Neurologic clinics
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Neurologic complications are a major cause of morbidity, complicating open heart surgery, cardiac catheterization, and interventional techniques. Global or focal brain ischemia related to embolism or hypoperfusion predominates. Breakthrough cerebral hemorrhage and infection can complicate cardiac transplantation. Identifying individuals at risk for cerebrovascular complications may lead to more effective preventative and treatment measures.
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Neurotoxicity is a common and potential dose-limiting complication of cancer chemotherapy. For most agents, high-dose therapy, combination chemotherapy, concomitant cranial radiotherapy, and intracarotid or intrathecal injection are more likely to produce neurologic complications than standard oral or intravenous therapy. Any portion of the nervous system can be damaged. ⋯ Differentiating the neurologic complications of chemotherapy from other neurologic complications of cancer is often difficult. As cancer patients are treated more aggressively, receive more chemotherapy, and live longer, and as new chemotherapeutic agents are developed and existing agents are used more intensively or in novel ways, neurologic complications of cancer chemotherapy will become more common, serious, and complex. The recognition and treatment of chemotherapy-induced neurotoxicity will become a frequent and important clinical problem for most neurologists.
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In the immunocompromised patient, even mild forms of any combination of headache, meningismus, altered mental status, or focal neurologic signs should initiate an evaluation for possible CNS infection. The limited signs and symptoms of acute CNS infection are not due to specific organisms but to pathologic changes at the neuroanatomic site of infection. The initial clinical history, examination, laboratory, and neuroradiographic data will narrow the problem to one of several groups of agents, although it may not be possible to specify a single causative agent. ⋯ The patient should always be reevaluated for the possibility of infection with a different opportunistic organism. CNS infections remain a major cause of morbidity and mortality in immunosuppressed patients with malignancies. In one series, 60% of such patients died as a result of their CNS infection, many at a time when the underlying disease had an otherwise good prognosis.(ABSTRACT TRUNCATED AT 400 WORDS)
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For all neoplasms, extraneural as well as brain, intrinsic, and acquired resistance to antineoplastic drugs constitutes a multifactorial problem. Much information has been generated concerning the individual mechanisms that play a role in drug resistance. The present decade will see a great deal of laboratory research emphasis in two related areas: (1) the molecular biology of resistance, including processes that regulate gene expression for critical detoxifying and transport proteins, and (2) further identification of DNA repair mechanisms in normal and neoplastic cells. ⋯ For brain tumor treatment, additional strategies to circumvent intrinsic and acquired resistance by increasing drug delivery, such as high-dose chemotherapy with marrow or growth factor rescue and local drug delivery to brain tumors by drug-impregnated biodegradable polymers, will continue to be examined. Previous experience with efforts to augment antineoplastic drug cytotoxicity indicates that this process may decrease the margin of cytotoxicity between normal tissue and tumor, often referred to as the therapeutic index. To avoid serious neurotoxicity as a dose-limiting or treatment-limiting factor for potentially important clinical strategies to modulate drug resistance, it will be important to develop a greater understanding of the relative treatment sensitivities of brain capillary endothelium, glial cells, and neurons, as well as their individual abilities to transport, detoxify, and repair the effects of these drugs.(ABSTRACT TRUNCATED AT 400 WORDS)
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Decisions to withhold or terminate treatment are common clinical dilemmas in patients dying from diseases of the nervous system. Decision making for such patients must be based upon ethical principles. ⋯ Physicians have the duty to assess the potential benefits and harms of various treatment options and to clearly communicate this information to patients and their proxies in a supportive manner. The authors illustrate the application of ethical principles in neurologists' management of patients in persistent vegetative states, dementia, and end-stage neuromuscular disease.