Handbook of clinical neurology
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The cerebrospinal fluid (CSF) space consists of the intracerebral ventricles, subarachnoid spaces of the spine and brain (e.g., cisterns and sulci), and the central spinal cord canal. The CSF protects the central nervous system (CNS) in different ways involving metabolic homeostasis, supply of nutrients, functioning as lymphatic system, and regulation of intracranial pressure. CSF is produced by the choroid plexus, brain interstitium, and meninges, and it circulates in a craniocaudal direction from ventricles to spinal subarachnoid space from where it is removed via craniocaudal lymphatic routes and the venous system. ⋯ The extracellular space volume, potassium buffering, CSF circulation, and interstitial fluid absorption are mainly regulated by aquaporin-4 channels, which are abundantly located at the blood-brain and brain-CSF interfaces. The composition of CSF shows a high dynamic range, and the levels of distinct proteins vary due to several influencing factors, such as site of production (brain or blood-derived), site of sampling (ventricular or lumbar), CSF flow rate (BCB function), diurnal fluctuations of CSF production rate, and finally, molecular size of blood-derived proteins (IgM vs. albumin) and circadian rhythm (glucose, prostaglandin D synthase). Alterations of lumbar CSF are mainly influenced by processes of the CNS located adjacent to the ventricular and spinal CSF space and less by pathologies in cortical areas remote from the ventricles.
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Delirium is common in critically ill patients and associated with increased length of stay in the intensive care unit (ICU) and long-term cognitive impairment. The pathophysiology of delirium has been explained by neuroinflammation, an aberrant stress response, neurotransmitter imbalances, and neuronal network alterations. Delirium develops mostly in vulnerable patients (e.g., elderly and cognitively impaired) in the throes of a critical illness. ⋯ Nonpharmacologic strategies with early mobilization, reducing causes for sleep deprivation, and reorientation measures may be effective in the prevention of delirium. Antipsychotics are effective in treating hallucinations and agitation, but do not reduce the duration of delirium. Combined pain, agitation, and delirium protocols seem to improve the outcome of critically ill patients and may reduce delirium incidence.
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Neurocritical care has two main objectives. Initially, the emphasis is on treatment of patients with acute damage to the central nervous system whether through infection, trauma, or hemorrhagic or ischemic stroke. Thereafter, attention shifts to the identification of secondary processes that may lead to further brain injury, including fever, seizures, and ischemia, among others. ⋯ The concepts and design of each monitor, in addition to the patient population that may most benefit from each modality, will be discussed, along with the various tools that can be used together to guide individualized patient treatment options. Major clinical trials, observational studies, and their effect on clinical outcomes will be reviewed. The future of multimodal monitoring in the field of bioinformatics, clinical research, and device development will conclude the chapter.
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Acute traumatic spinal cord injury (SCI) is a devastating disease process affecting tens of thousands of people across the USA each year. Despite the increase in primary prevention measures, such as educational programs, motor vehicle speed limits, automobile running lights, and safety technology that includes automobile passive restraint systems and airbags, SCIs continue to carry substantial permanent morbidity and mortality. Medical measures implemented following the initial injury are designed to limit secondary insult to the spinal cord and to stabilize the spinal column in an attempt to decrease devastating sequelae. ⋯ We discuss initial triage, immobilization, and transportation of the patient by emergency medical services personnel to a definitive treatment facility. Upon arrival at the emergency department, we review initial trauma protocols and the evidence-based recommendations for radiographic evaluation of the patient's vertebral column. Finally, we outline closed cervical spine reduction and various aggressive medical therapies aimed at improving neurologic outcome.
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Neurologic complications in polytrauma can be classified by etiology and clinical manifestations: neurovascular, delirium, and spinal or neuromuscular problems. Neurovascular complications include ischemic strokes, intracranial hemorrhage, or the development of traumatic arteriovenous fistulae. Delirium and encephalopathy have a reported incidence of 67-92% in mechanically ventilated polytrauma patients. ⋯ Neuromuscular complications include nerve and plexus injuries, and ICU-acquired weakness. In polytrauma, the neurologic examination is often confounded by pain, sedation, mechanical ventilation, and distracting injuries. Regular sedation pauses for examination and maintaining a high index of suspicion for neurologic complications are warranted, particularly because early diagnosis and management can improve outcomes.