is complex and dynamic with severity and duration thresholds for hypoxic stress and injury that are specific to tissue site, cell type, molecular pathway or gene expression investigated, and efficiency of collateral or residual flow and reperfusion. Identification of this ischemic penumbra in the acute stroke clinical setting is an important goal for stroke researchers and clinicians. Recent advances in neuroimaging allowed a better understanding of this physiopathological process. However, there is not a perfect penumbra imaging technique and each one has its own advantages and disadvantages. Numerous thrombolytic and potentially neuroprotective agents have been studied in stroke patients, with little success, as the only approved therapy is thrombolysis with recombinant tissue plasminogen activator within 3 h of stroke onset in highly selected patients (<10% of all acute stroke patients in some specialized centers). One major obstacle in the development of effective therapies for ischemic stroke has been the lack of versatile imaging techniques. The development of penumbra concept and its detection through modern cerebral image techniques can extend the patients’ selection for thrombolysis. A number of multicenter clinical trials are now under way to test these models and confirm the utility of penumbra imaging for treatment decisions. Present knowledge about visualization of the salvageable penumbra suggests a promising future in which penumbra imaging studies are performed routinely in the acute stroke setting and the data provided by these studies assist in individualizing therapeutic decisions and identifying effective therapies that can be delivered at late time points. So, the main target of management is ‘penumbra’, or salvageable tissue, which is primarily dependent upon the expediency of the whole process, better expressed by the phrase ‘Penumbra (and not Time) is Brain’.

Cerebral vascular events constitute the most common group of neurological diseases, and are usually followed by systemic infections, being pneumonia, urinary tract infection and sepsis the most frequent 1 . Brain abscess compromising the infarcted cerebral tissue is a rare condition 2,3 . It most frequently happens a few weeks after an infectious systemic insult, which had usually followed the ischemic stroke. There are only a few case reports on this subject in the literature. In spite of that, those patients with ischemic stroke should be considered at high risk of developing brain abscess, and should have this condition included in their differential diagnosis once neurologic or even systemic deterioration takes place following previous recovery. Cerebral ischemia is considered to be a predisposing factor for the genesis of brain abscess after stroke 4 . Due to impaired cerebral oxigenation and blood brain barrier disruption in the infarcted area, the formation of an abscess becomes feasible following bacteremia, a fact that has recently caught the attention of neurologists and neurosurgeons 2,3,5 . CASEA previously healthy 33-year-old white woman is admited to the emergency room complaining of severe right hemiparesis of acute onset and motor disphasia, which progressed to complete aphasia in a few minutes. Brain computed tomography (CT) revealed no abnormalities. Due to the hypothesis of acute obstruction of the left middle cerebral artery (MCA), a cerebral angiography was performed five hours after the onset of the symptoms, indicating oclusion of the distal portion of the left intracranial carotid artery, compromising both anterior and middle cerebral arteries. Intra-arterial thrombolytics were administered, with total reperfusion of the anterior cerebral artery territory. A MCA suboclusion (M2 segment) remained, despite multiple attempts to perform angioplasty with stent deployment. Patient was transferred to the intensive care unit (ICU) and was started on intravenous anticoagulants. About 24 hours after the procedure, patient developed anisocoria with left mydriasis, and tomographic evidence of hemispheric edema compromising the left MCA distribution with intracerebral hemorrhage and significant mass effect. A decompressive craniotomy was performed, and a ventricular catheter for intracranial pressure (ICP) measurement was placed (Fig 1).Elevated ICP was managed with mannitol and hypertonic saline. Four days after the ictus, patient developed fever (38 o C)with negative blood cultures. Pseudomonas aeruginosa and Staphylococcus aureus were then isolated in the tracheal aspirate, being both ciprofloxacin sensitive. Patient persisted febrile after seven days of antimicrobial therapy, and the previous germs were both once again isolated in the tracheal aspirate. Anaerobic gram positive cocci disposed in chains were identified in the blood culture; piperacilin and tazobactan for ciprofloxacin resistant pseudomonas were introduced, with favorable outcome. Seven weeks after the stroke, patient started with lo...

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