Seminars in respiratory infections
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Coccidioidomycosis is the most common endemic mycosis to cause disease in solid-organ transplant patients in North America. Underlying renal and liver disease, T-lymphocyte suppression from antirejection medication, and activation of immunomodulating viruses, such as cytomegalovirus, all increase the risk for coccidioidomycosis among these patients. About one half of all cases are the result of reactivation of previously acquired coccidioidal infection and occur during the first year after transplantation. ⋯ Serologic tests are particularly useful for identifying patients who are at high risk for reactivating coccidioidomycosis posttransplantation. Amphotericin B and azoles are the mainstay of therapy. Although there are no established approaches to preventing coccidioidomycosis among these patients, studies are underway examining the use of prophylactic azole antifungals with documented prior coccidioidal infection.
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Histoplasmosis is an endemic mycosis, which is most prevalent in the Ohio and Mississippi valleys of North America. The causative organism is a dimorphic fungus, Histoplasma capsulatum. Histoplasmosis can present as a self-limited disease or cause life-threatening diseases resulting in considerable morbidity and mortality. ⋯ Of these, a new triazole, posaconazole (SCH56592) appears most promising. Generally, amphotericin B or one of the lipid formulations is recommended as initial treatment in patients with more extensive diseases, felt to be ill enough to require hospitalization, and itraconazole for those who have milder illness, or to complete treatment after patients respond to amphotericin B. The role of intravenous formulation of itraconazole for severe histoplasmosis is unknown because studies comparing it with amphotericin B have not been conducted.
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The inflammatory response to infection is necessary for host defense but can contribute to the systemic toxicity and lung injury that may result from pneumonia. In some settings, adjunctive treatment of lower respiratory infections with anti-inflammatory agents can reduce morbidity. Corticosteroids have a well-documented role in the management of Pneumocystis carinii pneumonia complicating human immunodeficiency virus (HIV) infection. ⋯ Corticosteroids also may be effective under some circumstances in the treatment of inflammatory sequelae of respiratory tract infection, such as tuberculous pleurisy, bronchiolitis obliterans organizing pneumonia, or prolonged acute respiratory distress syndrome. Nonsteroidal anti-inflammatory drugs may have limited applications in the modulation of chronic airway inflammation. Strategies targeting specific cytokines have not been effective to date, but remain active areas of investigation.
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Semin Respir Infect · Dec 2000
ReviewVentilator-associated pneumonia: incidence, risk factors, and microbiology.
Ventilator-associated pneumonia (VAP) is a pulmonary infection that occurs after at least 48 hours of mechanical ventilation (MV). The incidence depends on several factors, although the most important are those related to the host and duration of MV. VAP can be differentiated into early-onset (<5 days) and late-onset types (> or =5 days). ⋯ After 5 days of MV, pathological colonization with gram-negative bacteria may occur, and late-onset VAP is more likely to be attributable to this group of microorganism. Incidence, risk factors, and microbiology depend strongly on the time frame in which the episode develops. However, initial and pathological colonization during the intensive care unit stay can modify this concept.
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Semin Respir Infect · Dec 2000
ReviewInfection control in intensive care units and prevention of ventilator-associated pneumonia.
Ventilator-associated pneumonia (VAP) is considered the most frequent infection in the intensive care unit (ICU), although incidence rates depend on the diagnostic methods. Because VAP has been associated with increased mortality and greater costs for medical care, prevention remains an important goal for intensive care medicine. Selective digestive decontamination (SDD), the most frequently studied method of infection prevention, is still controversial despite more than 30 prospective randomized trials and 6 metaanalyses. ⋯ Among these are the use of endotracheal tubes with the possibility of continuous aspiration of subglottic secretions, oropharyngeal decontamination with antiseptics, or the semirecumbent treatment position of patients. Although these methods were successful in single studies, more data are needed. Notwithstanding the potential benefits of these interventions, such classic infection control measures as handwashing remain the cornerstone of infection prevention.