Diagnosis can be made by the presence of a systolic bruit over the carotid

Diagnosis can be made by the presence of a systolic

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Diagnosis can be made by the presence of a systolic bruit over the carotid artery in the neck, mastoid process, or eyeball. Further confirmation can be obtained by CT scan, MRI, transcranial Doppler, or magnetic resonance angiography. 4n. Subarachnoid Hemorrhage Subarachnoid hemorrhage (SAH) occurs primarily in individuals with intracranial aneurysm (85% of cases); they can also occur with intracranial AVM, hypertension, or individuals who have sustained head injuries. An aneurysm located in the subarachnoid space can leak blood from thin areas in the aneurysm wall. This blood is then pumped into the subarachnoid space. An intense inflammatory response is initiated, with the release of numerous inflammatory cytokines and an influx of leukocytes. This hemorrhagic and inflammatory "soup" can spread through the
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cerebrospinal fluid (CSF) and involve the entire surface of the brain and the spinal cord. Excitotoxic amino acids are released, which promote the onset of seizures and contribute to neuronal injury. Two other important pathophysiologic phenomena are also common: - Impairment of CSF reabsorption—Due to obstruction of the arachnoid villi and leads to accumulation of CSF (hydrocephalus), and steady increases in intracranial pressure. - Delayed vasospasm—Inflammatory cytokines and neurohumoral agents, such as prostaglandins, serotonin, catecholamines, and calcium, in the CSF can result in intense spasm of cerebral vessels that can occur between three days and two weeks after the hemorrhage. This vasospasm can result in severe cerebral ischemia, rapid decline in neurologic function, and death. 4o. Clinical Manifestations of Subarachnoid Hemorrhage The affected individual is often an otherwise healthy young adult who may have a history of severe headaches, which may be the result of prodromal bleeds. Usually the individual presents with the rapid development of: - Severe headache - Stiff neck - Photophobia - Irritability - Loss of consciousness Physical exam may or may not reveal focal neurologic deficits. Meningismus (nuchal rigidity) may be elicited through a positive Kernig or Brudzinski sign. The severity of the neurologic symptoms in SAH can be categorized according to the Hunt and Hess grading system as depicted in Table 15-7 in your textbook. Neurologic stabilization may be followed by a rapid decline caused by rebleeding from the aneurysm or from delayed vasospasm. Markedly increased intracranial pressure is common in SAH. Individuals with SAH are at risk for the same cardiovascular, pulmonary, renal, gastrointestinal, endocrine, and electrolyte disorders as seen in individuals with acute brain infarction and intracerebral hemorrhage. 4p. Evaluation and Treatment of Subarachnoid Hemorrhage Individuals with SAH must first be assessed for adequate oxygenation and circulation. A rapid physical examination should be followed by a more thorough neurologic examination.
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  • Winter '15
  • Lisa Baba
  • cells, Cytotoxic Cells, NK Cell

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