Neurology
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Gray matter (GM) involvement is detected even in the earliest stages of multiple sclerosis (MS), and GM atrophy occurs at a faster rate than white matter (WM) atrophy early in the disease course. Studies published to date establish that 1) GM involvement and in particular cortical demyelination can be extensive in MS; 2) GM pathology may occur in part independently of WM lesion formation; 3) a primarily GM-related process may be the earliest manifestation of MS; 4) GM involvement is associated with physical disability, fatigue, and cognitive impairment in MS; and 5) GM disease might help explain the observed dissociation between markers of inflammatory demyelination (relapses, WM gadolinium enhancement, WM lesion burden) and disease progression. It remains likely that GM damage is related to WM damage. However, continued studies of GM pathology as well as neuronal and axonal involvement in MS and related experimental models are necessary to better understand the etiology and pathogenesis of the degenerative components.
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The use of antiepileptic drugs (AEDs) in the neurosurgical setting has a number of implications, including their possible role in the prevention of seizures after acute cerebral insults or brain tumors and the potential for toxicity and interactions when these agents are administered in association with radiotherapy or chemotherapy. This review discusses these controversial issues and draws the following conclusions. 1) AEDs should be prescribed on a short-term basis to prevent seizures occurring within the first week after a cerebral insult (trauma, neurosurgical procedure) but are ineffective to avoid true post-traumatic epilepsy or first seizures in patients with primary or secondary cerebral neoplasms. 2) The use of phenytoin and, to a lesser extent, phenobarbital and carbamazepine during cranial irradiation is associated with an increased risk for severe, potentially fatal, mucocutaneous reactions. In this context, new AEDs with a very low potential for allergic cutaneous reactions should be preferred. 3) Enzyme-inducing AEDs, such as phenytoin, phenobarbital, and carbamazepine, may increase the clearance and reduce the clinical efficacy of corticosteroids and anticancer agents that are also metabolized by the cytochrome P450 system. The newly developed AEDs that are devoid of hepatic metabolism, such as levetiracetam and gabapentin, are now recommended because of good results in preliminary studies and because they do not show interactions with anticancer agents.
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The mechanism of epilepsy in brain tumor patients is probably multifactorial, and its incidence depends on tumor type and location. Refractory epilepsy is common in patients with structural brain lesions, and a role for multidrug-resistance proteins has been suggested. The medical treatment of epilepsy in brain tumor patients has mainly been studied retrospectively, and the optimal management of seizures with antiepileptic drugs (AEDs) is unclear. ⋯ Although valproic acid is an enzyme inhibitor and may therefore lead to toxic levels of simultaneously administered chemotherapeutic agents, this does not appear to be a major problem in patients with brain tumors. Preliminary observations of add-on treatment with the AEDs levetiracetam or gabapentin suggest that these non-enzyme-inducing AEDs can be useful for control of seizures in patients with brain tumors. Conversely, prophylactic use of AEDs in brain tumor patients is generally not recommended.
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Preventive approaches in the field of Alzheimer disease (AD) is important but these trials raise many questions. Which protective factor should be studied? What population should be studied? With which principal and secondary criteria? We present here the design of the ongoing GuidAge Study. In the past, several studies suggest that Ginkgo biloba could have a potential benefit effect on cognitive function. The aim of the GuidAge Study is to evaluate the efficacy of 240 mg/d of EGb 761 in the prevention of AD. ⋯ The GuidAge study is the largest study carried out in Europe on the prevention of AD. Final results should be available in 2010.
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To review evidence on the assessment of the child with status epilepticus (SE). ⋯ Although common clinical practice is that blood cultures and lumbar puncture are obtained if there is a clinical suspicion of a systemic or CNS infection, there are insufficient data to support or refute recommendations as to whether blood cultures or lumbar puncture should be done on a routine basis in children in whom there is no clinical suspicion of a systemic or CNS infection (Level U). AED levels should be considered when a child with treated epilepsy develops SE (Level B). Toxicology studies and metabolic studies for inborn errors of metabolism may be considered in children with SE when there are clinical indicators for concern or when the initial evaluation reveals no etiology (Level C). An EEG may be considered in a child with SE as it may be helpful in determining whether there are focal or generalized epileptiform abnormalities that may guide further testing for the etiology of SE, when there is a suspicion of pseudostatus epilepticus (nonepileptic SE), or nonconvulsive SE, and may guide treatment (Level C). Neuroimaging may be considered after the child with SE has been stabilized if there are clinical indications or if the etiology is unknown (Level C). There is insufficient evidence to support or refute routine neuroimaging in a child presenting with SE (Level U).