Neurocritical care
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The sulfonylurea receptor 1 (Sur1)-transient receptor potential 4 (Trpm4) channel is an important molecular element in focal cerebral ischemia. The channel is upregulated in all cells of the neurovascular unit following ischemia, and is linked to microvascular dysfunction that manifests as edema formation and secondary hemorrhage, which cause brain swelling. Activation of the channel is a major molecular mechanism of cytotoxic edema and "accidental necrotic cell death." Blockade of Sur1 using glibenclamide has been studied in different types of rat models of stroke: (i) in conventional non-lethal models (thromboembolic, 1-2 h temporary, or permanent middle cerebral artery occlusion), glibenclamide reduces brain swelling and infarct volume and improves neurological function; (ii) in lethal models of malignant cerebral edema, glibenclamide reduces edema, brain swelling, and mortality; (iii) in models with rtPA, glibenclamide reduces swelling, hemorrhagic transformation, and death. ⋯ Here, we provide a comprehensive review of the basic science, preclinical experiments, and retrospective clinical studies on glibenclamide in focal cerebral ischemia and stroke. We also compare the preclinical work in stroke models to the updated recommendations of the Stroke Therapy Academic Industry Roundtable (STAIR). The findings reviewed here provide a strong foundation for a translational research program to study glibenclamide in patients with ischemic stroke.
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While the bioethical principle of beneficence originated in antiquity, the ascension of autonomy, or "self-rule," has redefined the physician-patient relationship to the extent that autonomy often dominates medical decision-making. Philosophical and social movements, medical research atrocities, consumerism, and case law have all had their influence on this paradigm shift. Consequently, the contemporary physician encounters an uncertainty in medical practice on how to resolve conflicts that arise in the pursuit of valuing both autonomy and beneficence. ⋯ This conundrum has been an important subject of the bioethics and social science literature but often this discourse is not disseminated to the clinicians confronting these issues. The purpose of this essay is to present a history of the principles of autonomy and beneficence and then present a shared medical decision-making model, collaborative autonomy, to provide guidance to neurologic critical care providers in how to resolve such dilemmas. Clinical vignettes will help illustrate the model.
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Observational Study
Subarachnoid Extension of Primary Intracerebral Hemorrhage is Associated with Fevers.
Extension of hemorrhage into the subarachnoid space in primary intracerebral hemorrhage (ICH) has recently been associated with poor outcomes, although the mechanisms underlying that association are uncertain. The objectives of this study are to confirm the association between fever and poor outcomes after ICH, and to determine whether subarachnoid hemorrhage extension (SAHE) is associated with fevers. ⋯ Our data confirm the deleterious effect of fever on the outcome of patients with ICH and show that SAHE is an independent predictor of fever after ICH. SAHE may provoke dysfunctional thermoregulation similar to what is observed after aneurysmal subarachnoid hemorrhage, creating mechanistic pathway between SAHE and poor functional outcomes.
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Brain edema is a serious complication of ischemic stroke that can lead to secondary neurological deterioration and death. Glyburide is reported to prevent brain swelling in preclinical rodent models of ischemic stroke through inhibition of a non-selective channel composed of sulfonylurea receptor 1 and transient receptor potential cation channel subfamily M member 4. However, the relevance of this pathway to the development of cerebral edema in stroke patients is not known. ⋯ Several surrogate markers of vasogenic edema appear to be reduced in the setting of IV glyburide treatment in human stroke. Verification of these potential imaging and blood biomarkers is warranted in the context of a randomized, placebo-controlled trial.
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Chronic traumatic encephalopathy (CTE) formerly known as dementia pugilistica is a long-term neurodegenerative disorder associated with repeated subconcussive head injuries in high-contact sports. We reviewed the existing literature on CTE and examined epidemiological trends, risk factors, and its temporal progression, and proposed the underlying pathophysiological mechanisms that may provide unique insights to clinicians with an in-depth understanding of the disease to aid in the diagnosis and prevention, and provide future perspectives for research via search of Medline and Cochrane databases as well as manual review of bibliographies from selected articles and monographs. The prevalence of CTE in recent years is on the rise and almost exclusively affects men, with pathologic signs characterized by progressive memory loss, behavioral changes, and violent tendencies with some patients demonstrating Parkinsonian-like symptoms and signs. ⋯ Postmortem pathologic analysis is characterized by neurofibrillary tangles and Aβ plaques in 50 % of cases. Currently, there are no ante-mortem diagnostic criteria, but modern imaging techniques such as functional magnetic resonance (MR) imaging, MR spectroscopy, and diffusion tension imaging hold promise for delineating the future diagnostic criteria. Further long-term longitudinal studies are warranted to investigate risk factors that will enhance understanding of the disease progression and its pathogenesis.