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Title | Creator | Description |
251 |
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Walsh & Hoyt: Mucoceles, Pyoceles, and Sinusitis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Although mucoceles, pyoceles, and sinusitis are not infections of neural tissue, they not infrequently produce neuro-ophthalmologic symptoms and signs through their effects on adjacent neural and vascular structures. In most cases, damage is caused by compression by an expanding mass; however, in so... |
252 |
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Walsh & Hoyt: Neuritis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Neuritis is a generic term indicating inflammation of a nerve. The inflammation may result from the direct effects of an organism, from its antigenic effects on the immune system, or from mechanisms unrelated to current or previous infection or insult. Organisms capable of producing neuritis by dire... |
253 |
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Walsh & Hoyt: Cerebral Edema | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Cerebral edema is an increase in brain volume caused by increased tissue water content. The causes of cerebral edema include an increase in intravascular pressure, damage to and increased permeability of the cerebral vascular wall, and a decrease in plasma colloid osmotic pressure. Aquaporins, a fam... |
254 |
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Walsh & Hoyt: Immunity and Infectious Disease | Barrett J. Katz, MD, MBA, Montefiore Medical Center | The increasing recognition of the role of cellular and humoral reactions in disease has led to a greater understanding of the pathogenesis of infection of the CNS. Depending on the immune response, the same organism may produce no, mild, recurrent, or fatal disease. The CNS is at a disadvantage when... |
255 |
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Walsh & Hoyt: Abscesses | Barrett J. Katz, MD, MBA, Montefiore Medical Center | An abscess is a circumscribed area of pus. Intracranial abscesses may be epidural, subdural, or intracerebral. An epidural abscess initially tends to be small and flat because the dura develops an increasingly strong adhesion to the bone of the skull throughout life, and it becomes more difficult to... |
256 |
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Walsh & Hoyt: Meningitis (Including Pachymeningitis) | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Meningitis is an infection of the leptomeningesthe surrounding surfaces of the brain. It is caused by a variety of organisms, including bacteria, viruses, fungi, and protozoa. The subarachnoid space offers little resistance to infection, and the CSF facilitates its spread over the brain and spinal c... |
257 |
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Walsh & Hoyt: Encephalitis (Meningoencephalitis) | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Encephalitis is inflammation confined to the brain; meningoencephalitis is inflammation of both the brain and the leptomeninges. Both encephalitis and meningoencephalitis are characterized by infection and destruction of neurons and glial cells. They are primarily diseases of children, with the youn... |
258 |
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Walsh & Hoyt: Demyelination | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Destruction of myelindemyelinationoccurs in a variety of diverse inflammatory disorders. In some of these disorders, myelin breakdown is secondary to destruction of neurons: neuronolytic demyelination. In others, demyelination is the primary process and associated with relative preservation of affec... |
259 |
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Walsh & Hoyt: Vasculitis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Intracranial arteries and veins may become infected by a variety of organisms. The infection may be a primary process within the vascular system itself or may result from the effects of an acute, subacute, or chronic contiguous process that penetrates the vessel. The inflammatory response varies gre... |
260 |
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Walsh & Hoyt: Mucoceles and Pyoceles | Barrett J. Katz, MD, MBA, Montefiore Medical Center | A mucocele is formed when drainage of mucus from one of the paranasal sinuses becomes blocked by obstruction of its ostium. If the contents of a mucocele become secondarily infected, the resulting mass is called a pyocele or mucopyocele. A mucocele or pyocele may develop in any of the paranasal sinu... |
261 |
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Walsh & Hoyt: Routes of Invasion | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Despite the protection provided by skin, bone, meninges, and vascular barriers, organisms can enter the intracranial cavity and vertebral canal. Such organisms reach the CNS in one of two ways: via the bloodstream (hematogenous spread) or by extension from local sources. |
262 |
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Walsh & Hoyt: Encephalomyelitis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | An encephalomyelitis produces signs of an encephalitis combined with a myelitisan inflammation of the spinal cord. Indeed, the main pathologic process is an infection of neurons in the anterior horn cells of the spinal cord, in the motor nuclei of the brainstem, and, to a lesser degree, in motor cor... |
263 |
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Walsh & Hoyt: Lesions Produced by Infection | Barrett J. Katz, MD, MBA, Montefiore Medical Center | A variety of lesion types may be produced by infections and inflammations. These include abscesses, aneurysms, areas of demyelination, cerebral edema, empyemas, encephalitis, granulomas, meningitis, mucoceles and pyoceles, neuritis, and vasculitis. In this section, we consider the origin, pathologic... |
264 |
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Walsh & Hoyt: Granuloma | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Granulomatous inflammation is a specialized form of chronic inflammation in which an accumulation of macrophages is the major part of the inflammatory infiltrate. Two defining maturations of this cell type are characteristically found in a granuloma: the epithelioid cell and the inflammatory giant c... |
265 |
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Walsh & Hoyt: Aneurysms Caused by Infection (""Mycotic"" Aneurysms) | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Bacteria, fungi, spirochetes, and other organisms have the potential to infiltrate the walls of intracranial and other arteries. In some instances, this results in the formation of one or more aneurysms. In 1885, Sir William Osler used the term ""mycotic"" to refer to such aneurysms. Although this t... |
266 |
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Walsh & Hoyt: Barriers to Infection | Barrett J. Katz, MD, MBA, Montefiore Medical Center | The structures of the CNS that limit the pathogenesis of infection include bone and fibrous membranes that cover the brain and spinal cord. These protective coverings may be overcome by transport of organisms from the scalp or face, by emissary veins, or by diploic veins that anastomose within the s... |
267 |
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Walsh & Hoyt: Edema | Barrett J. Katz, MD, MBA, Montefiore Medical Center | A common response of the brain to a variety of insults is edema. Infections and inflammations of the CNS produce several types of edema: vasogenic, cytotoxic, interstitial, and hypo-osmotic. Some of these types can be distinguished by MR imaging. A variety of organisms produce toxins that can cause ... |
268 |
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Walsh & Hoyt: Sinusitis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Infection of the paranasal sinuses by bacteria or other organisms may produce neuro-ophthalmologic symptoms and signs by extension of the process into the adjacent orbit, intracranial cavity, or both. Acute, bacterial sinusitis may produce meningitis, brain abscess, epidural or subdural empyema, orb... |
269 |
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Meningitis (Including Pachymeningitis) | Barrett J. Katz, MD, MBA, Montefiore Medical Center | Meningitis is an infection of the leptomeninges-the surrounding surfaces of the brain. |
270 |
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Mucoceles and Pyoceles | Barrett J. Katz, MD, MBA, Montefiore Medical Center | A mucocele is formed when drainage of mucus from one of the paranasal sinuses becomes blocked by obstruction of its ostium. |
271 |
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LESIONS PRODUCED BY INFECTIONS AND INFLAMMATIONS OF THE CNS: Cavernous Sinus Thrombosis | Barrett J. Katz, MD, MBA, Montefiore Medical Center | The clinical features of septic thrombosis of the cavernous sinus can be separated into those caused by the thrombosis and those related to the infection (1114). General symptoms and signs include headache, giddiness, nausea, vomiting, and somnolence. Fever usually is present and may be intermittent... |
272 |
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Walsh & Hoyt: Amphotericin B | Joel M. Weinstein, MD, Penn State Milton S. Hershey Medical Center | Amphotericin B is the mainstay of treatment in almost all systemic fungal infections, particularly those that affect the CNS. It destroys fungi primarily by binding to one or more sterols in their cytoplasmic membrane, thus altering membrane permeability. Almost all systemic mycoses respond to treat... |
273 |
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Walsh & Hoyt: General Concepts | Joel M. Weinstein, MD, Penn State Milton S. Hershey Medical Center | Fungi (from the Latin fungus, meaning ""mushroom"") are nonmotile organisms composed of eukaryotic cells whose nuclei contain multiple chromosomes and are surrounded by membrane. They differ from bacteria in that they have a rigid cell wall that usually contains chitin and polysaccharides. Inside t... |
274 |
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Walsh & Hoyt: Histoplasma Capsulatum (Histoplasmosis) | Joel M. Weinstein, MD, Penn State Milton S. Hershey Medical Center | Histoplasma capsulatum exists in the soil in the mycelial phase but converts to a yeast phase at the body temperature of mammals: 37C. The mycelial form consists of septate branching hyphae that bear spores at both lateral and terminal positions. The hyphae measure 12 micrometers in width, and the s... |
275 |
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Walsh & Hoyt: Imidazoles and Triazoles | Joel M. Weinstein, MD, Penn State Milton S. Hershey Medical Center | Azoles, also called imidazoles, are synthetic organic compounds that are characterized by at least one five-member ring that usually contains two nitrogen molecules (the azole ring). This ring is responsible for the antifungal properties of these substances. The addition of a third nitrogen to the a... |